Publications Repository - Helmholtz-Zentrum Dresden-Rossendorf

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33397 Publications

Whole-body-PET/MRI a new way of imaging in soft tissue sarcomas

Richter, S.; Platzek, I.; Beuthien-Baumann, B.; Laniado, M.; Kotzerke, J.; Kroschinsky, F.; Ehninger, G.; Schuler, M.
kein Abstract verfügbar
  • Abstract in refereed journal
    European Journal of Cancer 47(2011), 671-672
  • Lecture (Conference)
    The 2011 European Multidisciplinary Cancer Congress, 24.-27.09.2011, Stockholm, Schweden

Permalink: https://www.hzdr.de/publications/Publ-16854
Publ.-Id: 16854


Radiosynthesis and biological evaluation of novel receptor tyrosine kinase inhibitors for in vivo targeting of EGFR

Neto, C.; Fernandes, C.; Oliveira, C.; Gano, L.; Mendes, F.; Kniess, T.; Santos, I.
Objectives: The overexpression of the epidermal growth factor receptor (EGFR) in tumours underlines the recent interest in EGFR as an attractive target for the development of new cancer imaging agents. EGFR-tyrosine kinase inhibitors (EGFR-TKI) based on the 4-anilinoquinazoline scaffold have been explored as potential probes for EGFR imaging [1, 2]. However up to now, no optimal radiotracer is still available. Herein, we report the synthesis, radiosynthesis (125I- and 18F) and biological evaluation of three novel halogenated 6-substituted 4-anilinoquinazoline based EGFR-TKI as potential biomarkers.
Methods: The halogenated 6-substituted-4-anilinoquinazolines (2a, 2b and 2c) were obtained by reaction of 6-amino-4-anilinoquinazoline (1) with 3-/4-iodobenzoyl and 4-fluorobenzoyl chlorides as depicted in Scheme 1 [3].
Studies to inhibit EGFR autophosphorylation and A431 cellular proliferation were performed by Western blot and MTT colorimetric assays, respectively. 125I-radiolabelled anilinoquinazolines, [125I]-2a/b were prepared via destannylation of the corresponding tributylstannyl precursors with [125I]NaI. Cellular uptake studies were conducted in intact A431 cells. Optimization of the radiosynthesis of the 18F-radiolabeld anilinoquinazoline [18F]-2c was attempted by nucleophilic substitution of the trimethylammonium- and nitro-6-substituted 4-anilinoquinazoline precursors using different reaction temperatures and solvents.
Results: The 6-substituted-4-anilinoquinazolines (2a, 2b and 2c) were synthesised in high chemical yield (>90%) and fully characterized. The fluorinated quinazoline 2c with IC50 < 0.1 μM was shown to be the most potent inhibitor of EGFR autophosphorylation. Furthermore the three compounds are potent inhibitors of A431 cell proliferation as demonstrated by IC50 values (0.78µM (2a), 3.37 (2b), 2.43 µM (2c)). The 125I-radioiodinated analogues, obtained in high radiochemical purity and specific activity, displayed a relative high celular uptake (>35%) in intact A431 cells. Despite of all attempts the radiofluorinated compound [18F]-2c was only formed in a modest labeling yield (4%) what, up to now has hampered further radiopharmacological investigation.
Conclusions: Three novel halogenated 4-anilinoquinazoline-based EGFR-TK inhibitors, 2a, 2b and 2c, have been successful prepared and radiolabelled. The in vivo inhibition study of EGFR autophosphorylation and A431 cell proliferation proved that all three compounds show inhibitory properties at the micromolar level. In summary, data from this study suggest that this class of quinazolines derivatives encompasses promising derivatives with the potential to act as EGFR-TKI and should be further explored as biomarkers for SPECT and PET.
Research Support: The authors acknowledge FCT and DAAD for financial support. C. Neto thanks FCT for a Ph.D. grant (SFRH/BD/31319/2006).
References:
[1] Noble MEM. et al., (2004), Science, 303, 5665, 1800-5.
[2] Levitzki A. et al., (2003), Acc Chem Res, 36, 6, 462-9. [3] Hicks JW. et al., Molecules (2010), 15, 11, 8260-78.
[3] Fernandes C. et al., Bioorg Med Chem, (2007), 15, 12, 3974-80.
  • Poster
    19th International Symposium on Radiopharmaceutical Sciences, 28.08.-02.09.2011, Amsterdam, NL
  • Abstract in refereed journal
    Journal of Labelled Compounds and Radiopharmaceuticals 54(2011), S171

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Permalink: https://www.hzdr.de/publications/Publ-16851
Publ.-Id: 16851


Dual-labeled Anti-PSCA-antibody-based agent for PET and NIR Fluorescence imaging

Bergmann, R.; Pietzsch, J.; Steinbach, J.; Bachmann, M.
Prostate stem-cell antigen (PSCA) is a cell-surface antigen expressed in the normal prostate and overexpressed in over 80% of prostate cancer tissues. PSCA overexpression is associated with increased tumor stage, grade, and bone metastasis, as well as androgen independence and higher resistance to treatment. The aim of this work was to prepare and characterize a humanized monoclonal anti PSCA antibody (anti-PSCA mAb) for near infrared fluorescence (NIRF) and PET imaging using a near infrared (NIR) dye Alexa Fluor 750 (AF) and [64Cu]Cu-NOTA as a prerequisite for combination of both imaging methods. We evaluated the imaging potential of the [64Cu]Cu-NOTA-AF-anti-PSCA mAb in human prostate cancer xenograft mouse models by using the androgenindependent recombinant cell line PC3-PSCA as target and the non-transfected cell line as control. anti-PSCA mAb was conjugated with the bifunctional chelator 2-(p-isothiocyanatobenzyl)-1,4,7-triazacyclononane-1,4,7-triacetic acid (SCN-Bz-NOTA) and Alexa Fluor succinimidyl carboxic acid (Ex 752 nm; Em 776 nm; AF). NOTA-AF-anti-PSCA mAb was labeled with 64Cu within 30 min with high
radiolabeling yield and radiochemical purity. The [64Cu]Cu-NOTA- AF-anti-PSCA mAb showed high accumulation in xenotransplanted prostate carcinomas in mice after 24 hours demonstrated with both small animal PET and NIRF. The comparison of both methods in living animals showed the high signal intensity and accumulation of the probe in tumors; however only PET allowed the quantitative characterization of the probe distribution in vivo. Subsequent whole body cryosectioning of the animals into 40-micrometer sections permitted the direct comparison of the autoradiograms and NIRF images of the tissue cuts. The quantitative comparison of the registered autoradiograms and the NIRF images showed a good correlation of the pixel intensities, however, the different geometric resolution did not allow a pixel vise comparison. The NIRF images showed a higher differentiation than the autoradiograms. This was used to study the stability of the radio- and NIR-label on the mAbs. Dual labeling of antibodies is a promising tool for quantitative evaluation of the long time distribution in animals using also NIRF of cryosections beyond the decay of the radionuclide used.
Acknowledgement: This project was partially supported by FP7 project “GIPIO”, Project Reference: 223057
  • Poster
    World Molecular Imaging Congress 2011, 02.-10.09.2011, San Diego, USA
  • Contribution to proceedings
    World Molecular Imaging Congress, 02.-10.09.2011, San Diego, USA
    Proceedings of the 2011 World Molecular Imaging Congress, S82

Permalink: https://www.hzdr.de/publications/Publ-16850
Publ.-Id: 16850


Liquid metal alloy ion source based metal ion injection into a roomtemperature electron beam ion source

Thorn, A.; Ritter, E.; Ullmann, F.; Pilz, W.; Bischoff, L.; Zschornack, G.
We have carried out a series of measurements demonstrating the feasibility of using the Dresden electron beam ion source (EBIS)-A, a table-top sized, permanent magnet technology based electron beam ion source, as a charge breeder. Low charged gold ions from an AuGe liquid metal alloy ion source were injected into the EBIS and re-extracted as highly charged ions, thereby producing charge states as high as Au60 +. The setup, the charge breeding technique, breeding efficiencies as well as acceptance and emittance studies are presented.
Keywords: Liquid Metal ion Source, Electron Ion Beam Source, Metal Ion Injection
  • Review of Scientific Instruments 83(2012), 02A511-1-02A511-3
    DOI: 10.1063/1.3673504

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Permalink: https://www.hzdr.de/publications/Publ-16848
Publ.-Id: 16848


Study of dipole strength distributions in photon-scattering experimnets

Schwengner, R. Keywords: photon scattering, nuclear resonance fluorescence, gamma-ray cascades, photoabsorption cross section
  • Invited lecture (Conferences)
    Workshop on Statistical Gamma Rays, 06.02.2012, Oslo, Norwegen

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Permalink: https://www.hzdr.de/publications/Publ-16846
Publ.-Id: 16846


Radioiodinated sunitinib as a potential radiotracer for imaging angiogenesis - radiosynthesis and first radiopharmacological evaluation of 5-[125I]Iodo-sunitinib

Kuchar, M.; Oliveira, M. C.; Gano, L.; Santos, I.; Knieß, T.
Sunitinib® (SU11248) is a highly potent tyrosine kinase inhibitor targeting vascular endothelial growth factor receptor (VEGFR). Radiolabeled inhibitors of RTKs might be useful tools for monitoring RTKs levels in tumour tissue giving valuable information for anti-angiogenic therapy. We report here the synthesis of a 125I-labeled derivative of sunitinib® and its first radiopharmaceutical characterization.
The non-radioactive reference compound 5-iodo-sunitinib 4 was prepared by Knoevenagel condensation of 5-iodo-oxindole with the corresponding substituted 5-formyl-1H-pyrrole. In a competition binding assay against VEGFR-2 a binding constant (Kd) of 16 nM for 4 was found. The ability of 4 to inhibit tyrosine kinase activity was demonstrated on RTK expressing cells suggesting this radiotracer as a useful tool for monitoring VEGFR expression. 5-[125I]lodo-sunitinib, [125I]-4 was obtained via destannylation of the corresponding tributylstannyl precursor with [125I]NaI in the presence of H2O2 in high radiochemical yield (>95%) and radiochemical purity (<98%) after HPLC purification. Determination of human plasma protein binding at time intervals of 0; 1; 2; 4 and 24h suggested a low non-specific binding of 5-10%. Preliminary biodistribution studies of [125I]-4 in healthy CD-1 mice showed a relatively high uptake in VEGFR-2 rich tissues like kidney and lung followed by rapid washout (9.6 and 9.7; 4.5 and 3.8% ID/g of kidney and lung at 1 and 4 h, respectively).
Keywords: sunitinib®, VEGFR, RTKs, iodine-125, radiolabeling

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Permalink: https://www.hzdr.de/publications/Publ-16845
Publ.-Id: 16845


CFD modeling of free surface flow with and without condensation

Lucas, D.; Coste, P.; Höhne, T.; Lakehal, D.; Bartosiewicz, Y.; Bestion, D.; Scheuerer, M.; Galassi, M. C.
This paper presents some recent developments on CFD models suitable to simulate free surface flows, which so far represented an unresolved matter for industrial nuclear reactors issues. While the general dynamics of such a large interface should be simulated in a CFD approach all sub-grid scale effects have to be modelled. Depending on choice of the general approach – one-fluid or multi-fluid models different closures are required. The momentum transfer between the phases is usually reflected by a drag model in a two-fluid approach. The drag force depends on the local morphology (free surface or dispersed bubbles/drops) and has to be anisotropic at the free surface. Surface tension has to be considered at wavy surfaces. The situation becomes even more complex if mass transfer occurs at the interface. Three approaches with different detailedness are presented. Examples for CFD simulations for free surface flow using different CFD codes and approaches are discussed.
Keywords: CFD, free surface flow, PTS

Permalink: https://www.hzdr.de/publications/Publ-16844
Publ.-Id: 16844


Fast neutron inelastic scattering at the nELBE facility

Beyer, R.; Bemmerer, D.; Grosse, E.; Hannaske, R.; Junghans, A. R.; Kempe, M.; Kögler, T.; Massarczyk, R.; Nolte, R.; Schwengner, R.; Wagner, A.
At the superconducting electron accelerator ELBE at Helmholtz-Zentrum Dresden-Rossendorf the compact neutron time-of-flight facility nELBE has been built. There, neutrons in the kinetic energy region from some tens of keV to a few MeV are produced by means of electrons impinging onto a liquid lead target. The emitted neutron spectrum is well suited for measurements of cross sections of fast-neutron nuclear interactions relevant to the transmutation of nuclear waste. To study inelastic neutron scattering a rather unique double-time-of-flight was developed measuring both emitted particles, i.e., the scattered neutron and the de-excitation photon, in coincidence. By this method the inelastic scattering cross section can be measured with a continuous neutron source without the knowledge of the decay scheme of the sample nucleus. Beside inelastic scattering also transmission experiments to measure the total neutron cross section were performed and for the future neutron fission experiments are under preparation.
Keywords: Instrumentation and methods for time-of-flight (TOF) spectroscopy Instrumentation for neutron sources Neutron detectors nELBE

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Permalink: https://www.hzdr.de/publications/Publ-16843
Publ.-Id: 16843


Superconducting Ga-overdoped Ge layers capped with SiO2 – structural and transport investigations

Fiedler, J.; Heera, V.; Skrotzki, R.; Herrmannsdörfer, T.; Voelskow, M.; Mücklich, A.; Facsko, S.; Reuther, H.; Perego, M.; Heinig, K.-H.; Schmidt, B.; Skorupa, W.; Gobsch, G.; Helm, M.
Superconducting Ga-rich layers in Ge are fabricated by Ga implantation through a thin SiO2 cover layer. After annealing in a certain temperature window, Ga accumulation at the SiO2/Ge interface is observed. However, no Ga containing crystalline phases are identified. Thus it is suggested that the volatile Ga is stabilized in an amorphous mixture of all elements available at the interface. Electrical transport measurements reveal p-type metallic conductivity and superconducting transition. The superconducting properties of the samples with high Ga concentration at the interface change dramatically with etching the amorphous surface layer. A critical temperature of 6 K is measured before, whereas after etching it drops below 1 K. Therefore, one can conclude that the superconducting transport is based on two different layers: a Ga-rich amorphous phase at the interface and a heavily Ga-doped Ge layer. Finally, the comparison of the transport properties of Ga-rich Ge with those of Si demonstrates distinct differences between the interface layers and even the deeper lying doped regions.

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Permalink: https://www.hzdr.de/publications/Publ-16842
Publ.-Id: 16842


High Proton Energies from Cone Targets: Electron Acceleration Mechanisms

Kluge, T.; Gaillard, S.; Flippo, K.; Burris-Mog, T.; Enghardt, W.; Gall, B.; Geissel, M.; Helm, A.; Kraft, S. D.; Lockard, T.; Metzkes, J.; Offermann, D. T.; Schollmeier, M.; Schramm, U.; Zeil, K.; Bussmann, M.; Cowan, T. E.
Recent experiments in the Trident laser facility (Los Alamos National Laboratory) have shown that hollow conical targets with a flat top at the tip can enhance the maximum energy of proton beams created during the interaction of an ultra-intense short laser pulse with the target (Gaillard S A et al 2011 Phys. Plasmas 18 056710). The proton energies that have been seen in these experiments are the highest energies observed so far in laser-driven proton acceleration. This is attributed to a new acceleration mechanism, direct light pressure acceleration of electrons (DLLPA), which increases the number and energy of hot electrons that drive the proton acceleration. This acceleration process of protons due to a two-temperature sheath formed at the flat-top rear side is very robust and produces a large number of protons per shot, similar to what is regularly observed in target normal sheath acceleration (Hatchett S P et al 2000 Phys. Plasmas 7 2076, Maksimchuk A et al 2000 Phys. Rev. Lett. 84 4108, Snavely R A et al 2000 Phys. Rev. Lett. 85 2945) with flat foils. In this paper, we investigate the electron kinetics during DLLPA, showing that they are governed by two mechanisms, both of which lead to continuous electron acceleration along the inner cone wall. Based on our model, we predict the scaling of the hot electron temperature and ion maximum energy with both laser and target geometrical parameters. The scaling of T_e^{DLLPA}=m_e c_0 \frac {a_0^2} {4} with the laser strength parameter a0 leads to an ion energy scaling that surpasses that of some recently proposed acceleration mechanisms such as radiation pressure acceleration (RPA), while in addition the maximum electron energy is found to scale linearly with the length of the cone neck. We find that when optimizing parameters, high proton energies suitable for applications can be reached using compact short-pulse laser systems with pulse durations of only a few tens to hundreds of laser periods.
  • Open Access Logo New Journal of Physics 14(2012), 023038
    DOI: 10.1088/1367-2630/14/2/023038
  • Lecture (Conference)
    SPIE Oprics+Optoelectronics, 18.-21.04.2011, Prag, Tschechische Republik

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Permalink: https://www.hzdr.de/publications/Publ-16841
Publ.-Id: 16841


Was das Leben auf den Hinterlassenschaften des Uranerzbergbaus mit Zwergen zu tun hat

Raff, J.
Die Natur ist ausgesprochen erfinderisch und erfolgreich in der Herstellung und Nutzung nanoskaliger Strukturen. Aus diesem Grund sind in der Nanotechnologie biomolekulare und biologisch erzeugte Strukturen eine interessante Alternative zu technisch erzeugten Nanomaterialien. Im Rahmen des Vortrags werden mikrobiologische Forschungsarbeiten im Zusammenhang mit den Hinterlassenschaften des Uranerzbergbaus vorgestellt und an verschiedenen Beispielen ihr hohes Anwendungspotenzial in der Bionanotechnologie aufgezeigt.
  • Invited lecture (Conferences)
    Vom Molekül zum Muster (Selbstorganisationsphänomene in der Biologie), Vortragsreihe vom COM-LABBIO, 08.05.2012, Dresden, Deutschland

Permalink: https://www.hzdr.de/publications/Publ-16840
Publ.-Id: 16840


A short description of the Rossendorf Beamline at ESRF – and one scientific example of French-German collaboration: The formation of polynuclear Actinide(IV) carboxylates

Hennig, C.; Meyer, M.
The presentation will provide a short description of the Rossendorf Beamline at ESRF. Common results obtained with the University Burgundy will be discussed. The research is related with the formation of polynuclear Actinide(IV) carboxylates.
Keywords: EXAFS, Actinides
  • Invited lecture (Conferences)
    German-French research for nuclear safety: Chemistry of the f-elements, 22.-23.02.2012, Strasbourg, France

Permalink: https://www.hzdr.de/publications/Publ-16839
Publ.-Id: 16839


Standard and Helical Magnetorotational Instability: How Singularities Create Paradoxical Phenomena in MHD

Kirillov, O.; Stefani, F.
The magnetorotational instability (MRI) triggers turbulence and enables outward transport of angular momentum in hydrodynamically stable rotating shear flows, e.g., in accretion disks. What laws of differential rotation are susceptible to the destabilization by axial, azimuthal, or helical magnetic field? The answer to this question, which is vital for astrophysical and experimental applications, inevitably leads to the study of spectral and geometrical singularities on the instability threshold. The singularities provide a connection between seemingly discontinuous stability criteria and thus explain several paradoxes in the theory of MRI that were poorly understood since the 1950s.
Keywords: Rotating shear flow, Couette-Taylor flow, Accretion disk, Magnetorotational instability, WKB, Plücker conoid, Exceptional point

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Permalink: https://www.hzdr.de/publications/Publ-16838
Publ.-Id: 16838


A multi-field two-fluid concept for transitions between different scales of interfacial structures

Hänsch, S.; Lucas, D.; Krepper, E.; Höhne, T.
This paper presents a concept for the CFD-modelling of multiphase flows where both segregated and dispersed flow structures occur simultaneously. Transitions between such morphologies, characterized by different scales of interfacial structures, are investigated and a new multi-field two-fluid strategy for a generalized two-phase flow (GENTOP) is presented. The GENTOP-approach extends the inhomogeneous Multiple Size Group (MUSIG) –model by adding an additional continuous gas phase. In the MUSIG-framework, mass transfers between different bubble size groups due to coalescence and –breakup as well as gas-liquid transfers are described. By modelling an additional mass transfer between the polydispersed and continuous gas phase, transitions between the different gas morphologies can be considered dependent on the flow situation. The continuous gas phase summarizes gas structures which are large enough to be resolved within the computed mesh. Therefore a free surface detection and generalized formulations for interfacial transfer models are introduced. The appearance of one particular gas phase due to mass transfer from another gaseous morphology is demonstrated by means of two demonstration cases: the impingement of a liquid jet on a free surface with an associated bubble entrainment as well as a vertical bubble column showing a wide spectrum of bubble sizes.
Keywords: multiphase flow, CMFD, MUSIG-model, AIAD-model, gas-liquid interface, impinging jet

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Permalink: https://www.hzdr.de/publications/Publ-16837
Publ.-Id: 16837


Uranyl(VI) Complexation by Sulfonate Ligands: A Relativistic Density Functional and TRLFS Study

Kremleva, A.; Zhang, Y.; Shor, A. M.; Krüger, S.; Joseph, C.; Raditzky, B.; Schmeide, K.; Sachs, S.; Bernhard, G.; Rösch, N.
To study the role of sulfonate functional groups of humic substances in uranyl(VI) complexation, all-electron density functional calculations and time-resolved laser-induced fluorescence spectroscopy (TRLFS) were applied using small sulfonate ligands as models. A thiolate ligand was explored for comparison. As in an earlier experiment, 4-hydroxy¬benzenesulfonic acid (HBSA) and benzenesulfonic acid (BSA) were examined and compared to methylsulfonic acid (MSA). Structural parameters as well as energetic aspects of uranyl complexes by BSA and HBSA ligands were determined to be rather similar, in contrast to earlier experimental findings. The present TRLFS measurements show complexation of uranyl by both ligands in agreement with the computational results. Overall, the combined computational and experimental results indicate that sulfonate groups play only a minor role in uranyl complexation by sulfonate groups of humic substances because of the rather low stability constants.
Keywords: Density functional calculations, time resolved spectroscopy, TRLFS, uranium, sulfonates

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Permalink: https://www.hzdr.de/publications/Publ-16835
Publ.-Id: 16835


Local structure and charge distribution of Am bearing nuclear oxide fuels: (U,Am)O2±x and (U,Pu,Am)O2-x

Martin, P. M.; Belin, R. B.; Prieur, D.; Delahaye, T.; Gavilan, E.; Lebreton, F.; Robisson, A. C.; Dumas, J. C.; Scheinost, A. C.
INTRODUCTION
In the framework of recycling minor actinides (MA) in fast neutron reactors, americium can be transmuted either by adding it in a small amount to the fuel (e.g. (U,Pu,Am)O2-x) or by using dedicated blanket fuels (e.g. (U1-y,Amy)O2-x). In both strategies, the stoichiometry of the solid solution, commonly described as oxygen to metal atom ratio (O/M), is an important parameter affecting thermal, chemical, and physical properties of the fuel during irradiation. A thorough knowledge of its correlation with oxygen potential (µO2) during manufacturing and especially sintering is then of major interest. To better assess this issue, several thermodynamic descriptions have been developed1,2. Despite their differences, they all involve the valence state of actinide cations (e.g. U, Pu and Am) as an essential parameter. However, experimental data regarding actinide valence remains very limited in the literature.
As illustrated by our recent study of (U,Am)O2±x samples3, coupling X-ray diffraction (XRD) and X-ray absorption spectroscopy (XAS) measurements allows to determine actinide valence states and to describe the solid solution at both long-range and short range order as a function of oxygen potential. From these data, O/M ratio is eventually calculated using the cation molar fractions determined by XAS. In the present work, we realized a complete XAS characterization on (U,Am)O2±x and (U,Pu,Am)O2-x samples.

MATERIALS AND METHODS
Mixed oxide samples (U1-y,Amy)O2±x (y=0.10, 0.15, 0.20) and (U0.750Pu0.246Am0.004)O2-x were manufactured by conventional powder metallurgy process. By adding a controlled amount of either H2O or Ar/O2 to the furnace atmosphere (Ar/5%H2), oxygen potential were ranging from -520 kJ.mol-1 to -390 kJ.mol-1 during sintering. XAS measurements were performed at the ROssendorf Beam Line (BM20) located at the European Synchrotron Radiation Facility (ESRF, Grenoble, France). For each samples, U, Pu and Am LII,III edges were collected simultaneously in fluorescence and transmission modes at 15K using a helium cryostat.

RESULTS
Concerning americium, a complete reduction of Am4+ to Am3+ is observed for both (U,Am)O2 and (U,Pu,Am)O2 samples whatever the oxygen potential and the Am content. Unexpected results were obtained in the case of (U,Am)O2 solid solutions as, even for the lowest value of µO2 (-520 kJ.mol-1), pentavalent uranium is found, highlighting a charge compensation mechanism as the cause of this partial oxidation of uranium cations3. As a consequence, the expected hypo-stoichiometry was not observed and the solid solution can be described as .
For (U0.750Pu0.246Am0.004)O2-x samples, a radical difference is observed since uranium and americium cations remain respectively tetravalent and trivalent, regardless of the sintering conditions. On the other hand, a partial reduction of Pu4+ to Pu3+ as a function of µO2 is responsible for the continuous decrease in O/M (1.97≤O/M≤1.99). Furthermore, local environments given by EXAFS confirmed that the defects in hypo stoichiometric MOX are only located around Pu cations.
In the presentation, we will detail and compare these results and discuss their consequences on thermodynamical modeling, especially the actual temperature fixing the O/M ratio of the final material.

CONCLUSION
Using XAS measurement on (U,Am)O2±x and (U,Pu,Am)O2-x samples, O/M values were obtained as a function of oxygen potential at high temperature. Comparing these two materials, we evidenced (1) a distinct cation charge mechanism and (2) how the deviation from stoichiometry is supported in the solid solution structure. These results proved useful to better assess the thermodynamical models developed for actinides mixed oxides systems.

REFERENCES
1 M. Osaka et al. (2005) J. Nucl. Mater., 344, 230-234.
2 M. Osaka et al. (2007) J. Alloys Compounds, 428, 355-361.
3 D. Prieur et al. (2011) Inorg. Chem., 50, 12437–12445
Keywords: EXAFS XANES MOX
  • Invited lecture (Conferences)
    Plutonium Futures - The Science 2012, 15.-20.07.2012, Cambridge, United Kingdom

Permalink: https://www.hzdr.de/publications/Publ-16834
Publ.-Id: 16834


P1004 - Erzeugung kurzwelliger ultrakurzer Lichtpulse und deren Verwendung

Debus, A.; Bussmann, M.
Die Erfindung beschreibt eine Anordnung zur Erzeugung ultrakurzer und kurzwelliger Lichtpulse mit Hilfe des Thomson-wave-scattering-Verfahrens, wobei dispersive Elemente zwischen einer Elektronen-, Teilchen- oder Strahlenquelle, die mit einem Lasersystem synchronisiert ist, und einem in einer Richtung fokussierendem optischen Element angeordnet sind und die Verwendung dieser Anordnung zur Überlagerung eines pulsfrontverkippten Lichtpulses hoher Leistung mit einem ultrakurzen Puls relativistischer Elektronen in einem Laserlinienfokus. Durch die Variierung der Laserpulsfrontverkippung erhält man schmalbandige Strahlungspulse hoher Photonenzahl in einem breiten Wellenlängenbereich von EUV bis zu Röntgenwellenlängen und kann zudem die Bandbreite und Kohärenzeigenschaften anpassen. Diese Anordnung kann u. a. bei der EUV-Lithographie, bei der Planung und optimalen Auslegung von Lasersystem und Elektronenquelle, bei der Materialanalyse mittels Phasen-Kontrast-Bildgebung (phase constrast imaging), der Supraleiterforschung verwendet werden. Die vorgeschlagene Anordnung ist kleiner und kostengünstiger als vergleichbare heutige Anordnungen realisierbar.
  • Patent
    DE102010028994 - Offenlegung 17.11.2011, Nachanmeldung: WO, US - Erteilung 23.02.2016

Permalink: https://www.hzdr.de/publications/Publ-16833
Publ.-Id: 16833


P1001 - Reaktorkern in natriumgekühlten schnellen Reaktoren

Merk, B.
Hintergrund der Erfindung ist die Ausgestaltung von Reaktorkernen für natriumgekühlte schnelle Reaktoren wobei an verschiedenen Stellen im Reaktorkern feste Metall-Wasserstoff-Verbindungen eingefügt werden. Dadurch reduziert sich der Effekt der Verdampfung des Natriums deutlich und die Sicherheitskoeffizienten verbessern sich signifikant.
  • Patent
    DE102010003809A1: Offenlegung-13.10.2011
  • Patent
    WO2011123219A3: Offenlegung-15.03.2012; Nachanmeldung: EP, WO, IN, RU

Permalink: https://www.hzdr.de/publications/Publ-16832
Publ.-Id: 16832


P0908 - Verfahren zur Herstellung von SiC basierenden Dünnfilm-Solarzellen mit erhöhter Effizienz

Voelskow, M.; Kanjilal, A.; Skorupa, W.
Die Erfindung beschreibt ein Herstellungsverfahren von auf Siliziumkarbid basierenden Dünnfilm-Solarzellen. Durch eine impulsartige, intensive Lichtbestrahlung können die Silizium oder Silizium/Germanium auf Silizium Grenzflächen der Substrate kurzzeitig und facettenartig aufgeschmolzen werden. Die dadurch entstehende reliefartige Grenzfläche führt zu einer erhöhten Lichtabsorbtion in der Siliziumkarbidschicht, wodurch die Effizienz der Solarzellen erhöht wird.
  • Patent
    DE 10200905515 A1 - 29.09.2011

Permalink: https://www.hzdr.de/publications/Publ-16831
Publ.-Id: 16831


P0906-Anordnung zur Kontrolle der Strahlentherapie und Verwendungsvorschrift

Kunath, D.; Shakirin, G.; Enghardt, W.; Baumann, M.
Die Erfindung betrifft eine Anordnung zur Verbesserung der Kontrolle während der Strahlentherapie und deren Verwendung. Kern der Erfindung ist die Integration eines kombinierten PET/CT-Scanners in den Bestrahlungsplatz bzw. in unmittelbarer Nähe.

Vorteil dieser Erfindung ist, dass es zu einer Zeitersparnis für den Bestrahlungsablauf kommt, man erhält sicherere Werte für die Bestimmung des Bestrahlungserfolges. Die Positionierung des Patienten muss nur einmal vor Therapiefraktion durchgeführt werden.
  • Patent
    DE102009054676A1 - Offenlegung - 16.06.2011; Zurückweisung - 22.08.2012

Permalink: https://www.hzdr.de/publications/Publ-16830
Publ.-Id: 16830


P0901 - Koaxialer schlitzgekopplter Resonatordiplexer

Arnold, A.
Die Erfindung beschreibt eine koaxialen schlitzgekoppelten Resonatordiplexer, basierend auf der Verwendung unterschiedlicher Eigenmoden eines elektromagnetischen Resonators für die Einkopplung von wenigstens zwei Hochfrequenzwellen hoher Leistung und unterschiedlicher Wellenlänge in einen koaxialen mehrmodigen Wellenleiter. Diese Funktion ist zum Beispiel an supraleitenden Hochfrequenzresonatoren zur Beschleunigung von Elementarteilchen von großem Interesse. Ein weiteres mögliches Anwendungsgebiet findet sich in der Radartechnik.
  • Patent
    DE 102009046463 A1 - Offenlegung 04.08.2011, Erteilung 05.06.2014

Permalink: https://www.hzdr.de/publications/Publ-16829
Publ.-Id: 16829


Joint Project: Interaction and transport of actinides in natural clay rock with consideration of humic substances and clay organics - Characterization and quantification of the influence of clay organics on the interaction and diffusion of uranium and americium in the clay

Schmeide, K.; Joseph, C.; Sachs, S.; Steudtner, R.; Raditzky, B.; Günther, A.; Bernhard, G.
The objective of this project was the study of basic interaction processes in the systems actinide - clay organics - aquifer and actinide - natural clay - clay organics - aquifer. Thus, complexation, redox, sorption and diffusion studies were performed.
To evaluate the influence of nitrogen, phosphorus and sulfur containing functional groups of humic acid (HA) on the complexation of actinides in comparison to carboxylic groups, the Am(III) and U(VI) complexation by model ligands was studied by UV-Vis spectroscopy and TRLFS. The results show that Am(III) is mainly coordinated via carboxylic groups, however, probably stabilized by nitrogen groups. The U(VI) complexation is dominated by carboxylic groups, whereas nitrogen and sulfur containing groups play a minor role. Phosphorus containing groups may contribute to the U(VI) complexation by HA, however, due to their low concentration in HA they play only a subordinate role compared to carboxylic groups. Applying synthetic HA with varying sulfur contents (0 to 6.9 wt.%), the role of sulfur functionalities of HA for the U(VI) complexation and Np(V) reduction was studied. The results have shown that sulfur functionalities can be involved in U(VI) humate complexation and act as redox-active sites in HA for the Np(V) reduction. However, due to the low content of sulfur in natural HA, its influence is less pronounced.
In the presence of carbonate, the U(VI) complexation by HA was studied in the alkaline pH range by means of cryo-TRLFS (-120°C) and ATR FT-IR spectroscopy. The formation of the ternary UO2(CO3)2HA(II)4− complex was detected. The complex formation constant was determined with log β0.1 M = 24.57 ± 0.17.
For aqueous U(VI) citrate and oxalate species, luminescence emission properties were determined by cryo-TRLFS and used to determine stability constants. The existing data base could be validated.
The U(VI) complexation by lactate, studied in the temperature range 7 to 65°C, was found to be endothermic and entropy-driven. In contrast, the complex stability constants determined for U(VI) humate complexation at 20 and 40°C are comparable, however, decrease at 60°C.
For aqueous U(IV) citrate, succinate, mandelate and glycolate species stability constants were determined. These ligands, especially citrate, increase solubility and mobility of U(IV) in solution due to complexation.
The U(VI) sorption onto crushed Opalinus Clay (OPA, Mont Terri, Switzerland) was studied in the absence and presence of HA or low molecular weight organic acids, in dependence on temperature and CO2 presence using OPA pore water as background electrolyte. Distribution coefficients (Kd) were determined for the sorption of U(VI) and HA onto OPA with (0.0222 ± 0.0004) m3/kg and (0.129 ± 0.006) m3/kg, respectively. The U(VI) sorption is not influenced by HA (50 mg/L), however, decreased by low molecular weight organic acids (> 1×10-5 M), especially by citrate and tartrate. With increasing temperature, the U(VI) sorption increases both in the absence and in the presence of clay organics.
The U(VI) diffusion in compacted OPA is not influenced by HA at 25 and 60°C. Predictions of the U(VI) diffusion show that an increase of the temperature to 60°C does not accelerate the migration of U(VI). With regard to uranium-containing waste, it is concluded that OPA is suitable as host rock for a future nuclear waste repository since OPA has a good retardation potential for U(VI).
Keywords: Actinides, americium, uranium, neptunium, humic substances, clay organics, model ligands, Opalinus clay, complexation, reduction, sorption, diffusion, migration, repository
  • Open Access Logo Wissenschaftlich-Technische Berichte / Helmholtz-Zentrum Dresden-Rossendorf; HZDR-017 2012
    ISSN: 2191-8708
  • Contribution to external collection
    C.M. Marquardt: Interaction and transport of actinides in natural clay rock with consideration of humic substances and clay organic compounds, KIT Scientific Reports 7633, Karlsruhe: KIT Scientific Publishing, 2012, Annex B, Report No. 1

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Permalink: https://www.hzdr.de/publications/Publ-16828
Publ.-Id: 16828


Stability of the flow between two hemispherical electrodes

Shatrov, V.; Gerbeth, G.
The stability of the steady laminar flow driven by the meridional electromagnetic force due to an electric current from a hemispherical electrode to a hemispherical cavity surface is studied using a multi-domain pseudospectral method. The most unstable azimuthal wave number is found as m = 4. Even in a low external magnetic field, the meridional flow in the main toroidal eddy changes its direction from counter-clockwise to clockwise due to the rotation in the azimuthal direction.
  • Contribution to proceedings
    8th International pamir Conference on Fundamental and Applied MHD, 05.-09.09.2011, Borgo, Corsica, France
    Proceedings of the 8th PAMIR International Conference on Fundamental and Applied MHD, 235-239

Permalink: https://www.hzdr.de/publications/Publ-16826
Publ.-Id: 16826


Production of Σ±πpK+ in p+p reactions at 3.5 GeV beam energy

Agakishiev, G.; Balanda, A.; Belver, D.; Belyaev, A.; Berger-Chen, J. C.; Blanco, A.; Böhmer, M.; Boyard, J. L.; Cabanelas, P.; Castro, E.; Chernenko, S.; Christ, T.; Destefanis, M.; Dohrmann, F.; Dybczak, A.; Epple, E.; Fabbietti, L.; Fateev, O.; Finocchiaro, P.; Fonte, P.; Friese, J.; Fröhlich, I.; Galatyuk, T.; Garzon, J. A.; Gernhäuser, R.; Gilardi, C.; Golubeva, M.; Gonzalez-Diaz, D.; Guber, F.; Gumberidze, M.; Heinz, T.; Hennino, T.; Holzmann, R.; Ierusalimov, A.; Iori, I.; Ivashkin, A.; Jurkovic, M.; Kämpfer, B.; Kanaki, K.; Karavicheva, T.; Koenig, I.; Koenig, W.; Kolb, B. W.; Kotte, R.; Krasa, A.; Krizek, F.; Krücken, R.; Kuc, H.; Kühn, W.; Kugler, A.; Kurepin, A.; Lalik, R.; Lang, S.; Lange, J. S.; Lapidus, K.; Liu, T.; Lopes, L.; Lorenz, M.; Maier, L.; Mangiarotti, A.; Markert, J.; Metag, V.; Michalska, B.; Michel, J.; Moriniere, E.; Mousa, J.; Müntz, C.; Münzer, R.; Naumann, L.; Otwinowski, J.; Pachmayer, Y. C.; Palka, M.; Parpottas, Y.; Pechenov, V.; Pechenova, O.; Pietraszko, J.; Przygoda, W.; Ramstein, B.; Reshetin, A.; Rustamov, A.; Sadovsky, A.; Salabura, P.; Schmah, A.; Schwab, E.; Siebenson, J.; Sobolev, Y. G.; Spataro, S.; Spruck, B.; Ströbele, H.; Stroth, J.; Sturm, C.; Tarantola, A.; Teilab, K.; Tlusty, P.; Traxler, M.; Trebacz, R.; Tsertos, H.; Wagner, V.; Weber, M.; Wendisch, C.; Wüstenfeld, J.; Yurevich, S.; Zanevsky, Y.
We study the production of Σ±πpK+ particle quartets in p+p reactions at 3.5 GeV kinetic beam energy. The data were taken with the HADES experiment at GSI. This report evaluates the contribution of resonances like Λ(1405), Σ(1385)0, Λ(1520), Δ(1232), N and K0 to the Σ±πpK+ final state. The resulting simulation model is compared to the experimental data in several angular distributions and it shows itself as suitable to evaluate the acceptance corrections properly.

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Permalink: https://www.hzdr.de/publications/Publ-16825
Publ.-Id: 16825


Comparative study of wall-force models for the simulation of bubbly flows

Rzehak, R.; Krepper, E.; Lifante, C.
Accurate numerical prediction of void-fraction profiles in bubbly multiphase-flow relies on suitable closure models for the momentum exchange between liquid and gas phases. We here consider forces acting on the bubbles in the vicinity of a wall. A number of different models for this so-called wall-force have been proposed in the literature and are implemented in widely-used CFD-codes. Simulations using a selection of these models are compared with a set of experimental data on bubbly air-water flow in round pipes of different diameter. Based on the results, recommendations on suitable closures are given.
Keywords: dispersed gas liquid multiphase flow, bubble forces, Euler Euler two fluid model, CFD simulation, model validation

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Publ.-Id: 16824


The influence of the surface slope on ion induced mass drift

Kranz, A.; Heinig, K.-H.; Liedke, B.

The irradiation of solids with energetic ions can lead to the formation of periodic ripples on the surface. Furthermore, the wavevector of the ripples turns from parallel to perpendicular to the projected ion beam direction as the incidence angle increases beyond a critical angle. Here, we want to investigate this phenonemon theoretically by examination of the so called crater function.

The crater function is the average surface height change per single ion impact averaged over a stochastically representative number of ion impacts, each hitting an undisturbed target. It describes a mean mass drift that is induced by the impingment. Obviously, the crater function is symmetric to the projected ion beam direction when it is incident on a horizontal plane. But, if the beam is incident on a tilted plane the crater function is rotated and becomes asymmetric resulting in a mass drift up or down the slope.

By mathematical treatment, we give a condition on that mass can drift up the slope leading to an instability. It is shown with the help of atomistic simulations that this condition is fulfilled for gracing incidence. This explains the change in ripple orientation for increasing incidence angle as the flank of longitudinal ripples can be seen as tilted planes in a first order approximation.

Keywords: Crater function, ripples, ion beam irradiation, atomistic simulation
  • Lecture (others)
    Spring meeting of the DFG FOR 845 "Selbstorganisierte Nanostrukturen durch niederenergetische Ionenstrahlerosion", 07.-08.02.2012, Kaiserslautern, Deutschland

Permalink: https://www.hzdr.de/publications/Publ-16823
Publ.-Id: 16823


CFD for subcooled flow boiling: Coupling wall boiling and population balance models

Krepper, E.; Rzehak, R.; Lifante, C.; Frank, T.
In this work we investigate the present capabilities of CFD for wall boiling. The computational model used combines the Euler / Euler two-phase flow description with heat flux partitioning. Very similar modelling was previously applied to boiling water under high pressure conditions relevant to nuclear power systems. Similar conditions in terms of the relevant non-dimensional numbers have been realized in the DEBORA tests using Dichlorodifluoromethane (R12) as the working fluid. This facilitated measurements of radial profiles for gas volume fraction, gas velocity, liquid temperature and bubble size.
Essential for the momentum, mass and energy exchange between the phases is an adequate description of the interfacial area or respectively the bubble size. In a previous study (Krepper and Rzehak, 2011) it was shown that a monodisperse bubble size representation is not sufficient to this end. Therefore, in the present work a population balance approach is used, where bubbles are generated at the wall with a certain size that subsequently evolves due to both condensation / evaporation and coalescence / breakup processes. The results show the potential of this approach which is able to describe the observed bubble size increase after leaving the wall as well as the change of gas volume fraction profile from wall to core peaking with increasing inlet temperature.
Keywords: CFD, two phase flow, boiling, momentum exchange, population balance model

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Permalink: https://www.hzdr.de/publications/Publ-16822
Publ.-Id: 16822


Entwicklung der Radionuklid-markierten Komponente eines Tumor-Pretargeting-Systems für die Endoradionuklidtherapie auf der Basis L-konfigurierter Oligonukleotide

Förster, C.
kein Abstract verfügbar
  • Doctoral thesis
    TU Dresden, 2012
    165 Seiten

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Publ.-Id: 16821


Chirped Auger electron emission due to field-assisted post-collision interaction

Schütte, B.; Bauch, S.; Frühling, U.; Wieland, M.; Gensch, M.; Plönjes, E.; Gaumnitz, T.; Azima, A.; Bonitz, M.; Drescher, M.
We have investigated the Auger decay in xenon and krypton atoms in a terahertz streaking field. Linewidth asymmetries suggest a chirped Auger electron emission which can be understood by field-assisted post-collision interaction.
  • Contribution to proceedings
    XVIIIth International Conference on Ultrafast Phenomena, 08.-13.07.2012, Lausanne, Schweiz
    Proceedings of XVIIIth International Conference on Ultrafast Phenomena

Permalink: https://www.hzdr.de/publications/Publ-16820
Publ.-Id: 16820


How worms survive desiccation: Trehalose pro water

Erkut, C.; Penkov, S.; Fahmy, K.; Kurzchalia, T. V.
While life requires water, many organisms, known as anhydrobiotes, can survive in the absence of water for extended periods of time. Although discovered 300 years ago, we know very little about the fascinating phenomenon of anhydrobiosis. In this paper, we summarize our previous findings on the desiccation tolerance of the Caenorhabditis elegans dauer larva. A special emphasis is given to the role of trehalose in protecting membranes against desiccation. We also propose a simple mechanism for this process.
Keywords: infrared spectroscopy anhydrobiosis C. elegans

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Permalink: https://www.hzdr.de/publications/Publ-16819
Publ.-Id: 16819


Radiohalogenated 4-anilinoquinazoline-based EGFR-TK inhibitors as potential cancer imaging agents

Neto, C.; Fernandes, C.; Oliveira, M. C.; Gano, L.; Mendes, F.; Kniess, T.; Santos, I.
Introduction: The overexpression of epidermal growth factor receptor (EGFR) in tumors underlines the recent interest in EGFR as attractive target for the development of new cancer imaging agents. EGFR-tyrosine kinase inhibitors (EGFR-TKIs) based on the anilinoquinazoline scaffold have been explored as potential probes for EGFR imaging. However, up to now, no optimal radiotracer is available. Herein, we report the synthesis and biological evaluation of three novel halogenated 6-substituted 4-anilinoquinazoline based EGFR-TKIs. Radiosynthesis (125I and 18F) of the corresponding analogues was also performed.
Methods: 6a, 6b and 8 were obtained by reaction of 6-amino-4-anilinoquinazoline (5) with 3-/4-iodobenzoyl and 4-fluorobenzoyl chlorides. Inhibition of EGFR autophosphorylation and A431 cellular proliferation were assessed by Western blot and MTT assays. 125I-anilinoquinazolines [125I]6a/b were prepared via destannylation of the corresponding tributylstannyl precursors with [125I]NaI. Cellular uptake studies were conducted in A431 cells. Optimization of the radiosynthesis of the 18F-anilinoquinazoline [18F]8 was attempted by nucleophilic substitution of the trimethylammonium- and nitro-6-substituted 4-anilinoquinazoline precursors.
Results: 6a, 6b and 8 were synthesized in high chemical yield. All of them are inhibitors of EGFR autophosphorylation (0.1bIC50b1 μM) and A431 cell proliferation (IC50<3.5 μM). [125I]6a/b, obtained in high radiochemical purity and specific activity, were highly taken up by A431 cells. Biodistribution profile in mice indicated fast blood clearance and hepatobiliary excretion. Despite all attempts, [18F]8 was only formed in 4% yield, hampering further biological evaluation.
Conclusions: This study suggests that these quinazoline derivatives can act as EGFR-TKI, warranting further modifications in the chemical structure in order to be explored as potential molecular imaging agents for single photon emission computerized tomography and positron emission tomography.
Keywords: 4-Anilinoquinazolines; EGFR-TK inhibitors; Radiohalogenation; SPECT; PET; Iodine-125; Fluorine-18

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Publ.-Id: 16818


Investigations on bubble-Induced turbulence modeling for vertical pipe bubbly flows

Liao, Y.; Lucas, D.
Recently, the effect of bubbles on the generation and destruction of turbulence in the liquid phase, the so-called Bubble-Induced Turbulence (BIT), is getting more and more attention in the numerical simulation of bubbly flows. There are several theories and models available in the literature, which helps much to understand the inherent characteristics of BIT. However, a systematic validation of these models is still missing. In the current work, popular models considering the additional BIT are implemented into a 1D Test Solver, where the standard k-epsilon model for traditional Shear-Induced Turbulence (SIT) is available. The Test Solver was developed specially for the case of vertical pipe flows by Lucas et al. (2001) and for the purpose of an efficient pre-test of closure models for CFD codes. Its applicability has been tested in an amount of previous work such as Lucas et al. (2005) and (2007).

In the current work, turbulence parameters as well as liquid velocity profiles, which are predicted by the modified k-epsilon model with the consideration of BIT, are compared with experimental data published by different investigators. To exclude other uncertainties, the k-epsilon model is tested firstly for several single-phase cases with different average velocities and pipe diameters. In general, satisfying agreements are achieved in these cases. Then the contribution of BIT and the effect of various models are investigated for mono-dispersed bubbly flows. The flow is assumed to be fully-developed and moreover, the radial gas volume fraction profile is taken from the measurement. The results prove that for test cases with high gas volume fractions (high superficial gas velocity or low superficial liquid velocity) the neglecting of BIT will lead to an obvious underestimation of turbulence parameters. Furthermore, noticeable inconsistency can be observed in the results delivered by different BIT models, which indicates a need for further improvement in this aspect.
Keywords: Bubble-Induced Turbulence (BIT), Shear-Induced Turbulence (SIT), Additional eddy viscosity, Additional k-epsilon source term, Test Solver
  • Open Access Logo Contribution to proceedings
    20th International Conference on Nuclear Engineering, ICONE20, 30.07.-03.08.2012, Anaheim, USA
    Proceedings of the 20th International Conference on Nuclear Engineering
  • Lecture (Conference)
    20th International Conference on Nuclear Engineering, ICONE20, 30.07.-03.08.2012, Anaheim, USA

Permalink: https://www.hzdr.de/publications/Publ-16817
Publ.-Id: 16817


Adsorption mechanism of selenium(VI) onto maghemite

Jordan, N.; Ritter, A.; Foerstendorf, H.; Scheinost, A. C.; Weiß, S.; Heim, K.; Grenzer, J.; Mücklich, A.; Reuther, H.
In this study, the sorption properties of maghemite (γ-Fe2O3) towards selenium(VI) were studied for the first time both on the macroscopic and the molecular level. Using batch experiments, we found that the retention reaction was very fast. Both increase of pH and ionic strength led to a decrease of selenium(VI) sorption. Electrophoretic mobility measurements showed that selenium(VI) sorption had no significant effect on the isoelectric point of maghemite. These macroscopic results strongly suggested the formation of outer-sphere complexes across the investigated pH range (3.5 – 8.0). At the molecular level, the structure of the sorbed surface species was elucidated in situ using Attenuated Total Reflection Fourier-Transform Infrared (ATR FT-IR) spectroscopy and Extended X-ray Absorption Fine-Structure (EXAFS) spectroscopy. The ATR FT-IR results suggested the formation of outer-sphere complexes showing an unexpected bidentate symmetry, which possibly revealed the lack of accuracy of the actual widely-used classification of inner- and outer-sphere coordination for anionic species. EXAFS results revealed, that in addition to outer-sphere complexes, there is also a small (15%) contribution of an inner-sphere complex in binuclear corner-sharing geometry present.
Keywords: sorption; selenium(VI); maghemite; ATR FT-IR; EXAFS

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Publ.-Id: 16816


Probing origin of room temperature ferromagnetism in Ni ion implanted ZnO films with x-ray absorption spectroscop

Srivastava, P.; Ghosh, S.; Joshi, B.; Satyarthi, P.; Kumar, P.; Kanjilal, D.; Buerger, D.; Zhou, S.; Schmidt, H.; Rogalev, A.; Wilhelm, F.
We report x-ray absorption at Zn and Ni K-edges in 200 keV Ni(2+) ion implanted ZnO/sapphire films. The implantation fluences are 6 x 10(15) and 2 x 10(16) ions/cm(2), corresponding to 2% and 7% Ni in a ZnO matrix. The measurements reveal a marginal substitution of Ni in ZnO in both the films and also rule out the presence of ferromagnetic Ni metal clusters. The M-H and field cooled-zero field cooled measurements performed via SQUID magnetometry show that the films are ferromagnetic at room temperature, and the saturation magnetization of 2% Ni film is appreciably higher than that of 7% Ni film. The origin of ferromagnetism is understood on the basis of the oxygen vacancy mediated bound magnetic polaron model.

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Publ.-Id: 16815


Radiobiological effectiveness of laser accelerated electrons in comparison to electron beams from a conventional linear accelerator.

Laschinsky, L.; Baumann, M.; Beyreuther, E.; Enghardt, W.; Kaluza, M.; Karsch, L.; Lessmann, E.; Naumburger, D.; Nicolai, M.; Richter, C.; Sauerbrey, R.; Schlenvoigt, H. P.; Pawelke, J.
The notable progress in laser particle acceleration technology promises potential medical application in cancer therapy through compact and cost effective laser devices that are suitable for already existing clinics. Previously, consequences on the radiobiological response by laser driven particle beams characterised by an ultra high peak dose rate have to be investigated. Therefore, tumour and non-malignant cells were irradiated with pulsed laser accelerated electrons at the JETI facility for the comparison with continuous electrons of a conventional therapy LINAC. Dose response curves were measured for the biological endpoints clonogenic survival and residual DNA double strand breaks. The overall results show no significant differences in radiobiological response for in vitro cell experiments between laser accelerated pulsed and clinical used electron beams. These first systematic in vitro cell response studies with precise dosimetry to laser driven electron beams represent a first step toward the long term aim of the application of laser accelerated particles in radiotherapy.

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Permalink: https://www.hzdr.de/publications/Publ-16814
Publ.-Id: 16814


Laserbeschleunigte Ionenstrahlen für die Krebstherapie

Pawelke, J.
no abstract available
  • Invited lecture (Conferences)
    Vortragsforum Medica Vision, 16.-19.11.2011, Düsseldorf, Deutschland

Permalink: https://www.hzdr.de/publications/Publ-16813
Publ.-Id: 16813


Die Technologieplattform für translationale Forschung in der Protonentherapie am OncoRay Dresden..

Enghardt, W.; Bussmann, M.; Cowan, T.; Dersch, U.; Fiedler, F.; Pawelke, J.; Perrin, R.; Pieck, S.; Schramm, U.; Sauerbrey, R.; Baumann, M.
Gemäß ihrer Wechselwirkung mit (belebter) Materie sollten Protonenund Ionenstrahlen das Potenzial besitzen, den Erfolg der Strahlentherapie deutlich zu erhöhen. Begründet wird dies durch physikalische Vorteile gegenüber konventionellen Strahlenarten (Photonen, Elektronen), welche i. a. zu einer reduzierten Normalgewebsdosis und zur Möglichkeit der Dosiseskalation im Tumor führen. Im Falle der leichten Ionen kommt zu diesen physikalischen Vorteilen eine Erhöhung der relativen biologischen Wirksamkeit, welche bei adäquater technologischer Umsetzung der Strahlführung (Rasteroder Spotscanning) nahezu auf das Tumorvolumen begrenzt werden kann. Bisher konnten diese physikalisch und biologisch offenkundigen Vorteile der Partikelstrahlen für viele Bestrahlungssituationen nicht in verbesserte Tumorheilung umgesetzt werden.
Dafür sind drei Gründe anzusprechen: (1) Die in der Partikeltherapie angewendeten Behandlungs- und Qualitätssicherungstechniken wurden zum überwiegenden Teil für die konventionellen Therapie an medizinischen Elektronen-Linearbeschleunigern entwickelt und von dort übernommen. Letzteres erscheint nicht adäquat, weil Dosisverteilungen von Partikelstrahlen, im Gegensatz zu Photonenstrahlen, nicht robust gegen Ungenauigkeiten in der gesamten Kette der Strahlentherapie von der CT-Diagnostik bis zur Dosisapplikation sind. (2) Die Zahl der bisher weltweit an technologisch ausgereiften Protonen- oder Ionen-Therapieanlagen in qualitativ hochwertigen klinischen Studien behandelten Patienten ist nach wie vor klein, so dass oftmals statistisch gut gesicherte Therapieergebnisse nicht vorliegen. Generelle Anforderungen der heutigen evidenzbasierten Medizin, insbesondere auch randomisierte Studien, finden nur geringe Berücksichtigung. (3) Die unter (1) und (2) genannten Gründe folgen zu einem großen Teil aus den hohen Investitions- und Betriebskosten für Partikeltherapie-Anlagen, welche jene mit konventioneller Bestrahlungstechnologie um ca. eine Größenordnung übersteigen.
Diese Analyse definiert die medizinischen, strahlenbiologischen und physikalisch-technischen Arbeitsfelder der im Aufbau befindlichen Hochtechnologieplattform am Nationalen Zentrum für Strahlenforschung in der Onkologie - OncoRay, Dresden: (1) Die Entwicklung von Technologien, welche auf die der Partikeltherapie inhärenten Präzision zugeschnitten sind (Bewegungskompensation, Bildführung, dreidimensionale Dosislokalisation, ortsaufgelöste in-vivo Dosimetrie in Echtzeit). (2) Den Einschluss aller Patienten in klinische Studien. (3) Die Entwicklung neuartiger auf der Laser-Teilchenbeschleunigung beruhender Partikeltherapie-Anlagen, die kompakt und kostengünstig sind.
Diese klinischen und wissenschaftlichen Zielstellungen bestimmen die Auslegung der Anlage. Sie wird auf dem Gelände des Universitätsklinikums Carl Gustav Carus Dresden errichtet und in die bestehende Klinik und Poliklinik für Strahlentherapie und Radioonkologie integriert. Sie wird mit einer konventionellen Zyklotron basierten Protonen-Bestrahlungsanlage (Hersteller: Fa. IBA, Louvain-la-Neuve, Belgien) ausgerüstet. Der Protonenstrahl bedient vorerst einen klinischen Bestrahlungsbunker mit isozentrischer Gantry, ausgestattet mit einer universellen Strahlführung für passive und aktive Bestrahlungsfeld-Formierung. Ferner wird für experimentelle Arbeiten der Protonenstrahl in einen Experimentalbunker geführt. Auf dessen Dach wird ein Reinraum für einen Dioden gepumpten Hochintensitäts-Laser der Petawatt-Klasse errichtet. Das Laserlicht wird in den Experimentalbunker geführt, so dass dort sowohl konventionell als auch Laser beschleunigte Protonenstrahlen zur Verfügung stehen werden. Dies wird für die Entwicklung und Validierung dedizierter Strahlführungssysteme, dosimetrischer Messverfahren, Echtzeit-Verifikations- und Qualitätssicherungs-Techniken sowie für die Durchführung strahlenbiologischer Experimente an Laser beschleunigten Protonenstrahlen ein bisher weltweit nicht vorhandenes Umfeld bieten.
  • Lecture (Conference)
    3 Ländertagung der ÖGMP, DGMP und SGSMP – 2011 Medizinische Physik, 28.09.-01.10.2011, Wien, Österreich

Permalink: https://www.hzdr.de/publications/Publ-16812
Publ.-Id: 16812


Dosimetrie und biologische Wirksamkeit Laser beschleunigter Protonen

Schürer, M.; Baumann, M.; Beyreuther, E.; Burris-Mog, T.; Dammene, Y.; Enghardt, W.; Karsch, L.; Kraft, S.; Kroll, F.; Laschinsky, L.; Lessmann, E.; Metzkes, J.; Naumburger, D.; Oppelt, M.; Richter, C.; Schramm, U.; Sobiella, M.; Zeil, K.; Pawelke, J.
Einleitung: Bevor die neue Technologie der Laser Beschleunigung in der Strahlentherapie eingesetzt werden kann, müssen Beschleuniger einen stabilen, steuerbaren Strahl mit genügender Strahlstärke liefern. Ausserdem müssen die entstehenden ultra kurzen, sehr intensiven Strahlpulse auf ihre biologische Wirksamkeit und dosimetrische Erfassung hin untersucht werden.
Methoden: Es wurde ein integriertes Dosimetrie- und Zellbestrahlungssystem (IDOCIS) entwickelt, getestet und umfangreich kalibriert.
Die Kombination verschiedener Dosimeter erlaubt eine präzise Absolutdosimetrie und Strahlüberwachung in Echtzeit. Nach zusätzlicher Modifizierung und Optimierung des 150 TW Lasersystems DRACO (FZD) wurden Zellbestrahlungen mit Laser beschleunigten Protonen durchgeführt.
Ergebnisse: Der Laserbeschleuniger lieferte überWochen einen stabilen und reproduzierbaren Protonenstrahl. Zusammen mit der präzisen dosimetrischen Erfassung mit Hilfe des IDOCIS wurden Dosiseffektkurven bestimmt.
Schlussfolgerung: Vor einem Einsatz Laser beschleunigter Protonen in der Strahlentherapie sind verschiedene Verbesserungen der Lasertechnik und die Durchführung von tierexperimentellen Studien notwendig.
ST 1.4
  • Poster
    3 Ländertagung der ÖGMP, DGMP und SGSMP – 2011 Medizinische Physik, 28.09.-01.10.2011, Wien, Österreich

Permalink: https://www.hzdr.de/publications/Publ-16811
Publ.-Id: 16811


Bubble-induced Turbulence: Comparison of CFD Models

Rzehak, R.; Krepper, E.
Modeling of bubble-induced turbulence in dispersed gas-liquid multiphase flow is an important but still unresolved issue. A common approach to its solution is to add source terms to the single phase two-equation turbulence models. We here report a comparison of different models of this type some of which have been used previously in the literature, some of which are new. Special care has been given to the selection of a set of reference data allowing to qualify the validity of the different models. Conclusions towards best practice guidelines for modeling bubbly turbulence are drawn and needs for further reasearch identified.
Keywords: dispersed gas liquid multiphase flow, bubble induced turbulence, Euler Euler two fluid model, CFD simulation, model validation
  • Contribution to proceedings
    International Symposium on Multiphase flow and Transport Phenomena, 22.-25.4.2012, Agadir, Morocco
  • Lecture (Conference)
    International Symposium on Multiphase flow and Transport Phenomena, 22.-25.4.2012, Agadir, Morocco

Permalink: https://www.hzdr.de/publications/Publ-16810
Publ.-Id: 16810


Biological effectiveness of laser accelerated protons: In vitro dose response studies

Oppelt, M.; Baumann, M.; Beyreuther, E.; Murris-Mog, T.; Enghardt, W.; Karsch, L.; Kraft, S.; Laschinsky, L.; Leßmann, E.; Metzkes, J.; Naumburger, D.; Richter, C.; Schramm, U.; Schürer, M.; Zeil, K.; Pawelke, J.
The development of proton and ion acceleration by ultra-high intensity lasers for cancer therapy promises the realisation of compact and economic particle accelerators that can be integrated in already existing clinics. However, particle acceleration with high intensity lasers leads in comparison to the conventional used acceleration technique to ultra short beam pulses, generated with low pulse frequency, that apply a very high pulse dose. Prior to a clinical application the radiobiological consequences of laser accelerated and therewith ultra short pulsed particle beams have to be investigated.
For this in vitro dose effect curves have been determined, which required a high power laser system with a stable and reproducible acceleration of protons, precise beam monitoring and the technical ability to apply a prescribed dose to a cell sample and to determine the absolute dose received by the cells.
Systematic cell irradiations were performed at the 150 TW Ti:Sapphire laser system DRACO at HZDR that delivered laser pulseswith an energy of 3.5 J, a pulse duration of 30 fs and a frequency of 0.1 Hz. By focusing the laser on a 2 μm thin Ti foil, protons were accelerated from the target rear surface. The generated exponential energy spectrum was limited downwards to 6-20 MeV. An in-house developed integrated dosimetry and cell irradiation system was tested and calibrated, allowing precise dosimetry as well as the exact positioning of each cell sample.
In the present experiment radiosensitive head and neck tumour cells (SKX) were irradiated in a dose range from 0.5-4 Gy with an average pulse dose of 80 mGy and a mean dose rate of 0.5 Gy/min.
Investigated biological endpoints were the clonogenic cell survival and residual DNA-double strand breaks (DSB) 24 h post irradiation via γ-H2AX /p53BP1 assay.
Reference irradiation was performed with continuous, conventional accelerated 7.2 MeV proton beams at the Tandem accelerator at HZDR with a dose rate of 1.1 Gy/min.
The measured dose effect curves show no difference in biological effectiveness between laser accelerated ultra short pulsed and conventional continuous proton beams in clonogenic cell survival and residual DNA DSB.
  • Poster
    14th International Congress of Radiation Research (ICRR), 28.08.-01.09.2011, Warszawa, Poland

Permalink: https://www.hzdr.de/publications/Publ-16809
Publ.-Id: 16809


Dosimetry of laser-accelerated particle beams used for cell irradiation experiments

Pawelke, J.
no abstract available
  • Invited lecture (Conferences)
    HEPTech Workshop, Industry meets Academia: Beam Monitoring Instrumentation and Quality Assurance, 10.-11.11.2011, Darmstadt, Deutschland

Permalink: https://www.hzdr.de/publications/Publ-16808
Publ.-Id: 16808


Towards radiotherapy application of laser driven particle beams

Pawelke, J.
Abstract not available
  • Invited lecture (Conferences)
    International Conference on Medical Physics and Engineering, 21.-24.09.2011, Poznan, Poland
  • Abstract in refereed journal
    Polish Journal of Medical Physics and Engineering 17(2011)Suppl.1, 34

Permalink: https://www.hzdr.de/publications/Publ-16807
Publ.-Id: 16807


Laser driven accelerators for radiobiology experiment

Pawelke, J.; Beyreuther, E.; Burris-Mog, T.; Cowan, T.; Kraft, S.; Laschinsky, L.; Leßmann, E.; Metzkes, J.; Richter, C.; Schlenvoigt, H. P.; Schramm, U.; Zeil, K.; Baumann, M.; Dammene, Y.; Enghardt, W.; Karsch, L.; Naumburger, D.; Schürer, M.; Woithe, J.; Kaluza, M.; Nicolai, M.
no abstract available
  • Invited lecture (Conferences)
    ESTRO Anniversary Congress, 08.-12.05.2011, London, United Kingdom

Permalink: https://www.hzdr.de/publications/Publ-16806
Publ.-Id: 16806


Impinging jet simulations using a multi-field approach with free surface detection

Hänsch, S.; Lucas, D.; Krepper, E.; Höhne, T.; Danciu, D.-V.
The calculation of impinging liquid jets and the associated bubble entrainment is a challenging problem in two-fluid model applications. The various mechanisms behind these phenomena are not well understood and a better appreciation of them is vitally important for industrial and scientific issues. The difficulty of simulation arises from the fact that impinging jets show a mixture of both segregated and dispersed flow regimes. Therefore they demand a multi-fluid simulation to capture larger gas structures with resolved interfaces as well as many small bubbles of different sizes that require an averaged treatment. In order to deal with the complexity of these mechanisms a new CMFD-strategy of a generalized two-phase flow (GENTOP) is presented.
Currently, the GENTOP-concept combines a three-field simulation with the recently developed inhomogeneous Multiple Size Group (MUSIG)-approach. The flow is represented by a liquid phase, a polydispersed gas phase, containing different bubble size groups, and a continuous gas phase. Within the MUSIG-framework, transfers between the different bubble size groups due to bubble coalescence and -breakup are described. By modelling an additional mass transfer between the continuous and the polydispersed gas phase, transitions between different gas morphologies can be considered. The continuous gas phase summarizes all gas structures larger than a certain bubble diameter so that for these structures the gas-liquid interfaces are resolved. In order to blend the gaseous morphology basic ideas of the Algebraic Interfacial Area Density (AIAD)-model are used. Generalized formulations for interfacial area density and drag are introduced considering free surfaces within a multi-fluid simulation. This new concept can provide more detailed information about complex flow situations with higher gas fractions such as the impinging jet being just one particular application.
First results computed by the CFD-code CFX 13.0 are compared to experiments carried out at the HZDR and empirical correlations from literature. The flow field is adapted to the experiments considering inlet velocity of the jet v0=1.7m/s, jet length Lj=10mm and jet diameter d0=16mm as well as the dimensions of the water tank. The computational results show good qualitative agreement with the experiments regarding typical continuous and polydispersed gas structures. The values of air entrainment rate and bubble plume length are determined as quantitative values characterizing the results. Further developments consist of new generalized closure models for bubble coalescence and –breakup processes between continuous and dispersed gas phases.
Keywords: turbulent impinging jet, air entrainment, CMFD, gas-liquid interface, MUSIG-model, AIAD-model
  • Contribution to proceedings
    International Symposium on Multiphase Flow and Transport Phenomena, 22.-25.04.2012, Agadir, Marokko
  • Lecture (Conference)
    International Symposium on Multiphase Flow and Transport Phenomena, 22.-25.04.2012, Agadir, Marokko

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Permalink: https://www.hzdr.de/publications/Publ-16805
Publ.-Id: 16805


Status der Protonentherapie auf Basis von Hochintensitätslasern – Erste Dosis-Effekt-Kurven Laser beschleunigter Protonen.

Karsch, L.; Baumann, M.; Beyreuther, E.; Burris-Mog, T.; Kraft, S.; Laschinsky, L.; Metzkes, J.; Naumburger, D.; Oppelt, M.; Richter, C.; Schramm, U.; Schürer, M.; Zeil, K.; Pawelke, J.
no abstracts available
  • Lecture (Conference)
    17. Jahreskongress der Deutschen Gesellschaft für Radioonkologie, 02.-05.06.2011, Wiesbaden, Deutschland

Permalink: https://www.hzdr.de/publications/Publ-16803
Publ.-Id: 16803


Dosimetry and biological effectiveness of laser-accelerated particle beams

Karsch, L.; Baumann, M.; Beyreuther, E.; Burris-Mog, T.; Cowan, T.; Dammene, Y.; Enghardt, W.; Laschinsky, L.; Lessmann, E.; Kaluza, M. C.; Kraft, S.; Metzkes, J.; Naumburger, D.; Nicolai, M.; Richter, C.; Sauerbrey, R.; Schlenvoigt, H. P.; Schramm, U.; Schürer, M.; Sobiella, M.; Woithe, J.; Zeil, K.; Pawelke, J.
Purpose: Before laser particle accelerators can be used for radiation therapy, the supply of stable, reliable and reproducible beams with sufficient particle intensity and useable energy spectra is required. Moreover, consequences on dosimetry as well as on radiobiological effectiveness have to be investigated for laser-accelerated and therefore ultra-shortly pulsed particle beams with very high pulse dose rate.
Method and Materials: In vitro cell irradiations have been established and performed within the German multi-institutional research project onCOOPtics for both laser-accelerated electron and proton beams.
The experimental setups at two lasers, the 10 TW JETI laser for electron and the 150 TW DRACO laser for proton beams, includes a dedicated system for routine cell sample irradiation and precise determination of applied dose. After extensive tuning and optimization of the laser systems and particle beams as well as test and calibration of all dosimetric components, systematic radiobiological experiments with several tumor and normal tissue cell lines have been performed over the last three years measuring dose-effect-curves for cell survival and DNA double strand break induction.
Results: No significant differences in biological effectiveness between laser-accelerated and conventional electron beams were found, apart from one cell line at one end point. The evaluation of the recently finished proton irradiation campaign is in progress.
Conclusion: Laser accelerators can be used for radiobiological experiments, meeting all necessary requirements like homogeneity, stability and precise dose delivery. Nevertheless, before fulfilling the much higher requirements for clinical application, several improvements concerning i.e. proton energy, spectral shaping and patient safety are necessary.
  • Contribution to proceedings
    SPIE Optics and Optoelectronics 2011, 18.-21.04.2011, Prague, Czech Republic
    Proceedings of SPIE Optics and Optoelectronics 2011, 132-133
  • Lecture (Conference)
    Dosimetry and biological effectiveness of laser-accelerated particle beams, 18.-21.04.2011, Prague, Czech Republic

Permalink: https://www.hzdr.de/publications/Publ-16802
Publ.-Id: 16802


The Energy Dependence of the Electric Dipole Strength in Heavy Nuclei

Junghans, A. R.; Beyer, R.; Grosse, E.; Rusev, G.; Schwengner, R.; Wagner, A.
We investigate on the basis of new photon scattering measurements and photoneutron and average neutron resonance capture data how well Lorentzians adjusted to photoneutron data in the giant dipole resonances give a good description of the photon strength also below the neutron threshold. If deformation effects are properly taken into account it is verified that down to about 4 MeV for various nuclei with A £¾ 80 the previously employed differentiation between deformed and non-deformed nuclei is no longer necessary.

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Permalink: https://www.hzdr.de/publications/Publ-16801
Publ.-Id: 16801


Stable proton pulses for the measurement of the biological effectiveness of laser accelerated particle beams.

Zeil, K.; Metzkes, J.; Kraft, S.; Cowan, T.; Karsch, L.; Pawelke, J.; Richter, C.; Sauerbrey, R.; Schramm, U.
The advent of high power laser systems providing pulse rates of a few pulses per minute in the field of laser ion acceleration has brought medical applications such as ion therapy of cancer closer into reach. Although the proton energies are still not high enough for patient treatment, they are sufficient to start first experiments on dosimetry and the biological effectiveness. In contrary to conventional accelerators, the laser ion acceleration delivers proton bunches with a very high charge in short times with a broad energy spectrum. Thus new concepts in dosimetry and irradiation are necessary.
It is evident, that applications with biological material have demanding requirements to the proton energy spectrum and its stability. In this paper we present a robust scheme to provide stable energy spectra for first cell irradiation experiments performed with the Dresden 150 TW laser system DRACO at a dose rate of about 1 Gy/min. A second paper will concentrate on the radiobiological aspects of the experiment and the complex dosimetry issues.
In addition to the production of a reproducible proton spectrum the scheme involves magnetic filtering. Based on a simple non-focusing magnetic dipole equipped with two apertures it makes use of an energy dependent angular asymmetry of the proton spectra and protons with energies above 7 MeV originating from a 2 μm thick Titanium foil are led to the cell sample.
S.D. Kraft, et al., Dose dependent biological damage of tumour cells by laser-accelerated proton beams, New Journal of Physics 12, 085003(2010)
  • Invited lecture (Conferences)
    SPIE Optics and Optoelectronics 2011, 18.-21.04.2011, Prague, Czech Republic
  • Contribution to proceedings
    SPIE Optics and Optoelectronics 2011, 18.-21.04.2011, Prague, Czech Republic
    Proceedings of SPIE Optics and Optoelectronics 2011, 132

Permalink: https://www.hzdr.de/publications/Publ-16800
Publ.-Id: 16800


Development of a Neutron TOF Facility at KAERI

Song, T.-Y.; Park, S.-H.; Lee, B. C.; Lee, Y.-O.; Junghans, A. R.
KAERI (Korea Atomic Energy Research Institute) is developing a neutron TOF facility by using KAERI's electron accelerator. KAERI has a superconducting electron accelerator which can produce 17 MeV pulsed electron beams with a pulse width of 20 ps. The pulse current and maximum frequency of the electron accelerator are 20 A and 2 MHz respectively. Fast neutrons can be used for cross-section measurements. A short pulse width can provide a good neutron energy resolution for fast neutrons at relatively short flight lengths. The time resolution related to a neutron source target should be small enough to utilize the short pulse width. We adopted the liquid Pb target which was developed by FDZ (Forschungszentrum Dresden-Rossendorf). The first step of the neutron source development is to simulate a neutron production. MCNPX was used to simulate the neutron production when electron beams irradiate the Pb target. Those simulations were performed by varying beam energies and target sizes to find out optimal variables related to the beam and target. The information of heat deposition in the target was studied by MCNPX since a proper cooling system should be considered to operate the liquid Pb target safely. The thermal-hydraulic analysis was performed based on the result of heat deposition calculation. The study of the detection system is under progress. The design of an experimental hall and a collimator system is also being progressed with the development of the detection system.

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Permalink: https://www.hzdr.de/publications/Publ-16799
Publ.-Id: 16799


Laser particle acceleration for future ion beam therapy

Pawelke, J.
no abstract available
  • Poster
    Meeting of the Scientific Advisory Board of University Cancer Center Dresden, 13.04.2011, Dresden, Deutschland

Permalink: https://www.hzdr.de/publications/Publ-16798
Publ.-Id: 16798


Dosimetrie und biologische Wirksamkeit Laser beschleunigter Protonenstrahlen

Karsch, L.; Baumann, M.; Beyreuther, E.; Burris-Mog, T.; Cowan, T.; Dammene, Y.; Enghardt, W.; Laschinsky, L.; Lessmann, E.; Kraft, S.; Metzkes, J.; Naumburger, D.; Richter, C.; Sauerbrey, R.; Schramm, U.; Schürer, M.; Sobiella, M.; Woithe, J.; Pawelke, J.
Einleitung: Bevor die neue Technologie der Laser Beschleunigung in der Strahlentherapie eingesetzt werden kann, müssen Beschleuniger einen stabilen, steuerbaren Strahl mit genügender Strahlstärke liefern. Ausserdem müssen die entstehenden ultra kurzen, sehr intensiven Strahlpulse auf ihre biologische Wirksamkeit und dosimetrische Erfassung hin untersucht werden.
Methoden: Es wurde ein integriertes Dosimetrie- und Zellbestrahlungssystem (IDOCIS) entwickelt, getestet und umfangreich kalibriert.
Die Kombination verschiedener Dosimeter erlaubt eine präzise Absolutdosimetrie und Strahlüberwachung in Echtzeit. Nach zusätzlicher Modifizierung und Optimierung des 150 TW Lasersystems DRACO (FZD) wurden Zellbestrahlungen mit Laser beschleunigten Protonen durchgeführt.
Ergebnisse: Der Laserbeschleuniger lieferte überWochen einen stabilen und reproduzierbaren Protonenstrahl. Zusammen mit der präzisen dosimetrischen Erfassung mit Hilfe des IDOCIS wurden Dosiseffektkurven bestimmt.
Schlussfolgerung: Vor einem Einsatz Laser beschleunigter Protonen in der Strahlentherapie sind verschiedene Verbesserungen der Lasertechnik und die Durchführung von tierexperimentellen Studien notwendig.
  • Invited lecture (Conferences)
    75th Annual Meeting of the DPG and combined DPG Spring Meeting 2011, Radiation and Medical Physics Division, 13.-18.03.2011, Dresden, Deutschland

Permalink: https://www.hzdr.de/publications/Publ-16797
Publ.-Id: 16797


Experimental study of fragmentation products in the reactions 112Sn+112Sn and 124Sn+124Sn at 1A GeV

Föhr, V.; Bacquias, A.; Casarejos, E.; Enqvist, T.; Junghans, A. R.; Kelic-Heil, A.; Kurtukian, T.; Lukic, S.; Pérez-Loureiro, D.; Pleskac, R.; Ricciardi, M. V.; Schmidt, K.-H.; Taieb, J.
Production cross sections and longitudinal velocity distributions of the projectilelike residues produced in the reactions 112Sn+112Sn and 124Sn+124Sn, both at an incident beam energy of 1A GeV, were measured with the high-resolution magnetic spectrometer, the Fragment Separator of GSI. For both reactions the characteristics of the velocity distributions and nuclide production cross sections were determined for residues with atomic number Z≥10. A comparison of the results of the two reactions is presented.

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Permalink: https://www.hzdr.de/publications/Publ-16796
Publ.-Id: 16796


Temperature dependence of the intraexcitonic AC Stark effect in semiconductor quantum wells

Wagner, M.; Teich, M.; Helm, M.; Stehr, D.
We have investigated the temperature-dependent, intraexcitonic AC Stark effect that manifests itself in a line splitting of the heavy-hole 1s exciton transition in a GaAs/AlGaAs multi quantum well when the 1s-2p intraexciton transition is driven by intense THz light. The observed wavelength-dependent splitting at Helium temperature can still be distinguished at elevated temperatures up to 200 K. Although the thermal energy exceeds the exciton binding energy by a factor of 1.7, thermal exciton ionization influences the coherent nonlinear effect only indirectly via thermal line broadening. With a threefold transmission change on ultrafast timescales in a region accessible to Peltier-cooling the scheme could be promising for optical modulators.
Keywords: quantum well, intraexcitonic AC Stark effect, FEL, THz, temperature-dependent

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Permalink: https://www.hzdr.de/publications/Publ-16795
Publ.-Id: 16795


Towards laser driven proton therapy: Radiobiological experiments.

Pawelke, J.
no abstract available
  • Invited lecture (Conferences)
    Retreat of the Laser Particle Acceleration Department at the Helmholtz-Zentrum Dresden Rossendorf, 28.02.-01.03.2011, Griess, Österreich

Permalink: https://www.hzdr.de/publications/Publ-16794
Publ.-Id: 16794


Modeling of metal nanocluster growth on patterned substrates and surface pattern formation under ion bombardment

Numazawa, S.
This thesis addresses the metal nanocluster growth process on prepatterned substrates, the development of atomistic simulation method with respect to an acceleration of the atomistic transition states, and the continuum model of the ion-beam inducing semiconductor surface pattern formation mechanism.
Experimentally, highly ordered Ag nanocluster structures have been grown on pre-patterned amorphous SiO^2 surfaces by oblique angle physical vapor deposition at room temperature. Despite the small undulation of the rippled surface, the stripe-like Ag nanoclusters are very pronounced, reproducible and well-separated. The first topic is the investigation of this growth process with a continuum theoretical approach to the surface gas condensation as well as an atomistic cluster growth model. The atomistic simulation model is a lattice-based kinetic Monte-Carlo (KMC) method using a combination of a simplified inter-atomic potential and experimental transition barriers taken from the literature.
An effective transition event classification method is introduced which allows a boost factor of several thousand compared to a traditional KMC approach, thus allowing experimental time scales to be modeled. The simulation predicts a low sticking probability for the arriving atoms, millisecond order lifetimes for single Ag monomers and ≈1 nm square surface migration ranges of Ag monomers. The simulations give excellent reproduction of the experimentally observed nanocluster growth patterns.
The second topic specifies the acceleration scheme utilized in the metallic cluster growth model. Concerning the atomistic movements, a classical harmonic transition state theory is considered and applied in discrete lattice cells with hierarchical transition levels. The model results in an effective reduction of KMC simulation steps by utilizing a classification scheme of transition levels for thermally activated atomistic diffusion processes. Thermally activated atomistic movements are considered as local transition events constrained in potential energy wells over certain local time periods. These processes are represented by Markov chains of multi-dimensional Boolean valued functions in three dimensional lattice space. The events inhibited by the barriers under a certain level are regarded as thermal fluctuations of the canonical ensemble and accepted freely. Consequently, the fluctuating system evolution process is implemented as a Markov chain of equivalence class objects. It is shown that the process can be characterized by the acceptance of metastable local transitions. The method is applied to a problem of Au and Ag cluster growth on a rippled surface. The simulation predicts the existence of a morphology dependent transition time limit from a local metastable to stable state for subsequent cluster growth by accretion.
The third topic is the formation of ripple structures on ion bombarded semiconductor surfaces treated in the first topic as the prepatterned substrate of the metallic deposition. This intriguing phenomenon has been known since the 1960's and various theoretical approaches have been explored. These previous models are discussed and a new non-linear model is formulated, based on the local atomic flow and associated density change in the near surface region. Within this framework ripple structures are shown to form without the necessity to invoke surface diffusion or large sputtering as important mechanisms. The model can also be extended to the case where sputtering is important and it is shown that in this case, certain \lq magic' angles can occur at which the ripple patterns are most clearly defined. The results including some analytic solutions of the nonlinear equation of motions are in very good agreement with experimental observation.
Keywords: Nanocluster growth, Kinetic Monte-Carlo, Ion beam surface modification
  • Open Access Logo Wissenschaftlich-Technische Berichte / Helmholtz-Zentrum Dresden-Rossendorf; HZDR-021 2012
    ISSN: 2191-8708

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Permalink: https://www.hzdr.de/publications/Publ-16793
Publ.-Id: 16793


Focusing of short-pulse high-intensity laser-accelerated proton beams

Bartal, T.; Foord, M. E.; Bellei, C.; Key, M. H.; Flippo, K. A.; Gaillard, S. A.; Offermann, D. T.; Patel, P. K.; Jarrott, L. C.; Higginson, D. P.; Roth, M.; Otten, A.; Kraus, D.; Stephens, R. B.; Mclean, H. S.; Giraldez, E. M.; Wei, M. S.; Gautier, D. C.; Beg, N.
Recent progress in generating high-energy (>50 MeV) protons from intense laser–matter interactions (1018–1021Wcm2; refs 1–7) has opened up new areas of research, with applications in radiography8, oncology9, astrophysics10, medical imaging11, high-energy-density physics12–14, and ion-proton beam fast ignition15–19. With the discovery of proton focusing with curved surfaces20,21, rapid advances in these areas will be driven by improved focusing technologies. Here we report on the first investigation of the generation and focusing of a proton beam using a cone-shaped target.We clearly show that the focusing is strongly affected by the electric fields in the beam in both open and enclosed (cone) geometries, bending the trajectories near the axis. Also in the cone geometry, a sheath electric field effectively ‘channels’ the proton beam through the cone tip, substantially improving the beam focusing properties. These results agree well with particle simulations and provide the physics basis for many future applications.

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Permalink: https://www.hzdr.de/publications/Publ-16791
Publ.-Id: 16791


Biologische Wirksamkeit laserbeschleunigter Protonen im Vergleich zu konventionell beschleunigten Protonen.

Oppelt, M.; Beyreuther, E.; Burris-Mog, T.; Kraft, S.; Laschinsky, L.; Leßmann, E.; Metzkes, J.; Schramm, U.; Zeil, K.; Richter, C.
Strahlentherapie zur Krebsbehandlung nutz ionisierende Strahlung um letale Schäden im Tumor zu applizieren. Aufgrund der Art der Energiedeposition von Protonen in Materie kann dies, vergliechen mit konventioneller Therapie mit Photonen oder Elektronen, wesentlich schonender für umliegendes gesundes Gewebe realisiert werden.
  • Open Access Logo Contribution to proceedings
    20. Symposium Experimentelle Strahlentherapie und Klinische Strahlenbiologie, 10.-12.02.2011, Dresden, Deutschland
    Biologische Wirksamkeit laserbeschleunigter Protonen im Vergleich zu konventionell beschleunigten Protonen, ISSN 1432-864, Band 20, 73-77
  • Lecture (Conference)
    20. Symposium Experimentelle Strahlentherapie und Klinische Strahlenbiologie, 10.-12.02.2011, Dresden, Deutschland

Permalink: https://www.hzdr.de/publications/Publ-16790
Publ.-Id: 16790


Common Interests and Prospective Collaborations:Lawrence Livermore National Laboratory &Helmholtz-Zentrum Dresden-Rossendorf

Cowan, T. E.
no abstract available
  • Lecture (Conference)
    LLNL Seminar, 24.04.2011, Livermore, USA

Permalink: https://www.hzdr.de/publications/Publ-16789
Publ.-Id: 16789


R&D Plans II: Helmholtz Activities

Cowan, T. E.
no abstract available
  • Invited lecture (Conferences)
    EuCARD, EuroNNAc Workshop am CERN, 03.-06.05.2011, Genf, Schweiz

Permalink: https://www.hzdr.de/publications/Publ-16788
Publ.-Id: 16788


High Performance Radiation Sources at the ELBE Accelerator Facility at the Helmholtz-Zentrum Dresden-Rossendorf

Cowan, T. E.
no abstract available
  • Invited lecture (Conferences)
    Workshop "The Helmholtz Association and the NRC “Kurchatov Institute”: Prospects & Priorities for an Intensified Strategic Research Co-operation", 24.05.2011, Moskau, Russland

Permalink: https://www.hzdr.de/publications/Publ-16787
Publ.-Id: 16787


Verification of ion range in moving targets with in-beam PET

Laube, K.; Bert, C.; Fiedler, F.; Helmbrecht, S.; Priegnitz, M.; Saito, N.; Enghardt, W.
no abstract available
Keywords: in-beam PET, moving targets, ion beam therapy
  • Open Access Logo Contribution to external collection
    Katrin Große: GSI Scientific Report 2011, Darmstadt: GSI Helmholtzzentrum für Schwerionenforschung, 2012

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Permalink: https://www.hzdr.de/publications/Publ-16786
Publ.-Id: 16786


Lasergetriebene Protonenbeschleuniger auf dem Weg zur Strahlentherapie.

Beyreuther, E.; Baumann, M.; Burris-Mog, T.; Dammene, Y.; Enghardt, W.; Karsch, L.; Laschinsky, L.; Leßmann, E.; Metzkes, J.; Naumburger, D.; Oppelt, M.; Richter, C.; Schramm, U.; Schürer, M.; Woithe, J.; Zeil, K.; Pawelke, J.
Parallel zu den Experimenten mit laserbeschleunigten Elektronen wurde das 150 TW Lasersystem DRACO (Dresden laser acceleration source) am Helmholtz-Zentrum Dresden-Rossendorf (HZDR) aufgebaut und in Betrieb genommen. Die im Vergleich zum JETI Lasersystem mehr als zehnfach höhere Laserleistung ermöglicht die Beschleunigung von Protonen bis zu einer Maximalenergie von 20 MeV und damit deren strahlenbiologische Charakterisierung in vitro (3,4). Die für die Bestimmung von Dosis-Effekt-Kurven am laserbeschleunigten Protonenstrahl zu erfüllenden Anforderungen, sowie deren Realisierung werden zusammen mit ersten strahlenbiologischen Ergebnissen sowie einem Ausblick auf die weitere Entwicklung im Beitrag präsentiert.
  • Open Access Logo Contribution to proceedings
    20. Symposium Experimentelle Strahlentherapie und Klinische Strahlenbiologie, 10.-12.02.2011, Dresden, Deutschland
    Experimentelle Strahlentherapie und Klinische Strahlenbiologie, 1432-864X
  • Invited lecture (Conferences)
    20. Symposium Experimentelle Strahlentherapie und Klinische Strahlenbiologie, Dresden, 10.-12.02.2011, Dresden, Deutschland

Permalink: https://www.hzdr.de/publications/Publ-16785
Publ.-Id: 16785


Laser driven accelerators for proton therapy: Physical, technological and radiobiological aspects.

Pawelke, J.
no abstract available
  • Invited lecture (Conferences)
    26th Conference on Clinical and Experimental Research in Radiation Oncology (CERRO 26), 15.-22.01.2011, Menuires, France

Permalink: https://www.hzdr.de/publications/Publ-16783
Publ.-Id: 16783


Research group laser-radiooncology

Pawelke, J.
no abstract available
  • Invited lecture (Conferences)
    OncoRay Retreat, 12.-13.01.2011, Riesa, Deutschland

Permalink: https://www.hzdr.de/publications/Publ-16782
Publ.-Id: 16782


Eine Compton-Kamera für die in-vivo Dosimetrie bei der Partikeltherapie

Enghardt, W.
kein Abstract verfügbar
  • Lecture (others)
    Tagung des Wissenschaftlichen Beirates des HZDR, 23.11.2011, Dresden, Deutschland

Permalink: https://www.hzdr.de/publications/Publ-16781
Publ.-Id: 16781


Physics and instrumentation needs for improving hadron therapy

Enghardt, W.
no abstract available
  • Invited lecture (Conferences)
    Workshop: Hadrontherapy in France, 28.-29.11.2011, Lyon, France

Permalink: https://www.hzdr.de/publications/Publ-16780
Publ.-Id: 16780


A historical perspective of Gerhard Kraft’s scientific achievements: The therapy project

Enghardt, W.
kein Abstract verfügbar
  • Invited lecture (Conferences)
    Festkolloquium anlässlich des 70. Geburtstages von Gerhard Kraft, 01.11.2011, Darmstadt, Deutschland

Permalink: https://www.hzdr.de/publications/Publ-16779
Publ.-Id: 16779


Die Technologieplattform für translationale Forschung in der Protonentherapie am OncoRay Dresden

Enghardt, W.
kein Abstract verfügbar
  • Lecture (others)
    3 Ländertagung der ÖGMP, DGMP und SGSMP, 30.09.2011, Wien, Österreich

Permalink: https://www.hzdr.de/publications/Publ-16778
Publ.-Id: 16778


DiscussionProffered Papers: OncotechnologyThe impact of novel information processing to health care

Enghardt, W.
no abstract available
  • Invited lecture (Conferences)
    2011 European Multidisciplinary Cancer Congress, 26.09.2011, Stockholm, Schweden

Permalink: https://www.hzdr.de/publications/Publ-16777
Publ.-Id: 16777


Laser Accelerated Proton Therapy

Enghardt, W.
no abstract available
  • Invited lecture (Conferences)
    2011 European Multidisciplinary Cancer Congress, 26.09.2011, Stockholm, Schweden

Permalink: https://www.hzdr.de/publications/Publ-16776
Publ.-Id: 16776


The Future Proton Irradiation Facility at OncoRay Dresden

Enghardt, W.
kein Abstract verfügbar
  • Lecture (others)
    Enlight Annual Meeting 2011, 03.09.2011, Marburg, Deutschland

Permalink: https://www.hzdr.de/publications/Publ-16775
Publ.-Id: 16775


ENVISIONEuropean NoVel Imaging Systems for ION therapy

Enghardt, W.
kein Abstract verfügbar
  • Invited lecture (Conferences)
    Enlight Annual Meeting 2011, 03.09.2011, Marburg, Deutschland

Permalink: https://www.hzdr.de/publications/Publ-16774
Publ.-Id: 16774


Future Proton Irradiation Facility at OncoRay

Enghardt, W.
kein Abstract verfügbar
  • Lecture (others)
    Seminar am Institut für Kern- und Teilchenphysik, 14.07.2011, Dresden, Deutschland

Permalink: https://www.hzdr.de/publications/Publ-16773
Publ.-Id: 16773


Laser beschleunigte Protonenstrahlen

Enghardt, W.
Motivation
Kompakte Protonen- und Ionenbeschleuniger
Physik der Laserbeschleunigung
Stand von Forschung und Entwicklung
  • Lecture (others)
    Weiterbildung Klinik und Poliklinik für Strahlentherapie und Radioonkologie Universitätsklinikum C.G. Carus Dresden, 05.07.2011, Dresden, Deutschland

Permalink: https://www.hzdr.de/publications/Publ-16772
Publ.-Id: 16772


A Technology Platform for Translational Researchon Laser Driven Particle Acceleratorsfor Radiotherapy

Enghardt, W.
kein Abstract verfügbar
  • Lecture (Conference)
    SPIE Optics+Optoelectronics, 21.04.2011, Prag, Tschechische Republik

Permalink: https://www.hzdr.de/publications/Publ-16771
Publ.-Id: 16771


Erfolgreich gegen Krebs: Präzisionsbestrahlung und mathematische Zellmodellierung

Enghardt, W.
kein Abstract verfügbar
  • Lecture (Conference)
    Helmholtz-Humboldt-Sonntagsvorlesung, 10.04.2011, Berlin, Deutschland

Permalink: https://www.hzdr.de/publications/Publ-16770
Publ.-Id: 16770


Das Nationale Zentrum für Strahlenforschung in der Onkologie - OncoRay, Dresden

Enghardt, W.
kein Abstract verfügbar
  • Lecture (others)
    23. Weiterbildungsveranstaltung Mitteldeutscher Medizinphysiker, 08.-09.04.2011, Dresden, Deutschland

Permalink: https://www.hzdr.de/publications/Publ-16769
Publ.-Id: 16769


ENVISION Report on WP3 In-beam single particle tomography

Enghardt, W.
no abstract available
  • Lecture (others)
    ENVISION Annual Meeting, 04.02.2011, Lyon, Frankreich

Permalink: https://www.hzdr.de/publications/Publ-16768
Publ.-Id: 16768


Structural Study on 2,2′-(Methylimino)bis(N,N-Dioctylacetamide) Complex with Re(VII)O4- and Tc(VII)O4- by 1H NMR, EXAFS, and IR Spectroscopy

Saeki, M.; Sasaki, Y.; Nakai, A.; Ohashi, A.; Banerjee, D.; Scheinost, A. C.; Foerstendorf, H.
The structures of the complex of 2,2'-(methylimino)bis(N,N-dioctylacetamide) (MIDOA) with M-(VII)O-4(-) (M = Re and Tc), which were prepared by liquid-liquid solvent extraction, were investigated by using H-1 nuclear magnetic resonance (NMR), extended X-ray absorption fine structure (EXAFS), and infrared (IR) spectroscopy. The H-1 NMR spectra of the complex of MIDOA with Re(VII)O-4(-) prepared in the organic solution suggest the transfer of a proton from aqueous to organic solution and the formation of the H(+)MIDOA ion. The EXAFS spectra of the complexes of H(+)MIDOA with Re(VII)O-4(-) and Tc(VII)O-4(-) show only the M-O coordination of the aquo complexes, suggesting that the chemical state of M(VII)O-4(-) was unchanged during the extraction process. The results from H-1 NMR and EXAFS, therefore, provide evidence of M(VII)O-4(-)center dot center dot center dot H(+)MIDOA complex formation in the organic solution. The IR spectra of Re(VII)O-4(-)center dot center dot center do!
t H(+)MIDOA and Tc(VII)O-4(-)center dot center dot center dot H(+)MIDOA were analyzed based on the structures and the IR spectra that were calculated at the B3LYP/cc-pVDZ level. Comparison of the observed and calculated IR spectra demonstrates that an intramolecular hydrogen bond is formed in H(+)MIDOA, and the M(VII)O-4(-) ion interacts with H(+)MIDOA through multiple C-H-n center dot center dot center dot O hydrogen bonds.
Keywords: liquid-liquid solvent extraction, solvent extraction process, Complexation, DFT

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Permalink: https://www.hzdr.de/publications/Publ-16767
Publ.-Id: 16767


Laser driven proton accelerators on the way to application in cancer therapy?

Enghardt, W.
no abstract available
  • Lecture (others)
    470. WE-Heraeus-Seminar, 15.12.2010, Bad Honnef, Deutschland
  • Lecture (Conference)
    Seminar am Kernfysisch Versneller Instituut, 28.01.2011, Groningen, Niederland

Permalink: https://www.hzdr.de/publications/Publ-16766
Publ.-Id: 16766


Neue Strahlenarten in der Radioonkologie:Übersicht und Bewertung

Enghardt, W.
1. Physikalische Eigenschaften von Ionenstrahlen
2. Bestrahlungsfeld-Formierung für Ionenstrahlen
3. Kernreaktionen
4. Exotische Strahlen
  • Lecture (others)
    Strahlenschutz und Qualitätssicherung, 26.-27.11.2010, Dresden, Deutschland

Permalink: https://www.hzdr.de/publications/Publ-16765
Publ.-Id: 16765


Das Dresdener Protonenprojekt

Enghardt, W.
kein Abstract verfügbar
  • Lecture (others)
    Fachgespräch im Sächsischen Staatsministerium für Umwelt und Landwirtschaft, 25.11.2010, Dresden, Deutschland

Permalink: https://www.hzdr.de/publications/Publ-16764
Publ.-Id: 16764


Image based in-vivo dosimetry for proton and ion tumour therapy

Enghardt, W.
no abstract available
  • Lecture (Conference)
    Physikalisches Kolloquium, 12.11.2010, Bonn, Deutschland

Permalink: https://www.hzdr.de/publications/Publ-16763
Publ.-Id: 16763


Neue Entwicklungen in der Strahlentherapie

Enghardt, W.
kein Abstract verfügbar
  • Lecture (others)
    15. Strahlenschutzseminar der Staatlichen Fortbildungsstätte Reinhardtsgrimma, 11.-12.11.2010, Reinhardtgrimma, Deutschland

Permalink: https://www.hzdr.de/publications/Publ-16762
Publ.-Id: 16762


Technologie für die Radiotherapie

Enghardt, W.
1.Die Wechselwirkung ionisierender Strahlung mit (belebter) Materie
2.Die Formen der Strahlentherapie
3.Exkurs in die Radionuklid- und Brachytherapie
4.Teletherapie
4.1. Die Erzeugung von Photonen- und Elektronenstrahlen für
die Strahlentherapie (Elektronen-Linearbeschleuniger)
4.2. Ionenstrahl-Therapie
4.3. Adaptive Strahlentherapie
  • Lecture (others)
    Vorlesungen, 28.06.2010, Dresden, Deutschland

Permalink: https://www.hzdr.de/publications/Publ-16761
Publ.-Id: 16761


Moderne Technologie für die Strahlentherapie von Tumoren

Enghardt, W.
1. Die Wechselwirkung ionisierender Strahlung mit (belebter) Materie
2. Moderne strahlentherapeutische Techniken
3. Photonen- und Elektronenstrahlen für die Therapie
4. Ionenstrahl-Therapie
5. Adaptive Strahlentherapie
  • Lecture (others)
    Fakultät Maschinenwesen, 25.05.2010, Dresden, Deutschland

Permalink: https://www.hzdr.de/publications/Publ-16760
Publ.-Id: 16760


Medical Radiation Sciences

Enghardt, W.
kein Abstract verfügbar
  • Invited lecture (Conferences)
    Sitzung des Fachausschusses Strahlenschutz des Länderausschusses für Atomkernenergie, 18.02.2010, Bonn, Deutschland

Permalink: https://www.hzdr.de/publications/Publ-16759
Publ.-Id: 16759


Prospects in Medical Imaging - Summary

Enghardt, W.
no abstract available
  • Invited lecture (Conferences)
    Workshop "Physics for Health in Europe", 02.-04.02.2010, Genf, Schweiz

Permalink: https://www.hzdr.de/publications/Publ-16758
Publ.-Id: 16758


Helmholtz Beamline at the European XFEL

Cowan, T. E.
Kein Abstract vorhanden
  • Lecture (others)
    European XFEL Science Advisory Committee, 29.09.2011, Hamburg, Deutschland
  • Invited lecture (Conferences)
    Workshop on Petawatt-Lasers at Hard X-ray Light Sources, 05.-09.09.2011, Dresden, Deutschland

Permalink: https://www.hzdr.de/publications/Publ-16757
Publ.-Id: 16757


Prospects for Laser-Driven Ion Beam Therapy

Cowan, T. E.
Kein Abstract vorhanden
  • Lecture (Conference)
    OSA Frontiers in Optics 2011, 16.-20.10.2011, San Jose, USA

Permalink: https://www.hzdr.de/publications/Publ-16756
Publ.-Id: 16756


Laser-acceleration of ions and their potential for Radiation Therapy

Cowan, T. E.
Kein Abstrakt vorhanden
  • Lecture (Conference)
    Light at Extreme Intensities 2011, 14.-18.11.2011, Szeged, Ungarn

Permalink: https://www.hzdr.de/publications/Publ-16755
Publ.-Id: 16755


Helmholtz Beamlines

Cowan, T. E.
Kein Abstract vorhanden
  • Invited lecture (Conferences)
    LAALA 2011 Sino-German Symposium on Laser Acceleration and Applications of Lasers at Accelerators, 05.-08.12.2011, Beijing, China

Permalink: https://www.hzdr.de/publications/Publ-16754
Publ.-Id: 16754


Multi-scale thermalhydraulic analyses performed in NURESIM and NURISP projects

Bestion, D.; Lucas, D.; Anglart, H.; Niceno, B.; Vyskocil, L.
The NURESIM and NURISP successive projects of the 6th and 7th European Framework Programs joined the efforts of 21 partners for developing and validating a reference multi-physics and multi-scale platform for reactor simulation. The platform includes system codes, component codes, and also CFD or CMFD simulation tools. Fine scale CFD simulations are useful for a better understanding of physical processes, for the prediction of small scale geometrical effects and for solving problems that require a fine space and/or time resolution. Many important safety issues usually treated at the system scale may now benefit from investigations at a CFD scale. The Pressurized Thermal Shock is investigated using several simulation scales including Direct Numerical Simulation, Large Eddy Simulation, Very Large Eddy Simulation and RANS approaches. At the end a coupling of system code and CFD is applied. Condensation Induced Water-Hammer was also investigated at both CFD and 1-D scale. Boiling flow in a reactor core up to Departure from Nucleate Boiling or Dry-Out is investigated at scales much smaller than the classical sub-channel analysis codes. DNS was used to investigate very local processes whereas CFD in both RANS and LES was used to simulate bubbly flow and Euler-Lagrange simulations were used for annular mist flow investigations. Loss of Coolant Accidents are usually treated by system codes. Some related issues are now revisited at the CFD scale. In each case the progress of the analysis is summarized and the benefit of the multi-scale approach is shown.
Keywords: CFD, simulation, PTS, CHF, Reflooding, water hammer
  • Contribution to proceedings
    20th International Conference on Nuclear Engineering, ICONE20, 30.07.-02.08.2012, Anaheim, USA

Permalink: https://www.hzdr.de/publications/Publ-16753
Publ.-Id: 16753


Opportunities for Compression Science with the Helmholtz Beamline at the European XFEL

Cowan, T. E.
  • Invited lecture (Conferences)
    Dynamic Compression Sector, DCS @ APS Workshop, 19.-20.01.2012, Argonne, USA

Permalink: https://www.hzdr.de/publications/Publ-16752
Publ.-Id: 16752


Hollow Beam creation with continuous diffractive phase mask at PHELIX

Brabetz, C.; Eisenbarth, U.; Kester, O.; Stoehlker, T.; Cowan, T. E.; Zielbauer, B.; Bagnoud, V.
We propose and demonstrate a method for shaping the focus of high intensity lasers into an annular or “donut” mode. The method, based on helical phase plates, has been implemented at the PHELIX laser facility.
  • Contribution to proceedings
    CLEO 2012, 08.-10.05.2012, San Jose, USA

Permalink: https://www.hzdr.de/publications/Publ-16751
Publ.-Id: 16751


Influence of the copper impurity level on the irradiation response of reactor pressure vessel steels investigated by SANS

Wagner, A.; Ulbricht, A.; Bergner, F.; Altstadt, E.
Reactor pressure vessel (RPV) steel, when exposed to neutron irradiation, induces the formation of nano-sized features. Using small angle neutron scattering (SANS) we have studied the neutron fluence dependence of the precipitate volume fraction for high-Cu and low-Cu materials separately. Cu-rich precipitates have long been recognized to play the dominant role in embrittlement of Cu-bearing RPV steels. In contrast, Mn-Ni-rich precipitates seem to govern embrittlement in the case of low levels of impurity Cu. The objective is to work out the resulting differences from the microstructural point of view. For low-Cu materials, the volume fraction was found to be within the detection limit of SANS at fluences below an apparent threshold fluence, whereas the slope increases considerably beyond. The relationship between irradiation-induced yield stress increase and precipitate volume fraction was also considered. We have derived estimates of the obstacle strength for Cu-rich precipitates and for Mn-Ni-rich precipitates.
Keywords: Neutron irradiation; Irradiation hardening; Iron base alloy; Reactor pressure vessel steel; Cu impurity; SANS; Microstructure

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Permalink: https://www.hzdr.de/publications/Publ-16750
Publ.-Id: 16750


Stopping power dependence of nitrogen sputtering yields in copper nitride films under swift-ion irradiation: exciton model approach

Gordillo, N.; González-Arrabal, R.; Rivera, A.; Munnik, F.; Agulló-López, F.
Nitrogen sputtering yields as high as 2×103 N / ion are obtained by irradiating N-rich-Cu3N films (N concentration (33±2) at.%) with Cu ions at energies in the range 10-42 MeV. The kinetics of N sputtering as a function of ion fluence is determined at several energies (stopping powers) for films deposited on both, glass and silicon substrates. The kinetic curves show a three stage-behaviour: an initial inhibition stage I of low sputtering yield, followed by a more extended linear region II that finally reaches a saturation stage III at a low remaining nitrogen fraction (5-10 %). For the case of silicon substrates the contribution of the initial stage is not significant. The sputtering rate of stage II is found to be independent of the substrate and to linearly increase with electronic stopping power (Se). A Se threshold for nitrogen depletion of ~3.4 keV/nm is estimated. Experimental kinetic data are successfully analysed within the bulk molecular recombination model. All features are in accordance with electronic excitation mechanisms, showing for the first time evidence of the excitonic model.
Keywords: Copper nitride, ion beam modification of materials, swift heavy ion irradiation, electronic sputtering

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Permalink: https://www.hzdr.de/publications/Publ-16749
Publ.-Id: 16749


Atomic Layer Deposition of Aluminum and Titanium Phosphates

Hämäläinen, J.; Holopainen, J.; Munnik, F.; Heikkilä, M.; Ritala, M.; Leskelä, M.
The atomic layer deposition (ALD) of phosphate containing thin films using reactions between metal halide and phosphorus source without any additional oxygen sources was examined. Two very common metal halides, AlCl3 and TiCl4, were used in conjunction with trimethyl phosphate (TMPO) to grow corresponding metal phosphate films. Aluminum phosphate thin films were deposited at temperatures between 150 and 400 °C while titanium phosphate films grew between 275 and 450 °C. Amorphous films of Al2.6PO7.0 and Al1.6PO5.6 were deposited at 200 and 300 °C, respectively, while the amorphous titanium phosphate films deposited at 300 and 400 °C consisted of Ti0.8PO3.9 and Ti0.6PO3.5 (Ti1.2P2O7). The films were analyzed using high temperature XRD to study the crystallization and stability of the deposited films. Also the surface morphology of the annealed films was examined by FESEM.

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Permalink: https://www.hzdr.de/publications/Publ-16748
Publ.-Id: 16748


Lithium Phosphate Thin Films Grown by Atomic Layer Deposition

Hämäläinen, J.; Holopainen, J.; Munnik, F.; Hatanpää, T.; Heikkilä, M.; Ritala, M.; Leskelä, M.
Lithiumphosphate, Li3PO4, has been considered a potential electrolytematerial for lithiumion batteries and CO2 sensors in particular if the films can be made dense and of high quality already at low thickness. In this work, Li3PO4 thin films were deposited by atomic layer deposition (ALD) between 225 and 350°C using trimethyl phosphate and either of the two lithium sources, namely lithium hexamethyldisilazide or lithium tert-butoxide. The deposited films showed slightly crystalline Li3PO4 structure in X-ray diffraction and the elastic recoil detection analysis confirmed this stoichiometry with some carbon and hydrogen impurities. The crystallinity and thermal stability of the films at elevated temperatures in N2 were also examined. The long term stability of the deposited Li3PO4 films under ambient air may be an issue for the applicability of these processes.

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Permalink: https://www.hzdr.de/publications/Publ-16747
Publ.-Id: 16747


Radiation field characterization and shielding studies for the ELI Beamlines Facility

Ferrari, A.; Amato, E.; Margarone, D.; Cowan, T.; Rus, B.
The ELI (Extreme Light Infrastructure) Beamlines Facility in the Czech Republic, which is planned to complete the installation in 2015, is one of the four pillars of the ELI european project. Several laser beamlines with ultrahigh intensities and ultrashort pulses are foreseen, offering versatile radiation sources in an unprecedented energy range: laser-driven particle beams are expected to range between 1 GeV and 50 GeV for electrons and from 100 MeV up to 3 GeV for protons. The number of particles delivered per laser shot is estimated to be 109-1010 for the electron beams and 1010-1012 for the proton beams.
The high energy and current values of the produced particles, together with the potentiality to operate at 10 Hz laser repetition rate, require an accurate study of the primary and secondary radiation fields to optimize appropriate shielding solutions: this is a key issue to minimize prompt and residual doses in order to protect the personnel, reduce the radiation damage of electronic devices and avoid strong limitations in the operational time.
A general shielding study for the 10 PW (0.016 Hz) and 2 PW (10 Hz) laser beamlines is presented here. Starting from analytical calculations, as well as from dedicated simulations, the main electron and proton fields produced in the laser-matter interaction have been described and used to characterize the "source terms" in full simulations with the Monte Carlo code FLUKA. The secondary radiation fields have been then analyzed to assess a proper shielding. The results of this study and the proposed solutions for the beam dumps of the high energy beamlines are presented, together with a cross-check analysis performed with the Monte Carlo code GEANT4.
Keywords: particle acceleration from laser-matter interaction, shielding, Monte Carlo, radiation protection
  • Lecture (Conference)
    Plasma Production by Laser Ablation (PPLA 2011), 21.-23.09.2011, Catania, Italia

Permalink: https://www.hzdr.de/publications/Publ-16746
Publ.-Id: 16746


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