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41709 Publications

Decentralized resource management and project controlling - from business process modelling to software design - the case of a research center

Joehnk, P.

  • Lecture (Conference)
    int. conf.: information technology in innovation project, Izhevsk 29.05.-02.06.2003

Permalink: https://www.hzdr.de/publications/Publ-5584


Senkung von Betriebskosten durch Facility Management? Ein Praxisbeispiel aus der Leibniz-Gesellschaft

Joehnk, P.

  • Lecture (Conference)
    Tagung Technische Betriebsführung und Facility Management, Berlin, 03.-04.06.2003

Permalink: https://www.hzdr.de/publications/Publ-5583


Damage effects from medium energy ion bombardment during the growth of cubic boron nitride films

Gago, R.; Vinnichenko, M.; Abendroth, B.; Kolitsch, A.; Moeller, W.

Abstract

Cubic boron nitride (c-BN) films with low stress have been produced by simultaneous 35 keV N+ ion implantation during growth by Ion Assisted Sputtering (IAS). The stress release is achieved at the lost of a decrease in the c-BN content. Despite this fact, films with high c-BN content and relatively large thickness (~0.4 mm) have been successfully produced. The decrease on the c-BN content is discussed in terms of the damage induced by the medium energy ion implantation.

Keywords: PAC's: 81.15.Jj; 68.55.Ac; 61.80.Jh; 68.55.Nq

  • Journal of Vacuum Science and Technology A 21 (2003) 1739-1744

Permalink: https://www.hzdr.de/publications/Publ-5582


Growth and characterisation of boron–carbon–nitrogen coatings obtained by ion beam assisted evaporation

Gago, R.; Jiménez, I.; García, I.; Albella, J. M.

Abstract

Ion beam assisted deposition (IBAD)techniques have been employed to produce thin films composed of boron, carbon, and nitrogen atoms, including amorphous carbon (a-C), carbon nitride (CNx) and ternary compounds (BCxNy). The films were deposited by evaporating either graphite or boron carbide (B4C) targets, with simultaneous ion bombardment from a precursor N2 +CH4+Ar gas mixture. The composition and bonding structure of the films have been carefully studied, including the analysis with time of flight elastic recoil detection analysis (TOF-ERDA) and X-ray absorption near-edge spectroscopy (XANES). Mechanical characterisation of the films has been also performed, including measurements of hardness, elastic modulus, and friction coefficients. The optimal values encountered are hardness of B35 GPa, and friction coeffivients of B0.05. Also, the thermal stability of the films has been examined by annealing under vacuum conditions. The applicability of the coatings is discussed in terms of all these parameters.

Keywords: Hard coatings; BCN; IBAD; Mechanical properties; XANES

  • Vacuum 64 (2002) 199-204

Permalink: https://www.hzdr.de/publications/Publ-5581


Nanopatterning of silicon surfaces by low-energy ion-beam sputtering: dependence on the angle of ion incidence

Gago, R.; Vázquez, L.; Cuerno, R.; Varela, M.; Ballesteros, C.; Albella, J. M.

Abstract

We report on the production of nanoscale patterning on Si substrates by low-energy ion-beam sputtering. The surface morphology and structure of the irradiated surface were studied by atomic force microscopy (AFM) and high-resolution transmission electron microscopy (HRTEM). Under ion irradiation at off-normal incidence angle (~50◦), AFM images show the formation of both nanoripple and sawtooth-like structures for sputtering times longer than 20 min. The latter feature coarsens appreciably after 60 min of sputtering, inducing a large increase in the surface roughness. This behaviour is attributed to the preferential direction determined on the substrate by the ion beam for this incidence angle, leading to shadowing effects among surface features in the sputtering process. Under irradiation at normal incidence, the formation of an hexagonal array of nanodots is induced for irradiation times longer than 2 min. The shape and crystallinity of the nanodots were determined by HRTEM. At this incidence angle, the surface roughness is very low and remains largely unchanged even after 16 h of sputtering. For the two angle conditions studied, the formation of the corresponding surface structures can be understood as the interplay between an instability due to the sputtering yield dependence on the local surface curvature and surface smoothing processes such as surface diffusion.

  • Nanotechnology 13 (2002) 304-308

Permalink: https://www.hzdr.de/publications/Publ-5580


Radiolabelling of isopeptide NEpsilon-(Gamma-glutamyl)-L-lysine by conjugation with N-succinimidyl-4-[18F]fluorobenzoate

Wüst, F.; Hultsch, C.; Bergmann, R.; Johannsen, B.; Henle, T.

Abstract

The isopeptide NEpsilon-(Gamma-glutamyl)-L-lysine 4 was labelled with 18F via N-succinimidyl-4-[18F]fluorobenzoate ([18F]SFB). A modified approach for the convenient synthesis of [18F]SFB was used, and [18F]SFB could be obtained in decay-corrected radiochemical yields of 44-53% (n=20) and radiochemical purity >95% within 40 min after EOB. For labelling NEpsilon-(Gamma-glutamyl)-L-lysine with [18F]SFB the effects of isopeptide concentration, temperature, and pH were studied to determine the optimum reaction conditions. The coupling reaction was shown to be temperature and pH independent while being strongly affected by the isopeptide concentration. Using the optimized labelling conditions, in a typical experiment 1.3 GBq of [18F]SFB could be converted into 447 MBq (46%, decay-corrected) of [18F]fluorobenzoylated isopeptide within 45 min, including HPLC purification.

Keywords: 18F-labelling; positron emission tomography; isopeptide; [18F]SFB

  • Applied Radiation and Isotopes 59 (2003) 43-48

Permalink: https://www.hzdr.de/publications/Publ-5579


Nachweis, Interpretation und Bewertung bestrahlungsbedingter Gefügeänderungen in WWER-Reaktor-Druckbehälterstählen

Böhmert, J.; Gokhman, A.; Große, M.; Ulbricht, A.

Abstract

Im kernnahen Bereich verändert der Reaktordruckbehälter unter dem Einfluss der Neutronenbestrahlung seine Eigenschaften. Das Phänomen ist als Neutronenversprödung bekannt und insbesondere für die Reaktoren vom Typ WWER von hoher sicherheitstechnischer Relevanz. Zur Vertiefung des Verständnisses und zur quantitativen Beschreibung der Zusammenhänge zwischen Gefüge, mechanischen Eigenschaften und der Strahlenbelastung wurden an WWER-Reaktordruckbehälterwerkstoffen Mikrostrukturuntersuchungen durchgeführt.

  • Open Access Logo Wissenschaftlich-Technische Berichte / Forschungszentrum Rossendorf, FZR-381 Juni 2003
    ISSN: 1437-322X

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Permalink: https://www.hzdr.de/publications/Publ-5578


First operation of a superconducting rf photoelectron gun

Teichert, J.; Büttig, H.; Etushenko, P.; Freitag, M.; Janssen, D.; Konstantinov, S.; Kruchkov, J.; Matheisen, A.; Michel, P.; Moeller, W.; Myskin, O.; Pelkeler, M.; Petrov, V.; Quast, T.; Reppe, B.; Schneider, C.; Schurig, R.; vom Stein, P.; Tribendis, A.; Volkov, V.; Will, I.

Abstract

RF photo cathode electron guns are the source of choice for most high-performance accelerator systems. Their advantages are the ability to produce very bright beams of electrons with high bunch charges and small transverse and longitudinal emittance. At present, their drawback is the limited average current since the high RF fields in the cavities require a pulsed operation. On the other hand, advanced light sources uses linear accelerators with superconducting RF cavities which can operate in the cw mode and produce high average current electron beams. A preferred injector for these accelerators would be a photo electron gun with superconducting RF cavities.
In a research project [1], a superconducting RF photo electron gun (SRF gun) has been developed during the last years at the Forschungszentrum Rossendorf. The SRF gun was put successfully into operation and the efficiency of the concept could be demonstrated. A helium bath cryostat was used to cool down the cavity to 4.2 K. In a daily cycle the cryostat was filled up with liquid helium in the morning followed by a measuring time in the afternoon. The resonator is a niobium half cell with TESLA geometry operating at 1.3 GHz. The photo cathode had a Cs2Te layer deposited in a preparation chamber connected with the gun. In contrast to the cavity the cathode is not superconducting. It is thermally isolated from the cavity and its heat load goes in a special nitrogen cooling system. The cathode was illuminated by an UV laser of 263 nm with a micropulse frequency of 26 MHz and a maximum energy per pulse of 40 nJ. For evaluation of the produced electron beam a beam line is installed with two solenoids, insertable mask and view screens, spectrometer magnet, kicker cavity and Faraday-cup. Measurements of beam parameters and operation experience are reported.

1] E. Barthels et al., Nucl. Instr. and Meth. A 445 (2000) 408

  • Poster
    Workshop on Scientific Applications of Energy-Recovery-Linac-Driven Synchrotron Light Sources, Erlangen, Germany, September 27-29, 2002

Permalink: https://www.hzdr.de/publications/Publ-5577


Results of beam parameter measurement of the ELBE electron accelerator after commissioning

Teichert, J.; Büchner, A.; Evtushenko, P.; Gabriel, F.; Lehnert, U.; Michel, P.; Voigtländer, J.

Abstract

The ELBE accelerator, an electron linac with superconducting cavities, is designed for a beam energy of 40 MeV, a cw current up to 1 mA and a maximum bunch charge of 77 pC. After acceleration, the electron beam will be used to generate a variety of electromagnetic radiation with different wavelength. Two FELs will deliver coherent infrared radiation, monochromatic x-rays will be produced by means of a channeling target and MeV photons with a bremsstrahlung target. Furthermore, converter targets for neutron and positron production will be installed. For the first commissioning tests, the injector with a thermionic gun, one cryomodule with two nine-cell cavities and a diagnostic beam-line were in operation. Energy and energy width were determined with a magnetic spectrometer. Transverse emittance measurements were carried out with a pepper-pot mask in the injector and with the quadrupole scan method for the accelerated beam. Bunch length was determined from the autocorrelation function of the coherent transition radiation with a Martin-Puplett interferometer. The results of these beam parameter measurements will be presented and evaluated

  • Poster
    24th International Free Electron Laser Conference, Argonne, Illinois, USA., September 9-13, 2002
  • Nuclear Instruments and Methods in Physics Research A 507(2003)1-2, 354-356

Permalink: https://www.hzdr.de/publications/Publ-5576


First operation of a superconducting rf photoelectron gun

Teichert, J.; Büttig, H.; Evtushenko, P.; Freitag, M.; Janssen, D.; Konstantinov, S.; Kruchkov, J.; Matheisen, A.; Miche, P.; Moeller, W.; Myskin, O.; Pelkeler, M.; Petrov, V.; Quast, T.; Reppe, B.; Schneider, C.; Schurig, R.; vom Stein, P.; Tribendis, A.; Volkov, V.; Will, I.

Abstract

In the last year at the Forschungszentrum Rossendorf, in cooperation with the Budker Institute Novosibirsk, DESY, the Max-Born-Institut Berlin, and ACCEL, a superconducting rf photoelectron gun (SRF gun) has been developed [1]. On March 5, 2002 this gun is going into successful operation. A half-cell niobium cavity has been cooled down to 4 K. In this cavity a CsTe2 photocathode is installed, isolated electrically and thermally by a vacuum gap. The Q value and the accelerating field strength in the cavity have been measured. For 4 K, Q=2x108 and an accelerating field of 14 MV/m have been obtained. This value did not change during four weeks of operation time. The energy of the electron beam is 0.62 MeV and the bunch charge is 26 pC. The laser works with a duty factor of 25% and with a repetition rate of 26 MHz inside the macropulse. The average laser power in the macropulse is 1.5 W (l=260 nm), and the length of the micropulse is 5 ps FWHM. This corresponds to an average electron current of 170 µA and 680 µA in the macropulse. The isolated cathode allows the separate measurement of the cathode current and the current inside the beam dump as a function of the laser phase. The next measurements are planned for late May.

[1] E. Barthels et al., Nucl. Instr. and Meth. A 445 (2000) 408

  • Lecture (Conference)
    24th International Free Electron Laser Conference, Argonne, Illinois, USA., September 9-13, 2002

Permalink: https://www.hzdr.de/publications/Publ-5575


Bunch length measurements at ELBE

Evtushenko, P.; Lehnert, U.; Michel, P.; Teichert, J.

Abstract

Last year the first ELBE accelerating module was commissioned. During the commissioning the electron beam parameters such as transverse emittance, energy spread and bunch length were measured. Each of them was studied at different bunch charges as a function of RF field phase in the first accelerating cavity. Especially for an accelerator like ELBE, which is intended to be a driver for free electron laser (FEL), bunch length measurement in picosecond range becomes very important and impose some challenge. Coherent transition radiation (CTR) technique was used to measure bunch length. This technique uses the Martin-Puplett interferometer to measure the autocorrelation of the CTR pulse yielding a minimum 2 ps RMS bunch length at 77 pC bunch charge. Short description of the method, experimental setup, data evaluation procedure and results of the measurements will be presented.

  • Poster
    Deutsche Physikalische Gesellschaft, Nuclear Physics Spring Meeting, Münster, March 11-15, 2002

Permalink: https://www.hzdr.de/publications/Publ-5574


The electron beam properties of the ELBE accelerator

Lehnert, U.; Evtushenko, P.; Michel, P.; Teichert, J.

Abstract

By December 2001 we concluded the first operational period of the ELBE accelerator. The achieved results and measured parameters of the electron beam are presented here. Although the full beam energy of 20 MeV for the first accelerator stage has been reached, most measurements were performed at 12 MeV beam ernergy with varying beam currents and bunch charges. The nominal bunch charge of 77 pC was reched and the measured beam parameters (energy spread, bunchlength and transverse emittance) meet the previous predictions.

  • Lecture (Conference)
    Deutsche Physikalische Gesellschaft, Nuclear Physics Spring Meeting, Münster, March 11-15, 2002

Permalink: https://www.hzdr.de/publications/Publ-5573


First operation of the ELBE superconducting electron lineat accelerator

Büchner, A.; Evtushenko, P.; Gabriel, F.; Lehnert, U.; Michel, P.; Schneider, C.; Teichert, J.; Voigtländer, J.

Abstract

The ELBE project is intended to produce a wide spectrum of different radiation and neutrons, especially coherent light in the medium and far infrared by means of a free electron laser. The driver of the radiation source is a super-conducting electron linear accelerator designed for a wide range of beam parameters in order to satisfy the various requirements.
Recently, the forst cryostat containing two nine-cell niobium standing wave rf cavities for an acceleration up to 20 MeV has been put into operation and has been cooled down. For the first time, an accelerated electron beam has been produced successfully.
The helium cooling for the cryostat working at 1.8 K, the electron beam injector, the radio frequency system, beam control and beam diagnostics operate very reliably. In the paper the results of the beam parameter measurements and the experiences gained in the first operation period will be presented.

  • Poster
    23rd International Free Electron Laser Conference, 20.-24.08. 2001, Darmstadt, Deutschland
  • Open Access Logo Contribution to proceedings
    23rd International Free Electron Laser Conference, 20.-24.08.2001, Darmstadt, Deutschland
    Proceedings of FEL 2001, II-19

Permalink: https://www.hzdr.de/publications/Publ-5572


Sorption von Uran(VI) an Albit - Identifizierung von Uran(VI)-Oberflächenspezies mit mit spektroskopischen Methoden (EXAFS, TRLFS)

Walter, M.; Arnold, T.; Bernhard, G.

Abstract

Als Bestandteil der Nebengesteine von Uranlagerstätten und potentiellen Endlagern für radioaktive Abfälle stellen Feldspäte eine mögliche Mineraloberfläche für die Sorption von mobilisierten Uran(VI) dar. Durch die Wechselwirkung zwischen Feldspat und der wässrigen Phase kann es neben der Adsorption von Uran(VI) zu Mineralauflösung und -neubildung kommen. Ziel der Arbeit ist es, mittels EXAFS-Spektroskopie (Extended X-ray Absorption Fine Structure) und TRLFS (Time-Resolved Laser-induced Fluorescence Spectroscopy) die Sorptionsmechanismen von Uran(VI) an Albit in Abhängigkeit von Mineralauflösungs-prozessen aufzuklären.

Die U(VI)-Adsorption an Albit, Na0,86K0,09Ca0,05[Al1,05Si2,95O8] /1/, der Korngröße 2-6,3 µm (BET: 2,2 m2/g) wurde in 0,01 M NaClO4- Lösung im batch- und Durchflussversuch untersucht. Im Batchversuch erfolgte die U(VI)-Adsorption bei pH 6,4 und 1·10-5 M U innerhalb einer Sorptionsdauer von 24 Stunden. Die Durchflussversuche erfolgten ohne vorherige Equilibrierung des pH-Wertes mit U(VI)-Konzentrationen von 5·10-6 und 2·10-5 M bei pH 5,8 über einen Zeitraum von 170 Tagen. Zusätzlich wurde Albit bei 40°C über mehrere Monate in 0,01 M HClO4 sauer aktiviert. Die entstehende siliziumreiche Oberflächenschicht (leached layer) wurde duch Ultraschall abgetrennt und angereichert. An diesem sauer aktivierten Albit <2 µm (BET: 21,6 m2/g) wurde U(VI) bei pH 5,8 (2·10-5 M U) und 5,0 (1·10-4 M U) adsorbiert. Die Sorptionsproben wurden als feuchte Paste für die Messung der zeitaufgelösten Fluoreszenzspektren (TRLFS) und Röntgenabsorptionsspektren (EXAFS: ESRF, ROBL) präpariert.

Die Anpassung der EXAFS-Spektren ergeben für die U(VI)-Sorption an Albit im Batch und Durchflussversuch einen kurzen Abstand der äquatorialen Sauerstoffe Oeq von ca. 2,35 Å. Der kurze Abstand und der hohe Debye-Waller Faktor weisen auf eine inner-sphere Oberflächenkomplexierung hin. Bei Uran(VI) adsorbiert an sauer aktivierten Albit ist die äquatoriale Sauerstoffschale in zwei Schalen bei 2,23 Å und 2,44 Å gesplittet, was als die Präsenz einer inner-sphere Oberflächenspezies interpretiert werden kann. Bidentat koordiniertes Silizium wurde mit der EXAFS-Spektroskopie nicht beobachtet, die Detektion monodentater Uran(VI)-Silikat Koordinationen ist jedoch wegen destruktiv interferierender Mehrfachstreupfade stark eingeschränkt. Uran-Uran Rückstreuungen wurden nicht beobachtet, eine Präzipitation von Uran(VI)phasen ist demnach kein dominierender Sorptionsmechanismus. Die TRLFS zeigt für U(VI) sorbiert an Albit (Durchflussversuch) zwei Fluoreszenzspezies mit t1 = 1 µs und t2 = 10-20 µs, während bei U(VI) adsorbiert an sauer aktivierten Albit nur eine Fluoreszenzspezies beobachtet wurde, deren Spektrum und Lebensdauer t2 entspricht. Das Spektrum von Fluoreszenzspezies t2 ist dem von Uran(VI) adsorbiert an Silica ähnlich /2/. Sowohl die EXAFS- als auch die TRLFS-Ergebnisse zeigen, dass die Sorption von Uran(VI) an Albit bevorzugt als inner-sphere Oberflächenkomplexierung am Silikattetraeder stattfindet.

/1/ Zorn T. (2000) Dissertation TU Dresden.
/2/ Gabriel et al. (2001) J. Colloid Interface Sci. 239, 358-368.

Keywords: Uran(VI) Sorption Albit Feldpat leached layer

  • Lecture (Conference)
    Geochem 2003, 27.-28.06.2003 Oldenburg

Permalink: https://www.hzdr.de/publications/Publ-5571


Ion beam induced excess vacancies in Si and SiGe and related Cu gettering

Kögler, R.; Peeva, A.; Kuznetsov, A.; Christensen, J.; Svensson, B.; Skorupa, W.

Abstract

Implantation-induced excess vacancies and the related Cu gettering was studied in Si and in the solid solution Si0.93Ge0.07. The excess vacancy and interstitial generation during normal and inclined ion implantation can be simulated by a simple binary collision process. The excess defects are shown to control the Cu gettering observed in Si after rapid thermal annealing at a temperature of 900oC. The vacancy concentration in the SiGe layer is higher than in Si. An additional vacancy concentration of about 3.15´1018cm-3 was determined in the SiGe layer beside the implantation-generated excess vacancies. These vacancies are presumably incorporated by the SiGe layer deposition on Si substrate. Vacancies agglomerate and form cavities during annealing. The cavities in SiGe were found to be significantly larger than in Si.

Keywords: Ion Implantation; Excess Vacancies; Cavities; RP/2-gettering; Si; SiGe; Cu

  • Lecture (Conference)
    Gettering and Defect Engineering in Semiconductor Technology GADEST 2003, 21.-26.09.2003, Zeuthen / Berlin, Deutschland
  • Contribution to proceedings
    Gettering and Defect Engineering in Semiconductor Technology GADEST 2003, 21.-26.09.2003, Zeuthen/Berlin, Deutschland
    Solid State Phenomena 95-96(2004), 587-592, 587-592

Permalink: https://www.hzdr.de/publications/Publ-5570


Four-quasiparticle alignments in 66Ge

Stefanova, E. A.; Stefanescu, I.; de Angelis, G.; Curien, D.; Eberth, J.; Farnea, E.; Gadea, A.; Gersch, G.; Jungclaus, A.; Lieb, K. P.; Martinez, T.; Schwengner, R.; Steinhardt, T.; Thelen, O.; Weisshaar, D.; Wyss, R.

Abstract

The neutron-deficient nucleus 66Ge was populated at high spin in two experiments using the reaction 40Ca(32S, α2p) at beam energies of 105 and 95 MeV. In the first experiment, a self supporting 40Ca target was used, while a gold-backed target of similar thickness was used in the second experiment. αγ rays were detected with the EUROBALL array, combined with the charged-particle detector array EUCLIDES and the Neutron Wall. The level scheme of 66Ge was extended up to E=18MeV and I=(23- ). Above angular momentum 10+, we found two sequences, connected by energetically staggered I=1 M1 transitions. The total Routhian surface calculations describe 66Ge at lower spins as a αγ-soft nucleus a having moderate deformation of β2=0.23, while a triaxial deformation is predicted for the band structures above Iπ=10+. To our knowledge, this is the first observation of staggered M1 transitions in a deformed four-quasiparticle π(g2 9/2)νg2 9/2 ) structure.

  • Physical Review C 67, 054319 (2003)

Permalink: https://www.hzdr.de/publications/Publ-5569


Precipitation Formation in Al4Cu by Ion Irradiation

Mücklich, A.; Gushchina, N. V.; Wieser, E.; Ovchinnikov, V. V.

Abstract

precipitation formation in Al4Cu by ion irradiation

Keywords: Al4Cu; ion irradiation

  • Lecture (Conference)
    Proceedings, Microscopy Conference 2003, Deutsche Gesellschaft für Elektronenmikroskopie, 31st Conference, Dresden, September 07-12, 2003;
  • Microscopy and Microanalysis 9 (Suppl.3) 2003, 348-349
  • Contribution to proceedings
    Proceedings, Microscopy Conference 2003, Deutsche Gesellschaft für Elektronenmikroskopie, 31st Conference, Dresden, September 07-12, 2003;

Permalink: https://www.hzdr.de/publications/Publ-5568


Simulation of a thermionic electron gun including control grid effects

Teichert, J.; Büchner, A.; Evtushenko, P.; Michel, P.; Schneider, C.

Abstract

For a thermionic electron gun working at 250 kV and producing bunches up to 85 pC, the measurement of the transverse emittance shows an increase with bunch charge. In order to understand this effect numerical simulations have been performed. The influences of the electrode geometry, space charge and of the control mesh in front of the cathode are included in the simulation. The results show that the growth of the transverse emittance for higher bunch charges is mainly caused by the control mesh. The strong acceleration field penetrates through the mesh holes and for the electrons each hole acts as a small lens. The portion of electrons which are deflected increases with electron current. In the numerical simulation the field and electron trajector calculation was performed with the EGUN code [1]. For the electron transmission throught the potential barrier of the mesh the free electron gas approximation with a local penetration probability, a Maxwell energy distribution and an angular distribution according to Lambert´s law was applied.

1. W.B. Herrmannsfeldt, Report SLAC-331-UC-28, Stanford University, 1988

  • Poster
    6th International Computational Accelerator Physics Conference, 11.-14.09.2000, Darmstadt, Deutschland

Permalink: https://www.hzdr.de/publications/Publ-5567


Isomerism in 96Ag and non-yrast levels in 96Pd and 95Rh, studied in β decay

Batist, L.; Döring, J.; Mukha, I.; Plettner, C.; Bingham, C. R.; Borcea, R.; Gierlik, M.; Grawe, H.; Hauschild, K.; Janas, Z.; Johnstone, I. P.; Karny, M.; Kavatsyuk, M.; Kirchner, R.; La Commara, M.; Mazzocchi, C.; Moroz, F.; Pavan, J.; Plochocki, A.; Roeckl, E.; Salvachúa, B.; Schmidt, K.; Schwengner, R.; Skouras, L. D.; Tabor, S. L.; Wiedeking, M.

Abstract

The β decay of 96Ag (Z=47,N=49) was investigated by measuring positrons, X rays as well as β-delayed protons and γ rays. The γ radiation was studied by means of germanium detectors and a NaI total-absorption spectrometer. Two β-decaying isomers in 96Ag were established with half-lives of 4.40(6) and 6.9(6) s and tentative spin–parity assignments of (8+) and (2+), respectively. For both isomers, the intensities of β transitions to low-lying levels of 96Pd (Z=46,N=50) and β-delayed proton decays to levels in 95Rh (Z=45,N=50) were measured. Several new 96Pd levels were firmly established. The level energies, their γ decays and the Gamow–Teller decay of 96Ag are compared to shell-model predictions. A new low-lying level in 95Rh was found at 680 keV excitation energy. Through a comparison with low-lying states of N=50 isotones, this level is interpreted as the first excited 7/2+ state built on the proton 9/2+ ground state. The assignments of further excited states in 95Rh are discussed.

Keywords: RADIOACTIVITY; Eγ; Deduced level schemes; Shell-model calculations; 96Pd; 95Rh; isomers; QECSp value; from 60Ni(40Ca p3n); 96Ag; Iγ; Iβ; Ep; T1/2

  • Nuclear Physics A 720(2003)245-273

Permalink: https://www.hzdr.de/publications/Publ-5566


Molekular and Spectroscopie charakterization of Uranium....

Merroun, M.

  • Lecture (Conference)
    Uni Granada, Dez.2002

Permalink: https://www.hzdr.de/publications/Publ-5565


EXAFS investigations of the uranium complexes formed by bacterial cells, S-layers and bioceramics

Merroun, M.; Raff, J.; Rossberg, A.; Reich, T.; Selenska-Pobell, S.

Abstract

Microorganisms and their biocomponents affect the mobility and toxicity of radionuclides through solubility and speciation changes, biosorption, bioaccumulation or other bio-transformations. In this paper we report structural information on the uranium complexes formed by different bacterial isolates from uranium mining waste piles and by their purified biocomponents. EXAFS fits indicate that for B. sphaericus JG-A12 U(VI) is coordinated to carboxyl groups in a bidentate arrangement (RU-C= 2.91 ± 0.02 Å), and to phosphates in a mondentate fashion (RU-P = 3.59 ± 0.02 Å). For the other bacteria strains belonging to A. ferrooxidans, S. maltophilia, P. stutzeri, and P. migulae species U (VI) was bound only to phosphate (RU-P = 3.63 ± 0.02 Å). Because of the ability of the strain B. sphaericus JG A12 to bind selectively and reversibly U and other heavy metals, it was chosen for construction of so called biological ceramics (biorers) for bioremediation of metal-polluted waters. The sorption of U(VI) by the biocers occurs mainly via silicate and phosphate groups. The SiO2-matrix alone binds U (VI) via hydroxyl (water molecules) and silicate groups.

  • Poster
    XAFS-12 Conference Malmö, Schweden 22.-27.6.2003

Permalink: https://www.hzdr.de/publications/Publ-5564


BACTERIAL STRAINS ISOLATED FROM URANIUM MINING WASTE PILES AND THEIR INTERACTIONS WITH URANIUM

Merroun, M.; Hennig, C.; Rossberg, A.; Reich, T.; Geipel, G.; Selenska-Pobell, S.

Abstract

Uranium mining waste pile environments are rich in uranium and heavy metals. In addition, they are a reservoir of a large variety of metal-resistant microorganisms. These natural microbial populations are able to influence dissolution and/or precipitation of actinides. The overall goals of this work are to identify the key interactions between uranium and the strains JG-2 and JG-7B isolated from a uranium mining waste pile situated near the town of Johanngeorgenstadt in the Southeast of Germany. Phylogenetic analysis of these strains revealed that they are related to Stenotrophomonas maltophilia and Bacillus sphaericus. As estimated by using ICP-MS these natural isolates possess high ability to accumulate uranium and other heavy metals such as Cd, Pb, Ni and Ag. The Extended X-ray Absorption Fine Structure (EXAFS) analysis of the uranium complexes formed by these isolates demonstrated that the U(VI) is coordinated to phosphate groups in a monodentate fashion with an average distance between the U atom and the P atom of 3.59 ± 0.02 Å. Transmission Electron Microscope (TEM) and Enery-Dispersive X-ray (EDX) analysis demonstrated that the uranium accumulated by S. maltophilia JG-2 is located at the cell wall and in the cytoplasm. In the case of B. sphaericus JG-7B the uranium was located only in the cell wall. In addition, we applied TRLFS in order to determine the energy and the shape of the emission bands and the fluorescence lifetime of the uranium complexes formed by the two different bacterial strains studied in this work. The results may ultimately help to develop effective methods for remediation of heavy-metal-polluted environments.
This work was supported by grant No.03I4004B from the Bundesministerium für Bildung und Forschung, Germany.

  • Poster
    Migration 03, Korea 21.-26.9.2003

Permalink: https://www.hzdr.de/publications/Publ-5563


Experimental and numerical study about the solidification of a PbSn alloy exposed to a rotating magnetic field

Willers, B.; Eckert, S.; Michel, U.; Zouhar, G.; Nikrityuk, P.; Eckert, K.

Abstract

An important factor to influence the microstructure of a metallic alloy is the convection in the melt during the solidification process. The application of time varying magnetic fields can be considered as an effective tool to organise a well-defined flow structure in the liquid phase affecting the nucleation and growth process. The aim of our work is to improve the understanding of the basic mechanisms allowing us to find a strategy to refine the microstructure of castings by an optimal combination of magnetic field intensity, field frequency and cooling rate.
Directional solidification experiments were carried out with a Pb85wt%Sn alloy contained inside a cylindrical crucible with a diameter of 50 mm. A melt height of 60 mm was chosen. The container bottom is positioned on a water cooled copper chill allowing a directed solidification by a vertical heat flux. A rotating magnetic field was generated by an inductor system with 6 coils. A maximum field amplitude up to 25 mT can be applied. The frequency of the field can be varied between 10 and 400 Hz.
Local temperatures were determined during the solidification process using a set of thermocouples. Cooling curves measured at different locations inside the sample reveal the significant influence of the electromagnetic convection on the local heat transfer. Profiles of the melt velocity were obtained applying the ultrasonic Doppler method..
The Pb-85wt%Sn alloy shows a microstructure with primary tin-crystallites and eutectic. Specimens solidified without a rotating magnetic field showed a columnar dendritic microstructure which is orientated in heat flux direction. The tin crystallites and the eutectic are homogeneously distributed over the whole sample. If the alloy solidifies in a rotating magnetic field the microstructure changes. The shape of the dendrites changes from columnar to equiaxed in direction from the bottom to the top of the specimen and in the same direction the volume content of the eutectic increases.
Numerical calculations were performed using a continuum two-phase model for the directional solidification of a binary alloy. The model includes mass, momentum, energy and species mass conservation equations written in compressible form in order to be able to model shrinkage flow. The Lorentz force term has been included into the momentum conservation equation in order to take into account the effect of the applied magnetic field. The temperature-solute coupling has been described by conduction dominated solidification rule. The two-phase mushy zone has been treated by means of a porous medium approach.
The system of equations has been solved by means of a Finite Volume method. SIMPLE algorithm was used. The results are compared with numerical solutions for diffusion dominated solidification of PbSn and with the data obtained from the experiment.
It was demonstrated by the numerical simulations that a rotating liquid phase forms a mushy zone front showing a convex shape with the maximum on the axis of rotation. This phenomena is confirmed by the experiment.

  • Lecture (Conference)
    EPM 2003, 4th Int. Conference on Electromagnetic Processing of Materials, Lyon (Frankreich), 14-17.10.2003, CD-ROM, A2-3.7 (2003)
  • Contribution to proceedings
    EPM 2003, 4th Int. Conference on Electromagnetic Processing of Materials, Lyon (Frankreich), 14-17.10.2003, CD-ROM, A2-3.7 (2003)

Permalink: https://www.hzdr.de/publications/Publ-5562


Efficient melt mixing due to the combined action of a rotating and a travelling magnetic field

Cramer, A.; Eckert, S.; Heinzelmann, C.; Lampe, D.; Gerbeth, G.

Abstract

Various types of AC magnetic fields are already used as stirrers in liquid metal processing. We distinguish between rotating, travelling and pulsating magnetic fields depending on the coil arrangement and the number of phases of the coil currents. Considering the melt motion driven by each of these AC fields in a cylindrical cavity, the basic flow structures are well-known. As a common feature, they typically consist of a rather rigid flow configuration providing only a limited mixing of the melt. Instead a three-dimensional mixing is often needed in metallurgical applications, for instance, in order to dissolve alloying agents or to submerge lighter parts into the melt.

We report on model experiments for the electromagnetic stirring of liquid metals in a cylindrical cavity using a rotating and a travelling magnetic field. The eutectic melt InGaSn in a cylindrical cavity of aspect ratio 1.5 has been used. Velocity measurements are performed using both the ultrasonic Doppler velocimetry (UDV) as well as local potential probes. UDV delivers profiles of the vertical velocity component. In the case of the rotating magnetic field this component represents only a weak secondary flow compared to the primary azimuthal rotation. In case of a separate action of the two field types, the expected flow fields have been found. An efficient mixing can be obtained by a combination of the two field types. Velocity measurements will be presented demonstrating this behaviour.

  • Lecture (Conference)
    EPM 2003, 4th Int. Conference on Electromagnetic Processing of Materials, Lyon (Frankreich), 14-17.10.2003, CD-ROM, C3-10.5 (2003)
  • Contribution to proceedings
    EPM 2003, 4th Int. Conference on Electromagnetic Processing of Materials, Lyon (Frankreich), 14-17.10.2003, CD-ROM, C3-10.5 (2003)

Permalink: https://www.hzdr.de/publications/Publ-5561


New approaches to determine the velocity field in metallic melts

Eckert, S.; Gerbeth, G.; Gundrum, T.; Stefani, F.; Witke, W.

Abstract

During last decades magnetohydrodynamic (MHD) effects have attracted growing interest because of its potential impact on numerous industrial technologies. In processes involving electrically conducting liquids, the application of an external magnetic field offers efficient opportunities for a contactless flow control and fluid handling. However, for a well-aimed optimisation of the flow structure local information about flow quantities like velocity, pressure, temperature, concentration or void fraction is necessary. In case of liquid metals the choice of a suitable measuring technique is a crucial problem, because the user is confronted with the problems of opaque fluids, high temperatures as well as a strong chemical reactivity of the fluid against many materials. Therefore, measuring techniques well-known from ordinary hydrodynamics generally fail for liquid metal applications. As a consequence, no commercial measuring systems are available for liquid metal applications.
We present a summary of our R&D activities on velocity measuring techniques for liquid metal flows. Various model experiments with various liquid melts at different temperatures have been performed to test and evaluate local sensors as well as integral methods.
A mechano-optical probe was developed which has to be positioned directly inside the liquid metal flow. The measuring principle is based on the separation of a direct mechanical interaction between flow and sensor tip and the optical acquisition and processing of the signal. The insensitivity of the system to electrical noise and external magnetic fields can be considered as an important advantage. Until now, the sensor has been tested in metallic melts up to temperatures of about 450 °C, but an extension up to 800°C should be straightforward.
The ultrasound Doppler velocimetry (UDV) represents a powerful tool since it delivers a full velocity profile along the ultrasonic beam. It can operate with a direct contact to the melt, but also through a channel wall. To overcome the thermal restriction of the ultrasonic transducers an acoustic wave guide has been used. The acoustic wave guide and the piezoelectric element are combined in form of an integrated sensor. This approach allowed the first successful application of the ultrasound Doppler technique in liquid metals at temperatures above 200°C. The feasibility of this integrated sensor concept was demonstrated in experiments in metallic melts as sodium, PbBi, CuSn or aluminium.
In some applications even a coarse knowledge of the flow topology and the direction of the main eddies would be of high value. We study the possibility of velocity reconstruction in electrically conducting fluids from external measurements of induced magnetic fields. The method is based on the fact that an external magnetic field is deformed by the motion of the fluid. Applying the primary magnetic field in two different directions and measuring the related induced magnetic fields at an array of Hall probes, the three-dimensional velocity field can be reconstructed. Besides some theoretical basics, we present experimental results of a demonstration experiment.

  • Lecture (Conference)
    EPM 2003, 4th Int. Conference on Electromagnetic Processing of Materials, Lyon (Frankreich), October 14-17, 2003, Lyon, France, CD-ROM, PL13
  • Contribution to proceedings
    EPM 2003, 4th Int. Conference on Electromagnetic Processing of Materials, Lyon (Frankreich), October 14-17, 2003, Lyon, France, CD-ROM, PL13

Permalink: https://www.hzdr.de/publications/Publ-5560


Two-phase induction melting with tailored flow control

Priede, J.; Gerbeth, G.; Hermann, R.; Filip, O.; Behr, G.

Abstract

Induction heating is widely used in metals processing. In many cases, additional wishes exist for the flow structure in the melt and the heat and mass transport processes connected with it. The induction heating itself causes a flow in the melt which in a cylindrical configuration typically consists of a double vortex driving the flow on the melt surface radially outwards.
We present the solution of a two-phase stirrer which allows a flexible control of the melt motion in addition to the induction heater. In order to demonstrate this approach, we consider the case of a float-zone arrangement working with an RF induction heater. The two-phase stirrer basically consists in an additional coil superimposed to the primary induction coil. The additional coil is not connected to any power supply, but it is part of a secondary circuit with adjustable capacitor and resistance. The current in the secondary coil is solely induced by the primary coil. In that way, an electromagnetic pump is created. Its intensity and resulting flow direction can easily be adjusted to the process needs. The flexible system parameter are the location and distance of the secondary coil with respect to the primary one, and the capacitor and resistance of the secondary circuit.
We present numerical and experimental results for two applications: the float-zone crystal growth of Ni-based single crystals, and the solidification of the magnetic material NdFeB under varying flow conditions at the solidification front. In the first case, the main interest is directed to a change of the phase boundary geometry in order to obtain a single crystal at all. In the second case, the interest is focused on the microstructure of the solidified material resulting from strongly differing flow conditions in the molten phase. Compared to the usual induction heater, the two-phase stirrer allows to provide a much stronger flow in both directions, i.e. radially inwards or outwards at the solidification front, or an almost stagnant melt. The theoretical part contains the solutions of the electromagnetic problem and the heat & fluid flow equations with a free form of the solid-liquid interface. Experimental results will be given for the resulting phase boundary in single crystals of Ni97Si3, and the convection influenced microstructure of NdFeB alloys.

  • Poster
    EPM 2003, 4th Int. Conference on Electromagnetic Processing of Materials, Lyon (Frankreich), 14-17.10.2003, CD-ROM, P213 (2003)
  • Contribution to proceedings
    EPM 2003, 4th Int. Conference on Electromagnetic Processing of Materials, Lyon (Frankreich), 14-17.10.2003, CD-ROM, P213 (2003)

Permalink: https://www.hzdr.de/publications/Publ-5559


Application of a DC magnetic field to the filling process of aluminium investment casting

Eckert, S.; Galindo, V.; Witke, W.; Gerbeth, G.; Gerke-Cantow, R.; Nicolai, H.; Steinrücken, U.

Abstract

We present results on the design and application of a DC magnetic field in order to control the filling process of the investment casting of aluminium alloys. The configuration basically consists in a U-bend, and the main request is to reduce the high flow velocities during the starting phase of the filling process. They are considered as the main source of problems like bubble or inclusion entrapment.
At first, the process was simulated using a plexiglas model and the eutectic melt InGaSn which is liquid at room-temperature. Local velocity measurements have been performed using the ultrasonic Doppler velocimetry, whereas flow rates have been determined independently using the contact-less transmitter technique. Measurements and video visualizations clearly show effects like flow rate oscillations or gas bubble entrapment. Depending on geometric and process parameters, the time-scale to get rid of these entrapments may become longer than the process itself. In order to decrease the maximum values of the velocity at the beginning of the process, an external steady magnetic field has been applied. The measurements show that it is capable of reducing the velocity peaks significantly.
Numerical simulations have been performed for the filling process with DC magnetic field control. The free surface problem which occurs in the riser of the casting process is taken into account by a Volume of Fluids Method. The simulations have been compared to the model experiments, and afterwards scaled up to the realistic aluminium casting process. For the influence of the DC magnetic field, a good agreement is obtained between numerics and measurements.
Real tests have been performed with molten aluminium at an industrial investment caster. They clearly show the primary action of the magnetic field, i.e. to reduce the velocity peaks at the beginning of the process. In a second set of experiments the amplitude of the DC field has been adapted in such a way that at the beginning of the process the full breaking action takes place, whereas the field strength has been reduced during the course of the filling process. In this regime, a clear reduction of the peak velocities is obtained with an only slight increase of the overall filling period.
For the flow rate measurement in a pipe, a contact-less solution based on a pair of alternating magnetic field transmitter and receiver has been developed. Test results from a laboratory model and the industrial Al casting process will be presented.

  • Contribution to proceedings
    EPM 2003, 4th Int. Conference on Electromagnetic Processing of Materials, Lyon (Frankreich), 14-17.10.2003, CD-ROM, P205 (2003)

Permalink: https://www.hzdr.de/publications/Publ-5558


Effect of hydrodynamics on microstructure evolution of Nd-Fe-B alloys

Filip, O.; Hermann, R.; Gerbeth, G.; Priede, J.; Shatrov, V.

Abstract

The influence of melt convection on the microstructure formation of Nd-Fe-B alloys, mainly the volume fraction and grain size of the a-Fe phase, has been investigated experimentally using the electromagnetic levitation technique and a specially designed floating-zone arrangement. Samples were subjected to a strong rotation during levitation and compared to fixed samples without additional sample rotation in the levitation facility. A controlled influence on the melt flow is possible via tailored magnetic fields which enable enhancement or suppression of the melt convection using the floating-zone arrangement. A specially designed magnetic two-phase stirrer offers a strong influence on the melt flow in the floating-zone facility. The microstructure pattern, mainly the volume fraction and grain size of the a-Fe phase, vary strongly with the strength of the internal flow motion in both types of experiments. The melt flow in a levitated droplet was studied numerically under the additional effect of a global sample rotation giving rise to the assumption of strong suppression of internal motions. The electromagnetically driven flow in the inductively heated melt zone of the floating-zone arrangement turned out to be of strong influence on the resulting microstructure. Numerical simulations are essential in order to understand and design the various flow structures.

  • Lecture (Conference)
    "EUROMAT 2003", Lausanne (Schweiz), 01.-05.09.2003

Permalink: https://www.hzdr.de/publications/Publ-5557


First in-beam PET imaging with LSO/APD-array detectors.

Crespo, P.; Kapusta, M.; Pawelke, J.; Moszynski, M.; Enghardt, W.

Abstract

The performance and in-beam imaging capabilities of two Hamamatsu avalanche photodiode arrays (S8550) individually coupled to crystals of cerium-doped lutetium oxyorthosilicate (LSO) are presented. The two detectors were operated in coincidence at the GSI medical beam line of the Gesellschaft für Schwerionenforschung, in Darmstadt, Germany. In a first set of experiments their imaging performance was tested before, during and after the irradiation of phantoms of polymethylmethacrylate with carbon ion beams with fluences equivalent to 1000 typical daily therapeutic fractions. Only minor energy, time and spatial resolution deterioration was observed, with the initial values being recovered after stopping the irradiation. A second set of experiments successfully imaged the depth distribution of positron emitter radionuclides created in a phantom that stopped the high energy carbon ion beam. The particular details for the in-beam PET acquisition are shortly outlined. The obtained results show that LSO is a suitable material for in-beam PET and that its coupling with avalanche photodiode arrays is feasible for a PET system dedicated to in-beam monitoring of ion therapy.

Keywords: PET; ion therapy; proton therapy; LSO; APD

  • Poster
    IEEE Nuclear Science Symposium and Medical Imaging Conference, Portland, USA, Oct. 19-25, 2003
  • Contribution to proceedings
    IEEE Nuclear Science Symposium and Medical Imaging Conference, Portland, USA, Oct. 19-25, 2003

Permalink: https://www.hzdr.de/publications/Publ-5555


Response of the pig lung to irradation with accelerated 12C-ions.

Dörr, W.; Alheit, H.; Appold, S.; Enghardt, W.; Haase, M.; Haberer, T.; Hinz, R.; Jäkel, O.; Kellerer, A. M.; Krämer, M.; Kraft, G.; Kumpf, R.; Nitzsche, H.; Scholz, M.; Voigtmann, L.; Herrmann, T.

Abstract

The response of pig lungs to irradiation with 12C-ions was assessed in two experiments to validate the procedures for heavy ion therapy planning at the Gesellschaft für Schwerionenforschung (GSI) and to explore their range of applicability. In both experiments, the target volume (spread-out Bragg peak, SOBP) was planned to be a 4 cm long cylinder with a diameter of 4 cm. Doses in the SOBP were prescribed to be equivalent to 5x4 Gy, 5x5.5 Gy and 5x7 Gy of x-rays in the first experiment, and to 5 fractions of 7 Gy and 9 Gy in the second experiment. The lung response in the first experiment was less than exepted on the basis of earlier experiments with photons. Pneumonitis reaction and chronic fibrotic changes were observed outside the prescribed high-dose region. In the second experiment, the effects were more pronounced than had been expected on the basis of the first experiment. Changes were most intense in the high-dose region, but were also seen troughout the lung along the beam channel. Moreover, significant skin reactions were observed at the beam entrance site in all animals and - less pronounced - at the beam exit site in 3 of the 6 animals. In conclusion, the complex irradiation geometry of the pig lung, the changes of body weight between the two experiments, and in sufficient accounting for a change in the relative biological effectivness (RBE) computation led to substantial deviations of the observed reactions from expectations, the reasons for which could be identified in a subsequent analysis. The less pronounced lung reaction in the first experiment was due to an overestimation of RBE in a preliminary version of the algorithm for its determination. The extension of the fibrotic reaction resulted from the smear-out of the high-dose region due to density variations in tissue structures, respiratory movement, and limited positioning accuracy. The skin reactions at the entrance port reflect the different treatment geometry in the two experiments. The one unexplained observation is the mild skin reaction that was observed in the second experiment at the beam exit site.

Keywords: Normal tissue; Minipig; Lung; Heavy particles; Carbon ions

  • Radiation and Environmental Biophysics, Vol. 38 (1999) 185-194

Permalink: https://www.hzdr.de/publications/Publ-5554


Radiotherapy for chordomas and low-grade chondrosarcomas of the skull base with carbon ions.

Schulz-Ertner, D.; Haberer, T.; Jäkel, O.; Thilmann, C.; Krämer, M.; Enghardt, W.; Kraft, G.; Wannenmacher, M.; Debus, J.

Abstract

Purpose: Compared to photon irradiation, carbon ions provide physical and biologic advantages that may be exploited in chordomas and chondrosarcomas.
Methods and Materials: Between August 1998 and December 2000, 37 patients with chordomas (n = 24) and chondrosarcomas (n = 13) were treated with carbon ion radiotherapy within a Phase I/II trial. Tumor conformal application of carbon ion beams was realized by intensity-controlled raster scanning with pulse-to-pulse energy variation. Three-dimensional treatment planning included biologic plan optimization. The median tumor dose was 60 GyE (GyE =Gy x relative biologic effectiveness).
Results: The mean follow-up was 13 months. The local control rate after 1 and 2 years was 96% and 90%, respectively. We observed 2 recurrences outside the gross tumor volume in patients with chordomas. Progression-free survival was 100% for chondrosarcomas and 83% for chordomas at 2 years. Partial remission after carbon ion radiotherapy was observed in 6 patients. Treatment toxicity was mild.
Conclusion: These are the first data demonstrating the clinical feasibility, safety, and effectiveness of scanning beam delivery of ion beams in patients with skull base tumors. The preliminary results in patients with skull base chordomas and low-grade chondrosarcomas are encouraging, although the follow-up was too short to draw definite conclusions concerning outcome. In the absence of major toxicity, dose escalation might be considered.

Keywords: Chordoma; Chondrosarcoma; Carbon ion radiotherapy

  • Int. J. Radiation Oncology Biol. Phys., Vol. 53, No. 1 (2002) 36-42
  • International Journal of Radiation Oncology Biology Physics 2002(2002)53, 36-42

Permalink: https://www.hzdr.de/publications/Publ-5553


Erkenntnisse aus den Experimenten der FOREVER-Reihe und den begleitenden Finite Elemente-Rechnungen

Willschütz, H.-G.

Abstract

Für eine genauere Einordnung der Sicherheitsreserven des Reaktordruckbehälters im Falle einer Kernschmelze ist es notwendig, mögliche Versagensformen des Reaktordruckbehälters sowie Versagenszeiträume zu untersuchen. Dazu wurden und werden derzeit weltweit Versuche zum Versagen der Bodenkalotte durchgeführt, wie die amerikanischen OLHF- (OECD Lower Head Failure) oder die schwedischen FOREVER-Experimente (Failure of Reactor Vessel Retention). Am Institut für Sicherheitsforschung des Forschungszentrums Rossendorf bei Dresden wurde ein Finite-Elemente-Modell entwickelt, das sowohl die Thermofluiddynamik der Schmelze als auch die elastoplastische Mechanik des Reaktordruckbehälters modelliert. Nach der Validierung und der Anwendung dieses numerischen Modells bei der Simulation der FOREVER-Experimente führte die Analyse der Ergebnisse zur Einführung einer "Kriechstütze" und einer passiven Steuereinrichtung zur Flutung der Reaktorgrube im Falle einer Kernschmelze. Die Funktion der Kriechstütze besteht darin, die am schwersten beanspruchten Bereiche des Reaktordruckbehälters im Falle einer Kernschmelze zu entlasten und somit ein Versagen zu verhindern oder zumindest deutlich zu verzögern. Dazu werden unterhalb der Bodenkalotte des Reaktordruckbehälters sehr tragfähige Stützen in geeigneter Form angeordnet. Beide Ideen wurden erfolgreich als Patent angemeldet (vgl. "Abstützvorrichtung für Stahlbehälter" Patent DE 100 41 778 C2"Steuereinrichtung für einen Kühlkreislauf" Patent DE 100 41 779 C1). In ersten Rechnungen zur FOREVER-Anordnung wurde gezeigt, dass selbst bei einem Szenario ohne Flutung der Bodenkalotte von außen die Zeit bis zum Versagen durch die Wirkung der Kriechstütze bei gleichbleibenden Randbedingungen verdoppelt werden kann. Eine weitere Verfolgung dieses Konzepts bei bestehenden und zukünftigen Kernkraftwerken erscheint daher vielversprechend.

Keywords: Kernschmelzszenario; Finite Elemente Simulation; Versagenszeitpunkt; Kriechstütze

  • Lecture (Conference)
    Jahrestagung Kerntechnik 2003, 20.-22. Mai 2003, Berlin

Permalink: https://www.hzdr.de/publications/Publ-5552


Limited-angle 3D reconstruction of PET images for dose localization in light ion tumour therapy.

Enghardt, W.; Fromm, W.-D.; Manfrass, P.; Schardt, D.

Abstract

In vivo dose localization in light ion tumour therapy can be performed by measuring the range distributions of beta+ active ions in tissue employing positron emission tomographic techniques. For this purpose a multiplicative iteration scheme for reconstructing three-dimensional images from shift-variant, limited-angle data is presented. In the iterative correction steps the algorithm uses the geometric means of quotients calculated from the three-dimensional Radon transforms of the backprojected measured and approximated source distributions. When sources measured with poor statistics are reconstructed, an effective noise suppression is achieved.

  • Physics in Medicine and Biology, Vol. 37, No. 3 (1992) 791-798

Permalink: https://www.hzdr.de/publications/Publ-5551


A noise suppressing iterative reconstruction technique for positron emission tomoghraphy.

Enghardt, W.

Abstract

A multiplicative iteration scheme for reconstructing three-dimensional images from shift variant, limited angle data taken by a large area positron camera is proposed. Using simulated data sets the algorithm has been proven to be capable of reconstructing source distributions from a very small number of annihilation events. This suggests the applicability of the technique to the measurement of range distributions of beta+-active ions implanted into thick targets and especially to in-vivo dose localization in light ion tumor therapy by means of positron emission tomography.

  • Physica Medica, Vol. VII, No. 3 (1991) 119-124

Permalink: https://www.hzdr.de/publications/Publ-5550


Teilprojekt des Instituts für Radiochemie, Forschungszentrum Rossendorf e.V.

Sachs, S.; Schmeide, K.; Brendler, V.; Heise, K.-H.; Bernhard, G.

Keywords: Huminstoffe; Huminsäuren; Actiniden; Komplexierung; Sorption; Modellierung; Synthese; Charakterisierung; Uran; Neptunium; Plutonium; Thorium

  • Contribution to external collection
    In: Wissenschaftliche Berichte FZKA-PTE Nr. 8, Untertägige Entsorgung. Sechstes Statusgespräch zu FuE-Vorhaben auf dem Gebiet der Entsorgung gefährlicher Abfälle in tiefen geologischen Formationen am 27. und 28. Mai 2003 in Karlsruhe. Forschungsz...

Permalink: https://www.hzdr.de/publications/Publ-5549


In-line nitrogen PIII/ion nitriding processing of metallic materials

Ueda, M.; Gomes, G. F.; Abramof, E.; Reuther, H.

Abstract

In-line nitrogen PIII/ion nitriding processing of metallic materials

Permalink: https://www.hzdr.de/publications/Publ-5548


Improvements of tribological properties of Ti6Al4V by nitrogen plasma immersion ion implantation

Ueda, M.; Silva, M. M.; Otani, C.; Reuther, H.; Yatsuzuka, M.; Lepienski, C. M.; Berni, L. A.

Abstract

Improvements of tribological properties of Ti6Al4V by nitrogen plasma
immersion ion implantation

  • Surface & Coatings Technology, 169-170 (2003) 408-410.

Permalink: https://www.hzdr.de/publications/Publ-5547


Stress Measurement and Stress Relaxation during Magnetron Sputter Deposition of cubic Boron Nitride thin Films

Abendroth, B.; Gago, R.; Kolitsch, A.; Möller, W.

Abstract

Dynamic in situ analysis of stress and film thickness provide fast and more physical information on growth and stress evolution in cBN layers than integrating (ex situ) methods. Especially features of the layered structure of boron nitride films, like the evolution of instantaneous stress and growth rates during deposition can be resolved by in situ methods. This work is concerned with dynamic in-situ stress measurement by means of cantilever bending during magnetron sputter deposition of cBN thin films. Laser deflection in combination with in situ ellipsometry is used to determine the instantaneous stress of the films. The results show, in agreement with results that were obtained previously from ion beam assisted deposition (IBAD), that the hBN and cBN layers exhibit different levels of stress under constant deposition conditions. The stress increases from less than -4 GPa to very high values (-10 GPa) after the coalescence of the cBN nuclei. It is therefore possible to establish the point of cBN nucleation instantly. A simultaneous medium energy ion bombardment is used for stress relaxation during film deposition. A modified substrate bias voltage, combining negative high and low voltage pulses, is used to enable an ion bombardment of the growing film with energies up to 8 keV. In this way, cBN films with a stress as low as –1.7 GPa could be produced without destroying the sp3-bonds significantly.

Keywords: cubic boron nitride; magnetron sputtering; stress measurement; stress relaxation

  • Thin Solid Films, Vol. 447-448C, pp 131-135

Permalink: https://www.hzdr.de/publications/Publ-5545


Fractionated carbon ion irradiation of skull base tumors at GSI. First clinical results and future perspectives.

Debus, J.; Haberer, T.; Schulze-Ertner, D.; Jäkel, O.; Wenz, F.; Enghardt, W.; Schlegel, W.; Kraft, G.; Wannenmacher, M.

Abstract

Backround: Radiobiological and physical examinations suggest clinical advantages of heavy ion irradiation. We report the results of 23 women and 22 men (median age 48 years) with skull base tumors irradiated with carbon ion beams at the Gesellschaft für Schwerionenforschung (GSI), Darmstadt, from December 1997 until September 1999.
Patients and Methods: The study included patients with chordomas (17), chondrosarcomas (10) and other skull base tumors. It is the first time that the intensity-controlled rasterscan-technique and the application of positron emission tomography (PET) for quality assurance was used. All patients had computed tomography for three-dimensional treatment planning. Patients with chordomas and chondrosarcomas underwent fractionated carbon ion irradiation in 20 consecutive days (median total dose 60 GyE). Other histologies were treated with a carbon ion boost of 15 to 18 GyE delivered to the macroscopic tumor after fractionated stereotactic radiotherapy (median total dose 63 GyE).
Results: Mean follow-up was 9 months. Irradiation was well tolerated by all patients. Partial tumor remission was seen in 7 patients (15.5%). One-year local control rate was 94%. One patient (2.2%) deceased. No severe toxicity and no local recurrence within the treated volume were observed.
Conclusion: Clinical effectiveness and technical feasibility of this therapy modality could clearly be demostrated in our study. To evaluate the clinical relevance of the different beam modalities studies with larger patient numbers are necessary. To continue our project a new heavy ion accelator exclusively for clinical use is planned to be constructed in Heidelberg.

Keywords: skull base; carbon ion; heavy ion therapy; radiotherapy; GSi

  • Strahlentherapie und Onkologie, Vol. 176, No. 5 (2000) 211-216

Permalink: https://www.hzdr.de/publications/Publ-5543


Tumor therapy with carbon ion beams.

Crespo, P.; Debus, J.; Enghardt, W.; Haberer, T.; Jäkel, O.; Krämer, M.; Kraft, G.

Abstract

Beams of heavy charged particles like protons or carbon ions represent the optimum tool for the treatment of deep seated, inoperable and radioresistant tumors growing in close vicinity to organs at risk. In contrast to photon therapy, the dose deposited by heavy charged particles increases with the penetration depth, culminating in a sharp maximum at the end of the particle range - the Bragg peak. This peak can be shifted in depth by energy variation and distributed laterally through magnetic deflection of the particle beam, thus allowing a precise and conform irradiation of the selected target volume. Furthermore, carbon ions offer the most conform irradiation due to their lower lateral scattering when compared to protons. In addition to this excellent physical selectivity, the biological efficiency concerning cell killing increases towards the end of carbon ion range. Therefore, the high dose at the Bragg peak is further enhanced by an increase in biological efficiency. Finally, by applying PET techniques, an in-situ dose localization control can be performed by tracing the small amount of beta+ emitters (11C, 15O, 10C) which are produced in nuclear fragmentation reactions between the 12C projectiles and atomic nuclei in the target volume. A pilot tumor therapy unit that fully exploits the advantages of carbon ions is under operation at GSI since December 1997 and has now treadet more than 70 patients. Its mayor goal is to demonstrate the safe and routine application of charged particle beams for radiotherapy.

Keywords: Radiotherapy; Heavy ions; Protons; PET

  • Lecture (Conference)
    Topical Meeting on "Medical Radiation Physics and Engineering", Lisbon, Portugal, 20-22 Nov, 2000
  • Physica Medica, Vol. XVII, Supplement 4 (2001) 1-3
  • Contribution to proceedings
    Topical Meeting on "Medical Radiation Physics and Engineering", Lisbon, Portugal, 20-22 Nov, 2000

Permalink: https://www.hzdr.de/publications/Publ-5542


Hamamatsu S8550 APD arrays for high-resolution scintillator matrices readout

Kapusta, M.; Crespo, P.; Wolski, D.; Moszynski, M.; Enghardt, W.

Abstract

The performance of Hamamatsu S8550 avalanche photodiode (APD) arrays for scintillator matrices readout has been evaluated. The S8550 device is a monolithic 8 X 4 pixels structure with an active area of 2.56 mm² for each pixel. The device allows stable operation at gains up to 74, with a detection efficiency of about 60% for photons of 420 nm wavelength. It is characterized by a low noise equal to 27 electrons equivalent noise charge at room temperature. The energy resolution of 14.6%, for the 511 keV peak from ²2;Na source has been recorded with a 2 x 2 x 10 mm³ LSO crystal coupled to one pixel. The number of electron-hole pairs produced by the 511 keV photopeak absorbed in LSO is equal to 4830 ± 240 e-h/MeV. Coupling LSO scintillator crystals to individual pixels of the APD array a coincidence timing resolution of 3.0 ± 0.2ns FWHM has been measured for the 511 keV b3;-rays from a ²2;Na source. Finally, we compared the characteristics and readout performance of the Hamamatsu array with the results measured earlier under the same conditions for the quadrant large area avalanche photodiodes of Advanced Photonics Inc.

Keywords: Avalanche photodiode array

  • Nuclear Instruments and Methods in Physics Research A 504 (2003) 139-142

Permalink: https://www.hzdr.de/publications/Publ-5541


Evaluation of LAAPD arrays for high-resolution scintillator matrices readout.

Kapusta, M.; Crespo, P.; Moszynski, M.; Enghardt, W.; Szawlowski, M.; Zhou, B. L.; Wolski, D.

Abstract

In this paper, we evaluate the performance of recently released avalanche photodiode arrays from Advanced Photonix, Inc. (API) for scintillator matrices readout. The Large Area Avalanche Photodiode (LAAPD) quadrant device is a monolithic 2x2 pixels structure with an active area of 5.3 mm2 per pixel. The device allows stable operation with high gains up to 200, and detection efficiency of 73+-10 % for 420 nm photons. It is furthermore characterized by a high linear fill factor of 90 % and low noise equal to16 electrons ENC measured at room temperature. We have measured pixel-to-pixel gain non-uniformity smaller than 1.5 % and inter-pixel crosstalk of 1.7 % in the pulse mode operation with the device gain of 50. The energy resolution of 12.3+-0.5 % was achieved for the 511 keV photopeak from a 22Na source placed on top of a 2x2x10 mm3 LSO crystal coupled to one pixel of quadrant LAAPD. An array of LSO crystals was later coupled to the device allowing individual crystal identification. Coincidence timing resolution of 1.9+-0.1 ns FWHM has been obtained for quadrant pixel with LSO scintillator for the 511 keV peak from 22Na source. Finally, we compared the characteristics and readout performance of LAAPD array with published results of some commerciallly available APD arrays.

  • Poster
    IEEE Nuclear Science Symposium, San Diego, California, USA, 4-10 Nov, 2001
    Conference Record, N21-3 (2002) 1-6
  • IEEE Transactions on Nuclear Science, Vol. 49, No. 4 (2002) 1693-1698
  • Contribution to proceedings
    IEEE Nuclear Science Symposium, San Diego, California, USA, 4-10 Nov, 2001
    Conference Record, N21-3 (2002) 1-6

Permalink: https://www.hzdr.de/publications/Publ-5540


Application of the Master Curve Approach for the Irradiation Embrittlement Evaluation of Pressure Vessels Steels

Viehrig, H.-W.; Boehmert, J.

Abstract

The Master Curve (MC) approach and the associated reference temperature, T0, as defined in the test standard ASTM E1921, is rapidly moving from the research laboratory to application in integrity assessment of components and structures. T0 is the index temperature for the universal MC, which considers the behaviour of a specific material. “The Structural Integrity Assessment Procedures for European Industry” (SINTAP) contain a MC extension for analysing the fracture behaviour shown by inhomogeneous ferritic steels statistically. This paper presents the application of the MC approach to the T0 determination of different types of Russian WWER-type reactor pressure vessel (RPV) steels. In addition the SINTAP-MC approach was applied to determine an alternative reference temperature, TR.
The influence of different microstructures and compositions within one type of RPV steel and the effect of irradiation with fast neutrons on T0 are experimentally evaluated. In general the MC based T0 is about 72 K below the Charpy V-notch transition temperature related to an impact energy of 48J. The paper demonstrates the application of MC based T0 and TR as an alternative reference temperature for neutron embrittled RPV steels used in the RPV integrity assessment.

Keywords: fracture toughness; Master Curve; reference temperature; reactor pressure vessel; integrity assessment; neutron embrittlement

  • International Steel Research 74 (2003), No. 9, September, pp. 577-583

Permalink: https://www.hzdr.de/publications/Publ-5539


PET zur Qualitätssicherung bei der Schwerionentherapie

Pönisch, F.

Abstract

no abstact

  • Lecture (others)
    Seminarvortrag im Institut für Strahlenschutzphysik an der TU-Dresden 2000

Permalink: https://www.hzdr.de/publications/Publ-5538


Streukorrektur in der Rekonstruktion von PET-Daten

Pönisch, F.

  • Lecture (others)
    Seminarvortrag im Institut für Strahlenschutzphysik der TU-Dresden 2002

Permalink: https://www.hzdr.de/publications/Publ-5537


Rekonstruktion und Streukorrektur von PET-Daten bei der Schwerionentherapie

Pönisch, F.

Abstract

no abstact

  • Lecture (others)
    Heraeus Seminar Dresden, 2002

Permalink: https://www.hzdr.de/publications/Publ-5536


Quality Assurance in Heavy Ion Tumour Therapy by means of PET

Pönisch, F.; Enghardt, W.; Parodi, K.; Pawelke, J.; Crespo, P.; Lauckner, K.

Abstract

no abstact

  • Lecture (Conference)
    Book of abstract: ECAT Users Meetings 2000 in Barcelona
  • Contribution to proceedings
    Book of abstract: ECAT Users Meetings 2000 in Barcelona

Permalink: https://www.hzdr.de/publications/Publ-5535


Ergebnisse der Streukorrektur für PET bei der Schwerionentherapie

Pönisch, F.; Enghardt, W.

  • Poster
    Verhandlungen der Deutschen Physikalischen Gesellschaft Spring Meeting Münster 2002 Nuclear Physics, S. 44

Permalink: https://www.hzdr.de/publications/Publ-5533


Attenuation and Scatter Correction in Fully 3D Limited Angle PET

Pönisch, F.; Enghardt, W.; Lauckner, K.

Abstract

The in-beam dual head positron camera BASTEI (Beta+ Activity meaSurements at the Therapy with Energetic Ions) is used to monitor and control the applied dose distributions simultaneously to tumor irradiations with carbon ion beams at the experimental heavy ion therapy facility at GSI Darmstadt. Therefore, the PET system has been mounted directly at the treatment site. A fully 3D reconstruction algorithm based on the Maximum Likelihood Expectation Maximization algorithm has been developed and adapted to a spatially varying imaging situation. The scatter and attenuation correction is applied to the measured list mode data before each iterative step. This requires an attenuation map containing the information on the tissue composition and densities. This information is derived from the X-ray computed tomograms (CT) of the patient and the patient fixation system including the head rest. The scatter correction is included into the forward projection step of the Maximum Likelihood image reconstruction. The normalization of scattered events relative to the unscattered events is done by a global scatter fraction factor. The results are presented.

  • Poster
    Proc. IEEE Nuclear Science Symposium and Medical Imaging Conference, San Diego, USA (2001) M13B-23
  • Contribution to proceedings
    Proc. IEEE Nuclear Science Symposium and Medical Imaging Conference, San Diego, USA (2001) M13B-23

Permalink: https://www.hzdr.de/publications/Publ-5532


A Fully 3D Maximum Likelihood Estimator Algorithm with Attenuation and Scatter Correction Adapted to a Limited Angle Positron Camera

Pönisch, F.; Enghardt, W.

Abstract

The in beam dual head positron camera BASTEI (Beta+ Activity meaSurements at the Therapy with Energetic Ions) is used to monitor and control the applied dose distributions simultaneously to the irradiation of the therapeutic carbon ion beam at the experimental heavy ion therapy facility at GSI Darmstadt. Therefore, the PET system is mounted directly at the treatment site. A fully 3D reconstruction algorithm based on the Maximum Likelihood Estimator algorithm has been developed and adapted to a strongly spatially-varying imaging situation. A scatter and attenuation correction is applied to the measured listmode data prior to the image reconstruction. The scatter correction method uses the subtraction of scattered data from measured data.
In this particular PET-application the fluence of registered events at the detector surface is in the order of 10 to 102 cm-2 compared with about 102 to 103 cm-2 in conventional PET in nuclear medicine. The emission data are acquired in a 3D list mode. Since less than 100,000 out of approximately 4 millions coincidence channels typically contribute to the reconstruction all detected events have to be utilized. In addition, they cannot be sorted into sinograms because the necessary interpolation procedures would generate additional noise. Therefore the reconstruction algorithm takes the original emission data as input. The non-zero elements of the 3D transition matrix are calculated at run-time using a Monte-Carlo code that models the individual crystal responses along each coincidence channel. Results of the performance studies as well as examples of use are presented.

  • Poster
    Proc. F3D-2001 The Sixth International Meeting on Fully Three-Dimensional Image reconstruction in Radiology and Nuclear Medicine, Pacific Groove, USA (2001)
  • Contribution to proceedings
    Proc. F3D-2001 The Sixth International Meeting on Fully Three-Dimensional Image reconstruction in Radiology and Nuclear Medicine, Pacific Groove, USA (2001)

Permalink: https://www.hzdr.de/publications/Publ-5531


Proposal for a dedicated ion beam facility for cancer therapy.

Debus, J.; Wannenmacher, M.; Ertner, D.; Fuss, M.; Heeg, P.; Wenz, F.; Zur Hausen, H.; Bendel, R.; Bortfeld, T.; Hartmann, G.; Jäkel, O.; Karger, C.-P.; Kriessbach, A.; Lappe, C.; Massimino, M.; Ölfke, U.; Schlegel, W.; Specht, H.-J.; Angert, N.; Badura, E.; Becher, W.; Böhne, D.; Brand, H.; Brusasco, C.; Dolinskij, A.; Eickhoff, H.; Essel, H.-G.; Franzcak, B.; Geiss, O.; Haberer, T.; Hoffmann, J.; Krämer, M.; Kraft, G.; Kraft-Weyrather, W.; Krause, U.; Kurz, N.; Langenbeck, B.; Ott, W.; Pavlovic, M.; Poppensieker, K.; Richter, M.; Schardt, D.; Schempp, A.; Schlitt, B.; Scholz, M.; Spiller, P.; Steiner, R.; Stelzer, H.; Voss, B.; Weber, U.; Pobell, F.; Enghardt, W.; Hasch, B.-G.; Hinz, R.; Lauckner, K.; Pawelke, J.; Sobiella, M.

Abstract
The Radiologische Universitätsklinik Heidelberg, the Deutsche Krebsforschungszentrum Heidelberg (DKFZ) and the Gesellschaft für Schwerionenforschung Darmstadt (GSI) in cooperation with the Forschungszentrum Rossendorf jointly propose to build a hospital-based ion beam facility for tumour therapy in Heidelberg, Germany. Compared to conventional photon radiation, the use of ion beams in cancer therapy has a number of principal advantages which allow the effective tumour dose to be raised while the surrounding healthy tissue can be spared. The proposed facility is capable of treating some 1,000 patients per year. It centers around a synchrotron of 20 meters in diameter which will provide beams of protons, helium, carbon and oxygen ions with energies between 50 and 430 MeV per nucleon. Three therapy rooms will be available, two equipped with gantry systems for multifield irradiation and one with a fixed horizontal beam. The facility will make use of major innovations made in particle therapy during recent years, amongst them: the intensity-controlled rasterscan technique for a 3D tumour-conformal dose delivery, the in-situ verification of the beam position by positron emission tomography (PET), and the realisation of a biologically optimised treatment planning.
All these new developments were successfully realised and tested within a pilot project for ion beam therapy at the accelerator complex of GSI. Already the first patient treatments performed at the pilot facility demonstrated the realibility and clinical applicability of the newly developed techniques. The proposed facility is thus the next step on the path to establish clinical ion beam therapy in Germany and Europe, including techniques which are presently unique on a world-wide scale.
  • Other report
    K.D. Groß, M. Pavlovic (Eds.), D.O.G. Digital-Offsetdruck Gass, Darmstadt (September 1998)

Permalink: https://www.hzdr.de/publications/Publ-5530


Ionenstrahlen werden sichtbar: Tumortherapie-Kontrolle mit PET - vom Kohlenstoff zu den Protonen.

Enghardt, W.; Parodi, K.; Pawelke, J.; Pönisch, F.

  • Contribution to HZDR-Annual report
    Wissenschaftlich-Technische Berichte / Helmholtz-Zentrum Dresden-Rossendorf; FZR-349 Januar 2003, 47-52
    ISSN: 1437-322X

Downloads

Permalink: https://www.hzdr.de/publications/Publ-5529


Positronen-Emissions-Tomographie für die Qualitätssicherung bei der Schwerionen-Tumortherapie.

Enghardt, W.; Hasch, B.-G.; Hinz, R.; Lauckner, K.; Pawelke, J.; Sobiella, M.

Abstract

Bei der Gesellschaft für Schwerionenforschung in Darmstadt ist in den vergangenen Jahren eine experimentelle Anlage für die Krebstherapie mit Strahlen schwerer Ionen errichtet worden. Im Herbst 1997 sollen dort die ersten Tumorpatienten mit 12C Strahlen behandelt werden. Bei der Installation der Anlage und ihrem künftigen Betrieb kooperieren die Gesellschaft für Schwerionenforschung Darmstadt (GSI), das Deutsche Krebsforschungszentrum in Heidelberg (DKFZ), die Radiologischen Kliniken der Universitäten Heidelberg und Magdeburg sowie das Forschungszentrum Rossendorf. Der Rossendorfer Beitrag zur Therapieanlage besteht in der Entwicklung und Realisierung von Verfahren, welche die Positronen-Emissions-Tomographie (PET) für die Kontrolle der Schwerionen-Tumortherapie anwenden. Mit der Installation des in Rossendorf gebauten Positronen-Emissions-Tomographen am Therapieplatz in Darmstadt im Januar 1996 konnten die methodischen Vorarbeiten zum Einsatz von PET für die Tumortherapie mit schweren Ionen beginnen.

  • Other report
    H. Grünberg, W. Wendler (Eds.), Forschungszentrum Rossendorf Jahresbericht 1996, Initial Satz & Grafik Studio Rossendorf (1997) 29-35

Permalink: https://www.hzdr.de/publications/Publ-5528


PET bei der Krebstherapie mit 12C-Strahlen: Resultate der ersten klinischen Anwendungen.

Pönisch, F.; Debus, J.; Enghardt, W.; Haberer, T.; Hasch, B.-G.; Hinz, R.; Jäkel, O.; Krämer, M.; Lauckner, K.; Pawelke, J.; Poppensieker, K.

  • Lecture (Conference)
    Frühjahrstagung des Fachverbandes Physik der Hadronen und Kerne der Deutschen Physikalischen Gesellschaft, Freiburg, 22-26 Mar, 1999
    Verhandl. DPG, Vol. 34, No. VI (1999) 114
  • Contribution to proceedings
    Frühjahrstagung des Fachverbandes Physik der Hadronen und Kerne der Deutschen Physikalischen Gesellschaft, Freiburg, 22-26 Mar, 1999
    Verhandl. DPG, Vol. 34, No. VI (1999) 114

Permalink: https://www.hzdr.de/publications/Publ-5527


Comparison between the in-beam and the out-of-beam methods for PET control of carbon ion therapy.

Pawelke, J.; Enghardt, W.; Hasch, B.-G.; Hinz, R.; Lauckner, K.; Yoshikawa, K.; Tomitani, T.; Kanazawa, M.; Kanai, T.; Tsujii, H.

  • Lecture (Conference)
    Fifth Biennial ESTRO Meeting on Physics for Clinical Radiotherapy, Göttingen, 6-11 Apr, 1999
    Radiother. Oncol., Vol. 51, Suppl. 1 (1999) S7
  • Contribution to proceedings
    Fifth Biennial ESTRO Meeting on Physics for Clinical Radiotherapy, Göttingen, 6-11 Apr, 1999
    Radiother. Oncol., Vol. 51, Suppl. 1 (1999) S7

Permalink: https://www.hzdr.de/publications/Publ-5526


Quasi-monochromatic X-rays from the ELBE radiation source.

Enghardt, W.; Lehnert, U.; Naumann, B.; Neubert, W.; Pawelke, J.; Prade, H.; Wagner, W.

  • Poster
    18th International Conference on X-Ray and Inner-Shell Processes, Chicago, USA, 23-27 Aug, 1999
    Book of Abstracts (1999) 330
  • Contribution to proceedings
    18th International Conference on X-Ray and Inner-Shell Processes, Chicago, USA, 23-27 Aug, 1999
    Book of Abstracts (1999) 330

Permalink: https://www.hzdr.de/publications/Publ-5525


Simultaneous monitoring of heavy-ion therapy by positron emission tomography.

Hinz, R.; Enghardt, W.; Hasch, B.-G.; Lauckner, K.; Pawelke, J.; Pönisch, F.; Sobiella, M.

  • Lecture (Conference)
    Sixth International Conference on Medical Physics, Patras, Hellas, 1-4 Sep, 1999
    Physica Medica, Vol. XV, No. 3 (1999) 157
  • Contribution to proceedings
    Sixth International Conference on Medical Physics, Patras, Hellas, 1-4 Sep, 1999
    Physica Medica, Vol. XV, No. 3 (1999) 157

Permalink: https://www.hzdr.de/publications/Publ-5524


Positronen-Emissions-Tomographie zur retrospektiven Dosislokalisation bei der Schwerionen-Tumortherapie.

Enghardt, W.; Hinz, R.; Lauckner, K.; Pawelke, J.; Pönisch, F.

  • Lecture (Conference)
    Wiss. Konferenz der WGL über Naturwissenschaftlich-Technische Beiträge zur modernen Entwicklung der Medizin, München, 13 Okt, 1999
    Zusammenfassung der Beiträge, Wissenschaftsgemeinschaft Gottfried Wilhelm Leibniz, Bonn (1999) 32
  • Contribution to proceedings
    Wiss. Konferenz der WGL über Naturwissenschaftlich-Technische Beiträge zur modernen Entwicklung der Medizin, München, 13 Okt, 1999
    Zusammenfassung der Beiträge, Wissenschaftsgemeinschaft Gottfried Wilhelm Leibniz, Bonn (1999) 32

Permalink: https://www.hzdr.de/publications/Publ-5523


PET zur Qualitätskontrolle der Schwerionen-Tumortherapie.

Pönisch, F.; Debus, J.; Enghardt, W.; Haberer, T.; Hasch, B.-G.; Hinz, R.; Lauckner, K.; Pawelke, J.

  • Lecture (Conference)
    5. Deutscher Kongreß für Radioonkologie, Strahlenbiologie und Medizinische Physik, Karlsruhe, 6-9 Nov, 1999
    Strahlenther. Onkol., Band 175, Sondernr. 1 (1999) 143
  • Contribution to external collection
    5. Deutscher Kongreß für Radioonkologie, Strahlenbiologie und Medizinische Physik, Karlsruhe, 6-9 Nov, 1999
    Strahlenther. Onkol., Band 175, Sondernr. 1 (1999) 143

Permalink: https://www.hzdr.de/publications/Publ-5522


A project for radiobiological studies with channeling radiation.

Panteleeva, A.; Enghardt, W.; Lehnert, U.; Pawelke, J.; Prade, H.; Dörr, W.; Dörschel, B.

  • Lecture (Conference)
    3. Jahrestagung der Gesellschaft für Biologische Strahlenforschung, Dresden, 29-01 Sep/Okt, 1999
    W. Dörr (Ed.), Book of Abstracts (ISBN 3-00-004964-9) (1999) 25
  • Contribution to proceedings
    3. Jahrestagung der Gesellschaft für Biologische Strahlenforschung, Dresden, 29-01 Sep/Okt, 1999
    W. Dörr (Ed.), Book of Abstracts (ISBN 3-00-004964-9) (1999) 25

Permalink: https://www.hzdr.de/publications/Publ-5521


In-situ Kontrolle der Strahlentherapie mit Schwerionen durch Positronen-Emissions-Tomographie.

Pawelke, J.; Enghardt, W.; Hasch, B.-G.; Hinz, R.; Lauckner, K.; Pönisch, F.; Sobiella, M.

  • Lecture (Conference)
    3. Jahrestagung der Gesellschaft für Biologische Strahlenforschung, Dresden, 29-01 Sep/Okt, 1999
    W. Dörr (Ed.), Book of Abstracts (ISBN 3-00-004964-9) (1999) 32
  • Contribution to proceedings
    3. Jahrestagung der Gesellschaft für Biologische Strahlenforschung, Dresden, 29-01 Sep/Okt, 1999
    W. Dörr (Ed.), Book of Abstracts (ISBN 3-00-004964-9) (1999) 32

Permalink: https://www.hzdr.de/publications/Publ-5520


The potential of in-beam PET for proton therapy monitoring: first experimental investigation

Parodi, K.; Enghardt, W.; Haberer, T.

  • Lecture (Conference)
    Verhandl. Fruejahrstagung der DPG, Physik der Hadronen und Kerne, Muenster, Maerz 11-15, 2002
  • Contribution to proceedings
    Verhandl. Fruejahrstagung der DPG, Physik der Hadronen und Kerne, Muenster, Maerz 11-15, 2002

Permalink: https://www.hzdr.de/publications/Publ-5519


Potential capabilities of positron emission tomography for quality assurance of proton therapy

Parodi, K.; Enghardt, W.

  • Lecture (Conference)
    XXXIII PTCOG -Meeting, Berlin, Sept. 25-27, 2000
    Book of Abstract
  • Contribution to proceedings
    XXXIII PTCOG -Meeting, Berlin, Sept. 25-27, 2000
    Book of Abstract

Permalink: https://www.hzdr.de/publications/Publ-5518


Cell survival studies after X-ray irradiation.

Panteleeva, A.; Enghardt, W.; Lehnert, U.; Pawelke, J.; Prade, H.; Dörr, W.; Dörschel, B.

  • Lecture (Conference)
    Workshop on X-rays from electron beams, Dresden, 24-26 Feb, 2000
    H. Prade (Ed.), Wissenschaftlich-Technische Berichte, Forschungszentrum Rossendorf, FZR-287 (ISSN 1437-322X) (2000)
  • Contribution to proceedings
    Workshop on X-rays from electron beams, Dresden, 24-26 Feb, 2000
    H. Prade (Ed.), Wissenschaftlich-Technische Berichte, Forschungszentrum Rossendorf, FZR-287 (ISSN 1437-322X) (2000)

Permalink: https://www.hzdr.de/publications/Publ-5517


A device for cell irradiation with low energy quasi-monochromatic photons at ELBE.

Pawelke, J.; Enghardt, W.; Lehnert, U.; Naumann, B.; Neubert, W.; Panteleeva, A.; Prade, H.; Wagner, W.

  • Lecture (Conference)
    Workshop on X-rays from electron beams, Dresden, 24-26 Feb, 2000
    H. Prade (Ed.), Wissenschaftlich-Technische Berichte, Forschungszentrum Rossendorf, FZR-287 (ISSN 1437-322X) (2000)
  • Contribution to proceedings
    Workshop on X-rays from electron beams, Dresden, 24-26 Feb, 2000
    H. Prade (Ed.), Wissenschaftlich-Technische Berichte, Forschungszentrum Rossendorf, FZR-287 (ISSN 1437-322X) (2000)

Permalink: https://www.hzdr.de/publications/Publ-5516


The potential of positron emission tomography for the monitoring of proton therapy

Parodi, K.; Crespo, P.; Enghardt, W.; Hinz, R.; Lauckner, K.; Pawelke, J.; Pönisch, F.

  • Poster
    7th Workshop on Heavy Charged Particles in Biology and Medicine, Darmstadt , Sept. 28-30, 2000
    GSI Report 2000-4

Permalink: https://www.hzdr.de/publications/Publ-5515


Quasi-monochromatic X-rays from ELBE.

Wagner, W.; Enghardt, W.; Lehnert, U.; Naumann, B.; Neubert, W.; Panteleeva, A.; Pawelke, J.; Prade, H.

  • Lecture (Conference)
    Workshop on X-rays from electron beams, Dresden, 24-26 Feb, 2000
    H. Prade (Ed.), Wissenschaftlich-Technische Berichte, Forschungszentrum Rossendorf, FZR-287 (ISSN 1437-322X) (2000)
  • Contribution to proceedings
    Workshop on X-rays from electron beams, Dresden, 24-26 Feb, 2000
    H. Prade (Ed.), Wissenschaftlich-Technische Berichte, Forschungszentrum Rossendorf, FZR-287 (ISSN 1437-322X) (2000)

Permalink: https://www.hzdr.de/publications/Publ-5514


Schwächungs- und Streukorrektur für die Positronen-Emissions-Tomografie (PET) bei der Schwerionentherapie.

Lauckner, K.; Enghardt, W.; Hinz, R.; Pawelke, J.; Pönisch, F.

  • Lecture (Conference)
    Frühjahrstagung des Fachverbandes Physik der Hadronen und Kerne der Deutschen Physikalischen Gesellschaft, Dresden, 20-24 Mar, 2000
    Verhandl. DPG, Vol. 35, No. VI (2000) 212
  • Contribution to proceedings
    Frühjahrstagung des Fachverbandes Physik der Hadronen und Kerne der Deutschen Physikalischen Gesellschaft, Dresden, 20-24 Mar, 2000
    Verhandl. DPG, Vol. 35, No. VI (2000) 212

Permalink: https://www.hzdr.de/publications/Publ-5513


Improvements of the FLUKA simulation code for radiobiological applications

Parodi, K.; Squarcia, S.

  • Poster
    Fruehjahrstagung der DPG Physik der Hadronen und Kerne, Dresden, 20-24 Maerz 2000
    Verhandl. DPG (VI) 35 (2000) 218

Permalink: https://www.hzdr.de/publications/Publ-5512


Radiobiological studies with soft X-rays.

Panteleeva, A.; Enghardt, W.; Lehnert, U.; Pawelke, J.; Prade, H.; Dörr, W.; Dörschel, B.; Brankovic, K.; Slonina, D.

  • Poster
    30th Annual Meeting of the European Society for Radiation Biology, Waszawa, Poland, 27-31 Aug, 2000
    Book of Abstracts (2000) 55
  • Contribution to proceedings
    30th Annual Meeting of the European Society for Radiation Biology, Waszawa, Poland, 27-31 Aug, 2000
    Book of Abstracts (2000) 55

Permalink: https://www.hzdr.de/publications/Publ-5511


An Ultrafast Time-Resolved Fluorescence Spectroscopy System for Metal Ion Complexation Studies with Organic Ligands

Geipel, G.; Acker, M.; Vulpius, D.; Bernhard, G.; Nitsche, H.; Fanghänel, T.

Abstract

Abstract wir von Dr. Geipel nachgereicht

  • Spectrochimica Acta Part A 60(2004)1-2, 417-424

Permalink: https://www.hzdr.de/publications/Publ-5509


Multifragmentation and Flow: peripheral vs. central collisions

Pochodzalla, J.; Aiello, S.; Begemann-Blaich, M.; Bowman, D. R.; Charity, R. J.; Cosmo, A.; Ferrero, A.; Gelbke, C. K.; Hsi, W. C.; Hubele, J.; Imme, G.; Iori, I.; Kempter, J.; Kreutz, P.; Kunde, G. J.; Kunze, W. D.; Lindenstruth, V.; Lisa, M. A.; Lynch, W. G.; Lynen, U.; Mang, M.; Moretto, L. G.; Moroni, A.; Müller, W. F. J.; Neumann, M.; Ocker, B.; Ogilvie, C. A.; Pappalardo, V.; Peaslee, G. F.; Raciti, G.; Rosenberger, F.; Rubehn, T.; Sann, H.; Scardaoni, R.; Schüttauf, A.; Seidel, W.; Serfling, V.; Sobotka, L. G.; Stroth, J.; Stuttge, L.; Trautmann, W.; Tsang, M. B.; Tucholski, A.; Williams, C. W.; Wörner, A.; Zude, E.; Zwieglinski, B.; Blaich, T.

  • Nuclear Physics A583(1995) 553-560

Permalink: https://www.hzdr.de/publications/Publ-5507


Probing the Nuclear Liquid-Gas Phase Transition

Pochodzalla, J.; Möhlenkamp, T.; Rubehn, T.; Schüttauf, A.; Wörner, A.; Zude, E.; Begemann-Blaich, M.; Blaich, T.; Gross, C.; Emling, H.; Ferrero, A.; Imme, G.; Iori, I.; Kunde, G. J.; Kunze, W. D.; Lindenstruth, V.; Lynen, U.; Moroni, A.; Müller, W. F. J.; Ocker, B.; Raciti, G.; Saun, H.; Schwarz, C.; Seidel, W.; Serfling, V.; Stroth, J.; Trzcinski, A.; Trautmann, W.; Tuchalski, A.; Verde, G.; Zwieglinski, B.

  • GSI Preprint, GSI 95 - 13, Feb. 1995 und Phys. Rev. Lett. 75(1995)1040-1043

Permalink: https://www.hzdr.de/publications/Publ-5506


Squeeze-out of nuclear matter in Au+Au collisions

Tsang, M. B.; Danielewicz, P.; Hsi, W. C.; Huang, M.; Lynch, W. G.; Bowman, D. R.; Gelbke, K. C.; Lisa, M. A.; Peaslee, G. F.; Charity, R. J.; Sobotka, L. G.; Begemann-Blaich, M.; Cosmo, F.; Ferrero, A.; Hubele, J.; Imme, G.; Iori, I.; Kempter, J.; Kreutz, P.; Kunde, G. J.; Kunze, W. D.; Lindenstruth, V.; Lynen, U.; Mang, M.; Morroni, A.; Müller, W. F. J.; Neumann, M.; Ocker, B.; Ogilvie, C. A.; Pochodzalla, J.; Raciti, G.; Rosenberger, F.; Rubehn, T.; Saun, H.; Scardavnic, R.; Schüttauf, A.; Schwarz, C.; Seidel, W.; Serfling, V.; Trautmann, W.; Tucholski, A.; Wörner, A.; Zwieglinski, B.

  • MSU Preprint, MSUCL-983, Nov. 1995 Phys. Rev. C53(1996)1959

Permalink: https://www.hzdr.de/publications/Publ-5505


Speciation of Actinides (Environmental, Food, Clinical, Occupational, Health) (The contribution will follow then the arrangement of the actinides in the periodic table.)

Geipel, G.

Abstract

Outline
Actinides are the fourteen elements, which follow the element actinium in the periodic table of elements. The first three actinides uranium, protactinium and thorium can be found in the nature, the other elements are artificial elements. Most speciation studies are carried with actinides from thorium to curium. The elements uranium, neptunium and plutonium show a wide variety of oxidation states. In tetravalent oxidation state the solubility is very low. In this oxidation state the hydrolysis is the most important reaction.

All these elements are radioactive. Therefore special laboratories to handle these elements are necessary. The concentration range for speciation studies with actinides is below 1 x 10-5 M. Therefore several speciation techniques, mostly basing on laser induced methods, are developed. A short overview in these methods will be given.

For thorium and protactinium only few data are available. Thorium does only exist in tetravalent oxidation state. Hydrolysis and phosphate speciation will be described. Protactinium exists in the pentavalent oxidation state and forms a dioxy-cation.

Most data are available for uranium speciation. Uranium exists in four oxidation states. Uranium-(III) is only stable in non-aqueous environments and plays therefore no role in speciation studies. Under reducing conditions uranium-(IV) is formed. Speciation examples for hydrolysis, sulfate, phosphate and arsenate will be given. In aqueous solutions uranium?(V) disproportionates into uranium-(IV) and uranium-(VI). Hexavalent uranium exists only as dioxy-cation.
In a next section environmental aspects of the uranium-(VI) speciation will be described. Uranium is found in more or less high concentrations in anywhere in the environment. Speciation examples from mining and milling will be described.
Uranium speciation in plants (as example for the food chain) will be described.
Neptunium forms oxidation states from +3 to + 7. Np(III) is slightly oxidized to Np(IV). The most stable oxidation states are Np(IV) and Np(V), the latter also forms a dioxy-cation. As example for environmental speciation the speciation of Np(V) with humic substances will be quoted.
Plutonium has oxidation states from + 3 to + 6. The redox potentials between these oxidation states are close together, so one can often find several oxidation states existing together. Examples for speciation in environment (here as specials case the Oklo mine in Gabun and results of bomb tests will be included) are shown, clinical and health aspects should be discussed (Pu is one of the most toxic elements).
Americium and Curium form trivalent ions in solution. These elements are important in waste repositories. Speciation in concentrated salt solutions and in mineral (calcite) phases are important examples for speciation in natural environments.
Actinides higher than Curium show at least short half-life. The long living isotopes are Berkelium 247 (1400 y), Californium 251 (900 y) and Einsteinium 252 (1.24 y). Fermium, Mendelevium, Nobelium and Lawrencium as well as the transactinide elements have half-life less than 1 y. Due to the very low production rates most of these elements are less relevant in speciation chemistry. Berkelium is found to have two oxidation states (III and V). Only few data on chloride and sulfate speciation are available.

  • Contribution to external collection
    in: Handbook of Elemental Speciation II (Eds.R. Cornelis), London: Wiley Verlag, 2005, 509-563

Permalink: https://www.hzdr.de/publications/Publ-5504


A positron emission tomograph for the on-line control of heavy ion tumour therapy.

Enghardt, W.; Hasch, B.-G.; Hinz, R.; Lauckner, K.; Pawelke, J.; Sobiella, M.; Byars, L.

  • GSI-Nachrichten, Gesellschaft für Schwerionenforschung, Darmstadt, 07-95 (1995) 16-17

Permalink: https://www.hzdr.de/publications/Publ-5503


Application of secondary beams to treatment planning.

Tomitani, T.; Kanazawa, M.; Yoshikawa, K.; Pawelke, J.; Kanai, T.; Murakami, T.; Noda, K.; Torikoshi, M.; Kitagawa, A.; Kouda, S.; Muramatsu, M.; Suda, M.; Fukumura, A.; Wada, Y.; Shinoda, I.

Abstract

A secondary beam facility had been built at the end of last fiscal year and commenced the operation since the second term of HIMAC machine time. Optimum momentum spread was sought so as to compromise two contradictory factors, the blurring of sharp Bragg peak and broadening of the 11C end-point distribution. Three types of irradiation, namely, focused beam irradiation, line irradiation and curved surface irradiation, were tested to see the uniformity of the irradiation field. The field uniformity turned out competent with the assessment of beam end-point in all cases, since it only affects the statistical noise in PET images that degrades indirectly the assessment of end-point. Preliminary irradiation tests were performed on rabbits to see biological half-life of 11C in the thigh muscle of the rear leg.

  • Other report
    Report National Institute of Radiological Sciences, Chiba, Japan, 1999

Permalink: https://www.hzdr.de/publications/Publ-5502


Medical application of secondary beams.

Tomitani, T.; Kanazawa, M.; Yoshikawa, K.; Pawelke, J.; Futami, Y.; Kitagawa, A.; Kanai, T.; Kouda, S.; Suda, M.; Fukumura, A.; Matsuura, H.; Takizawa, S.

Abstract

In the application of positron emitting secondary beams to the verification of heavy ion treatment planning, the implanted radioactive isotopes undergo metabolism. Experiments on rabbit thigh muscle were performed using 11C secondary beams from HIMAC. PET allows us three-dimensional imaging of the implanted 11C, however, the early phase cannot be measured. The positron camera allows us in-situ measurement. By focusing the beam to narrow region, time-activity analysis of the volume of interest revealed the existence of faster metabolic component.

  • Other report
    National Institute of Radiological Sciences, Chiba, Japan, NIRS-M-139/HIMAC-026 (2000) 207-208

Permalink: https://www.hzdr.de/publications/Publ-5501


Can the autoactivation of a stable light ion beam be employed for dose control in light ion tumour therapy?

Enghardt, W.; Fromm, W.-D.; Manfraß, P.; Pawelke, J.; Sobiella, M.; Schardt, D.; Geissel, H.; Keller, H.; Kraft, G.; Magel, A.; Münzenberg, G.; Nickel, F.; Scheidenberger, C.

  • Particles Newsletter (Harvard University, Boston, USA), Number 11 (January 1993) 13-14

Permalink: https://www.hzdr.de/publications/Publ-5500


Electromagnetic Fission of 238U at 600 and 1000 MeV per Nucleon

Rubehn, T.; Müller, W. F. J.; Bassini, R.; Begemann-Blaich, M.; Blaich, T.; Ferrero, A.; Gross, C.; Imme, G.; Iori, I.; Kunde, G. J.; Kunze, W. D.; Lindenstruht, V.; Lynen, U.; Möhlenkamp, T.; Moretto, L. G.; Ocker, B.; Pochodzalla, J.; Raciti, G.; Reito, S.; Sann, H.; Schüttauf, A.; Seidel, W.; Serfling, V.; Trautmann, W.; Trzcinski, A.; Verde, G.; Wörner, A.; Zude, E.; Zwieglinski, B.

  • GSI Preprint, GSI 95-28, Mai 1995 und Zeitschrift für Physik A 353(1995) 197-204

Permalink: https://www.hzdr.de/publications/Publ-5499


The FOBOS* 4Pi-Detector of charged particles at the FLNR of the JINR Dubna

Andrassy, M.; Aleksandrov, A. A.; Aleksandrova, I. A.; Budzanowski, A.; Danziger, M.; Dietterle, L.; Doronin, V. N.; Dshemuchadse, S.; Fomichew, A. S.; Gippner, P.; Gebhardt, M.; Heidel, K.; Heinitz, S.; Herbach, C.-M.; Hilscher, D.; Holik, J.; Homeyer, H.; Ivanenko, A. I.; Ivanovski, S. A.; Janczur, W.; Kamanin, D. V.; Kolesov, I. V.; Matthies, A.; May, D.; Merzlyakov, S. I.; von Oertzen, W.; Oganessian, Y. T.; Ortlepp, H. G.; Penionzhkevich, Y. E.; Pausch, G.; Pokrovsky, V. N.; Pyatkov, Y. V.; Radnev, S. V.; Renz, G.; Rubinskaya, L. A.; Sandrev, I. D.; Schilling, K. D.; Seidel, W.; Shishkin, D. I.; Sodan, H.; Strekalovsky, O. V.; Trofimov, V. V.; Tsurin, I. P.; Umlauf, C.; Vakatov, D. V.; Vasko, V. M.; Wagner, W.; Zhuchko, V. E.; Ziem, P.; Zrodkowski, L.

  • Dubna, E7 - 95 - 148, March 1995

Permalink: https://www.hzdr.de/publications/Publ-5498


Nuclear Caloric Curve

Raciti, G.; Bassini, R.; Begemann-Blaich, M.; Fritz, S.; Gaff, S. J.; Groß, C.; Imme, G.; Iori, I.; Kleinevoß, U.; Kunde, G. J.; Kunze, W. D.; Lynen, U.; Mahi, M.; Moroni, A.; Möhlenkamp, T.; Müller, W. F. J.; Ocker, B.; Odeh, T.; Petruzelli, F.; Pochodzalla, J.; Riccobene, G.; Romano, F. P.; Rubehn, T.; Sajia, A.; Schnittker, M.; Schüttauf, A.; Schwarz, C.; Seidel, W.; Serfling, V.; Sfienti, C.; Trautmann, W.; Trzcinski, A.; Verde, G.; Wörner, A.; Xi, H.; Zude, E.; Zwieglinski, B.

  • Contribution to proceedings
    Proceedings of the 3rd INFN-RIKEN Meeting on Perspectives in Heavy Ions Physics, October 13-15, 1997, Padova, Italy, 11pp.

Permalink: https://www.hzdr.de/publications/Publ-5497


Breakup Temperature of Target Spectators in 197 AU + 197 AU Collisions at E/A = 1000 MeV

Hongfei, X.; Odeh, T.; Bassini, R.; Begemann-Blaich, M.; Botvina, A. S.; Fritz, S.; Gaff, S. J.; Groß, C.; Imme, G.; Iori, I.; Kleinevoß, U.; Kunde, G. J.; Kunze, W. D.; Lynen, U.; Maddalena, V.; Mahi, M.; Möhlenkamp, T.; Nociforo, C.; Ocker, B.; Petruzelli, F.; Pochodzalla, J.; Raciti, G.; Riccobene, G.; Romano, F. P.; Rubehn, T.; Saija, A.; Schnittker, M.; Schüttauf, A.; Schwarz, C.; Seidel, W.; Serfling, V.; Sfienti, C.; Trautmann, W.; Trzcinski, A.; Verde, G.; Wörner, A.; Zwieglinski, B.; Müller, W. F. J.; Moroni, A.

  • GSI- Preprint 97-20, März 1997 und Zeitschrift für Physik A 359 (1997) 379-406

Permalink: https://www.hzdr.de/publications/Publ-5496


Interview with a foreign researcher.

Pawelke, J.

  • Radiological Sciences (ISSN 0441-2540), Vol. 41, No. 12 (1998) 524-525

Permalink: https://www.hzdr.de/publications/Publ-5494


Metabolic studies of 11C in rabbit thigh muscle implanted by secondary beam of HIMAC.

Tomitani, T.; Pawelke, J.; Kanazawa, M.; Yoshikawa, K.; Yoshida, K.; Sato, M.; Takami, A.; Koga, M.; Futami, Y.; Kitagawa, A.; Urakabe, E.; Suda, M.; Kanai, T.; Matsuura, H.; Shinoda, I.; Takizawa, S.

  • Lecture (Conference)
    2nd Japan-Korean Joint Meeting on Medical Physics, Chiba, Japan, 5-6 Nov, 1999
  • Japanese Journal of Medical Physics, Vol. 19, No. 61 (1999) 192-195
  • Contribution to proceedings
    2nd Japan-Korean Joint Meeting on Medical Physics, Chiba, Japan, 5-6 Nov, 1999

Permalink: https://www.hzdr.de/publications/Publ-5493


Electrochemical behaviour of bimetallic Ni-Ti surface generated by ion implantation

Pham, M. T.; Maitz, M.; Reuther, H.; Richter, E.; Matz, W.; Muecklich, A.; Prokert, F.

Abstract

Thin films NiTi (< 100 nm) having surface Ni content below 5 at. % were prepared by ion implanting Ni into Ti surfaces. The Ni containing phase exposed or buried within the Ti matrix was amorphous. Following an anodic oxidation in NaOH the material was shown to be redox active and promote the electrocatalytic oxidation of glucose depending on the surface NiTi composition. Compared to the NiTi bulk alloy (55.9:44.08) the Ni implanted Ti displayed a more efficient catalytic activity and improved corrosion resistance.

Keywords: Ionenimplantation; Katalyse; NiTi-Legierung

  • Journal of Materials Research 19(2004), 439-446

Permalink: https://www.hzdr.de/publications/Publ-5492


Experimental and Numerical Studies of Flow in Rectangular Bubble Columns

Reddy, V. B. N.; Krepper, E.; Prasser, H.-M.; Zaruba, A.; Lopez De Bertodano, M. A.

Abstract

Bubbly flow is encountered in a wide variety of industrial applications ranging from flows in nuclear reactors to process flows in chemical reactors. The presence of a second phase, re-circulating flow, instabilities of the gas plume and turbulence, complicate the hydrodynamics of bubble column reactors. This paper describes preliminary experimental and numerical results obtained in a rectangular bubble column with a cross-sectional area of 20 cm2. Images obtained from a high speed camera have been processed to calculate bubble velocities, bubble turbulence parameters and bubble size distributions. Gas disengagement technique was used to obtain the volume averaged gas fraction over a range of superficial gas velocities. Numerical calculations were performed with an Eulerian-Eulerian two–fluid model approach using the commercial code CFX-4.4. In this paper, the image processing algorithms and numerical modeling are discussed and an analysis of the preliminary results presented.

Keywords: Bubble column; bubble plume; image processing; CFD; re-circulating flow

  • Lecture (Conference)
    The 10th International Topical Meeting on Nuclear Reactor Thermal Hydraulics (NURETH-10), Seoul, Korea, October 5-9, 2003
  • Lecture (Conference)
    Multiphase Flows in Industrial Applications CFX-Germany, FZ-Rossendorf 28.-30.04.03
  • Contribution to proceedings
    The 10th International Topical Meeting on Nuclear Reactor Thermal Hydraulics (NURETH-10), Seoul, Korea, October 5-9, 2003

Permalink: https://www.hzdr.de/publications/Publ-5491


Breakup density in spectator fragmentation

Fritz, S.; Schwarz, C.; Bassini, R.; Begemann-Blaich, M.; Gaff-Ejakov, S. J.; Gourio, D.; Groß, C.; Imme, G.; Iori, I.; Kleinevoß, U.

Abstract

Proton-proton correlations of protons, deuterons and tritons with alpha particles from spectator decays following 197Au+197Au collisions at 1000 MeV per nucleon have been measured with two highly efficient detector sodoscopes. The constructed correlation functions, interpreted within the approximation of a simultaneous volume decay, dedicate a moderate expansion and low breakup densities, similar to assumptions made in statistical multifragmentation models.

  • Phys. Letters B 461(1999) 315-321

Permalink: https://www.hzdr.de/publications/Publ-5489


First patients' treatment at GSI using heavy-ion beams.

Kraft, G.; Badura, E.; Becher, W.; Böhne, D.; Brand, H.; Brusasco, C.; Eickhoff, H.; Essel, H.-G.; Franzcak, B.; Geiß, O.; Haberer, T.; Hoffmann, J.; Kainsberger, P.; Krämer, M.; Krause, K.; Kurz, N.; Langenbeck, B.; Ott, W.; Poppensieker, K.; Richter, M.; von Rüden, W.; Schardt, D.; Scholz, M.; Spiller, P.; Steiner, R.; Stelzer, H.; Voss, B.; Weber, U.; Debus, J.; Ertner, D.; Russ, N.; Heeg, P.; Wannenmacher, M.; Wenz, F.; Enghardt, W.; Hasch, B.-G.; Hinz, R.; Lauckner, K.; Pawelke, J.; Sobiella, M.; Hartmann, G.; Jäkel, O.; Karger, C.-P.; Krießbach, A.; Lappe, C.; Massimino, M.

Abstract

Beams of heavy-charged particles of high energy like carbon ions are superior to any other type of radiation conventionally used in external radiotherapy. In contrast to photons and neutrons, the dose for the ions increases with penetration depth and culminates in a sharp maximum at the end of range. Due to the microscopic track structure this region of high energy deposition has an increased biological efficiency. In addition, a small amount of positron emitting isotopes is produced by the projectile and makes it possible to trace the beam inside the patient's body by PET techniques. At GSI an experimental heavy-ion therapy started with patient treatment. It is based on a totally active beam delivery and a biology-oriented treatment planning system in order to exploit the favourable particle properties to a maximum extent.

  • Lecture (Conference)
    6th European Particle Accelerator Conference, Stockholm, 22-26 Jun, 1998
    S. Myers, L. Liljeby, C. Petit-Jean-Genaz, J. Poole, K.G. Rensfelt (Eds.): Proceedings, Institute of Physics Publishing, Bristol and Philadelphia, Vol. 1 (1998) 212-216
  • Contribution to proceedings
    6th European Particle Accelerator Conference, Stockholm, 22-26 Jun, 1998
    S. Myers, L. Liljeby, C. Petit-Jean-Genaz, J. Poole, K.G. Rensfelt (Eds.): Proceedings, Institute of Physics Publishing, Bristol and Philadelphia, Vol. 1 (1998) 212-216

Permalink: https://www.hzdr.de/publications/Publ-5487


Fragment Kinetic Energies and Modes of Fragment Formation

Odeh, T.; Bassini, R.; Begemann-Blaich, M.; Fritz, S.; Gaff-Ejakov, S. J.; Gourio, D.; Groß, C.; Imme, G.; Iori, I.; Kleinevoß, U.; Kunde, G. J.; Kunze, W. D.; Lynen, U.; Maddalena, V.; Mahi, M.; Möhlenkamp, T.; Moroni, A.; Müller, W. F. J.; Nociforo, C.; Ocker, B.; Petruzzelli, F.; Pochodzalla, J.; Raciti, G.; Riccobene, G.; Romano, F. P.; Saija, A.; Schnittker, M.; Schüttauf, A.; Schwarz, C.; Seidel, W.; Serfling, V.; Sfienti, C.; Trautmann, W.; Trzcinski, A.; Verde, G.; Wörner, A.; Hongfei, X.; Zwieglinski, B.

Abstract

Kinetic energies of light fragments (A ? 10) from the decay of target spectators in 197Au + 197Au collisions at 1000 MeV per nucleon have been measured with high-resolution telescopes at backward angles. Except for protons and apart from the observed evaporation components, the kinetic-energy spectra exhibit slope temperatures of about 17 MeV, independent of the particle species, but not corresponding to the thermal or chemical degrees of freedom at breakup. It is suggested that these slope temperatures may reflect the intrinsic Fermi motion and thus the buld density of the spectator system at the instant of becoming unstable.

  • Phys. Rev. Letter 84 (2000)4557 and GSI - Preprint 2000-10/ März 2000

Permalink: https://www.hzdr.de/publications/Publ-5486


The spatial distribution of positron-emitting nuclei generated by relativistic light ion beams in organic matter.

Enghardt, W.; Fromm, W.-D.; Geissel, H.; Keller, H.; Kraft, G.; Magel, A.; Manfraß, P.; Münzenberg, G.; Nickel, F.; Pawelke, J.; Schardt, D.; Scheidenberger, C.; Sobiella, M.

  • Phys. Med. Biol., Vol. 37, No. 11 (1992) 2127-2131

Permalink: https://www.hzdr.de/publications/Publ-5485


Projects for Two-Color Pump-Probe Studies at the Radiation Source ELBE

Seidel, W.; Büchner, A.; Enghardt, W.; Evtushenko, P.; Gabriel, F.; Gippner, P.; Grosse, E.; Kalionka, D.; Lehnert, U.; Michel, P.; Schamlott, A.; Wagner, W.; Wohlfahrt, D.; Wolf, A.; Wünsch, R.

  • Poster
    22nd International Conference on Free Electron Lasers, 2000, Durkham, USA
  • Open Access Logo Contribution to proceedings
    22nd International Conference on Free Electron Lasers (FEL 2000), 13.-18.08.2000, Durkham, USA, Amsterdam, 11-53-54

Permalink: https://www.hzdr.de/publications/Publ-5484


The ELBE-Project at Dresden-Rossendorf

Büchner, A.; Gabriel, F.; Grosse, E.; Michel, P.; Seidel, W.; Voigtlaender, J.

  • Poster
    EPAC 2000, 26.-30.07. 2000, Wien, Österreich
  • Contribution to proceedings
    EPAC 2000, 26.-30.07.2000, Wien, Österreich
    Proceedings of EPAC 2000

Permalink: https://www.hzdr.de/publications/Publ-5483


An improved numerical study of the wall effect on hot-wire measurements

Shi, J.-M.; Breuer, M.; Durst, F.; Schaefer, M.

Abstract

Numerical investigations of the heat transfer from hot wires in near-wall measurements were carried out. Special attention was paid to the effect of the wall thickness, the flow conditions below the wall and the shear velocity connected to different wall
materials. Compared with previous studies, an improved physical model taking into account the flow region below the wall
in the computational domain was applied. The results obtained agree well with experimental data in the literature for walls consisting of both highly and poorly conducting materials. The investigation showed that the shear velocity $U_\tau$ has a significant influence on hot-wire measurements in the vicinity of a wall. Nevertheless, discernible effects of the wall thickness and the flow condition below the wall were found only in the case of a poorly conducting wall. In addition, the results also suggest a weak effect of the overheat ratio for a wire with an infinitely large aspect ratio.

Keywords: Hot wire; Heat Transfer; Near-wall measurement; Shear velocity; Overheat ratio; Wall material; Wall thickness; Numerical simulation; Convection boundary condition

  • ASME, J. Heat Transfer, 125:595-603, 2003

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Permalink: https://www.hzdr.de/publications/Publ-5482


MR perfusion measurements in contrast uptaking lesions: Comparison of three correction levels

Hietschold, V.; Kittner, T.; Appold, S.; Abolmaali, N.; Parodi, K.; Laniado, M.

Abstract

Susceptibilitys contrast based MR perfusion measurement in contrast uptaking tissues are complicated by the contribution of the interstitially deposited contrast medium (CM) to the shortening of both T1 and T2. Applying double echo sequences, both contributions can be corrected for. In this paper, the consequences of different degrees of correction on perfusion parameters are investigated.

  • Poster
    19th Annual Meeting of the European Society for Magnetic Resonance in Medicine and Biology, Cannes,August 22-25,2002

Permalink: https://www.hzdr.de/publications/Publ-5481


Positron emission tomography for quality assurance of cancer therapy with light ion beams.

Enghardt, W.; Debus, J.; Haberer, T.; Hasch, B.-G.; Hinz, R.; Jäkel, O.; Krämer, M.; Lauckner, K.; Pawelke, J.; Pönisch, F.

Abstract

Positron emission tomography (PET) offers the possibility of in-situ monitoring the tumour treatment with light ion beams by means of imaging the spatial distribution of positron-activity that is produced as a byproduct of the therapeutic irradiation via nuclear fragmentation reactions between the projectiles and the atomic nuclei of the tissue within the target volume. The implementation of this PET technique at the experimental tumour therapy facility at the Gesellschaft für Schwerionenforschung (GSI) in Darmstadt and first results of its clinical application are presented.

  • Nuclear Physics A, Vol. 654 (1999)1047c-1050c

Permalink: https://www.hzdr.de/publications/Publ-5480


Analysis of heat transfer from single wires close to walls

Shi, J.-M.; Gerlach, D.; Breuer, M.; Durst, F.; Lange, C. F.

Abstract

Two-dimensional numerical investigations of the forced heat convection from a microcylinder in laminar cross-flow, both in free stream and in near-wall flow, were carried out aiming at a better understanding of the physics behind the wall effects on hot-wire near-wall measurements. In the physical model, an infinitely thin plate with the same properties as the fluid (air) was used as an
artificial wall. The conjugate heat transfer between the flow regions on both sides of the plate was taken into account. The effect of the conjugate thermal conditions (temperature distribution and diffusive heat flux) at the interface of the two flow regions on the heat transfer from the wire was investigated by varying the flow conditions on the side opposite to the wire location. Careful energy balance analysis was performed for both the free-stream case and the near-wall case. This enabled the authors to verify their own understanding of the physical mechanism responsible for the wall effect on hot-wire measurements and to examine other mechanisms proposed in the literature. The numerical results showed that the heat diffusion from the wire is significantly enhanced in the case of small wire-to-wall distances (Y+ < 3). This is mainly caused by modifications of the thermal boundary condition (diffusive effect) at the fluid-wall interface. In contrast, the flow distortion (enhanced convection) was shown not to be the most important influencing factor for the heat transfer of a hot wire. Although the present model study was performed for a laminar
flow, the results obtained are applicable to hot-wire measurements in turbulent flows, as stated in the literature.

Keywords: Hot wire; Heat tranasfer; Near-wall measurement; Numerical simulation

  • Phys. Fluids, 15 (2003) 908-921

Permalink: https://www.hzdr.de/publications/Publ-5479


A combined analytical-numerical method for treating corner singularities in viscous flow predictions

Shi, J.-M.; Breuer, M.; Durst, F.

Abstract

A combined analytical-numerical method based on a matching asymptotic algorithm is proposed for treating angular (sharp corner or wedge) singularities in the numerical solution of the Navier-Stokes equations. We adopt an asymptotic solution for the local flow around the angular points based on the Stokes flow approximation and a numerical solution for the global flow outside the singular regions using a finite-volume method. The coefficients involved in the analytical solution are iteratively updated by matching both solutions in a small region where the Stokes flow approximation holds. Moreover, an error analysis is derived for this method, which serves as a guideline for the practical implementation. The present method is applied to treat the leading-edge singularity of a semi-infinite plate. The effect of various influencing factors related to the implementation are evaluated with the help of numerical experiments. The investigation showed that the accuracy of the numerical solution for the flow around the leading edge can be significantly improved with the present method. The results of the numerical experiments support the error analysis and show the desired properties of the new algorithm, i.e., accuracy, robustness and efficiency. Based on the numerical results for the leading-edge singularity, the validity of various classical approximate models for the flow, such as the Stokes approximation, the inviscid flow model and the boundary layer theory of varying orders are examined.

Keywords: Numerical method; numerical accuracy; angular singularity; Navier-Stokes equations; boundary layer; leading edge

Permalink: https://www.hzdr.de/publications/Publ-5478


Luminescence studies of blood phagocyte oxygenation activities in patients with antiphospholipid syndrome

Kopprasch, S.; Roch, B.; Pietzsch, J.; Kuhlisch, E.; Gräßler, J.

  • Book (Authorship)
    In: Stanley PE, Kricka LJ. (Hrsg.) Bioluminescence and Chemiluminescence 2002: Progress and Current Applications. World Scientific Publishing Company, New Jersey. S. 265-268

Permalink: https://www.hzdr.de/publications/Publ-5477


Chemiluminescence as a tool to assess hyperglycemia-induced systemic oxidative stress in different insulin-resistant states

Kopprasch, S.; Pietzsch, J.; Kuhlisch, E.; Gräßler, J.

  • Book (Authorship)
    In: Stanley PE, Kricka LJ. (Hrsg.) Bioluminescence and Chemiluminescence 2002: Progress and Current Applications. World Scientific Publishing Company, New Jersey. S. 261-264

Permalink: https://www.hzdr.de/publications/Publ-5476


Years: 2023 2022 2021 2020 2019 2018 2017 2016 2015


Pages: [1.] [2.] [3.] [4.] [5.] [6.] [7.] [8.] [9.] [10.] [11.] [12.] [13.] [14.] [15.] [16.] [17.] [18.] [19.] [20.] [21.] [22.] [23.] [24.] [25.] [26.] [27.] [28.] [29.] [30.] [31.] [32.] [33.] [34.] [35.] [36.] [37.] [38.] [39.] [40.] [41.] [42.] [43.] [44.] [45.] [46.] [47.] [48.] [49.] [50.] [51.] [52.] [53.] [54.] [55.] [56.] [57.] [58.] [59.] [60.] [61.] [62.] [63.] [64.] [65.] [66.] [67.] [68.] [69.] [70.] [71.] [72.] [73.] [74.] [75.] [76.] [77.] [78.] [79.] [80.] [81.] [82.] [83.] [84.] [85.] [86.] [87.] [88.] [89.] [90.] [91.] [92.] [93.] [94.] [95.] [96.] [97.] [98.] [99.] [100.] [101.] [102.] [103.] [104.] [105.] [106.] [107.] [108.] [109.] [110.] [111.] [112.] [113.] [114.] [115.] [116.] [117.] [118.] [119.] [120.] [121.] [122.] [123.] [124.] [125.] [126.] [127.] [128.] [129.] [130.] [131.] [132.] [133.] [134.] [135.] [136.] [137.] [138.] [139.] [140.] [141.] [142.] [143.] [144.] [145.] [146.] [147.] [148.] [149.] [150.] [151.] [152.] [153.] [154.] [155.] [156.] [157.] [158.] [159.] [160.] [161.] [162.] [163.] [164.] [165.] [166.] [167.] [168.] [169.] [170.] [171.] [172.] [173.] [174.] [175.] [176.] [177.] [178.] [179.] [180.] [181.] [182.] [183.] [184.] [185.] [186.] [187.] [188.] [189.] [190.] [191.] [192.] [193.] [194.] [195.] [196.] [197.] [198.] [199.] [200.] [201.] [202.] [203.] [204.] [205.] [206.] [207.] [208.] [209.] [210.] [211.] [212.] [213.] [214.] [215.] [216.] [217.] [218.] [219.] [220.] [221.] [222.] [223.] [224.] [225.] [226.] [227.] [228.] [229.] [230.] [231.] [232.] [233.] [234.] [235.] [236.] [237.] [238.] [239.] [240.] [241.] [242.] [243.] [244.] [245.] [246.] [247.] [248.] [249.] [250.] [251.] [252.] [253.] [254.] [255.] [256.] [257.] [258.] [259.] [260.] [261.] [262.] [263.] [264.] [265.] [266.] [267.] [268.] [269.] [270.] [271.] [272.] [273.] [274.] [275.] [276.] [277.] [278.] [279.] [280.] [281.] [282.] [283.] [284.] [285.] [286.] [287.] [288.] [289.] [290.] [291.] [292.] [293.] [294.] [295.] [296.] [297.] [298.] [299.] [300.] [301.] [302.] [303.] [304.] [305.] [306.] [307.] [308.] [309.] [310.] [311.] [312.] [313.] [314.] [315.] [316.] [317.] [318.] [319.] [320.] [321.] [322.] [323.] [324.] [325.] [326.] [327.] [328.] [329.] [330.] [331.] [332.] [333.] [334.] [335.] [336.] [337.] [338.] [339.] [340.] [341.] [342.] [343.] [344.] [345.] [346.] [347.] [348.] [349.] [350.] [351.] [352.]