Publications Repository - Helmholtz-Zentrum Dresden-Rossendorf

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35806 Publications

Test of scintillating-fiber calorimeter for photons with energies below 1 GeV

Hübner, B.; Brinkmann, K.-T.; Freiesleben, H.; Lange, J. S.; Naumann, B.; Naumann, L.; Schülke, A.

  • Nuclear Instruments and Methods in Physics Research A 382 (1996) pp.413-418

Publ.-Id: 862

Evolution of nanocluster ensembler: Computer simulation of diffusion and reaction controlled Ostwald ripening

Strobel, M.; Reiß, S.; Heinig, K.-H.

The Ion Beam Synthesis (IBS) of nanoclusters can be controlled by the flux and the fluence of ions as well as by the implantation and/or annealing temperature. The evolution of the precipitates, mainly described by their particle radius distribution (PRD), the number of remaining particles and the critical radius, depends on these parameters. However, the evolution is expected to behave different for systems like SiO2 and CoSi2 clusters in Si, because they are characterized by quite different ratios of diffusion to reaction constants. Here we present an unified model of Ostwald ripening of nanoclusters, which describes the pure diffusion and reaction controlled limits as well as all intermediate, mixed processes. Expressing the exact solution of the adiabatic diffusion equation by multipole moments we derive the governing equation for the evolution of an ensemble of nanoclusters in the leading monopole approximation. Whereas in the diffusion controlled regime we have the well known infinite range 1/r interaction among the nanoclusters, 1/r2 interactions come into play in the reaction limited regime. Computer simulations for ensembles of several thousands of nanoclusters demonstrate the evolution for typical cases.

  • Nuclear Instruments and Methods in Physics Research B 120 (1996) pp. 216-220

Publ.-Id: 861

Mathematisch-numerische Modellierung der Ultraschallstreuung an oberflächenverbundenen Rissen mit dem EFIT-Code

Bergmann, U.; Bergner, F.

An ultrasonic time-of-flight diffraction method for measuring stable crack growth in a three point bending specimen was analyzed by simulations of the wave field evolution in the test specimen. To calculate the actual crack length from the experimental measured time of flight of a crack tip diffracted ultrasound pulse the echo trains were successively measured during the whole bending test. The simulations deal with the generation and evolution of the ultrasound field in the specimen and with the design of the received signal. The simulations took into account the actual test geometry, the crack growth process, the blunted crack tip and the process of bending. With these simulations all individual received echoes are reproduced and interpreted. The echo, qualified for measuring the time of flight is undoubtedly the transverse wave diffracted on the crack tip. In order to optimize the test method and to increase the accuracy of measurements during the simulations Parameters like probe position, wave mode, measuring frequency and length of aperture of the probes wem separately varied. From the comparison between the simulations and the experimental measurements it can be concluded, that the developed method is weil suited for measuring stable crack growth in small specimens made from ductile material.

  • Open Access Logo Forschungszentrum Rossendorf; FZR-177 1997
    ISSN: 1436-3976


Publ.-Id: 859

Nachweis verformungsbedingter Strukturschädigung in Rißnähe durch Röntgenkleinwinkelstreuung

Böhmert, J.; Große, M.

  • Lecture (Conference)
    29. DVM-Tagung Bruchvorgänge, Februar 1997, Stuttgart, S. 299 ff.
  • Contribution to proceedings
    29. DVM-Tagung Bruchvorgänge, Februar 1997, Stuttgart, S. 299 ff.

Publ.-Id: 857

Detection of metastable defective regions in ion-implanted Silicon by means of metall gettering

Kögler, R.; Posselt, M.; Yankov, R. A.; Kaschny, J.; Mücklich, A.; Skorupa, W.; Danilin, A. B.

  • Lecture (Conference)
    MRS '97, Spring Meeting, San Francisco, March 31-April 4, 1997

Publ.-Id: 856

Methode zur schnellen Bestimmung von Actiniden in Bauschutt zur Freigabeentscheidung

Nebelung, C.; Nitsche, H.; Bernhard, G.

  • Lecture (Conference)
    V. Stillegungskolloquium, 24./25.6.1997 in Hannover
  • Contribution to external collection
    IV. Statusbericht Stillegung und Rückbau kerntechnischer Anlagen, S. 293-301

Publ.-Id: 855

EXAFS Investigations of the Interaction of Humic Acids and Model Compounds with Uranyl Cations in Solid Complexes

Denecke, M. A.; Reich, T.; Bubner, M.; Heise, K.-H.; Nitsche, H.; Allen, P. G.; Bucher, J. J.; Edelstein, N. M.; Shuh, D. K.

  • Lecture (Conference)
    MIGRATION '97, Konferenz vom 26.-31. Oktober 1997 in Sendoi, Japan

Publ.-Id: 854

Determination of Structural Parameters od Uranyl Ions Complexed with Organic Acids using EXAFS

Denecke, M. A.; Reich, T.; Bubner, M.; Pompe, S.; Heise, K.-H.; Nitsche, H.; Allen, P. G.; Bucher, J. J.; Edelstein, N. M.; Shuh, D. K.

  • Lecture (Conference)
    ACTINIDES '97, 21.-26. September 1997 in Baden-Baden

Publ.-Id: 853

Validation of complex formation of CA2+; UO22+ and CO32-

Bernhard, G.; Brendler, E.; Geipel, G.; Reich, T.; Nitsche, H.

  • Poster
    MIGRATION '97, Konferenz vom 26.-31. Oktober 1997 in Sendoi, Japan
  • Poster
    Euroconference and NEA Workshop: Actinide-XAS-98, Grenoble, France, 04.-06.10.1998

Publ.-Id: 852

Complex formation between UO22+ and CO32- studied by Laser-Induced photoacoustic Spectroscopy

Geipel, G.; Bernhard, G.; Brendler, V.; Nitsche, H.

  • Lecture (Conference)
    MIGRATION '97, Konferenz vom 26.-31. Oktober 1997 in Sendoi, Japan
  • Radiochimica Acta 82, 59 (1998)

Publ.-Id: 851

Convective, absolute and global instabilities of thermocapillary-buoyancy convection in extended layers, Page Number 4187

Priede, J.; Gerbeth, G.

  • Physical Review E, 10/31/97, October 1997, pp. 4187 - 4199

Publ.-Id: 849

Sorption of Uranium(VI) onto Phyllite

Arnold, T.; Zorn, T.; Bernhard, G.; Nitsche, H.

  • Chemical Geology 151(1998) 129-141
  • Lecture (Conference)
    Workshop: The Münster Workshop on Mineral Surface Science, Münster, Germany, 18.-20.03.1998
  • Lecture (Conference)
    Workshop: Surface Reactivity Meeting, University of Manchester, Department of Earth Sciences, Manchester, UK 30.03.-01.04. 1998

Publ.-Id: 848

Neutral Oxorhenium(V) and Oxotechnetium(V) Complexes with a novel Amide Thiother Dithiolate Ligand derived from Cysteine

Noll, B.; Hilger, C. S.; Spies, H.; Leibnitz, P.; Dinkelborg, L.; Johannsen, B.

  • Lecture (Conference)
    Chemische Berichte, COST-Meeting, Jülich, 13.-14.11.1997

Publ.-Id: 847

Effects of irradiation and annealing on the microstructure of Russian VVER-440-type reactor pressure vessel steels

Große, M.; Böhmert, J.

  • Lecture (Conference)
    International conference PLIM + PLEX 1997, Prague

Publ.-Id: 846

The structure of 113Sn from proton and alpha-particle induced reactions

Käubler, L.; Lobach, Y. N.; Trishin, V. V.; Pasternak, A. A.; Kudojarov, M. F.; Prade, H.; Reif, J.; Schwengner, R.; Winter, G.; Blomqvist, J.; Döring, J.

The result of in-beam investigation of 113Sn using the (p,n),
(p,3n), (alpha,n) and (alpha,2n) reactions are summarized. Excited states
have been identified until Ex=4715 MeV and JPi=(27/2-).
For a large number of levels mean lifetimes tau have been determined with
the DSA method. For the JPi=25/2+ state at Ex=4059
MeV, tau=1.0(4) ns has been measured with the gamma-RF method. The experimental
results are compared with the predictions of shell-model calculations.
Most of the positive-parity states may be considered as one- or three-quasiparticle
neutron excitations of the 2d5/2, 1g7/2, 3s1/2
and 2d3/2 shells, the negative-parity states asthe coupling
of one 1h11/2 neutron to the two- or four-quasiparticle neutron
excitations in even-mass 112Sn core. For the 25/2+
isomer the three-quasiparticle neutron configuration v(h2 11/2g-1 7/2)
has been proposed on the basis of a shell-model analysis using the mass-formula
formalism. The experimentally observed yrast states in 113 50Sn63
are compared with the corresponding states in the valence mirror nucleus
145 63Eu82 giving remarkable similarities
although the parameters for the shell-model calculations differ considerably.
The analysis of nearest.neighbour spacing distributions of experimentally
obtained 5/2+ states in 113Sn does not allow definite
conclusions about regularity or chaos.

  • Zeitschrift für Physik A 358, 303-315 (1997)

Publ.-Id: 845

Resolution-enhanced spectroscopy of 81Y

Schnare, H.; Winter, G.; Käubler, L.; Reif, J.; Schwengner, R.

The fusion-evaporation reaction 58Ni(32S,2 alpha
p ) has been used to study the neutron-deficient isotope 81Y.
Multiple particle gamma-ray coincidences have been detected by the GAMMASPHERE
array combined with the MICROBALL chrged-particle detector system. Gamma-ray
spectra with an improved resolution have been achieved from an event-by-event
determination of the nucleus recoil momentum, thus allowing a precise Doppler-shift
correction. In this way a resolution enhancement by a factor 2 was obtained
for a 1 MeV gamma line. During the analysis an Egamma - Egamma
matrix as well as an Egamma - Egamma - Egamma
cube have been used to extend the previously known level scheme to higher
spin ( I ca. 57/2 ) and excitation energy ( Ex ca. 17 MeV ).
More than 100 new gamma rays and 80 new levels have been added to the level
scheme and six new bands have been established. The interpretation of these
bands in terms of the cranking model and their comparison with similar
bands in neighboring nuclei is discussed.

  • Physical Review C Volume 56, Number 2, 729-743

Publ.-Id: 844

Ionenstrahlinduzierte Wachstumsprozesse amorpher Schichten in Silicium

Henkel, T.

  • Open Access Logo Forschungszentrum Rossendorf; FZR-175 (Dissertation TU Dresden); März 1997
    ISSN: 1436-3976


Publ.-Id: 843

Accumulation of U(VI) by Microorganisms Recovered from Uranium Mining Waste Pile

Panak, P.; Bernhard, G.; Kutschke, S.; Otto, A.; Röske, K.; Selenska-Pobell, S.; Barth, G.; Nitsche, H.

  • Poster
    Actinides '97 International Conference, 21.-26.9.1997, Baden-Baden

Publ.-Id: 842

Model investigations of aqueous UO2 2+/Ca 2+/humic acid complexation

Bubner, M.; Pompe, S.; Jander, R.; Heise, K.-H.; Nitsche, H.

  • Poster
    Actinides '97 International Conference, 21.-26.9.1997, Baden-Baden

Publ.-Id: 841

Thermochromatographic Adsorption Studies - an Approach to Metallic State Properties of the Heaviest Actinides

Hübener, S.; Taut, S.; Eichler, B.

  • Poster
    Actinides '97 International Conference, 21.-26.9.1997, Baden-Baden

Publ.-Id: 840

Thermochromatography of No-259

Taut, S.; Hübener, S.; Eichler, B.; Gäggeler, H. W.; Timokhin, S. N.; Zvara, I.

  • Poster
    Actinides '97 International Conference, 21.-26.9.1997, Baden-Baden

Publ.-Id: 839

Interaction of uranium(VI) with silicic acid in aqueous solutions by time-resolved laser-induced fluorescence spectroscopy (TRLFS)

Moll, H.; Geipel, G.; Brendler, V.; Bernhard, G.; Nitsche, H.

  • Poster
    Actinides '97 International Conference, 21.-26.9.1997, Baden-Baden
  • J. Alloys and Compounds 271-273, 765 (1998)

Publ.-Id: 838

A fast method for low-level actinide measurement in concrete

Nebelung, C.; Nitsche, H.; Bernhard, G.

  • Poster
    Actinides '97 International Conference, 21.-26.9.1997, Baden-Baden
  • J. Alloys and Compounds 271-273, 42 (1998)

Publ.-Id: 837

Uranium speciation in waters of different uranium mining areas

Bernhard, G.; Geipel, G.; Brendler, V.; Nitsche, H.

  • Poster
    Actinides '97 International Conference, 21.-26.9.1997, Baden-Baden
  • J. AlloysCompounds 271-273, 201 (1998)

Publ.-Id: 836

Uranyl carbonate complexes studied by Laser-Induced Spectroscopy

Geipel, G.; Bernhard, G.; Brendler, V.; Nitsche, H.

  • Poster
    Actinides '97 International Conference, 21.-26.9.1997, Baden-Baden

Publ.-Id: 835

Self-Consistent Pushing and Cranking Corrections to the Meson Fields of the Chiral Quark-Loop Soliton

Schleif, M.; Wünsch, R.; Meissner, T.

We study translational and spin-isospin symmetry restoration for the two-flavor chiral quark-loop soliton. Instead of a static soliton at rest we consider a boosted and rotating hedgehog soliton. Corrected classical meson fields are obtained by minimizing a corrected energy functional which has been derived by semi-classical methods ('variation after projection').
We evaluate corrected meson fields in the region 300 <= M <= 600 of constituent quark masses M and compare them with the uncorrected fields. We study the effect of the corrections on various expectation values of nuclear observables such as the root-mean square radius, the axial-vector coupling constant, magnetic moments and the delta-nucleon mass splitting.
  • Open Access Logo Forschungszentrum Rossendorf; FZR-173 Preprint
    ISSN: 1436-3976
  • International Journal of Modern Physics E, Vol. 7, No. 1 (February 1998) 121-138


Publ.-Id: 834

Aufbau eines behördlichen Fernüberwachungssystems zur betrieblichen Überwachung des KKW Saporoshje (Block 5), 3. Realisierungsstufe

Beyer, M.; Carl, H.; Nowak, K.; Schumann, P.; Seidel, A.

The report gives an overview of the further development of the remote monitoring system for the Ukrainian nuclear power plant Zaporozh'ye. The proposals for concept, structure and algorithmic design of the user software elaborated by Research Centre Rossendorf and TÜV Rheinland are presented and explained complemented by a short description of the conversion of the German proposals into the user´s software by the State Scientific-Technical Centre of the Ukrainian Supervisory Authority. Furthermore, there is an actual information about the operational use of the components of the monitoring system in the Zaporozh'ye NPP. The realization efforts for the completion of the NPP-site system and for the integration of the Kiev Centre into the system close the report. The industrial testing phase of the system was started in June of 1996. Since then, supervisory authority and operator have been able to fulfil their monitoring duties more efficiently than before by direct access to the actual operational data.

  • Open Access Logo Forschungszentrum Rossendorf; FZR-174 März 1997
    ISSN: 1436-3976


Publ.-Id: 833

Detection of Aerosol Losses in Glass Vessels

Rettig, D.; Merker, P.; Nitsche, H.

  • Poster
    European Aerosol Conference, 15.-19. Sept. 1997, Hamburg, Germany
  • Journal of Aerosol Science, Vol. 28, Suppl. 1,pp. S139-S140, 1997

Publ.-Id: 832

Density and structural changes of SiC after amorphization and annealing

Heera, V.; Prokert, F.; Schell, N.; Seifarth, H.; Fukarek, W.; Voelskow, M.; Skorupa, W.

The density of amorphous SiC layers formed by 2 MeV Si+ implantation into single crystalline 6H-SiC was measured by X-ray reflectometry and compared with the resultts of step height measurements. Reactive ion
etching was used to investigate the density as function of depth. The density of the as-amorphized SiC is about 12 % less than that of the crystalline material. Within the experimental accuracy the density reduction is homogeneous
over the whole layer thickness. Low temperature annealing leads to the formation of relaxed amorphous SiC with a density about 7 % below the crystalline one. These large density changes are in contrast to results in amorphous
Si. They can be explained by the high atomic density of SiC and the chemical disorder in the amorphous state of SiC.

  • Applied Physics Letters 70(26), 3531

Publ.-Id: 831

Hot and dense pion gas with finite chemical potential

Kolomeitsev, E. E.; Voskresensky, D. N.; Kämpfer, B.

  • Acta Physica Polonica B 27 (1996) 11 pp. 3263-3270

Publ.-Id: 829

The response of the Euroball Cluster detector to gamma-radiation up to 10 MeV

Wilhelm, M.; Eberth, J.; Pascovici, G.; Radermacher, E.; Thomas, H. G.; von Brentano, P.; Prade, H.; Lieder, R. M.

  • Nuclear Instruments and Methods in Physics Research A 381 (1996) pp. 462-465

Publ.-Id: 828

Lineshape, linewidth and spectral density of parametric x-radiation at low electron energy in diamond

Freudenberger, J.; Genz, H.; Morokhovskii, V. V.; Richter, A.; Morokhovskii, V. L.; Nething, U.; Zahn, R.; Sellschop, J. P. F.

  • Applied Physics Letters 70 (1997) 2 pp. 267-269

Publ.-Id: 827

Characteristic features of the lineshape in the spectrometry of ions using Si detectors

Ilyashenko, I. N.; Strokan, N.; Schmidt, B.

A model which explains the characteristic distortions of the spectral lineshape of a Si detector during the recording of heavy ions is proposed. The appearence of a group of pulses in the right-hand (high-energy) region of the amplitude spectrum is associated with nonequilibrium-charge recombination. The recombination occurs in the skin layer of the detector structure, where charge transfer occurs by diffusion. The amplitude of the signal fluctuates because of the participation of Si recoil atoms, which generate electron-hole pairs at specific cross sections of the "input-window" of the detector. Heavy particles directly produce ionization uniformly over depth, which results in definite losses of charge but is not accompanied by appreciable fluctuations.

  • Semiconductors 30 (1996) 12 pp. 1158-1161

Publ.-Id: 826

Rißfortschrittsmessung an Dreipunkt-Biegeproben mit Ultraschall

Bergmann, U.; Bergner, F.; Böhmert, J.

Ein Ultraschall-Laufzeit-Beugungsverfahren wurde zur Messung des Rißfortschritts im quasistatischen Dreipunkt-Biegeversuch an Proben unterschiedlicher Werkstoffe eingesetzt. Der mit diesem Verfahren bestimmte Gesamtrißfortschritt steht in guter Übereinstimmung mit dem jeweiligen fraktografisch bestimmten Wert.
Durch eine geeignete Darstellungsweise der Ultraschallsignale konnte die Aussagekraft der Messungen deutlich erhöht werden. Insbesondere für Gußeisen zeigt sich ein ausgeprägter Übergang von Rißspitzenabstumpfung zu Rißausbreitung. Durch Ausnutzen der Bildinformationen kann der Rißfortschritt auch dann gemessen werden, wenn das Rißspitzenecho durch ein anderes Echo überlagert wird.
Es wurde gezeigt, daß Rißfortschrittsmessungen prinzipiell auch auf der Grundlage von rißspitzengebeugten Longitudinalwellen möglich ist.

  • Lecture (Conference)
    Werkstoffprüfung '96, 5.-6.12.1996, Bad Nauheim, Deutscher Verband für Materialforschung und -prüfung e.V.
  • Contribution to proceedings
    Vortrags- und Diskussionstagung "Werkstoffprüfung 1996", 5.-6.12.96, Bad Nauheim, Tagungsband S. 143-151

Publ.-Id: 825

Freeze-Out Time in Ultrarelativistic Heavy Ion Collisions from Coulomb Effects in Transverse Pion Spectra

Barz, H.-W.; Bondorf, J. P.; Gaardhoje, J. J.; Heiselberg, H.

The influence of the nuclear Coulomb field on transverse spectra of λ + and λ- measured in Pb + Pb reactions at 158 A GeV has been investigated. Pion trajectories are calculated in the field of an expanding fireball. The observed enhancement of the λ-+ ratio at small momenta depends on the temperature and transverse expansion velocity of the source, the rapidity distribution of the net positive charge, and mainly the time of the freeze-out.

  • Physical Review C 56, No. 3, September 1997, 1553-1556
  • Open Access Logo Forschungszentrum Rossendorf; FZR-168 Preprint
    ISSN: 1436-3976


Publ.-Id: 824

Ladungsverteilungen und kollektives Verhalten in 197Au + 197Au - Stößen bei Eprog = 150 bis 1000 A MeV

Biegansky, J.

  • Other report

Publ.-Id: 823

Institute of Bioinorganic and Radiopharmaceutical Chemistry; Annual Report 1996

Johannsen, B.; Seifert, S.

  • Open Access Logo Forschungszentrum Rossendorf; FZR-165
    ISSN: 1436-3976


Publ.-Id: 822

Analytische Modellierung mechanischer Schwingungen von Primärkreiskomponenten des Druckwasserreaktors WWER-440 mit finiten Elementen

Altstadt, E.; Grunwald, G.; Scheffler, M.; Weiß, F.-P.

The project contributes to the improved evaluation of the mechanical integrity of the soviet-type VVER-440 reactors especially, to a sensitive early failure detection and to the localization of mechanical damages of reactor components by means of vibration monitoring. For that purpose the mechanical vibration of all primary circuit
components was modelled by finite elements. Modeling was built on the finite element code ANSYS. The interaction between the coolant flowing in the downcomer and the vibrating components has been considered by a fluid-structure element, which describes additional mode selective damping and intertia due to the coolant displacement when the downcomer geometry changes. The calculation model was adjusted using results from experimental vibration investigations. To some extent data from earlier measurements were available. But additionally dedicated experiments had to be performed at original VVERs. Now, the model can be regarded to be widely verified. Mainly it was applied to clarify how hypothetical damages of reactor internals influence the vibration signature of the primary circuit. Such kind of damage simulation is an appropriate means to find sensitive measuring positiones for on-line monitoring and to define physically based threshold values. In principle, the model is even suited to estimate the loads of reactor components which might be imposed by external events (explosion, earthquake).

  • Open Access Logo Forschungszentrum Rossendorf; FZR-172 April 1997
    ISSN: 1436-3976


Publ.-Id: 821

Kaonen in Kernmaterie

Kolomeitsev, E. E.

  • Open Access Logo Forschungszentrum Rossendorf; FZR-167
    ISSN: 1436-3976


Publ.-Id: 820

Correlations between resonances in a statistical scattering model

Gorin, T.; Dittes, F.-M.; Müller, M.; Rotter, I.; Seligman, T. H.

The distortion of the regular motion in a quantum system by its coupling to the continuum of decay channels is investigated. The regular motion is described by means of a Poissonian ensemble. We focus on the case of only few channels K < 10. The coupling to the continuum induces two main effects, due to which the distorted system differs from a chaotic system (described by a Gaussian ensemble): 1. The width distribution for large coupling becomes broader than the corresponding Χ2 K distribution in the GOE case. 2. Due to the coupling to the continuum, correlations are induced not only between the positions of the resonances but also between positions and widths. These correlations remain even in the strong coupling limit. In order to explain these results, an asymptotic expression for the width distribution is derived for the one channel case. It relates the width of a trapped resonance state to the distance between its two neighboring levels.

  • Open Access Logo Forschungszentrum Rossendorf; FZR-162 Preprint
    ISSN: 1436-3976
  • Physical Review E 56, (1997), 2481-2491


Publ.-Id: 819

Proton-Proton Correlations in Central Collisions of Ni+Ni at 1.93 A GeV and the Space-Time Extent of the Emission Source

Kotte, R.; Biegansky, J.; Mösner, J.; Neubert, W.; Plettner, C.; Wohlfarth, D.; Alard, J. P.; Amouroux, V.; Basrak, Z.; Bastid, N.; Belyaev, I.; Berek, G.; Best, D.; Buta, A.; Caplar, R.; Cindro, N.; Coffin, J. P.; Crochet, P.; Dona, R.; Dupieux, P.; Dzelalija, M.; Eskef, M.; Fintz, P.; Fodor, Z.; Fraysse, L.; Genoux-Lubain, A.; Göbels, G.; Gobbi, A.; Guillaume, G.; Häfele, E.; Herrmann, N.; Hildenbrand, K. D.; Hölbling, S.; Hong, B.; Jundt, F.; Kecskemeti, J.; Kirejczyk, M.; Korolija, M.; Kuhn, C.; Lebedev, A.; Legrand, I.; Leifels, Y.; Maazouzi, C.; Manko, V.; Merlitz, H.; Mohren, S.; Pelte, D.; Petrovici, M.; Pinkenburg, C.; Pras, P.; Rami, F.; Reisdorf, W.; Ritman, J. L.; Roy, C.; Schüll, D.; Seres, Z.; Sikora, B.; Simion, V.; Siwek-Wilczynska, K.; Sodan, U.; Somov, A.; Tizniti, L.; Trzaska, M.; Vasiliev, M. A.; Wagner, P.; Wang, G. S.; Wienold, T.; Yatsunenko, Y.; Zhilin, A.


Small-angle correlations of Proton pairs produced in central Ni+Ni collisions at a beam energy of 1.93 AGeV are investigated with the FOPI detector System at GSI Darmstadt. A well-defined emission source is selected by triggering on central events which comprise about 8% of the total cross section. Simultaneous comparison of longitudinal and transverse correlation functions with the predictions of the Koonin model allows to unravel the space-time ambiguity of the emission process. Taking into account the strong collactive expansion of the participant zone, which introduces a reduction of the extracted source radius of more than 30% r.m.s. radius and emission time parameters of Rrms = ( 4.2 ± 1.2) fm and trms = (11+7 -5) fm/c are extracted, respectively. In contrast, the analysis of the angle-integrated correlation function gives an upper limit Rrms = (7.0 ± 1.4) fm of the source radius.

  • Zeitschrift für Physik A 359, (1997) 47-54
  • Open Access Logo Forschungszentrum Rossendorf; FZR-164 Preprint
    ISSN: 1436-3976


Publ.-Id: 818

The Binary and Ternary Decay of Hot Heavy Nuclei Produced in the Reaction 14N (34 AMeV) + 197Au

Wagner, W.; Herbach, C.-M.; Ortlepp, H.-G.; Aleksandrov, A. A.; Aleksandrova, I. A.; Dietterle, L.; Doronin, V. N.; Dshemuchadse, S.; Gippner, P.; Kamanin, D. V.; Matthies, A.; Pausch, G.; Penionzhkevich, Y. E.; Renz, G.; Schilling, K.-D.; Shishkin, D. I.; Strekalovsky, O. V.; Tichtchenko, V. G.; Tsurin, I. P.; Umlauf, C.; Vakatov, D. V.; Vasko, V. M.; Wilpert, M.; Zuchko, V. E.

  • Open Access Logo Forschungszentrum Rossendorf; FZR-163 Preprint
    ISSN: 1436-3976


Publ.-Id: 817

Wear mechanisms in titanium implanted silicon nitride ceramics

Brenscheidt, F.; Oswald, S.; Mücklich, A.; Wieser, E.; Möller, W.

The wear of silicon nitride ceramics is reduced by titanium
implantation albeit the friction coefficient is slightly increased. X-ray
excited photoelectron spectroscopy indicates that silicon oxide is formed
in the wear track while possible lubricating titanium oxides are not found.
Therefore we attribute the observed wear reduction to the amorphization
of the surface as proved by transmission electron microscopy.

  • Nuclear Instruments and Methods in Physics Research B 129 (1997) 483-486

Publ.-Id: 815

In-situ Investigation of Ion Driff Processes in Glass ...

Schmidt, B.

  • Lecture (Conference)
    EUROSENSORS XI, Warshaw, 21.-24.9.1997

Publ.-Id: 814

Two-phonon J=1 states in even-mass Te isotopes with A=122-130* Account No.: 0076898

Schwengner, R.; Winter, G.; Schauer, W.; Grinberg, M.; Becker, F.; von Brentano, P.; Eberth, J.; Enders, J.; von Egidy, T.; Herzberg, R.-D.; Huxel, N.; Käubler, L.; von Neumann-Cosel, P.; Nicolay, N.; Ott, J.; Pietralla, N.; Prade, H.; Raman, S.; Reif, J.; Richter, A.; Schlegel, C.; Schnare, H.; Servene, T.; Skoda, S.; Steinhardt, T.; Stoyanov, C.; Thomas, H. G.; Wiedenhöver, I.; Zilges, A.

Excited states of the nuclei 122, 126, 130Te were populated
via the (gamma, gamma') reaction at endpoint energies of the bremsstrahlung
between 4.5 and 5.5 MeV. Gamma rays were detected with a EUROBALL CLUSTER
detector and a single HPGe detector. In all investigated nuclei two or
three prominent dipole transitions were identified at Egammaca.
3 MeV. The corresponding low-lying J=1 states are interpreted as two-phonon
excitations. Quasiparticle-phonon-model calculations predict at about 3
MeV on 1- state arising from coupling of the first quadrupole
and the first octupole phonon, and one 1+ state arising from
the coupling of the first and the second quadrupole phonon, where the latter
has isovector character. Such an excitation mode can be considered as an
analogue of the scissors mode in vibrational nuclei. The calculated transition
strengths are compatible with experimental ones within a factor of about

  • Nuclear Physics A 620 (1997) 277-295

Publ.-Id: 813

Dichtemessung mit Positronenstrahlung

Hensel, F.

Ein berührungsloses Dichtemeßverfahren für Medien geringer Dichte wird vorgestellt, das auf der Abhängigkeit der Reichweite von Positronenstrahlung von der Dichte des Meßmediums beruht. Die Positronen werden von einem Radionuklid in einer festen Quelle erzeugt und in das zu untersuchende Volumen emittiert. Seitlich angeordnete Detektoren registrieren die bei der Annihilation der Positronen entstehenden Gammaquanten. Das Verfahren wurde in einem Dichtebereich von 15 kg/m3 bis 38 kg/m3 getestet, eine Erweiterung des Meßbereichs von 5 kg/m3 bis 300 kg/m3 ist möglich.

Einsatzfelder sind mehrphasige Strömungen mit hohem Massenstromanteil der gasförmigen Phase (Schäume und Dämpfe) sowie unter Druck stehende Gase. Der Vorteil des Verfahrens besteht in einer Kombination der hohen Dichtesensitivität der Betastrahlung mit der geringen Absorption der bei der Annihilation entstehenden Gammastrahlung in Rohr- bzw. Behälterwänden.

  • Lecture (Conference)
    ACHEMA 97: Int. Treffen für chem. Technik, Umweltschutz und Biotechnologie, 25. Ausstellungstagung, 9.-14. Juni 1997, Frankfurt/Main

Publ.-Id: 812

Studies of Bubble Flows by Positron Emitting Radiotracers

Hensel, F.; Prasser, H.-M.

Positron Emission Tomography was used in a series of experiments in the field of two-phase flow systems. The main goal was to observe mixing and flow phenomena in efficient spatial and time resolution [1].

Liquid positron emitting tracers were used for monitoring the mixing of a tracer distribution in a bubbly flow. At the beginning of the experiment an aqueous solution of Sodium Fluorine (NaF), labelled with 18F is injected into the two-phase mixture at a certain local position. This tracer starts to disperse caused by turbulence. The radiation originating from the annihilation of the positrons is detected by two opposite detector arrays, a double head spherical PET-scanner [2]. From the recorded event rates, a spatial intensity distribution of the annihilation events is calculated, which corresponds to the local concentration of the tracer.

For the experiments two setups were used. The fist consists of a flat rectangular water tank. Here the bubbly flow was generated by air injection near the tank bottom and by catalytic H2O2 decomposition, respectively. In the other setup, a vertical pipe was used. The bubbles were generated along a rod centred in the pipe, using catalytic H2O2 decomposition. In another experiment, the liquid drainage in a cellular foam was monitored.

The quantity of the active nuclide was restricted to several MBq, due to radiation protection requirements. Despite of this limitation, a good imaging is possible if the evaluation of event data can be restricted to two dimensions. For that case, a simple and time sparing midplane backprojection of the annihilation events can be applied. For the tracer, 18F was used in solution.

Using this technique, time sequences of images of the tracer concentration distribution with a time resolution of 0.5s were obtained and will be presented in the paper. This time base provides an appropriate statistical accuracy for the determination of the dispersion coefficients, too, which were determined for the bubbly flow and in the foam zone of the vertical pipe.

Transport processes in bubbly flows and foams seem to be interesting topics for investigation using a PET technique. The main advantage of PET tracers is the fact that many organic substances can be labelled with positron emitting isotopes which is important for the component sensitive investigation of many industrial processes, an objective of the further work.

  • Lecture (Conference)
    Frontiers in industrial Process Tomography, Delft, April 9-12, 1997
  • Contribution to proceedings
    Proceedings of the Conference Frontiers in Industrial Process Tomography II Delft, The Nederlands, April 9 - 12, 1997, pp. 47 - 51

Publ.-Id: 811

Stand der Projektvorhaben BMFT 02 S 7442 2 und Ziele des Neuantrages

Nebelung, C.; Nitsche, H.; Hübener, S.; Bernhard, G.

  • Lecture (Conference)
    5. Sitzg. Arbeitskreis "Freimessg. v. Anlageteilen u. Bauschutt aus dem Abbau kerntechn. Anlagen des Brennstoffkreislaufes" TU München, 15.3.96

Publ.-Id: 809

Direktmessung alpha-aktiver Nuklide

Nebelung, C.; Nitsche, H.

  • Lecture (Conference)
    6. Sitzg. Arbeitskreis "Freimessg. v. Anlageteilen u. Bauschutt aus dem Abbau kerntechn. Anlagen des Brennstoffkreislaufes" Rossendorf, 6.11.96

Publ.-Id: 808

Untersuchungen der Erwärmungsprozesse in Lagertanks mit gefährdenden Flüssigkeiten bei äußerer Brandeinwirkung

Aszodi, A.; Liewers, P.; Krepper, E.; Prasser, H.-M.

Wenn ein zylindrischer Lagertank durch ein externes Feuer von der Seite intensiver Wärmeeinwirkung ausgesetzt ist, so setzt der Massenverlust infolge von Dampffreisetzung viel eher ein, als im Fall einer Wärmezuführung vom Behälterboden. Mittels eines vereinfachten Modells konnten die Details des Erwärmungsprozesses und die Ursachen für das unterschiedliche Verhalten in Abhängigkeit von der Art und Weise der Wärmezufuhr erklärt werden. Die ZUfuhr vom Boden führt zu einer irregulären thermischen Konvektion und damit einer guten Durchmischung des Fluids, so daß die Sättigungstemperatur an allen Punkten im Behälter nahezu gleichzeitig erreicht wird. Die maximale Enthalpie im Behälter verbleibt während der gesamten Zeit nahe dem Mittelwert. Wird der Behälter von der Seite beheizt, so bildet sich eine stabile horizontale Temperaturschichtung heraus. Die Bildung von Dampf erfolgt bereits lange bevor die mittlere Temperatur den Siedepunkt erreicht hat. Passive konstruktive Maßnahmen, wie der Einbau von Prallplatten, können die Schichtung stören, das verstärkte Aufheizen an der Oberfläche vermeiden und die Freisetzung von Dampf verzögern. Eine durchgreifende Vermischung des flüssigen Inhalts konnte jedoch nicht erreicht werden. Die genaue Gestalt und die Wirkung dieser Prallplatten hängt von der konkreten Behältergeometrie ab und läßt sich weiter optimieren.

  • Technische Überwachung 38 (1997) 4, pp. 22-25

Publ.-Id: 807

Dynamic instabilities in electromagnetic levitation

Priede, J.; Gerbeth, G.

  • Contribution to proceedings
    3rd Int. Conference Transfer Phenomena in Magnetohydrodynamic & Electroconducting Flows, Aussois, France, September, 22-26, 1997, Vol. 2, pp. 377 - 384

Publ.-Id: 806

Velocity profile optimization for the Riga dynamo experiment

Stefani, F.; Gerbeth, G.; Gailitis, A.

  • Contribution to proceedings
    3rd Int. Conference Transfer Phenomena in Magnetohydrodynamic & Electroconducting Flows,Aussois, France, September, 22-26, 1997, Vol. 1, pp. 27 - 32

Publ.-Id: 805

Two- and three-dimensional instabilities of the cylinder wake in an aligned magnetic field

Mutschke, G.; Gerbeth, G.; Shatrov, V.; Tomboulides, A.

  • Physics of Fluids, Vol. 9, No.11, 1997, pp.3114-3116

Publ.-Id: 804

Technetium Coordination Ability of Cysteine-containing Peptides: X-ray Absorption Spectroscopy of a 99 Tc Labelled Endothelin Derivative

Johannsen, B.; Jankowsky, R.; Noll, B.; Spies, H.; Reich, T.; Nitsche, H.; Dinkelborg, L.; Hilger, C. S.; Semmler, W.

  • Applied Radiation and Isotopes Vol. 48, No. 8, pp. 1045-1050, 1997

Publ.-Id: 803

Synthesis and Molecular Structure of a Rhenium Complex derived from 6-Methyl-8 Alpha-amino-ergoline

Spies, H.; Noll, B.; Noll, S.; Findeisen, A.; Leibnitz, P.; Schulze, P. E.; Johannsen, B.

  • Chemische Berichte, Recueil 1997, 130, 839-841

Publ.-Id: 802

Das sächsische Windenergiepotential und seine Wirtschaftlichkeit

Rindelhardt, U.; Hirsch, W.

Auf der Basis der Ergebnisse eines speziellen Windmeßprogramms und unter Nutzung des Windatlasprogramms WASP wurde das sächsische Windenergiepotential zu 6000 GWh/Jahr ermittelt. Das Erwartungspotential liegt bei 1700 GWh/Jahr (entsprechend 10% der derzeitigen Elektroenergiebedarfes). Bei einem jährlichen Ertrag einer Windenergieanlage von 2000 Vollbenutzungsstunden kann diese unter den derzeitigen Rahmenbedingungen wirtschaftlich betrieben werden. Die bisher vorliegenden Betriebsergebnisse unterstreichen die Notwendigkeit qualifizierter Standortgutachten.

  • Lecture (Conference)
    Energie und Umwelt '97, Chemnitz, 19./20.3.97, Tagungsband S. 159
  • Contribution to proceedings
    Energie und Umwelt '97, Chemnitz, 19./20.3.1997, Tagungsband S. 159

Publ.-Id: 801

2-D and 3-D instabilities of the cylinder wake in external magnetic fields

Mutschke, G.; Gerbeth, G.; Shatrov, V.

  • Contribution to external collection
    APS/DFD '96, Syracuse, USA, Nov. 1996
  • Bulletin of the American Physical Society 41 (1996) 9, pp. 1715

Publ.-Id: 800

Separation Control of the cylinder wake using surface localized electromagnetic forces

Weier, T.; Gerbeth, G.; Mutschke, G.; Lielausis, O.; Platacis, E.

  • Contribution to external collection
    APS/DFD '96, Syracuse, USA, 25. Nov. 1996
  • Bulletin of the American Physical Society 41 (1996) 9, pp. 1750

Publ.-Id: 799

Hydrothermal Wave Instability of Thermocapillary-Driven Convection in a Coplanar Magnetic Field

Priede, J.; Gerbeth, G.

  • Journal Fluid Mechanics 11 (1996) pp. 1-000

Publ.-Id: 798

Experiments on cylinder wake stabilization in an electrolyte solution by means of electromagnetic forces localized on the cylinder surface

Weier, T.; Gerbeth, G.; Mutschke, G.; Platacis, E.; Lielausis, O.

Electromagnetic body forces, i.e. Lorentz forces, have been used to modify the boundary layer around a circular cylinder in cross flow. Depending on the polarity of the applied electric field different effects on the flow can be obtained. Lorentz forces directed with the mean flow are able to prevent the boundary layer from separation. Therefore flow separation as well as the von Karman vortex trail can be suppressed. When the momentum gain produced by the Lorentz forces in the boundary layer is high enough, thrust is produced, what results in a jet flow originated from the cylinders back side. If the Lorentz forces are directed opposite to the mean flow, the separation points are shifted towards the front stagnation point, the recirculation region broadens and the von Karman vortex trail is modified. The described technique gives a variety of opportunities to control the flow around the cylinder and the flow structure of the cylinder wake. Results from flow visualizations and numerical calculations are presented.

  • Lecture (Conference)
    Flow Control - Workshop, Cargese, July 1996
  • Experimental Thermal and Fluid Science, Vol.16, 1998, pp.84-91, Elsevier Science

Publ.-Id: 797

On some instabilities of electromagnetically levitated spherical bodies

Priede, J.; Galindo, V.; Gerbeth, G.

  • Contribution to proceedings
    Proceedings of the Int. Congress "Electromagnetic Processing of Materials", Paris, May 27 - 29, 1997, Vol. 2, pp. 419 - 424

Publ.-Id: 795

Influence of thermal boundary conditions on the stability of thermocapillary driven convection low-Prandtl-numbers convection

Priede, J.; Gerbeth, G.

  • Physics of Fluids, Vol. 9, 1997, pp. 1621 - 1634

Publ.-Id: 794

Modelling of the Isothermal Melt Flow due to Rotating Magnetic Fields in Crystal Growth

Barz, R.-U.; Gerbeth, G.; Wunderwald, U.; Buhrig, E.; Gelfgat, Y. M.

  • Journal of Crystal Growth, Vol. 180, 1997, pp. 410-421
  • Poster
    Int. Workshop on Modelling in Crystal Growth, Durbuy , Oct. '96

Publ.-Id: 793

Untersuchungen zur Spezitation von f-Elementen mittels laserinduzierter photoakustischer Spektroskopie

Geipel, G.; Bernhard, G.; Brachmann, A.; Brendler, E.; Nitsche, H.

  • Poster
    Anakon '97, Konstanz, 06.-08. 1997

Publ.-Id: 792

Light-scattering spectroscopy of a liquid gallium surface

Kolevzon, V.; Gerbeth, G.

  • Journal of Physics D: Applied Physics 29 (1996) pp. 2071-2081

Publ.-Id: 789

Light scattering study of the mercury liquid-vapor interface

Kolevzon, V.; Gerbeth, G.; Pozdniakov, G.

  • Physical Review E Volume 55, Number 3, March 1997, pp. 3134 - 3142
  • Lecture (Conference)
    Int. Workshop on Hydrodynamic Aspects of Electron Beam Technologies, Dresden, March 16 - 18, 1997

Publ.-Id: 788

Advances in technetium chemistry towards 99m Tc receptor imaging agents

Johannsen, B.; Spies, H.

  • Transition Metal Chemistry, 22. 318-320 (1997)

Publ.-Id: 787

Measurements of random and channeling stopping powers and charge state distributions in silicon for 0.2 - 1.2 MeV/u heavy ions

Jiang, W.; Grötzschel, R.; Pilz, W.; Schmidt, B.; Möller, W.

  • Physical Review B Volume 59, Number 1, 1 January 1999, pp. 226-234

Publ.-Id: 786

The Kinetics of the Ion-Beam-Induced Interfacial Amorphization in Silicon, Seite 5360, Manuskript-Nr.: 015721 JAP

Henkel, T.; Heera, V.; Kögler, R.; Skorupa, W.; Seibt, M.

  • Journal of Applied Physics, 82 (11), 1 December 1997, S. 5360-5373

Publ.-Id: 785

Synthesis of 17 Alpha-Substituted Mercaptoalkynyl Derivatives of 3,17 Beta-Estradiol

Wüst, F.; Spies, H.; Johannsen, B.

  • Tetrahedron Letters 38 (1997) 17 pp. 2931-2932

Publ.-Id: 784

Comparison of Uranyl Complexation Behavior with Natural and Model Humic Acids

Pompe, S.; Brachmann, A.; Bubner, M.; Heise, K.-H.; Geipel, G.; Nitsche, H.

  • Poster
    Migration '97, 26.-31.10.1997

Publ.-Id: 783

Sorption of Uranium(VI) on Rock Material of a Mine Tailing Pile: Solution Speciation by Fluorescence Spectroscopy

Geipel, G.; Bernhard, G.; Brendler, V.; Nitsche, H.

  • Radiochimica Acta 74 (1996) pp. 235-238
  • Poster
    Migration '95

Publ.-Id: 782

Methodenentwicklung zur Freimessung von Bauschutt auf alpha-aktive Nuklide (Th, U, Np, Pu, Am)

Nebelung, C.; Hübener, S.; Bernhard, G.

  • Other report
    zum Fördervorhaben BMBF 02 S 7442 2 (Schlußbericht)

Publ.-Id: 780

Light scattering study of viscoelastic properties of a liquid Gallium surface

Kolevzon, V.

  • The journal of chemical physics 106 (14), 8 April 1997

Publ.-Id: 779

Determination of relative arsenite and arsenate Concentrations in aqueous mixtures by XANES

Denecke, M. A.; Friedrich, H.; Reich, T.; Bernhard, G.; Knieß, T.; Rettig, D.; Zorn, T.; Nitsche, H.

  • Other report
    HASYLAB - Annual Report 1996 I, 751(1997)
  • Lecture (Conference)
    HASYLAB Nutzertreffen, Hamburg, Germany, 31.01.1997

Publ.-Id: 777

Structural Analysis of Uranium(VI) Complexes by X-ray Absorption Spectroscopy

Reich, T.; Hudson, E. A.; Denecke, M. A.; Allen, P. G.; Nitsche, H.

  • Contribution to external collection
    Poverkhnost (Moskau) 4-5, 149 (1997)
  • Surface Investigations 13, 557 (1998)

Publ.-Id: 776

EXAFS Investigations on the Interaction of Uranium(VI) with Natural and Synthetic Humic Acids

Denecke, M. A.; Pompe, S.; Reich, T.; Moll, H.; Bubner, M.; Heise, K.-H.; Nicolai, R.; Nitsche, H.

  • Radiochimica Acta 79 (1997), 151-159

Publ.-Id: 772

Corrosion Behavior and Microstructure of Titanium implanted with alpha and beta stabilizing elements

Pham, T.; Zyganow, V.; Matz, W.; Reuther, H.; Oswald, S.; Richter, E.; Wieser, E.

  • Thin Solid Films 310 (1997) 251-259

Publ.-Id: 771

Blue photoluminescence from high-dose Si+ - and Ge+ - implanted silicon dioxide layers

Rebohle, L.; Tyschenko, I. E.; Fröb, H.; Leo, K.; Yankov, R. A.; von Borany, J.; Skorupa, W.

  • Microelectronic Engineering 36 (1997) 107
  • Lecture (Conference)
    10th Biennial Conf. on Insulating Films on Semiconductors, Stenungsund, Sweden, June 11 - 14, 1997

Publ.-Id: 769

Impurity gettering effects in SIMOX wafers: what getters what, where and how

Yankov, R. A.; Kaschny, J.; Fichtner, P.; Mücklich, A.; Kreißig, U.; Skorupa, W.

  • Microelectronic Engineering 36 (1997) 129

Publ.-Id: 768

Relativistic Description of Exclusive Deuteron Break-up Reactions

Kaptari, L. P.; Kämpfer, B.; Dorkin, S. M.; Semikh, S. S.

The exclusive deuteron break-up reaction is analyzed within a covariant approach based on the Bethe-Salpeter equation with realistic meson-exchange interaction. Relativistic effects in the cross section, tensor analyzing power and polarization transfer are investigated in explicit form. Results of numerical calculations are presented for kinematical conditions in forthcoming p + D reactions at COSY.

  • Physics Letters B 404(1997)8-14
  • Open Access Logo Forschungszentrum Rossendorf; FZR-161 Preprint
    ISSN: 1436-3976


Publ.-Id: 767

Self-organization Kinetics in Finite Precipitate Ensembles During Coarsening

Borodin, V.; Heinig, K.-H.; Reiß, S.

A rate equation approach is applied for the description of the self-organization (layering) phenomenon predicted in recent computer experiments. This layering was observed in finite precipitate systems during annealing and is caused by Ostwald ripening. We demonstrate that the layering is triggered by local inhomogenities in the spatial distribution of precipitate sizes and should not be treated in terms of the frequently considered "spinodal
decomposition" approach. The change of the spatial profile of precipitate size starts from the boundary of the system and occurs within a "reaction shell" having a thickness of the order of the diffusional screening
length. During annealing this "reaction shell" shifts progressively into the system, leaving behind layers of precipitates. The layering is shown to occur only in sufficiently large systems with characteristic dimensions of at least several diffusional screening lengths. The reason for the weak sensitivity of interlayer distance to variations of system parameters is elucidated.

  • Phys. Rev. B56 (1997) 5332

Publ.-Id: 766

Influence of Input Neutron Spectrum Covariances on Results of Pressure Vessel Neutron Spectrum Adjustments

Böhmer, B.; Manturov, G.

One of the most critical problems in practical applications of spectrum adjustment in pressure vessel dosimetry is the insufficient knowledge of the input spectrum covariance matrix. Usually very crude approximations for this covariance matrix are used in adjustment procedures and, moreover, it is not clear to which extent these approximations influence the final results. Therefore it appeared useful to calculate this matrix as carefully as possible for a typical system and in positions for which a sufficient amount of activation measurements and precise transport calculations was available. The paper presents and discusses results of such calculations for a VVER-1000 type reactor. They base on the one hand on sensitivity coefficients estimated in transport calculations by means of the ANISN code and on the other hand on cross section covariance data taken from the Obninsk ABBN-93 data library. The results of spectrum adjustments based on the estimated covariance matrix are compared with results based on formerly used matrices. The obtained differences are discussed.

  • Poster
    9th International Symposium on Reactor Dosimetry, Sept. 2-6, 1996, Prague Eds H. Ait Abderrahim, P. D'hondt, B. Osmera, World Scientific Publishing, Singapore (1998) ISBN 981-02-3346-9, pp 294-301
  • Contribution to proceedings
    9th International Symposium on Reactor Dosimetry, Sept. 2-6, 1996, Prague Eds H. Ait Abderrahim, P. D'hondt, B. Osmera, World Scientific Publishing, Singapore (1998) ISBN 981-02-3346-9, pp 294-301

Publ.-Id: 765

Rossendorfer Intranet-Bibliotheks-Informationssystem

Rücker, C.; Koch, R.

  • Merkmale des Internets
  • Was ist ein Intranet?
  • Entwicklungen im Internet/Intranet
  • Integrierbarkeit lokaler Bibliothekssysteme
  • Vorarbeiten zum Rossendorfer Intranet
  • Probleme mit File-Server-Datenbanken (z. B. MS-ACCESS und dBASE)
  • Ziele und Arbeitsprogramm
  • Weitere Informationsdienste im Rossendorfer Intranet-Bibliotheks-Informationssystem
  • Oracle als Basis des Informationssystems
  • Zum Oracle WebServer
  • Lecture (others)
    Nutzung naturwissenschaftlich-technischer Datenbanken durch Forschungseinrichtungen in den neuen Bundesländern (NDF), 1996

Publ.-Id: 764

Natural circulation experiments at the ISB-VVER integral test facility and calculations using the code athlet

Krepper, E.

In 1995 at the integral test facility ISB-VVER in Elektrogorsk near Moscow natural circulation experiments were performed, which were scientifically accompanied by the Forschungszentrum Rossendorf. These experiments were the first of this kind at a test facility, which models VVER-1000 thermalhydraulics. Using the code ATHLET which is being developed by "Gesellschaft für Anlagen- und Reaktorsicherheit", pre- and posttest calculations were done to determine the thermalhydraulic events to be expected and to define and tune the boundary conditions of the test. The conditions found for natural circulation instabilities and cold leg loop seal clearing could be confirmed by the tests. Besides the thermalhydraulic standard measuring system, the facility was equipped with needle shaped conductivity probes for measuring the local void fractions.

  • Lecture (Conference)
    Jahrestagung Kerntechnik Aachen 1997
  • Contribution to proceedings
    Jahrestagung Kerntechnik Aachen 1997, Proceedings pp. 85-88

Publ.-Id: 763

Simulation der einphasigen Naturkonvektion auf der Sekundärseite der NOKO Anlage mit dem CFD-Code CFX 4

Aszodi, A.

  • Lecture (Conference)
    Jahrestagung Kerntechnik 1997

Publ.-Id: 762

Eine Methodik zur Bestimmung der Neutronenbelastung von Reaktordruckbehältern und deren Anwendung auf WWER

Barz, H.-U.; Böhmer, B.; Stephan, I.

  • Lecture (Conference)
    Jahrestagung Kerntechnik 1997 (KT6)
  • Contribution to proceedings
    Jahrestagung Kerntechnik 97, Aachen, 13.-15. Mai 1997, Tagungsbericht S. 37-40

Publ.-Id: 761

Determination of Pressure Vessel Neutron Fluence Spectra for a Low Leakage Rovno-3 Reactor Core Using Three Dimensional Monte Carlo Neutron Transport Calculations and Ex-vessel Neutron Activation Data

Barz, H.-U.; Böhmer, B.; Konheiser, J.; Stephan, I.; Borodkin, G.

Three dimensional Monte Carlo calculations considering all known geometrical and composition details were used for the determination not only of fluence integrals but also of fluence spectra with good statistical accuracy. This was possible by the application of own specially developed codes (TRAMO) and successfully modifying variance reduction on the basis of the weight window method (TRAWEI). Modern multigroup data sets were applied. For the real representation of fission sources the burn up and power history also for the fuel rods within the fuel assemblies was considered.
The investigation was accomplished for the irradiation period seven with a special low leakage loading of the reactor. During this period Russian and German detectors were irradiated in the ex-vessel cavity and analysed by advanced gamma spectrometric methods.
The reaction rates obtained with the calculated fluence spectra were compared with activation reaction rates measured in the ex-vessel cavity. Furthermore the calculated spectra were adjusted to the experimental reaction rates taking into account the variances and correlations of calculated input spectra, detector sensitivities and measurements. Using the adjustment code COSA2 based on the maximum likelihood method best estimate fluence spectra and fluence integrals could be provided.

  • Lecture (Conference)
    9th International Symposium on Reactor Dosimetry, Sept. 2-6, 1996, Prague
  • Contribution to proceedings
    in H.A. Abderrahim, P. D'hondt and B. Osmera (Ed.), Proceedings of the 9th International Symposium on Reactor Dosimetry, Prag (pp.58-66)

Publ.-Id: 760

Alpha-ERDA analysis of the energy distribution of oxygen ions implanted into silicon with plasma immersion ion implantation

Barradas, N.; Maas, A. J. H.; Mändl, S.; Günzel, R.

Plasma immersion ion implantation was used to implant
oxygen ions into silicon with applied voltage pulses of -40 kV and 2.5
ms lenght. Positive ions, O2+ and O+, with a continuous energy distribution
between 0 and 40 keV were implanted. Between 3x104 and 3x105 pulses, corresponding
to nominal doses from 2x1016 to 2x1017/cm2 were used. The resulting oxygen
depth profiles were measured with elastic recoil detection analysis (ERDA)
using 13.4 MeV a particles. Rutherford backscattering was used to determine
possible co-implanted contaminations. The obtained depth profiles were
simulated using a linear supersposition of calculated single-energy profiles.
The results obtained for the energy distribution of the incident ions are
compared with calculations obtained from a theoretical model, and the agreement
is very good. The incident flux is found to be composed of 34(5)% O2+ and
66(5)% O+ ions with an Fe contamination of ca. 0.5%.

  • Journal of Applied Physics 81 (10), 15 Mai 1997

Publ.-Id: 759

The Rossendorfer Beamline at the ESRF (Project ROBL)

Matz, W.; Prokert, F.; Schlenk, R.; Claußner, J.; Schell, N.; Eichhorn, F.; Bernhard, G.

In this final design report the general layout and the optics of the beamline ROBL is described. The beamline is buildt by the Research Center Rossendorf at the bending magnet source BM20 of the European Synchrotron Radiation Facility (ESRF), Grenoble. The design criteria for the beamline optics and the adopted solutions are reported in detail. Some performance data of the beamline as resolution, focussing and intensity are modelled by the ray-tracing code SHADOW. Furthermore tha layout of the vacuum system is described.

  • Open Access Logo Forschungszentrum Rossendorf; FZR-158
    ISSN: 1436-3976


Publ.-Id: 758

Bericht der Herbsttagung der Studiengruppe für Elektronische Instrumentierung vom 30. September bis 2. Oktober 1996 in Zeuthen

Gabriel, F.

  • Open Access Logo Forschungszentrum Rossendorf; FZR-160
    ISSN: 1436-3976


Publ.-Id: 755

Decay Study of Hot Nuclei Below the Multifragmentation Threshold with the FOBOS Detector at Dubna

Herbach, C.-M.; Ortlepp, H.-G.; Gippner, P.; Kamanin, D. V.; Penionzhkevich, Y. E.; Renz, G.; Schilling, K.-D.; Strekalovsky, O. V.; Tichtchenko, V. G.; Wagner, W.; u. a.

  • Open Access Logo Forschungszentrum Rossendorf; FZR-159 Preprint
    ISSN: 1436-3976
  • Contribution to proceedings
    Int. Research Workshop, Poiana Brusov, Romania, Oct. 7 - 14, 1996


Publ.-Id: 754

Conductive Tungsten-Based Layers Synthesized by Ion Implantation into 6H-Silicon Carbide

Weishart, H.; Schöneich, J.; Voelskow, M.; Renkewitz, S.; Skorupa, W.

We studied high dose implantation of tungsten into 6H-silicon carbide in order to synthesize an electrically conductive layer. Implantation was performed at 200 keV with a dose of 1.2×10(17) W(+)cm(-2) at temperatures between 200°C and 400°C. The influence of implantation temperature on the distribution of W in SiC was investigated and compared to results obtained earlier from room temperature (RT) and 500°C implants. Rutherford backscattering spectrometry (RBS) was employed to study the structure and composition of the implanted layers. Implantation at temperatures between RT and 300°C did not influence the depth distribution of C, Si and W. The W depth profile shows a conventional Gaussian shape. Implanting at higher temperatures led to a more confined W rich layer in the SiC. This confinement is explained by Ostwald ripening which is enabled during implantation at temperatures above 300°C. The depth of the implantation induced damage decreases slightly with increasing implantation temperature, except for 400°C implantation. The amount of damage, however, is significantly reduced only for implantation at 500°C.

  • Materials Research Society symposium proceeding 438 (1997) pp. 283-288 (MRS 1996 Fall Mtg)

Publ.-Id: 753

Resonant photon scattering on the semi-magic nucleus 89Y up to 7 MeV* Account Nr.: 00269871

Reif, J.; von Brentano, P.; Eberth, J.; Enders, J.; Herzberg, R.-D.; Huxel, N.; Käubler, L.; von Neumann-Cosel, P.; Nicolay, N.; Pietralla, N.; Prade, H.; Richter, A.; Schlegel, C.; Schnare, H.; Schwengner, R.; Servene, T.; Skoda, S.; Thomas, H. G.; Wiedenhöver, I.; Winter, G.; Zilges, A.

The semi-magic nucleus 89Y has been investigated in a (gamma,gamma')
experiment at an endpoint energy of the bremsstrahlung of E0=
7 MeV. The scattered photons have been detected with a EUROBALL Cluster
detector. The observed excitations are discussed in the framework of the
shell model and a coupling of the unpaired proton to milti-phonon structures
in the doubly even neighbours. Transitions above 4.7 MeV are considered
to have E1 character. Around 6.3 MeV an unusually large concentration of
E1 strength is found. Its origin is likely to correspond to similar structures
in the 88Sr and 90Zr isotones which can be interpreted
to result from the constructive interference of strong two-phonon amplitudes
with weak admixtures from the low-energy tail of the giant dipole resonance.

  • Nuclear Physics A 620 (1997) 1-15

Publ.-Id: 752

A Simple and Effecient Synthesis of a Derivatized Pseudotripeptide containing a Methylene Thioether Isoster and its Use for the Design of Bifunctional Rhenium and Technetium Chelating Agents

Scheunemann, M.; Johannsen, B.

  • Tetrahedron Letters 38 (1997) 1371-1372

Publ.-Id: 751

Synthesis and Molecular Structure of a Rhenium Complex Derived from 8-alpha-Amino-6-methyl-ergoline

Spies, H.; Noll, B.; Noll, S.; Findeisen, M.; Leibnitz, P.; Schulze, P.; Johannsen, B.

  • Chemische Berichte, Recueil 1997, 130, 839-841

Publ.-Id: 750

Institute of Safety Research, Annual Report 1995

Weiß, F.-P.; Rindelhardt, U.; (Editors)

The report gives an overview on the scientific work of the Institute of Safety Research in 1995.

  • Open Access Logo Forschungszentrum Rossendorf; FZR-152 September 1996
    ISSN: 1436-3976


Publ.-Id: 748

Quantitative AMS depth profiling of the hydrogen isotopes collected in Graphite Divertor and Wall Tiles of the Tokamak ASDEX - Upgrade

Sun, G.; Friedrich, M.; Grötzschel, R.; Bürger, W.; Behrisch, R.; Garcia-Rosales, C.

The accelerator mass spectrometry (AMS) facility at the
3 MV Tandetron in Rossendorf has been applied for quantitative depth profiling
of deuterium and tritium in samples cut from the vessels walls of the fusion
experiment ASDEX-Upgrade in Garching. The tritium originates from D(d,p)T
fusion reaction in the plasma and it is implanted in the vessel walls together
with deuterium atoms and ion from the plasma. The high deuterium concentrations
in the samples were measured by a conventional SIMS mode. The concentrations
in the surface layers down to the analysing depth of about 25 mm are for
deuterium in the range of up to 3x1018 to 8x1021 atoms/cm3, corresponding
to a deuterium retention of 2.5x1016 to 2.5x1018 atoms/cm2 in a surface
layer £ 25 mm, and for tritium in the range form 1011 to 5x1015 atoms/cm3,
corresponding to a tritium retention of 3.0x1010 to 3.5x1012 atoms/cm2
in a surface layer £25 mm. The estimated total amount of tritium
in the vessel walls is in agreement with the total number of neutrons produced
in D(d,n)3He reaction.

  • Journal of Nuclear Materials 246 (1997) 9-16

Publ.-Id: 747

Study of the ion-acoustic effect using focused ion beams

Teichert, J.; Bischoff, L.; Köhler, B.

Acoustic waves induced by an intensity-modulated focused
ion beam (FIB) have been measured. The experiments were performed with
Ga+ ions of 35 keV at a current of 3 nA and variable chopping frequency
up to 10 MHz. The acoustic signals were detected by means of a piezoelectric
sensor with integrated pre-amplifier. A dependence on the sample material
was found. The results suggest that the ion-acoustic effect can be utilized
for imaging and material characterization of surface and subsurface structures
in FIB systems.

  • Lecture (Conference)
    Proc. bei MRS Fall Meeting, Boston, Dez. 1996
  • MRS Symp. Proc. 438 (1997) 453

Publ.-Id: 746

Entwicklung einer einfachen Alpha-Meßmethode

Nebelung, C.; Nitsche, H.

  • Lecture (Conference)
    Seminar "Freigabemessung" 19.11.1995, Stuttgart

Publ.-Id: 745

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