Publications Repository - Helmholtz-Zentrum Dresden-Rossendorf

"Online First" included
Without submitted and only approved publications
Only approved publications

31735 Publications
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.;
no abstract
  • GSI-Nachrichten, Gesellschaft für Schwerionenforschung, Darmstadt, 07-95 (1995) 16-17

Publ.-Id: 5503 - Permalink

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.;
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

Publ.-Id: 5502 - Permalink

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.;
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

Publ.-Id: 5501 - Permalink

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.;
no abstract
  • Particles Newsletter (Harvard University, Boston, USA), Number 11 (January 1993) 13-14

Publ.-Id: 5500 - Permalink

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

Publ.-Id: 5499 - Permalink

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

Publ.-Id: 5498 - Permalink

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.

Publ.-Id: 5497 - Permalink

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

Publ.-Id: 5496 - Permalink

Interview with a foreign researcher.
Pawelke, J.;
no abstract
  • Radiological Sciences (ISSN 0441-2540), Vol. 41, No. 12 (1998) 524-525

Publ.-Id: 5494 - Permalink

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.;
no abstract
  • 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

Publ.-Id: 5493 - Permalink

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.;
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

Publ.-Id: 5492 - Permalink

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.;
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

Publ.-Id: 5491 - Permalink

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.;
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

Publ.-Id: 5489 - Permalink

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.;
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

Publ.-Id: 5487 - Permalink

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.;
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

Publ.-Id: 5486 - Permalink

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

Publ.-Id: 5485 - Permalink

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 LogoContribution to proceedings
    22nd International Conference on Free Electron Lasers (FEL 2000), 13.-18.08.2000, Durkham, USA, Amsterdam, 11-53-54

Publ.-Id: 5484 - Permalink

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

Publ.-Id: 5483 - Permalink

An improved numerical study of the wall effect on hot-wire measurements
Shi, J.-M.; Breuer, M.; Durst, F.; Schaefer, M.;
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


Publ.-Id: 5482 - Permalink

MR perfusion measurements in contrast uptaking lesions: Comparison of three correction levels
Hietschold, V.; Kittner, T.; Appold, S.; Abolmaali, N.; Parodi, K.; Laniado, M.;
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

Publ.-Id: 5481 - Permalink

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.;
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

Publ.-Id: 5480 - Permalink

Analysis of heat transfer from single wires close to walls
Shi, J.-M.; Gerlach, D.; Breuer, M.; Durst, F.; Lange, C. F.;
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

Publ.-Id: 5479 - Permalink

A combined analytical-numerical method for treating corner singularities in viscous flow predictions
Shi, J.-M.; Breuer, M.; Durst, F.;
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
  • International Journal for Numerical Methods in Fluids 45(2004), 659-688
    DOI: 10.1002/fld.722

Publ.-Id: 5478 - Permalink

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

Publ.-Id: 5477 - Permalink

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

Publ.-Id: 5476 - Permalink

Untersuchungen zur in vivo-Kinetik humaner Lipoproteine mittels stabiler Isotope: Störungen des Lipoproteinstoffwechsels bei Diabetesvorstadien
Pietzsch, J.;
  • Lecture (others)
    Lebensmittelchemisches Kolloquium der Universität Stuttgart-Hohenheim, 30.01.2003

Publ.-Id: 5475 - Permalink

FTIR- and Fluorescence-Spectroscopic Analyses of Receptor G-Protein Coupling in Photoreception Curr. Org. Chem. 2002, 6, 1259-1284.
Fahmy, K.;
G protein-coupled receptors (GPCRs) are heptahelical transmembrane proteins. They transduce a large variety of extracellular signals, allowing perception of taste, odor, hormones, and light. Binding of an extracellular ligand induces structural changes in the cytosolic domain of a GPCR which, thereby, catalyzes nucleotide exchange in a G protein. Rhodopsins, the visual pigments, are prototypical GPCRs that are activated by photoisomerization of covalently bound 11-cis retinal. Unlike other GPCRs, bovine rhodopsin and transducin, its cognate G protein, can be prepared from cow eyes in large quantities for spectroscopic and biochemical investigations. Rhodopsin is the best studied GPCR and the only one for which an X-ray structure has been solved. Structural information together with the wealth of biophysical data on native and recombinant rhodopsins allows to determine structure function relationships that are relevant to GPCR-dependent signaling in general. Here, results from Fourier-transform-infrared (FTIR) spectrocopic studies of rhodopsin and measurements of nucleotide-dependent transducin fluorescence are reviewed. Intra- and intermolecular processes during signaling by the photoreceptor have thus been identified and analyzed kinetically. Recent applications of these techniques concern rhodopsin transducin coupling in synthetic lipidic matrices and analysis of drug action at the receptor G protein interface.The data are discussed in the context of the crystal structure of rhodopsin and additional biochemical information if required for the understanding of the spectroscopic results.
  • Curr. Org. Chem. 2002, 6, 1259-1284.

Publ.-Id: 5474 - Permalink

Investigation of deep implanted fluorine channeling profiles in silicon using resonant NRA
Kokkoris, M.; Perdikakis, G.; Vlastou, R.; Papadopoulos, C. T.; Aslanoglou, X. A.; Posselt, M.; Grötzschel, R.; Harrissopulos, S.; Kossionides, S.;
Si (100) and (111) crystals were irradiated in the random as well as in the channeling direction, using 5 MeV 19F+ ions, to a maximum dose of approximately 1×1017 particles/cm2. The occurring deep implanted profiles were subsequently investigated using the Resonant Nuclear Reaction Analysis technique in the energy range Ep=950-1200 keV. The reaction 19F(p, αγ)16O reaction exhibits a strong resonant behavior in the above mentioned energy range, thus providing an excellent tool for the depth profiling of fluorine, yielding minimum detection limits of the order of a few ppm. The occurring profiles are analyzed with SRIM and c-TRIM and an attempt is made to explain the peculiarities of the experimental spectra, as well as to compare with results already existing in literature
Keywords: High-energy implantation; Channeling; Nuclear resonance; Fluorine profiling; Resonant NRA; c-TRIM

Publ.-Id: 5473 - Permalink

Nuclear Transparency with the gamma n to pi- p Process in 4He
Dutta, D.; Xiong, F.; Zhu, L. Y.; Arrington, J.; Averett, T.; Beise, E.; Calarco, J.; Chang, T.; Chen, J. P.; Chudakov, E.; Coman, M.; Clasie, B.; Crawford, C.; Dieterich, S.; Dohrmann, F.; Fissum, K.; Frullani, S.; Gao, H.; Gilman, R.; Glashauser, C.; Gomez, J.; Hafidi, K.; Hansen, O.; Higinbotham, D. W.; Holt, R. J.; Dejager, C. W.; Jiang, X.; Kinney, E.; Kramer, K.; Kumbartzki, G.; Lerose, J.; Liyanage, N.; Mack, D.; Markowitz, P.; Mccormick, K.; Meziani, Z.-E.; Michaels, R.; Mitchell, J.; Nanda, S.; Potterveld, D.; Ransome, R.; Reimer, P. E.; Reitz, B.; Saha, A.; Schulte, E. C.; Seely, J.; Sirca, S.; Strauch, S.; Sulkosky, V.; Vlahovic, B.; Weinstein, L. B.; Wijesooriya, K.; Williamson, C.; Wojtsekhowski, B.; Xiang, H.; Xu, W.; Zeng, J.; Zheng, X.;
We have measured the nuclear transparency of the fundamental process gamma n to pi- p in 4He. These measurements were performed at Jefferson Lab in the photon energy range of 1.6 to 4.5 GeV and at thetacmSUP>pi = 70 and 90 . These measurements are the first of their kind in the study of nuclear transparency in photoreactions. They also provide a benchmark test of Glauber calculations based on traditional models of nuclear physics. the transparency results suggest deviations from the traditional nuclear physics picture. The momentum transfer dependence of the measured nuclear transparency is consistent with Glauber calculations which include the quantum chromodynamics phenomenon of color transparency.
Keywords: nuclear transparency, color transpareny, photon scattering.
  • Phys.Rev.C68:021001,2003 e-Print Archive: nucl-ex/0305005

Publ.-Id: 5472 - Permalink

Subthreshold K+ production in deuteron and alpha induced nuclear reactions
Debowski, M.; Senger, P.; Boivin, M.; Le Bornec, Y.; Courtat, P.; Gacougnolle, R.; Grosse, E.; Kabana, S.; Kirchner, T.; Koczon, P.; Mang, M.; Schwab, E.; Tatischeff, B.; Wagner, A.; Walus, W.; Willis, N.; Wolf, G.; Wurzinger, R.; Yonnet, J.;
Double differential cross sections d2?/dpd? have been measured for ?+ and K+ emitted around midrapidity in d+A and ?+A collisions at a beam kinetic energy of 1.15 GeV/nucleon. The total ?+ yield increases by a factor of about 2 when using an alpha projectile instead of of a deuteron whereas the K+ yield increases by a factor of about 4. According to transport calculations, the K+ enhancement depends both on the number of hadron-hadron collisions: their center-of-mass energy increases with increasing number of projectile nucleons.
  • Phys. Lett. B 413(1997)8

Publ.-Id: 5471 - Permalink

Alloy liquid metal ion sources and their application in mass separated focused ion beams
Bischoff, L.;
During the last decades, the focused ion beam (FIB) became a very useful and versatile tool in the microelectronics industry, as well as in the field of research and development. For special purposes like writing ion implantation or ion mixing in the µm- or sub-µm range ion species other than gallium are needed. Therefore alloy liquid metal ion sources (LMIS) were developed. The energy distribution of the ions from an alloy LMIS is one of the determining factors for the performance of an FIB column. Different source materials like Au73Ge27, Au82Si18, Au77Ge14Si9, Co36Nd64, Er69Ni31, and Er70Fe22Ni5Cr3 were investigated with respect to the energy spread of the different ion species as a function of emission current I, ion mass m and emitter temperature T. For singly charged ions a predicted dependence of the energy spread, DE µ I2/3 m1/3 T1/2 found for Ga could be reasonable confirmed. The alloy LMIS`s discussed above have been used in the Rossendorf FIB system IMSA-100 especially for writing implantation to fabricate sub-µm pattern without any lithographic steps. A Co-FIB obtained from a Co36Nd64 alloy LMIS was applied for the ion beam synthesis of CoSi2 micro-structures down to 60 nm. Additionally, the possibility of varying the current density of the FIB by changing the pixel dwell-time was used for investigations of radiation induced damage and its dynamic annealing in Si and SiC at elevated implantation temperatures. Furthermore, a broad spectrum of ions was employed to study the sputtering process depending on temperature, angle of incidence and ion mass on a couple of target materials using the volume loss method. Especially this direct patterning 3D technique was used for the fabrication of various kinds of micro-tools.
All these examples underline the importance of FIBs in modern research and the new possibilities opened up by a mass separated system applying a broad spectrum of ion species.

Keywords: focused ion beam, alloy liquid metal ion sources, applications
  • Lecture (Conference)
    The 9th Frontiers of Electron Microscopy in Materials Sience Conference, FEMMS 2003, Claremont Resort and Spa in Berceley, Ca., USA, 05.-10. Oct. 2003

Publ.-Id: 5470 - Permalink

Experimental and Theoretical Background of Multi-component Cluster Formation in Reactor Pressure Vessel Steels due to Neutron Irradiation
Gokhman, A.; Böhmert, J.; Ulbricht, A.;
Sophisticated microstructural analysis methods like small angle neutron scattering and atom probe field ion microscopy have proven the presence of so-called multicomponent clusters due to neutron irradiation in ferritic reactor pressure vessel steels. The formation of such clusters is surprising from the thermodynamic point of view. The cluster formation from the solid solution was modelled as phase transformation of the first kind that corresponds to the negative minimum of the so-called thermodynamic force under consideration of six components. The essential parameter is the sum of interaction energy between all pairs of atoms in the system. The approach result in stable multicomponent cluster if the clusters exhibit a high content of vacancies and a core-shell structure with very high vacancy content within the shell. The kinetics background of the suggested model was investigated using the cluster dynamic approach generalized for multiple components. The computed results are consistent with the experimental findings.
  • Lecture (others)
    Paper on VII. Research Workshop Nucleation Theory and Applications, Dubna, Russia, April 2003

Publ.-Id: 5469 - Permalink

Increased cholesteryl ester transfer protein (CETP) activity in impaired glucose tolerance: relationship to high density lipoprotein metabolism
Pietzsch, J.; Fücker, K.;
Aim. To investigate the mechanisms and dynamics of cholesteryl ester (neutral lipid) transfer protein activity in subjects with impaired glucose tolerance. Methods. Eighty six Caucasian subjects were recruited by advertisement from the local population between January 1998 and December 1999. The activity of cholesteryl ester transfer protein in 44 non-obese subjects with impaired glucose tolerance (plasma triglycerides 1.56-/+0.64 mmol/L; high density lipoprotein (HDL) cholesterol 0.96-/+0.25 mmol/L; and plasma insulin 78-/+8 pmol/L) and in 42 normoglycemic controls (plasma triglycerides 0.88-/+0.41 mmol/L; HDL cholesterol 1.48-/+0.29 mmol/L; and plasma insulin 38-/+14 pmol/L) was measured with a new fluorometric assay. Results. Cholesteryl ester transfer protein activity was increased in subjects with impaired glucose tolerance by 47% (39.5-/+7.8 vs 26.8-/+6.8 nmol/mL x h-1; t-test, p<0.05). Linear regression analysis showed that cholesteryl ester transfer protein activity in subjects with impaired glucose tolerance significantly correlated with the following parameters: plasma triglycerides (r=0.614, p<0.05), HDL-triglycerides (r=0.595, p<0.05), percentage of HDL-triglyceride (r=0.667, p<0.05), percentage of HDL cholesterol ester (r=-0.751, p<0.01), percentage of HDL phospholipid (r=0.648, p<0.05), 2-h-insulin (r=0.668, p<0.05), and 2-h-proinsulin (r=0.658, p<0.01). In a subgroup of 13 subjects with impaired glucose tolerance, cholesteryl ester transfer protein activity correlated with HDL apoA-I fractional catabolic rate (r=0.701, p<0.01). In normoglycemic subjects, significant correlations were found only between cholesteryl ester transfer protein activity and percentage of HDL-triglycerides (r=0.541, p<0.05), percentage of HDL cholesteryl ester (r=-0.639, p<0.01), 2-h-proinsulin (r=0.642, p<0.05), and HDL apoA-I fractional catabolic rate (n=10, r=0.587, p<0.05). Conclusion. Cholesteryl ester transfer is important for HDL composition and HDL catabolism both in normoglycemic subjects and subjects with impaired glucose tolerance. Under insulin resistant conditions, increased cholesteryl ester transfer protein activity modulates HDL metabolism more drastically than in normoglycemic conditions. This modulation may be explained by increased availability of triglyceride-rich lipoproteins for neutral lipid exchange in subjects with impaired glucose tolerance.
  • Croatian Medical Journal 44 (2): 171-177, 2003

Publ.-Id: 5468 - Permalink

Lack of association between serum paraoxonase (PON1) activities and increased oxidized LDL levels in impaired glucose tolerance and newly diagnosed diabetes mellitus
Kopprasch, S.; Pietzsch, J.; Kuhlisch, E.; Gräßler, J.;
Several in vitro investigations showed that serum paraoxonase 1 (PON1) that is located on high-density lipoprotein reduces or prevents low-density lipoprotein (LDL) oxidation and therefore retards atherosclerosis. Accordingly, the well documented loss of PON1 activity in patients with overt diabetes mellitus was causally related to the development of micro- and macroangiopathy in the disease course. Because vascular complications start already in prediabetic states, e.g. impaired glucose tolerance (IGT), we investigated serum PON1 activities and circulating levels of oxidized LDL (oxLDL) in 125 IGT subjects, 75 patients with newly diagnosed diabetes mellitus type 2, and 403 individuals with normal glucose tolerance. Using three different substrates (paraoxon, phenylacetate, p-nitrophenylacetate) we found that PON1 activity is not significantly altered in IGT and diabetes mellitus subjects, respectively, when compared with normoglycemic controls. Both IGT subjects and diabetes mellitus patients had significantly increased levels of oxLDL in the circulation. However, serum PON1 activity variations and glutamine/arginine phenotype were not related to the levels of oxLDL. The data suggest that 1) PON1 activity loss is an event occurring later in the course of diabetes mellitus; and 2) PON1 does not affect oxidation of circulating LDL, at least in early diabetes mellitus.
  • Journal of Clinical Endocrinology & Metabolism 2003; 88: 1711-1716

Publ.-Id: 5467 - Permalink

Analysis of 3-chlorotyrosine as a specific marker of protein oxidation: The use of N(O,S)-ethoxycarbonyl trifluoroethyl ester derivatives and gas chromatography/mass spectrometry
Pietzsch, J.; Kopprasch, S.; Bergmann, R.;
N(O,S)-Ethoxycarbonyltrifluoroethyl amino acid esters are formed by the reaction of amino acids with ethylchloroformate plus trifluoroethanol plus pyridine. The use of these derivatives for a rapid and sensitive determination of 3-chlorotyrosine, a highly specific marker of myeloperoxidase-catalyzed protein oxidation, by using standard gas chromatography/electron impact mass spectrometry, is discussed.
  • Rapid Commun. Mass Spectrom 17 (2003):767-770

Publ.-Id: 5466 - Permalink

Intraindividual comparison of two extracorporeal LDL apheresis methods: lipidfiltration and HELP
Julius, U.; Metzler, W.; Pietzsch, J.; Fassbender, T.; Klingel, R.;
Low density lipoprotein (LDL) apheresis is an effective treatment option for patients with severe hypercholesterolemia not adequately responding to diet and drug therapy. Membrane differential filtration (MDF), synonymous with double filtration plasmapheresis (DFPP), here named Lipidfiltration, and heparin-induced extracorporeal LDL-precipitation (HELP) are two of the five methods available for extracorporeal LDL apheresis. In this prospective investigation 6 patients with severe LDL-hypercholesterolemia and CAD were treated in a cross-over design with Lipidfiltration at two stages of technical development and HELP to compare the efficacy of these two LDL apheresis methods with respect to lowering and modifying plasma lipids and rheologically relevant plasma proteins, especially fibrinogen. In total, 44 LDL apheresis sessions were investigated. In weekly intervals, patients were treated with consecutive LDL apheresis sessions with either Lipidfiltration and HELP, treating identical plasma volumes. In one part of the investigation Lipidfiltration was performed with the novel Lipidfilter EC-50, combined with a newly developed blood and plasma therapy machine allowing optimized plasma heating. The results showed that the reduction rates of LDL-cholesterol, lipoprotein(a) and triglycerides were essentially identical for both methods. Also pretreatment levels of total cholesterol, triglycerides, LDL-cholesterol and HDL-cholesterol were not significantly different in both treatment groups. Both methods lead to a significant reduction of serum lipoproteins, especially for LDL-cholesterol, which was decreased by 61.4% with Lipidfiltration (treated plasma volume: 2998 ml) and 61.3% with HELP (treated plasma volume: 3013 ml). With respect to Lipidfiltration LDL-cholesterol reduction was more efficient with the novel Lipidfilter EC-50. Mean pretreatment HDL cholesterol concentrations remained unchanged. Comparing Cascadeflo AC-1770 with the novel Lipidfilter EC-50 reduction rates of HDL-cholesterol (17.4% versus 6.4%) and total protein (17.9% versus 7.8%) were significantly reduced. Lipidfiltration and HELP both resulted in a reduction of plasma viscosity and hemorheologically relevant plasma proteins, like fibrinogen.
  • Int J Artif Organs 25 (2002): 1180-1188

Publ.-Id: 5465 - Permalink

An LSO-based scanner for in-beam PET: A feasibility study.
Lauckner, K.; Crespo, P.; Enghardt, W.; Pawelke, J.; Kraft, G.;
Over the last 3 years in-beam PET has proven its capability of quality assurance in carbon ion tumour therapy at the pilot project of cancer therapy at the Gesellschaft für Schwerionenforschung (GSI) in Darmstadt, Germany. In this paper we investigate the possibility of using LSO as the scintillation material for the next generation of in-beam PET cameras. We address the issue of background coincidences arising from the natural radioactivity of LSO. Because the true count rate measured with a BGO-based dual-head positron camera (total sensitive area of each head 21 x 42 cm2) during the cancer treatment averages at only 100 coincidences/s we studied the influence of the LSO backround on realistic in-beam PET-images.
  • Lecture (Conference)
    IEEE Nuclear Science Symposium and Medical Imaging Conference, Lyon, France 15-20 Oct, 2000
    Book of Abstracts(2000)164
    Conference Record M14(2001)14-51--14-54
  • Contribution to proceedings
    IEEE Nuclear Science Symposium and Medical Imaging Conference, Lyon, France 15-20 Oct, 2000
    Book of Abstracts(2000)164
    Conference Record M14(2001)14-51--14-54

Publ.-Id: 5464 - Permalink

Die relative biologische Wirksamkeit von weicher Röntgenstrahlung.
Pawelke, J.; Brankovic, K.; Dörr, W.; Dörschel, B.; Enghardt, W.; Lehnert, U.; Panteleeva, A.; Prade, H.; Slonina, D.;
no abstract
  • Lecture (Conference)
    4.Jahrestagung der Gesellschaft für Biologische Strahlenforschung, Bad Kissingen, 4-6 Oct, 2000
    F. Eckardt-Schupp, F. Ahne, M. Kistler (Hrsg.): Proceedings (ISBN 3-00-996800-7)(2000)52
  • Contribution to proceedings
    4.Jahrestagung der Gesellschaft für Biologische Strahlenforschung, Bad Kissingen, 4-6 Oct, 2000
    F. Eckardt-Schupp, F. Ahne, M. Kistler (Hrsg.): Proceedings (ISBN 3-00-996800-7)(2000)52

Publ.-Id: 5463 - Permalink

First experimental results of measurements on air/water flow in a vertical pipe with an inner diameter of 194 mm
Lucas, D.; Prasser, H.-M.;
The new TOPFLOW facility of the Forschungszentrum Rossendorf allows investigations of two-phase flow phenomena in vertical pipes with an inner diameter up to 194 mm (DN200) and a length up to 8.5 m. The maximum water mass flow of 50 kg/s equals to a superficial velocity of 1.7 m/s in such a pipe, while the maximum air flow rate of 900 m3/h corresponds to a superficial velocity of 8 m/s. For the measurements presented here, a wire-mesh sensor with 64*64 measuring points was installed. It corresponds to a lateral resolution of 3 mm. The senor delivers instantaneous void fraction distributions over the entire cross section with a time resolution of 2500 frames per second, which can be used for fast flow visualisation as well as to obtain averaged void fraction profiles and bubble size distributions. Earlier, similar experiments were carried out at a 51.2 mm pipe. In this case, sensors with 16x16 and 24x24 points were applied. A comparison of the data obtained for the two diameters allows to identify the effects of scaling on void fraction profiles, bubbles size distributions and the flow patterns. In the small pipe, the increase of the air flow rate leads to a transition from bubbly to slug flow. In the bubble size distributions a second peak corresponding to the class of large Taylor bubbles respectively gas plugs was found in the slug flow region. In the large pipe at identical superficial velocities a similar behaviour was found, though the large bubble fraction has a significantly bigger mean diameter, the peak is less high but wider. This reflects the fact that large bubbles move more freely than in the small pipe. The transition from a mono-modal to a bimodal bubble size distribution starts in both pipes, if bubbles with an equivalent diameter larger 1/3 of the pipe diameter occur. Due to the less pronounced confining action of the pipe walls, the bubbles show much more deformations. Their shape can be complicated and far from an ideal Taylor bubble. The small bubble fraction can also develop more freely in the large pipe. This is reflected by a wider bubble size distribution in the small bubble region. Small bubbles that surround the large bubbles obstruct the view and lead to the empirical impression of a direct transition from bubbly to churn turbulent flow.
Keywords: Two phase flow, large pipe, bubble flow
  • Lecture (Conference)
    41st European Two-Phase Flow Group meeting, Norway, May 12-13, 2003
  • Contribution to proceedings
    41st European Two-Phase Flow Group meeting, Norway, May 12-13, 2003

Publ.-Id: 5462 - Permalink

Radioactive beam project at HIMAC.
Kitagawa, A.; Endo, M.; Hosaka, M.; Kanai, T.; Kanazawa, M.; Koda, K.; Minohara, S.; Murakami, T.; Noda, K.; Suda, M.; Tomitani, T.; Torikoshi, M.; Urakabe, E.; Yamada, S.; Yoshikawa, K.; Mizuno, H.; Nishio, T.; Shinbo, M.; Futami, Y.; Pawelke, J.; Hanawa, K.; Iseki, Y.; Sato, K.; Mizota, M.; Hirata, M.; Komiyama, A.;
Heavy-ion radiotherapy gives a good localized dose distribution just on a cancer tumor. In order to emphasize this advantage, the verification system of a particle range and an irradiated area in a human body has been developed for the Heavy Ion Medical Accelerator in Chiba (HIMAC) at National Institute of Radiological Sciences (NIRS). The idea comes from the fact that the stopping position of a short-lived positron emitting nuclei, such as 11C, 15O or 19Ne, can be precisely detected by measuring annihilation gamma-rays.
  • Lecture (Conference)
    Proceedings of the Second Asian Particle Accelerator Conference, Beijing, China, 17-21 Sep (2001) 800-802
  • Other report
    Report, National Institute of Radiological Sciences, Chiba, Japan, HIMAC-044 (Dec 2001) 26-28
  • Contribution to proceedings
    Proceedings of the Second Asian Particle Accelerator Conference, Beijing, China, 17-21 Sep (2001) 800-802

Publ.-Id: 5461 - Permalink

Therapie mit Radionukliden
Wiegrebe, W.; Johannsen, B.;
  • Pharm. Ztg. 148, 2003, 1610-1611

Publ.-Id: 5458 - Permalink

Nanopatterning of Si Surfaces by low-energy ion sputtering
Gago, R.;
In this seminar the production of nanopatterning by ion beam sputtering (IBS) is presented, namely ripple and dot morphologies. The work is focused on the irradiation of Si surfaces but a general view of this research field is also discussed. Finally, the search of potential applications for these nanostructures is addresed.
Keywords: Ion sputtering, nanopatterning, ripples, nanodots.
  • Lecture (others)
    05.05.2003 Forschungsseminar Micro- und Nano-Elektronik, Institut Für Materialwissenschaften Bergische Universität, Wuppertal (gez. Prof. Dr. Clivia SOTOMAYOR-TORRES)

Publ.-Id: 5457 - Permalink

Influence of plasma parameters on properties of ITO films produced by reactive pulsed dual magnetron deposition
Rogozin, A.; Vinnichenko, M.; Shevchenko, N.; Kolitsch, A.; Moeller, W.;
Middle frequency dual reactive magnetron sputter deposition was used in order to prepare the Indium tin oxide (ITO) films with an optimum of resistance and transmittance. The films were deposited on Si covered with 500 nm SiO2 and soda lime glass substrates. The plasma ions and neutrals flow parameters have been studied during the deposition process by the Langmuir probe, HIDEN analyzer, and optical emission spectroscopy. Complex characterization of the ITO films have been carried out in order to relate their properties with pulsed magnetron operation parameters. The optical constants and the thickness of these films were determined by means of spectroscopic ellipsometry (SE) operating within the wavelength range l=300-1700 nm. The optical transmittance was measured for l=350-2000 nm. Four probe technique was used to determine the film specific resistance. The dependence of the ITO film properties on the O2/Ar partial pressure relation was obtained similarly to known researches. The influence of the pulse duration and base pressure level on the film characteristics was detected. The decrease of the magnetron pulse on-time to the values of about 50 micro seconds, leads to strong increase of the films resistance at their high transmittance. The AFM data for these samples demonstrated five-times increase of the film grain sizes compared to those obtained at the on-time values 100 micro seconds. The observed decrease of optical transmittance in the near IR spectral range corresponds to the decrease of the film resistance. High optical transmittance at low resistance is found only at certain relation between the free electron plasma and relaxation frequency. The grading of optical constants was revealed by SE while the other techniques did not show depth grading of the film properties. Annealing of the ITO films in air atmosphere reduces the film resistance.
Keywords: reactive dual magnetron sputtering, tin doped indium oxide, plasma assisted deposition
  • Lecture (Conference)
    The International Conference on Metallurgical Coatings and Thin Films, San Diego, California, USA, April 26 - May 2, 2003

Publ.-Id: 5456 - Permalink

Optimierung der Positronen-Emissions-Tomographie bei der Schwerionentherapie auf der Basis von Röntgentomogrammen
Pönisch, F.;
Die Positronen-Emissions-Tomographie (PET) bei der Schwerionentherapie ist eine wichtige Methode zur Qualitätskontrolle in der Tumortherapie mit Kohlenstoffionen. Die vorliegende Arbeit beschreibt die Verbesserungen des PET-Verfahrens, wodurch sich in der Folge präzisere Aussagen zur Dosisapplikation treffen lassen. Aufbauend auf den Grundlagen (Kap. 2) werden die Neuentwicklungen in den drei darauf folgenden Abschnitten (Modellierung des Abbildungsprozesses bei der PET, Streukorrektur für PET bei der Schwerionentherapie, Verarbeitung der rekonstruierten PET-Daten) beschrieben. Die PET-Methode bei der Schwerionentherapie basiert auf dem Vergleich zwischen den gemessenen und vorausberechneten Aktivitätsverteilungen. Die verwendeten Modelle in der Simulation (Erzeugung der Positronenemitter, deren Ausbreitung, der Transport und der Nachweis der Annihilationsquanten) sollten so präzise wie möglich sein, damit ein aussagekräftiger Vergleich möglich wird. Die Genauigkeit der Beschreibung der physikalischen Prozesse wurde verbessert und zeiteffiziente Algorithmen angewendet, die zu einer erheblichen Verkürzung der Rechenzeit führen. Die erwarteten bzw. die gemessenen räumlichen Radioaktivitätsverteilungen werden mit einem iterativen Verfahren rekonstruiert [Lau99]. Die gemessenen Daten müssen hinsichtlich der im Messobjekt auftretenden Comptonstreuung der Annihilationsphotonen korrigiert werden. Es wird ein geeignetes Verfahren zur Streukorrektur für die Therapieüberwachung vorgeschlagen und dessen Realisierung beschrieben. Zur Einschätzung der Güte der Behandlung wird die gemessene und die simulierte Aktivitätsverteilung verglichen. Dazu wurde im Rahmen der vorliegenden Arbeit eine Software entwickelt, das die rekonstruierten PET-Daten visualisiert und die anatomischen Informationen des Röntgentomogramms mit einbezieht. Nur durch dieses Auswerteverfahren war es möglich, Fehler im physikalischen Strahlmodell aufzudecken und somit die Bestrahlungsplanung zu verbessern.
Keywords: PET Schwerionentherapie Streukorrektur MLEM Rekonstruktion
  • Open Access LogoWissenschaftlich-Technische Berichte / Forschungszentrum Rossendorf; FZR-378, Mai 2003


Publ.-Id: 5455 - Permalink

Study of the reaction pp to ppπ0 within 10 MeV above the threshold
Abdel Samad, S.; Bilger, R.; Böhm, A.; Brinkmann, K.-T.; Clement, H.; Dshemuchadse, S.; Eyrich, W.; Filges, D.; Freiesleben, H.; Fritsch, M.; Geyer, R.; Hesselbarth, D.; Jakob, B.; Kilian, K.; Koch, H.; Karsch, L.; Kress, J.; Kuhlmann, E.; Marwinski, S.; Michel, P.; Möller, K.; Morsch, H. P.; Naumann, L.; Richter, M.; Roderburg, E.; Rogge, M.; Schamlott, A.; Schmitz, M.; Schönmeier, P.; Schroeder, M.; Schulte-Wissermann, M.; Sun, G. Y.; Steinke, M.; Stinzing, F.; Wagner, G. J.; Wagner, M.; Wilms, A.; Wirth, S.;
Kinematographically complete measurement of the pp to ppc0;0 reaction were performed for beam energies in the range 292 - 298 MeV. By detecting both protons in coincidence with the large acceptance COSY-TOF spectrometer set up at an external beam line of the proton synchrotron COSY-Jülich, total and differential cross sections and energy distributions were obtained. A strong enhancement is observed in the Dalitz plots resulting from the final state interaction between the outgoing proton pair; the data are well reproduced by Monte Carlo simulations with standard parameters for scattering lengths a0 = 7.83 fm and effective range r0 = 2.8 fm. The total cross section exceed the ones measured recently in internal target experiments at IUCF and CELSIUS by roughly 50%. Arguments are presented which link this discrepancy with the effect of the final state interaction pushing yield into the very small-angle region and the near-impossibility of an internal target experiment to cover just this range.

Publ.-Id: 5453 - Permalink

Radiopharmazie - Herausforderung und Chance für Apotheker
Wiegrebe, W.; Johannsen, B.;
  • Pharm. Ztg. 148, 2003, 1526-1530

Publ.-Id: 5452 - Permalink

Measurement of the η production in proton-proton collisions with the COSY time-of-flight spectrometer
Abdel-Bary, M.; Abdel-Samad, S.; Bilger, R.; Brinkmann, K.-T.; Clement, H.; Dshemuchadse, S.; Dorochkevitch, E.; Dutz, H.; Eyrich, W.; Erhardt, A.; Filges, D.; Filippi, A.; Freiesleben, H.; Fritsch, M.; Geyer, R.; Gillitzer, A.; Hesselbarth, D.; Jakob, B.; Karsch, L.; Kilian, K.; Koch, H.; Kreß, J.; Kuhlmann, E.; Marcello, S.; Marwinski, S.; Mauro, S.; Meyer, W.; Michel, P.; Möller, K.; Morsch, H. P.; Naumann, L.; Paul, N.; Richter, M.; Roderburg, E.; Rogge, M.; Schamlott, A.; Schmitz, M.; Schönmeier, P.; Schulte-Wissermann, M.; Schroeder, W.; Sefzik, T.; Stinzing, F.; Sun, G. Y.; Wagner, G. J.; Wagner, M.; Wilms, A.; Wintz, P.; Wirth, S.; Zupranski, P.;
The reaction pp to pp η was measured at excess energies of 15 and 41 MeV at an external target of the Jülich Cooler Synchrotron COSY with the time-of-flight spectrometer. About 25000 events were measured for the excess energy of 15 MeV and about 8000 for 41 MeV. Both protons of the process pp η were detected with an acceptance of nearly 100 % and the η was reconstructed by the missing-mass technique. For both excess energies the angular distributions are found to be nearly isotropic. In the invariant-mass distributions strong derivations from the pure phase space distributions are seen.

Publ.-Id: 5451 - Permalink

Investigation of flashing-induced instabilities at the CIRCUS test facility using the code ATHLET
Schäfer, F.; Manera, A.;
The CIRCUS test facility (Circulation during startup) has been built to study the start-up phase of a natural-circulation BWR. During the start-up so called flashing-induced instabilities can arise. These instabilities are induced by flashing, due to steam production in the long adiabatic riser section, which is placed above the core to enhance the flow rate. Flashing occurring in the riser causes an unbalance between driving force and pressure losses in the natural-circulation loop, giving rise to flow oscillations.

Within the European-Union 5th Framework Programme, a project, NACUSP, has been started in December 2000, having as one of its main aims the understanding of the physics of the phenomena involved during the start-up phase of natural-circulation-cooled BWRs, providing a large experimental database and validating state-of-the-art thermalhydraulic codes in the low-pressure, low-power operational region of these reactors.

One part of this project deals with the modeling of selected CIRCUS tests using the thermo-hydraulic code ATHLET. This paper gives an overview about experimental results and the physics of the instabilities. ATHLET is used to investigate the dynamic behavior of the CIRCUS test facility and the results of the calculations are compared with the experimental data.
Keywords: Natural Circulation, Flow Instabilities, ATHLET, CIRCUS Test Facility
  • Lecture (Conference)
    The 10 th International Topical Meeting on Nuclear Reactor Thermal Hydraulics (NURETH-10), Seoul, Korea, October 5-9, 2003
  • Contribution to proceedings
    The 10 th International Topical Meeting on Nuclear Reactor Thermal Hydraulics (NURETH-10), Seoul, Korea, October 5-9, 2003

Publ.-Id: 5450 - Permalink

Mössbauer-effect study of metastable c-FeSi synthesized by molecular beam epitaxy (MBE) and by ion implantation
Walterfang, M.; Keune, W.; Reuther, H.;
Mössbauer-effect study of metastable c-FeSi synthesized by molecular beam epitaxy (MBE) and by ion implantation
  • Phase Transitions 76 (2003) 437-444

Publ.-Id: 5449 - Permalink

Mikronukeus-Induktion in Keratinocyten und Fibroblasten durch Bestrahlung mit weichen Röntgenstrahlen.
Spekl, K.; Slonina, D.; Brankovic, K.; Hoinkis, C.; Panteleeva, A.; Pawelke, J.; Dörr, W.;
no abstract
  • Experimentelle Strahlentherapie und Klinische Strahlenbiologie, Vol. 11 (2002) 135-139

Publ.-Id: 5448 - Permalink

Determination of RBE of X-rays by a novel quasi-monochromatic X-ray source.
Pawelke, J.; Brankovic, K.; Dörr, W.; Dörschel, B.; Enghardt, W.; Lehnert, U.; Neubert, W.; Panteleeva, A.; Prade, H.; Slonina, D.;
In the last years, there were several reports about the enhanced risk from irradiation with soft X-rays (below 50 keV). This energy range is relevant for diagnostic radiology, such as mammography, radiotherapy, and for the application of novel radiotherapy approaches such as use of miniature X-ray devices. In order to study this phenomenon, the relative biological effectiveness (RBE) of the X-rays in this energy range has to be determined more precisely. Experiments for determination of biological response after conventional X-ray tube irradiation were performed at TU Dresden. Cell survival for NIH/3T3 mouse fibroblasts was measured for soft X-rays (25 kV) and reference X-rays (200 kV). RBE value of 1.28 ± 0.5 was determined from the linear-quadratic model fit at 10% survival level. Further endpoint to be studied is the formation of micronuclei. At present, experiments are performed on human keratinocytes and chinese hamster fibroblasts. However, the precise determination of the energy dependence of RBE has to be performed by means of irradiation with a monochromatic source. One of the applications of the superconducting electron linear accelerator ELBE, at present under construction at Forschungscentrum Rossendorf, will be to provide such X-rays. The first cell irradiation will be performed with X-rays in the range 10 - 50 keV generated by channeling radiation from relativistic electrons in a diamond crystal. The properties of the electron beam (picosecond structure) as well as the intrinsic energy and intensity distribution of the channeling radiation require consideration of precise dose delivery and monitoring, the results of which will be also presented.
  • Contribution to external collection
    K. Mück, A. Hefner, N. Vana (Hrsg.), Proceedings, TÜV-Verlag GmbH, Köln, ISBN 3-8249-0661-9 (2001) 13-16
  • Lecture (Conference)
    Gemeinsame Tagung des Österreichischen Verbandes für Strahlenschutz und des Fachverbandes für Strahlenschutz e.V. und 33. Jahrestagung des FS "Strahlenschutz für Mensch und Gesellschaft im Europa von morgen", Gmunden, Österreich, 17.-21.09.2001

Publ.-Id: 5447 - Permalink

Chromosomal damage and survival of keratinocytes and fibroblasts after irradiation with 200 kV or 25 kV X-rays.
Slonina, D.; Brankovic, K.; Panteleeva, A.; Dörr, W.;
no abstract
  • Lecture (Conference)
    5th Conference under the auspices of the Polish Society of Radiation Oncology, "Advances in Radiation Oncology", Poznan, Poland, 19-21 Apr, 2001
    Reports of Practical Oncology and Radiotherapy, Vol. 6 (No. 1) (2001) 39 (ISSN 1507-1367)
  • Contribution to proceedings
    5th Conference under the auspices of the Polish Society of Radiation Oncology, "Advances in Radiation Oncology", Poznan, Poland, 19-21 Apr, 2001
    Reports of Practical Oncology and Radiotherapy, Vol. 6 (No. 1) (2001) 39 (ISSN 1507-1367)

Publ.-Id: 5446 - Permalink

Chromosomal damage and survival of keratinocytes and fibroblasts after irradiation with 200 kV or 25 kV X-rays.
Slonina, D.; Spekl, K.; Brankovic, K.; Panteleeva, A.; Dörr, W.;
no abstract
  • Poster
    11th European Cancer Conference, Lisbon, Portugal, 21-25 Oct, 2001
    European Journal of Cancer, Vol. 37 (Suppl. 6) (2001) S207 (Abstract No. 758)
  • Contribution to proceedings
    11th European Cancer Conference, Lisbon, Portugal, 21-25 Oct, 2001
    European Journal of Cancer, Vol. 37 (Suppl. 6) (2001) S207 (Abstract No. 758)

Publ.-Id: 5445 - Permalink

The estimation of the absorbed dose in the cell.
Panteleeva, A.;
no abstract
  • Lecture (Conference)
    Workshop Dosimetrie von Teilchenstrahlung und weicher Röntgenstrahlung, FZ Rossendorf, 10.11.2000
    Proceedings, Institut für Strahlenschutz der Berufsgenossenschaft der Feinmechanik und Elektrotechnik, Köln, Bestell-Nr. IfS 8 (2000) 43-47
  • Contribution to proceedings
    Workshop Dosimetrie von Teilchenstrahlung und weicher Röntgenstrahlung, FZ Rossendorf, 10.11.2000
    Proceedings, Institut für Strahlenschutz der Berufsgenossenschaft der Feinmechanik und Elektrotechnik, Köln, Bestell-Nr. IfS 8 (2000) 43-47

Publ.-Id: 5444 - Permalink

Klonogenes Zellüberleben von Keratinozyten und Fibroblasten nach Bestrahlung mit 25 kV und 200 kV Röntgenstrahlen.
Brankovic, K.; Slonina, D.; Panteleeva, A.; Dörr, W.;
no abstract
  • Lecture (Conference)
    Gemeinsamer Jahreskongress der Deutschen Gesellschaft für Radioonkologie, Strahlenbiologie und Medizinische Physik, der ÖGRO und der DGMP, München, 06-09 Okt, 2000
    Strahlentherapie und Onkologie, Vol. 176, Sondernr. 1 (2000) 110
  • Contribution to proceedings
    Gemeinsamer Jahreskongress der Deutschen Gesellschaft für Radioonkologie, Strahlenbiologie und Medizinische Physik, der ÖGRO und der DGMP, München, 06-09 Okt, 2000
    Strahlentherapie und Onkologie, Vol. 176, Sondernr. 1 (2000) 110

Publ.-Id: 5443 - Permalink

Preparation of RBE measurements of soft X-rays at ELBE.
Panteleeva, A.; Enghardt, W.; Lehnert, U.; Neubert, W.; Pawelke, J.; Prade, H.; Brankovic, K.; Dörr, W.; Dörschel, B.; Slonina, D.;
no abstract
  • Poster
    7th Workshop on Heavy Charged Particles in Biology and Medicine, Darmstadt, 28-30 Sep, 2000
    G. Kraft, K. Langbein (Eds.): Book of Abstracts, GSI Report 2000-04, GSI Darmstadt (2000) attachment
  • Contribution to proceedings
    7th Workshop on Heavy Charged Particles in Biology and Medicine, Darmstadt, 28-30 Sep, 2000
    G. Kraft, K. Langbein (Eds.): Book of Abstracts, GSI Report 2000-04, GSI Darmstadt (2000) attachment

Publ.-Id: 5442 - Permalink

Radiobiological studies with soft X-rays.
Panteleeva, A.; Enghardt, W.; Lehnert, U.; Pawelke, J.; Prade, H.; Dörr, W.; Dörschel, B.; Brankovic, K.; Slonina, D.;
no abstract
  • Contribution to external collection
    V.L. Korogodina, N.A. Zyuzikov (Eds.): Book of Abstracts, Joint Institute for Nuclear Research, Dubna, ISBN 5-85165-572-0 (2000) 142
  • Poster
    Int. Conf. on Modern Problems of Radiobiology, Radioecology and Evolution (Timofeeff-Ressovsky Centennial Conference), Dubna, Russia, 06.-09.09.2000.

Publ.-Id: 5441 - Permalink

Skutecznosc bilologiczna niskoenergetycznego promieniowania X (25 kV) oceniana na ludzkich fibroblastach i keratynocytach.
Slonina, D.; Brankovic, K.; Spekl, K.; Panteleeva, A.; Dörr, W.;
no abstract
  • Lecture (Conference)
    12th Meeting of Polish Radiation Research (materialy XII Zjazdu Polskiego Towarzystwa Badan Radiacyjnych), Krakow, Poland, 10-12 Sep, 2001
    Proceedings, Instytut Fizyki Jadrowej, Krakow, ISBN 83-908998-3-3 (2001) 74
  • Contribution to proceedings
    12th Meeting of Polish Radiation Research (materialy XII Zjazdu Polskiego Towarzystwa Badan Radiacyjnych), Krakow, Poland, 10-12 Sep, 2001
    Proceedings, Instytut Fizyki Jadrowej, Krakow, ISBN 83-908998-3-3 (2001) 74

Publ.-Id: 5440 - Permalink

CFD modelling of subcooled boiling
Krepper, E.;
Heat transfer and boiling are key phenomena for power generation facilities. Whereas for 1D thermalhydraulic system codes modeling of boiling was state aof the art from the beginning of their development, the 3D modelling of boiling has not yet reached this maturity. In the paper the boiling model implemented in the CFD-code CFX-4 was applied, to analyse lots of experiments, their results were published in the literature. The validity of the implemented correlations is examined. In many cases the model yields a good agreement to experiments. Especially in the low pressure region, the steam volume fraction is calculated too low. The used models are critical reviewed and compared to alternative solutions. The sensitivity of the calculated results on different influences are compared. Needs for improvements of the model and for further experiments are derived. Main attention should be focused on measuring and modelling of the correct size of the generated steam bubbles.
Keywords: Boiling, CFD, multiphase flow simulations, two fluid model
  • Lecture (Conference)
    The 10th International Topic Meeting on Nuclear Reactor Thermal Hydraulics (NURETH-10), Seoul, Korea, October 5 - 9, 2003
  • Contribution to proceedings
    The 10th International Topic Meeting on Nuclear Reactor Thermal Hydraulics (NURETH-10), Seoul, Korea, October 5 - 9, 2003

Publ.-Id: 5438 - Permalink

Determination of hydrogen in GaMnN and GaMnMgN by nuclear reaction analysis
Podsiadlo, S.; Szyszko, T.; Grzegorz, W.; Turos, A.; Ratajczak, R.; Kowalczyk, A.; Gebicki, W.; Strzalkowski, I.; Grambole, D.; Herrmann, F.;
Gallium nitride is a novel material for short wavelength (blue) optoelectronics. Our previous investigation showed that Mn doped GaN has paramagnetic or antiferromagnetic properties opening new possible applications. The high concentration of magnetic ions possibly allows for the use of such a material in magnetooptic and spintronic devices. GaMnN and GaMnMgN powders were prepared by heating mixtures of gallium and manganese powder or powders of gallium nitride and manganese in a stream of ammonia at the temperature up to 1250°C. The powders have a grain size about 1-10 µm and they contain more than 2% of manganese by weight. Powders of doped GaN were prepared in a series of technological processes at various temperatures, ammonia flow rates and concentration of dopants in initial mixtures. Since hydrogen largely attributes to the passivation of p-dopants it plays an essential role in determination of electrical properties of these materials. Hydrogen content analysis was performed by the NRA method using the 1H(15Na,alpha gamma)12C reaction. This reaction has a sharp resonance of the cross-section at 6.385 MeV. Therefore it is possible by changing the incident 15N beam energy to measure depth distribution of hydrogen. It was found out that hydrogen concentration in our materials was below 1.5at%.
Keywords: Gallium nitride; Doping; Manganese: Magnesium; Ion beam analysis
  • Vacuum 70 (2003) 207-213
  • Poster
    4th Internat. Symposium on Ion Implantation and other Application of Ions and Electrons, ION 2002, 10.-13.06.2002, Kazimierz Dolny, Poland

Publ.-Id: 5437 - Permalink

Modelling of bubble flow in vertical pipes
Lucas, D.; Krepper, E.; Prasser, H.-M.;
To qualify CFD codes for two-phase flows, they have to be equipped with constitutive models standing for the interaction between the gaseous and the liquid phases. In case of bubble flow this particularly concerns the forces acting on the bubbles and bubble coalescence and break-up. Information on the local structure of the flow is also required by 1D thermal-hydraulic codes. Gas-liquid flow in vertical pipes is a very good object for studying the corresponding phenomena. Here, the bubbles move under clear boundary conditions, resulting in a shear field of nearly constant structure where the bubbles rise for a comparatively long time. The evolution of the flow within the pipe depends on a very complex interaction between bubble forces and bubble coalescence and break-up. E.g. the Lift-force, which strongly influences the radial distribution of the bubbles, changes its sign depending on the bubble diameter. Basing on extensive experimental data with a high resolution in space and time the applicability and the limits for the simulation of bubble flow with current CFX-codes are demonstrated, using the simulation of vertical pipe flow with CFX-4 as an example. Using a simplified model, parametric studies can be conducted. They give an indication for necessary improvements of the codes. Finally a possible way for the improvement of the CFD-codes is shown.
Keywords: two phase flow, bubble flow, bubble size, vertical pipe flow, CFD
  • Lecture (Conference)
    The 10 th International Topical Meeting on Nuclear Reactor Thermal Hydraulics (NURETH-10), Seoul, Korea, October 5-9, 2003, Paper A00301
  • Contribution to proceedings
    The 10 th International Topical Meeting on Nuclear Reactor Thermal Hydraulics (NURETH-10), Seoul, Korea, October 5-9, 2003, Paper A00301

Publ.-Id: 5436 - Permalink

Phase changes in steels irradiated with intense pulsed plasma beams
Sartowska, B.; Piekoszewski, J.; Walis, L.; Kopcewicz, M.; Werner, Z.; Stanislawski, J.; Kalinowska, J.; Prokert, F.;
It is known that transformation of martensite into austenite (alpha'--> gamma) can take place in the surface layers of steels treated with sufficiently intense pulses of laser, ion or plasma beams. Our present work focuses on the phase transformations in the near-surface layer of various types of steel irradiated with short(µs range) intense (5-6 xE-4 J/m2) argon and nitrogen plasma pulses. The results of CEMS measurements, the pin-on-disc wear tests and SEM observations are presented.
Keywords: Intense pulsed plasma beams; Carbon steels; Paramagnetic phases; SEM; CEMS; Wear tests
  • Vacuum 70 (2003) 285-291

Publ.-Id: 5435 - Permalink

Alkyl-Substituted 2,6-Dioxadiazolylpyridines as Selective Extractants for Trivalent Actinides
Weigl, M.; Müllich, U.; Geist, A.; Gompper, K.; Zevaco, T.; Stephan, H.;
2,6-di(3-alkyl-1,2,4-oxadiazol-5-yl)pyridines, 2,6-di(5-alkyl-1,3,4-oxadiazol-2-yl)pyridines, and 2,6-di(5-alkyl-1,2,4-oxadiazol-3-yl)pyridines were synthesized and tested for their americium(III)-europium(III) selectivity by liquid-liquid extraction. 0.02 M solutions of the compounds extract americium(III) 2-bromohexanoates as monosolvates, AmA3B, from solutions of pH = 2, with an americium(III)-europium(III) separation factor of up to 23. Decreasing the alkyl chain length (butyl < ethyl < methyl) or the polarity of the diluent (chlorobenzene < toluene < tert.-butyl benzene) increased both americium(III) distribution ratio and americium(III)-europium(III) separation factor.
  • Journal of Radioanalytical and Nuclear Chemistry, 256/3 (2003) 403-412

Publ.-Id: 5434 - Permalink

Where the anion extraction is going?
Gloe, K.; Stephan, H.; Grotjahn, M.;
Reactive extraction processes represent efficient and smart technologies for separation and concentration of metal ions in solution, which are frequently used in industry. Despite the importance of anions in biology, medicine, environment and industry, practical examples of anion extraction are relatively limited compared to metal ion separation. Anion extraction processes are mainly based on the non-specific ion pair formation with hydrophobic ammonium cations. In this case the phase transfer of anions is dominated by their lipophilicity. The reasons for this situation are closely connected with the specific features of anions in contrast to cations. Novel approaches for specific binding and selective transport of anionic components are based both on the better understanding of the biological role of anions and on the possibilities of supramolecular chemistry to build up receptor architectures with complementary binding modes for anions. In the given review the authors discuss present research tendencies and application possibilities of new extractant types for separation and concentration of anionic species in solution.
  • Chem. Eng. Technol. 26 (2003) 1107-1117

Publ.-Id: 5433 - Permalink

Towards promising oxoanion extractants: azacages and open-chain counterparts
Farrell, D.; Gloe, K.; Gloe, K.; Goretzki, G.; Mckee, V.; Nelson, J.; Nieuwenhuyzen, M.; Pál, I.; Stephan, H.; Town, R. M.; Wichmann, K.;
The efficiency of a series of amino-azacryptands for encapsulation and etraction of the oxoanions pertechnetate and perrhenate from aqueous solution is investigated and compared with that of their open-chain counterparts. The aqueous formation constants for oxoanion association with the cryptands were determined by pH potentiometry and/or NMR, and X-ray analysis of single crystals provides evidence for encapsulation. The extractabilities could not be explained solely on the basis of ligand lipophilicity; the level of protonation also plays an important role.
  • J. Chem. Soc., Dalton Trans. (2003) 1961-1968
  • Lecture (Conference)
    Dalton Discussion 5 "Ligand Design for Functional Complexes", Noordwijkerhout, The Netherlands, 10.-12.04.2003

Publ.-Id: 5432 - Permalink

Binding and Extraction of Pertechnetate and Perrhenate by Azacages
Stephan, H.; Gloe, K.; Kraus, W.; Spies, H.; Johannsen, B.; Wichmann, K.; Chand, D. K.; Bharadwag, P. K.; Müller, U.; Müller, W. M.; Vögtle, F.;
The design and synthesis of anion receptors of technical and biochemical significance is receiving more and more attention.1-8 Currently, effective binding and selective phase transfer of the oxoanions pertechnetate and perrhenate is of considerable interest from different point of view. Due to its long half-life and environmental mobility, the radioactive pertechnetate is one of the most hazardous contaminants. In this context, effective and selective separation processes are of utmost importance.9-12 On the other hand, there are some emerging possibilities for the application of the radiochemically active oxoanions pertechnetate and perrhenate in nuclear medicine.13,14 The most commonly used isotope in diagnostic nuclear medicine 99mTc is readily available from a 99Mo/99mTc generator system.15-19 Likewise, the b-emitting 188Re – discussed as one of the most interesting radionuclides for specific therapeutic applications – is conveniently produced by a 188W/188Re generator.20-22 In both cases the radionuclides are available as oxoanions in isotonic solution, and it appears highly desirable to directly complex 99mTcO4- and 188ReO4- as they exist in the generator eluate itself. But, the binding of such large, lowly charged anions is a difficult venture. The enthalpic contribution for complexation is rather small. Hence, host compounds being capable to encapsulate these oxoanions are of great interest.
For both directions discussed above, some different requirements have to be fulfilled for the design of ligands. The essential properties of ligands serving as extractants and imaging/therapeutic agents are summarized in Table 1.
  • Contribution to external collection
    B. A. Moyer, R. P. Singh (Eds.): Fundamentals and Applications of Anion Separation, New York: Kluwer Academic/Plenum Publishers, 2004, 151-168

Publ.-Id: 5431 - Permalink

Proceedings of the 6th International Conference on Computer Simulation of Radiation Effects in Solids, Dresden, Germany June 23 - 27, 2002
Möller, W.; Posselt, M.; Jäger, H.-U.; (Editors)
no abstract
  • Book (Authorship)
    Nuclear Instruments and Methods B 202 (2003) 1- 322

Publ.-Id: 5430 - Permalink

Effect of deposition parameters on properties of ITO films prepared by reactive MF pulsed dual magnetron sputtering
Rogozin, A. I.; Vinnichenko, M. V.; Kolitsch, A.; Möller, W.;
ITO layers with low resistivity and high visible transmittance were produced by means of middle frequency reactive dual magnetron sputtering. The influence of base pressure, Ar/O2 ratio and magnetron pulse duration on the film composition, structure, electrical and optical properties has been investigated. The deposition rate is proportional to the magnetron operation power at changing pulse duration and constant Ar and O2 flows. At enhanced O2 flows an onset of the magnetron target oxidation is discussed as a reason for the decrease of the deposition rate. The presence of water vapor in the residual gas is determined to be a reason for deterioration of resistivity and optical transmittance observed for ITO films produced at base pressures higher than 5×10-4 Pa. It is demonstrated that spectroscopic ellipsometry can be used as a non contact tool to monitor the resistivity of ITO films.
Keywords: middle frequency reactive dual magnetron sputtering, indium tin oxide, resistivity, optical properties, spectroscopic ellipsometry
  • Journal of Vacuum Science and Technology A 22(2004), 349-355
    DOI: 10.1116/1.1647595

Publ.-Id: 5429 - Permalink

Strangeness Saturation: Dependence on System-Size, Centrality, and Energy
Kämpfer, B.; Cleymans, J.; Wheaton, S.; Steinberg, P.;
The dependence of the strangeness saturation factor on the system size, centrality and energy is studied in relativistic
heavy-ion collisions.
Keywords: relativistic heavy-ion collisions, statistical hadronization, strangeness
  • Contribution to external collection
    Proc. Nuclear Dynamics 19 (2003) 103-108
  • Acta Physica Hungarica A 21(2004)2-4, 207-213

Publ.-Id: 5428 - Permalink

Kaons in dense matter: results from KaoS
Koczon, P.; Laue, F.; Schwab, E.; Senger, P.; Förster, A.; Oeschler, H.; Sturm, C.; Uhlig, F.; Shin, Y.; Ströbele, H.; Böttcher, I.; Kohlmeyer, B.; Menzel, M.; Pühlhofer, F.; Debowski, M.; Surowka, G.; Walus, W.; Dohrmann, F.; Grosse, E.; Naumann, L.; Scheinast, W.; Wagner, A.;
The production of kaons and antikaons in nucleus-nucleus collisions has been studied with the kaon spectrometer at SIS/GSI. The K-/K+ ration was measured in C+C, Ni+Ni, Au+Au collisions at 1.5 AGeV and was found to be almost independent of the system size. In Ni+Ni collisions at 1.93 AGeV we measured the phase-space distributions of K- and K+ mesons. Within the framework of transport models, the measured K+ and K- yields can only be explained if in-medium modifications of the K meson masses are assumed.
In Au-Au collisions at 1 AGeV, we observe non-vanishing elliptic flow near mid-rapidity and in-plane flow at target rapidity for K+ mesons. This effect can be explained by transport models when a repulsive in-medium K+ N potential is taken into account. The ratio of the K+ meson excitation functions for Au+Au and C+C collisions increases with decreasing beam energies. This effect is expected for a soft nuclear equation of state.
  • J.Phys. G: Nucl. Part. Phys. 27 (2001) 275-281

Publ.-Id: 5427 - Permalink

Improved 3C-SiC films epitaxially grown on Si by flash lamp processing
Stoemenos, J.; Panknin, D.; Eickhoff, M.; Heera, V.; Skorupa, W.; (Editors)

For the realization of good quality 3C-SiC films, epitaxially grown on Si, the perfection of the film during the early stage of growth is substantial. In this work the beneficial role of Flash Lamp Process (FLP) for defect elimination and strain reduction in the 3C-SiC films is discussed. FLP is a highly transient process with a flash duration of a few milliseconds (ms), preferentially occurring at the SiC/Si interface where the irradiated flux has its maximum absorption. If the energy density is sufficiently high, the temperature at the interface increases above the melting point of silicon. As a result, Si at the interface melts and subsequently dissolves the 3C-SiC in the vicinity of the interface, while the non-melted part of the film is annealed. During the re-solidification phase separation occurs and that part of the SiC film which is already dissolved into silicon is epitaxially deposited on the annealed uppermost part, which acts as the seed layer. The process resembles liquid phase epitaxy (LPE) resulting in substantial improvement of the SiC film. This process also eliminates the cavities and the stress at the 3C-SiC/Si interface. The irradiated 3C-SiC films were characterized by Transmission Electron Microscopy.

Keywords: 3C-SiC interface, flash lamp processing, TEM
  • Journal of the Electrochemical Society 151(2004)2, G136-G143

Publ.-Id: 5426 - Permalink

First Measurement of Antikaon Phase-Space Distributions in Nucleus-Nucleus Collisions at Subthreshold Beam Energies
Menzel, M.; Böttcher, I.; Debowski, M.; Dohrmann, F.; Förster, A.; Grosse, E.; Koczon, P.; Kohlmeyer, B.; Laue, F.; Naumann, L.; Oeschler, H.; Pülhofer, F.; Schwab, E.; Senger, P.; Shin, Y.; Ströbele, H.; Sturm, C.; Surowka, G.; Uhlig, F.; Wagner, A.; Walus, W.;
Differential production cross sections of K- and K+ mesons have been measured as function of the polar emission angle in Ni+Ni collisions at a beam energy of 1.93 AGeV. In near-central collisions, the spectral shapes and the widths of the rapidity distributions of K- and K+ mesons are in agreement with the assumption of isotropic emission. In non-central collisions, the K- and K+ rapidity distributions are broader than expected for a single thermal source. In this case, the polar angle distributions are strongly forward-backward peaked and the nonisotropic contribution to the total yield is about one third both for K+ and K- mesons. The K-K+ ratio is found to be about 0.03 independent of the centrality of the reaction. This value is significantly larger than predicted by microscopic transport calculations if in-medium modifications of K mesons are neglected.
  • Physics Letters B, 495 (2000) 26-32

Publ.-Id: 5425 - Permalink

Fragment isospin as a probe of heavy-ion collisions
Xu, H.; Alfaro, R.; Davin, B.; Beaulieu, L.; Larochelle, Y.; Lefort, T.; Yanez, R.; de Souza, R. T.; Liu, T. X.; Liu, X. D.; Lynch, X. D.; Shomin, R.; Tan, W. P.; Tsang, M. B.; Vander Molen, A.; Wagner, A.; Xi, H. F.; Gelbke, C. K.; Charity, R. J.; Sobotka, L. G.; Botvina, A. S.;
Isotope ratios of fragments produced at midrapidity in peripheral and central collisions of 114Cd ions with 98Mo target nuclei at E/A = 50 MeV are compared. The influence of the size (A), density, N/Z, E*/A, and Eflow/A of the emitting source on the measured isotope ratios was explored by comparison with a statistical model (SMM). The midrapidity region associated with peripheral collisions does not appear to be neutron-enriched relative to central collisions.
  • Physical Review C, 65 (2002) 061602-061605

Publ.-Id: 5424 - Permalink

Fragment production in noncentral collisions of intermediate-energy heavy ions
Davin, B.; Alfaro, R.; Xu, H.; Beaulieu, L.; Larochelle, Y.; Lefort, T.; Yanez, R.; Hudan, S.; Caraley, A. L.; de Souza, R. T.; Liu, T. X.; Liu, X. D.; Lynch, W. G.; Shomin, R.; Tan, W. P.; Tsang, M. B.; Vandermolen, A.; Wagner, A.; Xi, H. F.; Gelbke, C. K.; Charity, R. J.; Sobotka, L. G.;
The defining characteristics of fragment emission resulting from the noncentral collision of 114Cd ions with 92Mo target nuclei at E/A = 50 MeV are presented. Charge correlations and average relative velocities for midvelocity fragment emission exhibit significant differences when compared to standard statistical decay. These differences associated with similar velocity dissipation are indicative of the influence of the entrance channel dynamics on the fragment production process.
  • Physical Review C, 65 (2002) 064614-064620

Publ.-Id: 5423 - Permalink

Assessment of reactor vessel integrity (ARVI)
Sehgal, B. R.; Theerthan, A.; Giri, A.; Karbojian, A.; Willschütz, H.-G.; Kymäläinen, O.; Vandroux, S.; Bonnet, J. M.; Seiler, J. M.; Ikkonen, K.; Sairanen, R.; Bhandari, S.; Bürger, M.; Buck, M.; Widmann, W.; Dienstbier, J.; Techy, Z.; Taubner, R.; Theofanous, T.; Dinh, T. N.;
The cost-shared project ARVI (assessment of reactor vessel integrity) involves a total of nine organisations from Europe and
USA. The objective of the ARVI Project is to resolve the safety issues that remain unresolved for the melt vessel interaction
phase of the in-vessel progression of a severe accident. The work consists of experiments and analysis development. Four tests were performed in the EC-FOREVER Programme, in which failure was achieved in-vessels employing the French pressure
vessel steel. The tests were analysed with the commercial code ANSYS-Multiphysics, and the codes SYSTUS+ and PASULA, and quite good agreement was achieved for the failure location. Natural convection experiments in stratified pools have been performed in the SIMECO and theCOPOfacilities, which showed that much greater heat is transferred downwards for immiscible layers or before layers mix. A model for gap cooling and a set of simplified models for the system codes have been developed.
MVITA code calculations have been performed for the Czech and Hungarian VVERs, towards evaluation of the in-vessel melt retention accident management scheme.
Tests have been performed at the ULPU facility with organised flow for vessel external cooling. Considerable enhancement
of the critical heat flux (CHF) was obtained. The ARVI Project has reached the halfway stage. This paper presents the results obtained thus far from the project.
Keywords: Severe Accident, In Vessel Retention, Reactor Vessel Integrity, Experiments and Analysis
  • Nuclear Engineering and Design, vol 221, pp 23-53

Publ.-Id: 5422 - Permalink

Analysis of PWR core behaviour after the entrance of underborated water
Kliem, S.; Rohde, U.; Weiß, F.-P.;
For a realistic description of the coolant mixing during stationary and transient processes inside the reactor pressure vessel, a fast running semi-analytical model has been developed. This model is based on the technique of linear superposition of response functions on Dirac impulse shaped perturbation functions. The model has been coupled to the 3D neutron kinetic core model DYN3D.

A parameter study for a hypothetical boron dilution event including stationary and transient core calculations has been carried out. For the analysis a generic core loading pattern of the PWR KONVOI has been used. By varying the initial slug volume was found, that slugs of less than 16 m3 do not lead to over-criticality in stationary calculations. Transient calculations with higher slug volumes revealed a further conservatism of the calculations. An initial slug volume of 20 m3 is necessary to reach over-criticality in transient calculations. This leads to a significant reactivity insertion into the core and results in a power peak of more than 6500 MW. The power excursion is stopped by the Doppler feedback very effectively. The limited integral energy release does not lead to a significant rise of the coolant temperature. In the calculation with the bounding slug volume, the magnitude of the power peak is with about 8500 MW higher than in the previous calculation. The Doppler feedback stops the further power increase, too. Contrary to the 20 m3 case, the power peak occurs even before the boron concentration has reached its minimum. Because the positive reactivity insertion is continued after the power peak, typical secondary power peaks are observed. At the location of the power maximum, coolant boiling with a maximum void fraction of up to 70 % occurs for a short time. However, no heat transfer crisis was obtained.

The influence of the cross section library on the results of the boron dilution transient has been investigated by using an alternative library. Differences in global core parameters lead to quantitative differences in the time and the height of the power excursion.

A special model, based on a particle-in-cell method for the description of the boron transport through the reactor core has been used. It is shown, that a proper description of the boron transport in case of transients with low fluid velocity is absolutely necessary to calculate the neutron kinetic behaviour of the core in a right manner.

According to all calculations, even a reactivity insertion of about 2 $ connected with a 36 m3 slug did not lead to safety relevant consequences. The power excursion is mitigated and stopped by the Doppler feedback.
  • Lecture (Conference)
    Fachsitzung "Experimentelle und theoretische Untersuchungen zu Borverdünnungstransienten in DWR" auf der Jahrestagung Kerntechnik 2003, Berlin, 20.-22. Mai 2003, Berichtsheft S.85-96
  • Contribution to proceedings
    Fachsitzung "Experimentelle und theoretische Untersuchungen zu Borverdünnungstransienten in DWR" auf der Jahrestagung Kerntechnik 2003, Berlin, 20.-22. Mai 2003, Berichtsheft S.85-96

Publ.-Id: 5421 - Permalink

Ion implantation and ion-beam-induced defect formation in Si and SiC studied by atomistic computer simulations
Posselt, M.;
Ion implantation is one of the major techniques to introduce dopants into Si and SiC in a controlled manner. However, ion irradiation produces defects which prevent their electrical activation. Therefore, subsequent annealing is necessary in order to restore the crystallinity and to obtain dopant activation. The precise knowledge of the spatial distribution of the implanted ions and the radiation damage as well as the understanding of the nature of ion-beam-induced defects are important prerequisites for further improvements in the technology of ion implantation doping. Besides experimental investigations, atomistic computer simulations play an important role to achieve progress in this field. Simulations based on the binary collision approximation (BCA) are employed to determine the depth profile of implanted ions and atomic displacements. The influence of various implantation parameters like energy, direction of ion incidence, dose, dose rate and temperature is considered. A phenomenological model is used to treat the dependence of channeling effects on damage buildup and dynamic annealing during ion bombardment. The implantation profiles determined by the simulations show a good agreement with available experimental data. On the other hand, BCA simulations are limited to the treatment of ballistic processes. They do not yield details of the (meta)stable defect structure formed in subsequent fast relaxation processes. In order to obtain such information, a combined simulation method is employed. Processes in the collision cascade with energy transfers above 100 eV are treated by BCA simulations. Classical molecular dynamics (MD) calculations are applied to consider processes in certain parts of the cascade which start with energy transfers less than 100 eV. Detailed investigations are performed to study the temporal evolution of the defect structure, and to determine the damage morphology obtained after the fast relaxation is finished. The influence of nuclear energy deposition and target temperature is discussed. The combination of BCA and MD methods allows the effective calculation of the total number and the depth distribution of different defect species (e.g. isolated vacancies and self-interstitials as well as more complex defects) formed on average per incident ion. The results obtained allow a microscopic interpretation of the phenomenological model employed in conventional BCA simulations to describe the enhanced dechanneling of implanted ions due to damage buildup during implantation. In particular the explicit dependence on the ion mass can be explained. Furthermore, the procedure yields more realistic initial conditions for the simulation of post-implantation annealing than hitherto used.
Keywords: ion implantation, ion-beam-induced defect formation, computer simulation, Si, SiC
  • Invited lecture (Conferences)
    Int. Workshop on Physics of Group-IV Semiconductors, Exeter, UK, April 7-10, 2003 (invited talk)

Publ.-Id: 5420 - Permalink

Ex-vessel core melt stabilization research (ECOSTAR)
Steinwarz, W.; Koller, W.; Dyllong, N.; Häfner, W.; Journeau, C.; Seiler, J. M.; Froment, K.; Cognet, G.; Goldstein, S.; Fischer, M.; Hellmann, S.; Nie, M.; Eddi, M.; Alsmeyer, H.; Allelein, H.-J.; Spengler, C.; Bürger, M.; Sehgal, B. R.; Koch, M. K.; Büscher, T.; Alkan, Z.; Petrov, J. B.; Gaune-Escard, M.; Weiss, F.-P.; Altstadt, E.; Bandini, G.;
The project ECOSTAR (acronym for ex-vessel core melt stabilization research) involves in total 17 orgnizations from five European countries. The objective of the project is to demonstrate the technical feasibility of core melt mitigation measures outside the reactor pressure vessel (RPV) as well as the validation of a selected set of codes in order to provide the necessary input for the definition of a convincing safety concept to control corium melts for both existing and future reactors.
The ECOSTAR projects is focused on three key phenomena for ex-vessel mitigation measures, namely melt release from RPV, ex-vessel corium transport and long-term corium stabilization. The extensive work program covers different scenarios and consists of a large number of experiments with both simulant and real materials, code development and validation as well as analytical activities.
This paper presents the progress of work per end of the year 2001 and the results obtained since the launch of the project.
  • Nuclear Engineering and Design, 221 (2003) 77-94
  • Nuclear Engineering and Design 235(2005)2-4, 271-284

Publ.-Id: 5419 - Permalink

Molekulare Analyse der bakteriellen Diversität in Uranabraumhalden
Geißler, A.;
kein Abstract
  • Open Access LogoWissenschaftlich-Technische Berichte / Forschungszentrum Rossendorf; FZR-377 April 2003, Diplomarbeit


Publ.-Id: 5418 - Permalink

3D particle tracking technique for FEL start-up and saturation effects
de Loos, M. J.; van der Geer, C. A. J.; van der Geer, S. G.; van der Meer, A. F. G.; Oepts, D.; Wünsch, R.;
We show that the 3D simulation code GPT (General Particle Tracer) can give very detailed results on both the produced radiation and the evolution of the elctron bunch when special subsets of electrons are tracked instead of individual macro- particles. The model and two apllications are presented.
Keywords: Free-eleectron laser
  • Poster
    Proc. 24th Int. Conf. on Free Electron Lasers, Argonne (USA) 2002;
  • Nucl. Instr. Meth. A507 (2003) 97
  • Contribution to external collection
    Proc. 24th Int. Conf. on Free Electron Lasers, Argonne (USA) 2002;

Publ.-Id: 5417 - Permalink

A transport and diagnostic system for the IR beam of ELBE
Dekorsy, T.; Grosse, E.; Helm, M.; Seidel, W.; Wohlfarth, D.; Wolf, A.; Wünsch, R.;
We outline the diagnostic and transport system of the infrared beam produced by the two free-electron lasers of the ELBE facility.
  • Poster
    Proc. 24th Int. Conf. on Free Electron Lasers, Argonne (USA) 2002, Nucl. Instr. Meth. A 507 (2003) II-35
  • Contribution to external collection
    Proc. 24th Int. Conf. on Free Electron Lasers, Argonne (USA) 2002, Nucl. Instr. Meth. A 507 (2003) II-35

Publ.-Id: 5416 - Permalink

Design study of a waveguide resonator for an infrared FEL at ELBE
Gallerano, G. P.; Gover, A.; Grosse, E.; Seidel, W.; Tecimer, M.; Wolf, A.; Wünsch, R.;
Es werden Entwurf und Rechnungen zu einem partiellen Wellenleiter f"ur den U50 Undulator des Rossendorfer ELBE Projektes vorgestellt.
  • Poster
    Proc. 22nd Int. Conf. on Free Electron Lasers, Durham USA 2000, (North-Holland, Amsterdam 2001) ed. V.N.Litvinenko, Y.K.Wu, pp. II-45,46
  • Contribution to external collection
    Proc. 22nd Int. Conf. on Free Electron Lasers, Durham USA 2000, (North-Holland, Amsterdam 2001) ed. V.N.Litvinenko, Y.K.Wu, pp. II-45,46

Publ.-Id: 5415 - Permalink

The FEL projects at the Rossendorf radiation source ELBE
Büchner, A.; Gabriel, F.; Gippner, P.; Janssen, D.; Michel, P.; Schamlott, A.; Seidel, W.; Wolf, A.; Voigtländer, J.; Wünsch, R.;
Die FEL Projekte am FZR werden vorgestellt.
  • Poster
    21st International Conference on Free Electron Lasers, 1999, Hamburg, Deutschland
  • Open Access LogoContribution to proceedings
    21st Int. Conf. on Free Electron Lasers (FEL 1999), 23.-28.08.1999, Hamburg, Deutschland
    Proceedings of FEL 1999, Amsterdam, II-49-50

Publ.-Id: 5414 - Permalink

Production of Charged Pions, Kaons and Antikaons in Relativistic C+C and C+Au Collisions
Laue, F.; Sturm, C.; Böttcher, I.; Debowski, M.; Förster, A.; Grosse, E.; Koczon, P.; Kohlmeyer, B.; Mang, M.; Naumann, L.; Oeschler, H.; Pühlhofer, F.; Schwab, E.; Senger, P.; Shin, Y.; Speer, J.; Ströbele, H.; Surowka, G.; Uhlig, F.; Wagner, A.; Walus, W.;
Production cross sections of charged pions, kaons and antikaons have been measured in C+C and C+Au collisions at beam energies of 1.0 and 1.8 AGeV for different polar emission angles. The kaon and antikaon energy spectra can be described by Boltzmann distributions whereas the pion spectra exhibit an additional enhancement at low energies. The pion multiplicity per participating nucleon M(pi+)/A_part is a factor of about 3 smaller in C+Au than in C+C collisions at 1.0 AGeV whereas it differs only little for the C and the Au target at a beam energy of 1.8 AGeV. The K+ multiplicities per participating nucleon M(K+)/A_part are independent of the target size at 1 AGeV and at 1.8 AGeV. The K- multiplicity per participating nucleon M(K-)/A_part is reduced by a factor of about 2 in C+Au as compared to C+C collisions at 1.8 AGeV. This effect might be caused by the absorption of antikaons in the heavy target nucleus. Transport model calculations underestimate the K-/K+ ratio for C+C collisions at 1.8 AGeV by a factor of about 4 if in-medium modifications of K mesons are neglected.
  • Eur.Phys.J. A9 (2000) 397-410

Publ.-Id: 5413 - Permalink

Reconstitution techniques qualification and evaluation to study aging phenomena of nuclear pressure vessel materials (RESQUE)
van Walle, E.; Scibetta, M.; Valo, M. J.; Viehrig, H.-W.; Richter, H.; Atkins, T.; Wooton, M. R.; Keim, E.; Debarberis, L.; Horsten, M.;
The RESQUE project aims at optimising and normalising reconstitution techniques and is now in its final phase. The project belongs to the AGE-cluster, that also involves the REFEREE project being used as an input to RESQUE. At FISA 97 the reference data on non-reconstituted specimens were presented together with a set of recommendations on temperature measurements (WP1, WP2). Now, the results on the quality and limiting conditions of the reconstituted weld seam are discussed.
Keywords: reactor pressure vessel steel, reconstitution technique, Charpy-V testing, fracture toughness testing, Master Curve
  • Nuclear Engineering and Design 209 (2001) 67 - 77

Publ.-Id: 5412 - Permalink

Radionuklide in der medizinischen Diagnostik
Zessin, J.;
Übersichtsvortrag zu Methoden der Nuklearmedizin
  • Lecture (others)
    Ehrenkolloquium zum 60. Geburtstag von Frau Prof. G. Schmidt, TU Clausthal-Zellerfeld, 11.04.2003

Publ.-Id: 5411 - Permalink

SIMS investigations of gettering centers in ion-implanted and annealed silicon
Gammer, K.; Gritsch, M.; Peeva, A.; Kögler, R.; Hutter, H.;
no abstract
  • Journal Trace Microprobe Tech. 20 (2002) 47

Publ.-Id: 5408 - Permalink

On the nature of ion implantation induced dislocation loops in 4H-silicon carbide
Persson, P. O. A.; Hultman, L.; Janson, M. S.; Hallén, A.; Yakimova, R.; Panknin, D.; Skorupa, W.;
no abstract
  • Journal of Applied Physics 92 (2002) 2501

Publ.-Id: 5407 - Permalink

Features of structure formation of TiN coatings obtained by plasma immersion ion implantation assisted deposition
Shevchenko, N.; Rogozin, A.; Matz, W.; Günzel, R.;
no abstract
  • Lecture (Conference)
    Proc. 6th Int. Conf. on Modification of Materials with Particle Beams and Plasma Flows, Tomsk, Russia, Sept. 23-28, 2002, pp. 540-543
  • Contribution to external collection
    Proc. 6th Int. Conf. on Modification of Materials with Particle Beams and Plasma Flows, Tomsk, Russia, Sept. 23-28, 2002, pp. 540-543

Publ.-Id: 5406 - Permalink

Implantation temperature dependence of He bubble formation in Si
Silva, D. L. D.; Fichtner, P. F. P.; Behar, M.; Peeva, A.; Kögler, R.; Skorupa, W.;
no abstract
  • Nuclear Instruments and Methods B 190 (2002) 756

Publ.-Id: 5405 - Permalink

Angular dependence of post-implantation damage recovery under 1 MeV electron irradiation in GaAs
Warchol, S.; Rzewuski, H.; Krynicki, J.; Grötzschel, R.;
no abstract
  • Nukleonika 47 (2002) 19

Publ.-Id: 5404 - Permalink

Palladium profiles in titanium treated by high-intensity plasma pulses
Werner, Z.; Piekoszewski, J.; Szymczyk, W.; Bonilla, F. A.; Ong, T. S.; Skeldon, P.; Thompson, S. G.; Zielinski, E.; Chmielewski, A.; Grötzschel, R.;
no abstract
  • Surface Coatings and Technology 158 - 159 (2002) 21

Publ.-Id: 5403 - Permalink

Post Service Investigations of VVER-440 RPV Steel from NPP Greifswald
Böhmer, B.; Böhmert, J.; Rindelhardt, U.;
Only the investigation of reactor pressure vessel steel from operated NPPs offers the opportunity to evaluate the real toughness response of the material to neutron/ gamma radiation. By investigation of material from the formerly Greifswald NPP the evaluation of a standard VVER-440-RPV design and the assessment of the quality of the used as well prediction rules as assessment tools will be possible. The rather different states (irradiated, irradated/annealed, and irradated/annealed/reirradiated) of the RPVs are a special advantage of the four units operated in Greifswald between 1973 and 1990. The paper describes the first results of these investigations and the next steps.
Keywords: neutron embrittlement, RPV
  • Lecture (Conference)
    Structural Integrity and Life of NPP Equipment "SIL 2003" Kyiv, Ukraine, May 20-22,2003
  • Contribution to external collection
    Structural Integrity and Life of NPP Equipment "SIL 2003" Kyiv, Ukraine, May 20-22,2003

Publ.-Id: 5402 - Permalink

A comparative study of structure and energetics of elementary defects in 3C- and 4H-SiC
Posselt, M.; Gao, F.; Weber, W. J.; Belko, V.;
The potential non-equivalent defects in both 3C- and 4H-SiC are classified by a new method that is based on symmetry considerations. In 4H-SiC their number is considerably higher than in 3C-SiC, since the hexagonal symmetry leads to diversification. The different theoretical methods hitherto used to investigate defects in 3C-SiC are critically reviewed. Classical MD simulations with a recently developed interatomic potential are employed to investigate the stability, structure and energetics of the large number of non-equivalent defects that may exist in 4H-SiC. Most of the potential defect configurations in 4H-SiC are found to be stable. The interstitials between hexagonal and trigonal rings, which do not exist in 3C-SiC, are characteristic for 4H-SiC and other hexagonal polytypes. The structure and energetics of some complex and anisotropic dumbbells depend strongly on the polytype. On the other hand, polytypism does not have a significant influence on the properties of the more compact and isotropic defects, such as vacancies, antisites, hexagonal interstitials, and many dumbbells. The results allow conclusions about the energy hierarchy of the defects.
Keywords: silicon carbide, defects, computer simulation, polytypism
  • Journal of Physics: Condensed Matter 16(2004), 1307

Publ.-Id: 5401 - Permalink

Experimental and Numerical Mixing Studies inside a Reactor Pressure Vessel
Höhne, T.; Kliem, S.; Prasser, H.-M.; Rohde, U.;
The work was aimed at the experimental investigation and numerical simulation of coolant mixing in the downcomer and the lower plenum of pressurized water reactors (PWR). For the investigation of the relevant mixing phenomena, the Rossendorf test facility ROCOM has been designed. ROCOM is a 1:5 scaled Plexiglas model of a German PWR allowing conductivity measurements by wire mesh sensors and velocity measurements by LDA technique. The CFD calculations were carried out with the CFD-code CFX-4. For the design of the facility, calculations were performed to analyze the scaling of the model. It was found, that the scaling of 1:5 to the prototype meets both: physical and economical demands. Flow measurements and the corresponding CFD calculations in the ROCOM downcomer under steady state conditions showed a Re number independency at nominal flow rates. The flow field is dominated by recirculation areas below the inlet nozzles. Transient flow measurements with high performance LDA-technique showed in agreement with CFX-4 results, that in the case of the start up of a pump after a laminar stage large vortices dominate the flow. In the case of stationary mixing, the maximum value of the averaged mixing scalar at the core inlet was found in the sector below the inlet nozzle, where the tracer was injected. At the start-up case of one pump due to a strong impulse driven flow at the inlet nozzle the horizontal part of the flow dominates in the downcomer. The injection is distributed into two main jets, the maximum of the tracer concentration at the core inlet appears at the opposite part of the loop where the tracer was injected. For turbulent flows the CFD-Code CFX-4 was validated and can be used in reactor safety analysis. Due to the good agreement between measured results and the corresponding CFD-calculation efficient modules for the coupling of thermal hydraulic computer codes with three-dimensional neutron-kinetic models using the results of this work can be developed. A better description of the mixing processes inside the RPV is the basis of a more realistic safety assessment.
Keywords: Mixing, Boron Dilution, CFD, RPV
  • Lecture (Conference)
    4th ASME/JSME Joint Fluids Engineering Conference, July 2003, Hawaii, USA, CD-ROM
  • Contribution to proceedings
    4th ASME/JSME Joint Fluids Engineering Conference, July 2003, Hawaii, USA, CD-ROM

Publ.-Id: 5400 - Permalink

Measuring techniques for liquid metal velocity measurements
Eckert, S.; Gerbeth, G.; Stefani, F.; Witke, W.;
A better understanding and optimisation of liquid metal processes requires experimental data of the velocity field. Numerical simulations alone are often of limited value. To measure local velocities in liquid metals or to measure channel flow rates in a contact-less way, almost nothing is available commercially.
We report on various measuring technique developments, their test in different liquid metals, and applications in hot melts. For local velocity measurements, a mechano-optical probe working up to temperatures of about 800°C has been developed [1]. It delivers the two mean velocity components perpendicular to the sensor axis. In the presence of an external steady magnetic field, the use of local potential probes allows to analyse the turbulent properties of the flow in addition to the mean velocity [2]. However, both sensor techniques rely on the introduction of probes into the melt and are thus mainly of interest for laboratory purposes.
The Ultrasound Doppler Velocimetry (UDV) became a powerful tool to measure the velocity structure of liquid flows. Because of the ability to work in opaque fluids and to deliver complete velocity profiles in real time it is very attractive for liquid metal applications. In addition, it can principally operate through the channel wall though a direct contact to the melt reduces ultrasonic losses. However, in case of hot metallic melts the user is confronted with several problems: the application of the ultrasonic transducers is usually restricted to maximum temperatures of 200°C, and a good acoustic coupling between the liquid metal and the related interfaces has to be provided. We report on successful measurements in liquid sodium at 150°C [3] which were performed through the channel wall. To overcome the limitation of ultrasonic transducers to temperatures lower than 200°C, an integrated ultrasonic sensor with acoustic wave-guide has been developed. This sensor can presently be applied at maximum temperatures up to 1000°C. Stable and robust velocity measurements have been performed in various PbBi flows at about 250-300°C. We report on first successful measurements in a CuSn melt of about 620°C and in an Al melt of about 750°C.
Evidently, a fully contact-less measuring technique would be most desirable. Such a method has been developed making use of external magnetic field measurements and inverse reconstruction techniques [4]. We will report on a first demonstration experiment showing the feasibility of this approach for the reconstruction of the three-dimensional mean velocity structure.
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 an industrial Al casting process will be presented.
  • Lecture (Conference)
    Int. Symposium on liquid metal processing and casting, Nancy (France), Sept. 21-24, 2003. Proceedings, Eds.: P.D.Lee, A.Mitchell, J.-P.Bellot, A.Jardy, 261-271, 2003.
  • Contribution to proceedings
    Int. Symposium on liquid metal processing and casting, Nancy (France), Sept. 21-24, 2003. Proceedings, Eds.: P.D.Lee, A.Mitchell, J.-P.Bellot, A.Jardy, 261-271, 2003.

Publ.-Id: 5399 - Permalink

Liquid metal model experiments on casting and solidification processes
Eckert, S.; Gerbeth, G.; Cramer, A.; Willers, B.; Witke, W.; Galindo, V.;
We report on laboratory studies using cold liquid metals as a model of realistic light metal processes. The main feature of such cold (temperatures up to about 300°C) liquid metal models is the availability of measuring techniques allowing to analyse the local transport phenomena with a sufficient resolution. Note that water models of liquid metal processes are only meaningful if the melt flow Reynolds number represents the only determining parameter of the transport processes under consideration, which is seldom the case for real casting processes. As soon as temperature gradients, free-surface phenomena, two-phase flows or electromagnetic phenomena play a role, the water model is always of very limited value.
First we present results on the flow modelling of an investment casting process 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. 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 these velocity peaks significantly. The experimental results are compared to numerical simulations.
As a second example we report on model experiments of the electromagnetic stirring of liquid metals in a cylindrical cavity. Different types of alternating magnetic fields, like rotating or travelling fields, are employed for such stirrers. The model experiments reveal that by application of just one type of those fields a strong flow results, but this flow is often of a rather rigid type without a noticeable three-dimensional mixing of the melt. An efficient mixing can be obtained by a combination of the field types. Velocity measurements in rotating, travelling, and combined rotating-travelling fields will be presented demonstrating this behaviour.
Third, we report on systematic studies about the influence of a rotating magnetic field (RMF) on the resulting microstructure of Pb-Sn alloys. The RMF strongly influences the flow in the liquid phase and, thus, the local heat transfer. It results in a significant influence on the nucleation and growth processes, leading to a variety of microstructures. Temperature as well as ultrasonic velocity profile measurements have been performed. Main goal is to find a strategy for refining the microstructure of castings by an optimal combination of magnetic field intensity, field frequency and cooling rate. For a Pb-85wt%Sn alloy, the application of the RMF is capable of changing the columnar dendritic microstructure to an equiaxed one.
  • Lecture (Conference)
    Int. Symposium on liquid metal processing and casting and solidification processes, Nancy (France), Sept. 21-24, 2003. Proceedings, Eds.: P.D.Lee, A.Mitchell, J.-P.Bellot, A.Jardy, 333-343, 2003.
  • Contribution to proceedings
    Int. Symposium on liquid metal processing and casting and solidification processes, Nancy (France), Sept. 21-24, 2003. Proceedings, Eds.: P.D.Lee, A.Mitchell, J.-P.Bellot, A.Jardy, 333-343, 2003.

Publ.-Id: 5398 - Permalink

Experimental study of non-normal non-linear transition to turbulence in a rotating magnetic field driven flow
Grants, I.; Gerbeth, G.;
Transition to turbulence of a rotating magnetic field driven liquid metal flow in a cylinder is studied experimentally by a probe-less method. A sudden, wide frequency band transition as well as intermittency are observed just at the theoretically predicted linear instability limit. A small geometrical imperfection triggers the transition in the linearly stable regime in a control parameter range where additional unstable steady solutions have been detected numerically. We discuss possibilities to predict theoretically the non-normal transition and its characteristics.
  • Physics of Fluids, USA, Vol. 15, No 10 (2003) 2803-2809

Publ.-Id: 5395 - Permalink

Kalorimetrische und potentiometrische Untersuchungen an Dendrimeren auf PAMAM Basis: Protonierung und Wechselwirkung mit HSA
Kirchner, R.; Seidel, J.; Gloe, K.; Stephan, H.;
Dendrimere sind nanoskalige, dreidimensional verzweigte Moleküle mit sphärischer Architektur, die auf vielfältige Weise funktionalisiert und modifiziert werden können. Die speziellen Eigenschaften der Dendrimere eröffnen zahlreiche neue Anwendungsmöglichkeiten, insbesondere im Pharmabereich (drug delivery systems, tumor targeting etc.) und motivieren damit auch zu umfassenden Untersuchungen der zugrunde liegenden physiko-chemischen Prozesse. Es ist bekannt, dass die Struktur und die Komplexierungseigenschaften von Dendrimeren in wässrigen Lösungen wesentlich von den Säure-Base-Eigenschaften (Protonierungsgrad) der funktionellen Gruppen und damit vom pH-Wert bestimmt werden.
Im Rahmen dieses Beitrages werden Ergebnisse kalorimetrischer und potentiometrischer pH-Titrationsexperimente in wässriger Lösung an Polyamidoamin-Dendrimeren (PAMAM), die an der Peripherie unterschiedlich funktionalisiert sind (-NH2, -OH, -COOH Gruppen), vorgestellt und diskutiert. Die potentiometrischen pH-Titrationskurven können unter Verwendung von minimal drei simultanen Protonierungsgleichgewichten mit guter Genauigkeit beschrieben werden. Die Ergebnisse sind konsistent mit dem typischen Verhalten von Polyelektrolyten.
Die kalorimetrischen pH-Titrationskurven widerspiegeln die komplexe Natur der ablaufenden Prozesse wesentlich deutlicher. Neben unterschiedlichen Stufen in den kalorimetrischen Titrationskurven, die prinzipiell den Protonierungsgleichgewichten zugeordnet werden können, treten zum Teil endotherme Effekte auf, deren Ursachen noch nicht geklärt sind. Die quantitative Beschreibung der Titrationskurven auf der Basis reiner Protonierungsreaktionen gelingt dadurch nicht vollständig.
Weiterhin werden erste kalorimetrische Ergebnisse zur aus pharmakologischer Sicht wichtigen Wechselwirkung von Dendrimeren mit potentiellen Targetmaterialien am Beispiel von Human Serum Albumin (HSA) präsentiert und diskutiert.
Keywords: Dendrimere, PAMAM, Kalorimetrie, Potentiometrie, Protonierung, HSA
  • Poster
    15. Ulm-Freiberger Kalorimetrietage, Freiberg, 19.-21. März 2003

Publ.-Id: 5394 - Permalink

Modulation of the electronic transitions of silicon light-emitting diodes produced by boron implantation
Sun, J. M.; Dekorsy, T.; Skorupa, W.; Schmidt, B.; Mücklich, A.; Helm, M.;
Two asymmetric electroluminescence bands with tunable maxima at around 1.044-1.065 and 0.90-1.00 eV are observed at low temperature in silicon pn diodes prepared by boron ion implantation and subsequent high temperature annealing. The intensity of the two bands increases strongly with increasing the boron concentration above the solubility. A large blue shift of the two bands with increasing the injection carrier concentration was attributed to the three-dimensional confinement of holes in p-type doped spikes localized on a nanometer scale. They are produced by the boron clustering at the end of range defects close to the pn junction. The two bands with a smaller binding energy is attributed to the spatially indirect recombination of the excitons confined around the strain-free p-type doped spike. The band with a higher binding energy is associated with highly strained p-type doped spikes around dislocations. A significant enhancement of the room temperature electroluminescence efficiency of the silicon diode is observed which is attributed to the spatial modulation of the band structure around these p-type doped spikes.

Keywords: Electroluminescence, silicon, pn diode, bound excitons, temperature dependence, boron clusters, implantation, electronic transitions
  • Lecture (Conference)
    E-MRS 2003 Spring Meeting Strasbourg (France) June 10-14 2003, symposium E-VI.3

Publ.-Id: 5393 - Permalink

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