Publications Repository - Helmholtz-Zentrum Dresden-Rossendorf

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Only approved publications

34138 Publications

N.C.A.11C-Labelling of Benzenoid Compounds in Ring Positions: Synthesis of 3-Nitro-/ 3-11C/ Toluene and 4-Nitro-/ 4-11C/ Toluene and Their Corresponding Toluidines

Mäding, P.; Steinbach, J.

  • Journal of Labelled Compounds and Radiopharmaceuticals XLI, 647-656 (1998)

Publ.-Id: 1070

Bestimmung der Neutronenflußdichten in den Bestrahlungseinrichtungen des BER II bei der HEU-LEU Umstellung

Stephan, I.; Gawlik, D.; Gatschke, W.

  • Lecture (Conference)
    Jahrestagung Kerntechnik 1998, Tagungsbericht, Mannheim 1998, S. 631 ff.
  • Contribution to proceedings
    Jahrestagung Kerntechnik 1998, Tagungsbericht, Mannheim 1998, S. 631 ff.

Publ.-Id: 1069

Finite Element Based Vibration Analysis of WWER-440 Reactors

Altstadt, E.; Weiß, F.-P.

A finite-element-model describing the mechanical vibrations of the whole
WWER-440 primary circuit was established to support the early detection of mechanical component faults. A special fluid-structure module was developed to consider the reaction forces of the fluid in the downcomer upon the moving core barrel and the rector pressure vessel. This fluid-structure interaction module is based on an approximated analytical 2D-solution of the coupled system of 3D fluid equations and the structural equations of motions. By means of the vibration model all eigenfrequencies up to 30 Hz and the corresponding mode shapes were calculated. It is shown that the fluid-structure interaction strongly influences those modes that lead to a relative displacement between reactor pressure vessel and core barrel. Moreover, by means of the model the shift of eigenfrequencies due to the degradation or to the failure of internal clamping and spring elements was investigated.Comparing the frequency spectra of the normal and the faulty structure, it could be proved that a
recognition of such degradations and failures even inside the reactor pressure vessel is possible by pure excore vibration measurements.

  • Lecture (Conference)
    ICONE‘98, International Conference on Nuclear Engineering, San Diego, May 10-15, 1998
  • Contribution to proceedings
    Proceedings of the 6th International Conference on Nuclear Engineering (ICONE-6) San Diego, May 10-15, 1998

Publ.-Id: 1066

Finite Element Based Stress Analysis of BWR Internals Exposed to Accident Loads

Altstadt, E.; Weiß, F.-P.; Werner, M.; Willschütz, H.-G.

During a hypothetical accident the reactor pressure vessel internals of boiling water reactors can be exposed to considerable loads resulting from temperature gradients and pressure waves. The finite element (FE) analysis is an efficient tool to evaluate the consequences of those loads by computing the maximum mechanical stresses in the components. 3 dimensional FE models were developed for the core shroud, the upper and the lower core supporting structure, the steam separator pipes and the feed water distributor. The models of core shroud, upper core support structure and lower core support structure were coupled by means of the substructure technique. All FE models can be used for thermal and for structural mechanical analyses. As an example the FE analysis for the case of a station black-out scenario (loss of power supply for the main circulating pumps) with subsequent emergency core cooling is demonstrated. The transient temperature distributions within the core shroud and within the steam dryer pipes as well were calculated based on the fluid temperatures and the heat transfer coefficients provided by thermo-hydraulic codes. At the maximum temperature gradients in the core shroud, the mechanical stress distribution was computed in a static analysis with the actual temperature field being the load. It could be shown that the maximum resulting material stresses do not exceed the permissible thresholds fixed in the appropriate regulations. Another scenario which was investigated is the break of a feed water line leading to a non-symmetric subpressure wave within the reactor pressure vessel. The dynamic structural response of the core shroud was assessed in a tranisient analysis. Even for this load case the maximum resulting stresses remain within the allowed limits at any time.

  • Lecture (Conference)
    Jahrestagung Kerntechnik‘98, München, 26.-28. Mai 1998, Tagungsbericht S. 721-724
  • Contribution to proceedings
    Jahrestagung Kerntechnik‘98, München, 26.-28. Mai 1998, Tagungsbericht S. 721-724

Publ.-Id: 1065

Dynamic in situ Diagnostics Using High-Energy Ion Beam Analysis

Möller, W.

  • Nuclear Instruments and Methods in Physics Research B136-138 (1998) 1203

Publ.-Id: 1064

Main Steam Line Break Analysis of a NPP with VVER by Means of the Coupled Code DYN3D/ATHLET

Kliem, S.; Grundmann, U.; Rohde, U.

The coupling of advanced thermohydraulic codes with 3-dimensional neutron kinetic codes corresponds to the effort to replace conservative estimations by best estimate calculations. ATHLET is an advanced thermohydraulic code, developed by the German "Gesellschaft für Anlagen- und Reaktorsicherheit" (GRS). The DYN3D code, developed at Forschungszentrum Rossendorf (FZR) for the simulation of reactivity initiated accidents in nuclear reactors with hexagonal and Cartesian fuel element cross section geometry comprises 3-dimensional neutron kinetics, models for the thermohydraulics of the core and the thermomechanical fuel rod behaviour.

Both versions of DYN3D for hexagonal and Cartesian fuel element geometry were coupled with ATHLET according to two basically different strategies. The first way of coupling uses only the neutron kinetics part of DYN3D (internal coupling). In the second way, the whole core is cut out from the ATHLET plant model and is completely described by DYN3D (external coupling). In this case the values of pressure, mass flow rate, enthalpy and boron acid concentration at the bottom and at the top of the core have to be transferred between the codes. This way of coupling is efficiently supported by the General Control and Simulation Module (GCSM) of ATHLET.

The coupled code DYN3D/ATHLET was used to investigate the possibility of recriticality during an asymmetrical overcooling of the reactor core of a NPP with VVER-440 after a main steam line break (MSLB). This MSLB analysis was performed for hot zero power and end of fuel cycle conditions. Different coolant mixing conditions in the lower plenum of the reactor were simulated. The results show the importance of these conditions. In case of a realistic mixing model and without consideration of mixing, i.e. where each loop is connected to a particular 1/6 sector of the core, a recriticality after reactor scram was predicted. For ideal mixing only, recriticality can be avoided.

  • Contribution to proceedings
    Tagungsband Jahrestagung Kerntechnik '98, S. 15-19
  • Lecture (Conference)
    Jahrestagung Kerntechnik '98
  • Contribution to proceedings
    Proc. TOPSAFE `98, Session TSC-1a, ENS, Valencia (Spain), 1998
  • Lecture (Conference)
    TOPSAFE `98, Session TSC-1a, ENS, Valencia (Spain), 1998

Publ.-Id: 1063

Mechanical Response of a BWR to Loads Imposed by External Events

Altstadt, E.; Weiß, F.-P.; Werner, M.

In the case of external events (e.g. earthquake or explosion pressure wave) the reactor pressure vessel (RPV) and its internal components are excited to mechanical vibrations. In such cases it is important to know the dynamic component stress for the assessment of the mechanical integrity of the system.
For this reason a theoretical global vibration model based on the finite element method (FEM) was developed for a German BWR. The model comprises the RPV including the main coolant pumps (MCP), the control element drives, the core flux measuring pipes and the RPV internals.

  • Lecture (Conference)
    Proceedings of IMORN-27, Valencia, Nov. 18-20, 1997
  • Contribution to external collection
    Proceedings of IMORN-27, Valencia, Nov. 18-20, 1997

Publ.-Id: 1062

Calculation of the NOKO Test B6-4

Schaffrath, A.; Dumaz, P.

In 1997 a "BWR Physics and Thermohydraulic Complementary Action (BWR-CA)" was established to further assist and broaden the objectives of the "European BWR R&D Cluster for Innovative Passive Safety Systems". The activities are divided into 4 work packages (WP). The work presented in this paper is performed in WP2: Passive decay heat removal from the core region, where two different decay heat removal systems were investigated. These are isolation condensers (e.g. as operated in Gundremmingen A, Dodewaard or in the PANDA facility) or emergency condensers (e.g. as foreseen on the SWR1000 and tested in the NOKO facility).

Within the BWR Cluster the Forschungszentrum Jülich had performed 10 NO-KO tests. Six of these tests were carried out with a four tube bundle, four tests with a single tube. Several post test calculations of NOKO tests were performed in the BWR-CA by CEA with CATHARE V1.3U and FZR with an improved version of ATHLET Mod. 1.1 Cycle C. Additionally FZJ had specified data for a blind calculation. The blind NOKO calculation - as well as the other NOKO post test calculations - proves, that the modified version of CATHARE as well as the improved version of ATHLET (ATHLET coupled with KONWAR) are able to predict the global parameters in the range of the fluctuations of the measured values. In the next complementary action it is planned to perform additional post test calculations of the single tube experiments, experiments with gas/non-condensable mixtures and pretest calculations of a second optimized emergency condenser test bundle. The optimization suggest is to increase the heat transfer, which allows to decrease the number of heat exchanger tubes and the emergency condenser dimensions. This is desirable because it reduces the surface of the pressurized BWR circuit and the possibilities for leakages, which is a safety relevant task.

  • Contribution to proceedings
    Jahrestagung Kerntechnik '98 (1998), INFORUM GmbH, ISSN 0720-9207, S. 87-90
  • Lecture (Conference)
    Jahrestagung Kerntechnik '98 in München

Publ.-Id: 1061

Experimental and Analytical Investigations to Loss of Vacuum Accidents for Fusion Reactors

Krüssenberg, A.-K.; Moormann, R.; Hinssen, H.-K.; Hofmann, M.; Wu, C. H.

Loss of vacuum accidents (LOVA) in fusion reactors will
lead to an air ingress into the vacuum vessel, oxidation
of the hot armour material and a partial mobilization of
the sorbed tritium. Also burnable carbon monoxide will
be formed during these accidents. In continuation to the
testing of carbon candidate materials for the First Wall
under oxidizing conditions in oxygen and steam in
collaboration with NET the carbon compound Aerolor AO5
of Carbone Lorraine has been examined in detail in the
experiments INDEX2 and SPALEX of the Institute of Safety
Research and Reactor Technology of Forschungszentrum
Jülich. The chosen parameters for these oxidation
experiments with oxygen in the inpore diffusion
controlled regime are temperatures between 973 K and
1173 K and partial pressures of oxygen between 1140 Pa
and 21000 Pa at system pressures between and; that means
reaction gas con centrations between 1 vol.-% and 20
vol.% oxygen in argon. From these results a semi-
empirical kinetic equation for the heterogeneous primary
reaction was developed. The equation considers the
dependence of the reaction rate on temperature, partial
pressure and burn-off of the material.
For calculations of LOVA the code RALOC Mod 4.0 AD -
developed by the Gesellschaft für Anlagen- und
Reaktorsicherheit (GRS) mbH has been extended by the
model COX (Carbon Oxidation) to consider carbon
oxidation kinetics. This kinetic model is based on the
above mentioned experimental results. First calculations
have been done for leak areas of 0.01 m², 0.1 m² and 1.0
m² and for different numbers of nodes in the reaction
chamber. The comparison of these results with earlier
calculations of JRC Ispra, GRS and Technicatome showed
that the new model COX and the nodalisation scheme lead
to more reliable statements concerning the spatial
dependencies especially for the burn-off of the armour
material and for the masses of the formed gases CO and

  • Contribution to proceedings
    1998 ASME/JSME/SFEN ICONE-6, Proceedings of the 6th International Conference on Nuclear Engineering, May 10-14, 1998, San Diego, California, Beitrag 6515.
  • Lecture (Conference)
    6th International Conference on Nuclear Engineering, May 10-14, 1998, San Diego, California

Publ.-Id: 1060

Depth Profile Analysis: STEM-EDX versus RBS

Markwitz, A.; Matz, W.; Schmidt, B.; Grötzschel, R.

  • Surface and Interface Analysis, Vol. 26, 359-366 (1998)

Publ.-Id: 1059

Anwendung der Entscheidungsanalyse bei der Sanierung von Altlasten

Kruber, S.

  • Open Access Logo Wissenschaftlich-Technische Berichte / Forschungszentrum Rossendorf; FZR-201
    ISSN: 1436-3976


Publ.-Id: 1058

Berührungslose Detektion der Struktur und Messung ausgewählter Paramater von Zweiphasenströmungen durch Mustererkennungsverfahren unter Verwendung von Ultraschall als Meßsonde. Abschlußbericht zum Vorhaben 1500 967

Prasser, H.-M.; Schütz, P.; Kossok, N.

Es wird ein Ultraschall-Meßverfahren für Zweiphasenströmungen vorgestellt, das die simultane Messung der Volumenstromdichte der Gas- und der Flüssigphase in einer Rohrleitung ermöglicht. Ein Prototyp wurde in Zusammenarbeit mit der Universität Nishny Novgorod (Rußland) aufgebaut. Es realisiert einen gepulsten Transmissions- und Reflexionsbetrieb mit Wellenleitersensoren, die auch an heiße Rohrleitungen bis zu 350°C direkt angekoppelt werden können. Kernstück der Meßmethode ist ein Mustererkennungsverfahren, das in bestimmten Volumenstrombereichen nach einer umfangreichen Kalibrierung (Trainingsprozeß) einen Meßfehler von kleiner 10 % besitzt, wenn die thermodynamischen und geometrischen Randbedingungen nahezu konstant bleiben. Durch die Erweiterung der Trainingsmatrizen um einen, die thermodynamischen Eigenschaften determinierenden Parameter (z. B. Temperatur, Druck) kann das Klassifizierungsverfahren auch auf Fälle mit veränderlichen Stoffwerten angewandt werden. Das Mustererkennungsverfahren und die Ultraschalltechnik wurden experimentell optimiert und erprobt. Die Ultraschallsignale wurden außerdem mit Hilfe der Methode des unüberwachten Lernens klassifiziert. Die gefundenen Gruppen von Signalmustern weisen eine deutliche Ähnlichkeit zu bekannten Strömungskarten auf. Es wird gezeigt, daß das Verfahren des unüberwachten Lernens sich für die objektive Aufstellung von Strömungskarten eignet. In einem speziellen Kapitel werden die Ergebnisse von Tests zur Füllstandsmessung in einem Segment der Hauptumwälzleitung von Druckwasserreaktoren vorgestellt.

  • Open Access Logo Forschungszentrum Rossendorf; FZR-203 November 1997
    ISSN: 1436-3976


Publ.-Id: 1057

Polarization Observables in the Reaction NN -> NN O|

Titov, A. I.; Kämpfer, B.; Shklyar, V.

We study the reaction NN → NNΦ slightly above the threshold within an extended one-boson exchange model which also accounts for uud knock-out. It is shown that olarization observables, like the beam-target asymmetry, are sensible quantities for identifying a ss admixture in the nucleon wave function on the few per cent level.

  • Open Access Logo Forschungszentrum Rossendorf; FZR-202
    ISSN: 1436-3976


Publ.-Id: 1055

Bericht der Herbsttagung der Studiengruppe für Elektronische Instrumentierung vom 29. September bis 1. Oktober an der Universität in Frankfurt am Main

Gabriel, F.; Jainsch, R.

  • Open Access Logo Forschungszentrum Rossendorf; FZR-199
    ISSN: 1436-3976


Publ.-Id: 1054

X-Ray Diffraction Study of Phase Transitions in Sr0.75Ba0.25Nb2O6 between 20 and 400K

Prokert, F.; Ritter, H.; Ihringer, J.

  • Ferroelectrics Letters, 1998, Vol. 24, pp. 1-7

Publ.-Id: 1053

Characterization of Vacancy-Type Defects in Ion Implanted and Annealed SiC by Positron Annihilation Spectroscopy

Anwand, W.; Brauer, G.; Coleman, P. G.; Skorupa, W.

New examples of characterization of vacancy-type defects
in ion implanted and annealed SiC by the established technique of slow
positron implantation spectroscopy are presented. In particular, the estimation
of the depths of damaged regions and their change (a) after post-irradiation
annealing, or (b) due to variation of substrate temperature during implantation,
is addressed.

  • Lecture (Conference)
    Konferenz MRS Fall Meeting, Boston, MA, USA, Dec. 1 - 5, 1997

Publ.-Id: 1052

Sonderuntersuchungen zu Strömungsformen am NOKO Einzelrohr

Schaffrath, A.; Prasser, H.-M.; Böttger, A.; Jaegers, H.

Im Rahmen des Forschungsvorhabens 15 NU 09485 "Berechnung des passiven Notkondensators eines mit Naturumlauf arbeitenden innovativen Siedewasserreaktors (SWR600) mit ATHLET" wurden vom Forschungszentrum Rossendorf e.V. Auswertungen und Interpretationen von Messungen zu Strömungsformen bei Kondensationsvorgängen in einem umfangreich instrumentierten Einzelrohr durchgeführt. Ziel der Experimente war, die Aussagesicherheit der NOKO-Bündelexperimente zu erhöhen sowie experimentelle Daten für die Validierung von Thermohydraulikprogrammsystemen (u.a. den ATHLET-Code) bereitzustellen.
Die theoretische Modellierung des Wärmeübergangs an der Innenseite der Notkondensatorrohre erfordert die Identifizierung der im aktuell betrachteten Rohrquerschnitt vorliegenden Strömungsform sowie die Auswahl einer geeigneten (d.h. strömungsformabhängigen) Korrelation zur Berechnung des Wärmeübergangskoeffizienten. Sensitivitätsanalysen haben gezeigt, daß sich im Betrieb der Notkondensatoren in Abhängigkeit von der Wirkung der Dampfschubspannung auf den Kondensatfilm sowie dessen Schwerkrafteinfluß zahlreiche Strömungsformen (z.B. eine Ring-, Schichten, Blasen-, Schwall- und Pfropfenströmung) einstellen. Da der Flüssigkeitsanteil längs des Kondensatorrohres zunimmt, können die verschiedenen Strömungsfor-men nacheinander auftreten bzw. ineinander übergehen.

  • Lecture (Conference)
    Jahrestagung Kerntechnik 98 (1998), INFORUM GmbH, ISSN 0720-9207, S. 83-86
  • Contribution to proceedings
    Jahrestagung Kerntechnik 98 (1998), INFORUM GmbH, ISSN 0720-9207, S. 83-86

Publ.-Id: 1051

Neue Rechnungen zu Lufteinbruchstörfällen bei Fusionsreaktoren mit einer Beschichtung des Reaktorraums aus CFC-Material

Krüssenberg, A.-K.; Hicken, E. F.

  • Contribution to proceedings
    Jahrestagung Kerntechnik 1998 S. 573-576
  • Lecture (Conference)
    Jahrestagung Kerntechnik 1998, 26.-28.5.1998, München

Publ.-Id: 1050

Stickstofftransport während der plasmagestützten Randaufstickung nichtrostender Stähle - der Einfluß der passivierenden Oxidschicht

Parascandola, S.; Kruse, O.; Richter, E.; Möller, W.

Plasmagestütztes Randaufsticken ist eine erfolgversprechende Technologie zur Verbesserung der Verschleiß- und der Korrosionseigenschaften von Bauteilen aus nichtrostendem Stahl. Bei moderaten Temperaturen (ca. 400°C) kann eine Randschicht mit einem hohem Gehalt an gelöstem Stickstoff (ca. 20at.%) erzeugt werden. Diese Randschicht weist eine deutlich erhöhte Härte und Verschleißbeständigkeit und eine hervorragende Korrosionsbeständigkeit auf. Die Prozesse, die zur Bildung dieser Randschicht führen, sind weitgehend unverstanden. Um den Einfluß der passivierenden Oxidschicht auf die Bildung der stickstoffreichen Randschicht zu untersuchen, ist ein in-situ Experiment mit einer gekreuzten Strahlgeometrie aufgebaut worden. Bei kontrollierten Restgaszusammensetzungen wird während des plasmagestützten Randaufstickens zeit- und tiefenaufgelöste Elementanalyse betrieben. Dabei wird zum Randaufsticken eine Hochstrom-Ionenquelle und zur tiefenaufgelöste Elementanalyse „elastic recoil detection analysis“ (ERDA) verwendet. ERDA ist sensitiv auf die leichten Elemente und wurde hier hinsichtlich schneller Datenaufnahme optimiert. Quantitative zeitaufgelöste Messungen der Elementverteilungen werden für verschiedene Sauerstoffpartialdrücke vorgestellt. Die Bildung der stickstoffreichen Randschicht ist stark mit der Reduzierung der Oxidschicht korreliert. Hohe Sauerstoffpartialdrücke stabilisieren die Oxidschicht. Dieses Ergebnis stimmt gut überein mit einem einfachen Transportmodell, das die Sauerstoffadsorptionsrate und die Zerstäubungsrate berücksichtigt.

  • Lecture (Conference)
    Nichtmetalle in Metallen: Tagung des Gemeinschaftsausschusses "Nichtmetalle in Metallen" der GDMB, 23-25 März 1998 in Münster / Nichtmetalle in Metallen '98: Vortragstexte einer Tagung des Gemeinschaftsausschusses "Nichtmetalle in Metallen" der G...
  • Contribution to proceedings
    Nichtmetalle in Metallen: Tagung des Gemeinschaftsausschusses "Nichtmetalle in Metallen" der GDMB, 23-25 März 1998 in Münster / Nichtmetalle in Metallen '98: Vortragstexte einer Tagung des Gemeinschaftsausschusses "Nichtmetalle in Metallen" der G...

Publ.-Id: 1049

Härtung von Edelstahl durch Stickstoff-Plasma-Immersions-Ionenimplantation

Richter, E.; Günzel, R.

  • Ingenieur-Werkstoffe 6 (1997) 44

Publ.-Id: 1046

Noise Analysis Measurements and Numerical Evaluations of the Moderator Temperature Coefficient in PWRs

Laggiard, E.; Grundmann, U.; Rohde, U.; Weiß, F.-P.; Runkel, J.; Stegemann, D.

The moderator temperature coefficient (MTC) of a 1400 MW pressurized water reactor (PWR) has been measured from neutron and temperature fluctuations in different reactor positions. In order to explain the deviations observed between the estimations, numerical evaluations of the MTC were performed using the 3D two energy groups DYN3D code for a prototype PWR. The differences between the experimental MTC estimations can be partially explained considering that the numerical MTC evaluations show a definite devitation of the neutronics from point kinetics.

  • Other report
    27th Informal Meeting on Reactor Noise (IMORN 27), Valencia, November 18 - 20, 1997
  • Lecture (Conference)
    27th Informal Meeting on Reactor Noise (IMORN 27), Valencia, November 18 - 20, 1997

Publ.-Id: 1045

Nicotinamide-Substituted Complexes as Redox Marker

Knieß, T.; Spies, H.; Brandau, W.; Johannsen, B.

  • Journ. Labelled Comp. and Radiopharm. XLI, 605-614 (1998)

Publ.-Id: 1044

Annealing studies of chromium implanted silicon nitride ceramics

Brenscheidt, F.; Matz, W.; Wieser, E.; Möller, W.

The effect of chromium implantation and subsequent annealing
on the hardness and wear behaviour of a silicon nitride-based ceramic is
investigated. Implantation energies were 200, 400, 1000 and 2000 keV, the
fluence was 1017 Cr+ ions cm-2 in all cases. The annealing temperatures
were 800 C, 1000 C and 1200 C. The phase composition was determined with
X-ray diffraction. Annealing at 800 C does not affect the crystal structure.
At 1000 C the -Si3N4-phase is formed for 1 and 2 MeV implantation energy.
At 1200 C, Cristobalite and Keiviite are formed at the lower implantation
energies; at higher energies -Si3N4 is formed. We discuss the phase formation
for the different implantation energies and annealing temperatures and
the relationship with the observed hardness and wear.

  • Nuclear Instruments and Methods in Physics Research B 127/128 (1997) 677-680

Publ.-Id: 1043

Surface Roughness with Nanometer-Scale Ag Particles Generated by Ion Implantation

Pham, M. T.; Matz, W.; Seifarth, H.

Surfaces of SiO2, Si3N4, Ta2O5 and glass were implanted
with Ag+ ions. Studies using X-ray diffraction (XRD) and atomic force microscopy
(AFM) show that the surface morphology is dominated by metallic silver
features consisting of regularly shaped, mostly spherical, Ag particles
spanning a size range from some nanometers to some 100 nm in diameter.
The particle size metrics, distribution, shape, and their density are shown
to be controlled by the process paramters ion dose, dose rate, and ion
energy. Adjusting the energy of the incident ions results in various degrees
of submerging into the substrate including exposed Ag features anchored
onto the surface or buried Ag particles overcoated by a thin layer of the
matrix material. The substrate material differs by its ability of stabilizing
the dispersion and blocking the Ag movement. Ta2O5 and glass substrates
provide more homogeneously dispersed Ag particles, much smaller in size
and regularly shaped compared to SiO2 and Si3N4 substrate systems. Potential
application refers to surface enhanced Raman scattering.

  • Analytica Chimica Acta 350 (1997) 209-220

Publ.-Id: 1042

Comparison of Computer Generated and ERDA depth Profiles of Oxygen Implanted into Silicon with Plasma Immersion Ion Implantation

Barradas, N. P.; Maas, A. J. H.; Mändl, S.

Plasma immersion ion implantation was used to implant
oxygen into silicon with nominal doses ranging from 2 x 1016 to 2 x 1017/cm2.
Positive Ions, O+2 and O+, with a continuous energy distribution between
0 and 40 keV were implanted. The plasma parameters and the geometrical
configuration of the implantation were chosen in order to follow closely
the assumptions of a theoretical model, which allowed to calculate the
energy distribution of the incident ions. Computer simulations were performed
to derive the resulting theoretical oxygen depth distribution. The agreement
found with the experimental depth profiles, measured by elastic recoil
detection analysis, is good. The small discrepancy observed is discussed
in terms of the shortcomings of the model used.

  • Nuclear Instruments and Methods in Physics Research B 124 (1997) 63-68

Publ.-Id: 1041

Quality assurance of heavy ion tumour therapy by means of positron emission tomography.

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

no abstract

  • Poster
    IEEE Nuclear Science Symposium and Medical Imaging Conference, Albuquerque, New Mexico, 9-15 Nov, 1997
    Book of Abstracts(1997)102
  • Contribution to proceedings
    IEEE Nuclear Science Symposium and Medical Imaging Conference, Albuquerque, New Mexico, 9-15 Nov, 1997
    Book of Abstracts(1997)102

Publ.-Id: 1040

ULIII Polarized XAFS Studies on Ba[UO2PO4]2.8H2O

Hennig, C.; Denecke, M. A.; Roßberg, A.; Zahn, G.; Reich, T.; Nitsche, H.

U LIII Polarized XAFS studies on Ba[UO2PO4]2·8H2O
C. Hennig 1, M. A. Denecke 1, A. Roßberg 1, G. Zahn 2,
T. Reich 1, H. Nitsche1
1 Forschungszentrum Rossendorf, Institut für Radiochemie,
PF 510119, D-01314 Dresden
2 Technical University of Dresden, Institute of Crystallography
and Solid State Physics, Zellescher Weg 16,
D-01062 Dresden

An experimental and theoretical study of the U LIII -edge polarization dependent XANES and EXAFS is presented for a single crystal of barium uranyl phosphate hydrate. Ba[UO2PO4]2·8H2O is built up by layers of [UO2]2+ and equatorial coordinated [PO4]3- tetrahedra. Layers are bridged by Ba2+, H+ and H3O+ cations giving an overall tetragonal (or nearly tetragonal) symmetry. The orientation of a crystal obtained by cleaving a larger crystal and used for the XAFS measurements was determined by x-ray diffraction. The layered structure of Ba[UO2PO4]2·8H2O exhibits preferred cleavage along {001} and parallel to {100}. Linear uranyl units are aligned parallel to [001]. {100} represents the least squares plane for the equatorial oxygen atoms. XAFS measurements were performed with the polarization vector aligned in the equatorial plane (parallel to [100] and [110]), as well as with the polarization vector oriented perpendicular to [010], with 90°, 60°, 45°, and 30° angles to [001].
Two different explanations of the resonance » 15 eV above the LIII -edge white-line maximum have been discussed. One explanation, based on pressure dependent measurements of UO3, attributed this feature to shake-up processes [1]. The other interpretation stems from ab initio multiple-scattering calculations using the FEFF program package. These calculations identify this feature as a multiple-scattering resonance associated with the axial U-O bonds in various uranium compounds [2], [3]. Our experimental investigations show that the relative intensity of this resonance increases if the polarization vector is aligned along the axial U-O bonds. This observation confirms the multiple-scattering assignment of this feature and is supported by our own theoretical FEFF calculations.
The U LIII -edge EXAFS show a strong polarization dependence, especially evident in the Fourier transforms at distances corresponding to uranyl axial oxygen atoms and equatorial atoms. This dependence strongly influences the effective coordination numbers, Ni, obtained in the data analysis.
The marked characteristics of such polarization-dependent XAFS spectra renders them useful as a unique indicator of uranyl orientation. For example, the specific binding sites and orientation of sorbed uranyl (actinyl) ions onto mineral surfaces can be determined with this method.

[1] Bertram, S., Kaindl, G., Jové, J., Pagès, M., Gal, J.: Phys.
Rev. B 52 (1989) 2680
[2] Hudson, E.A., Rehr, J.J., Buchner, J.J.: Phys. Rev. B 52
(1995) 13815
[3] Hudson, E.A., Allen, P.G., Terminello, L.J., Denecke, M.A.,
Reich, T.: Phys. Rev. B 54 (1996) 156

  • Contribution to proceedings
    Abstract für die Tagung der Deutschen Gesellschaft für Kristallographie 2.-5.3.1998 in Karlsruhe
  • Suppl. Z. Krist. 15, 156 (1998)
  • Poster
    Euroconference and NEA Workshop: Actinide-XAS-98, Grenoble, France, 04.-06.10.1998

Publ.-Id: 1039

Physically-based modeling of two-dimensional and three-dimensional implantation profiles: Influence of damage accumulation

Murthy, C. S.; Posselt, M.; Feudel, T.

The alteration of the shape of one-dimensional, two-dimensional (2D), and three-dimensional (3D) range distributions with growing dose as well as the extension of amorphous zones formed at high doses is studied for 15 keV BF2+ and 30 keV P+ implantations into (100)Si using the dynamic binary collision code Crystal-TRIM. The range and damage profiles are calculated for the area 97.74 (parallel to [010]) × 97.74 (parallel to [001]) nm2 at the target surface irradiated by the ion beam and surrounded by impenetrable masks. The change of the shape of the 2D and 3D distributions in the lateral direction is less pronounced than in the depth direction. At low doses the lateral profile branches are determined by rechanneled particles, at high doses the enhanced dechanneling is the reason for the increased lateral straggling. The latter effect is responsible for the relatively large lateral extension of the amorphous zone beneath the masks. The simulated depth profiles of boron and phosphorus and the predicted thickness of the amorphous layer are in good agreement with experimental data.

  • Journal of Vacuum Science and Technology B 16 (1998) 440
  • Lecture (Conference)
    Proc. 4th Int. Workshop Measurement, Characterization and Modeling of Ultra-Shallow Doping Profiles in Semiconductors, Res. Triangle Park, USA, April 1997

Publ.-Id: 1037

Structure Investigation of the Influence of the Irradiation Temperature on the Formation of Defects in Nuclear Pressure Vessel Steel A 533-B-1

Große, M.; Nitzsche, P.; Böhmert, J.; Hempel, A.; Brauer, G.; Haggag, F. M.

  • Contribution to proceedings
    Proceedings MRS 1996 Fall Meeting

Publ.-Id: 1036

Präparation und In-Vivo-Testung von Melanom-affinen '3+1' (99mTc)-Oxotechnetium(V)-Gemischt-Ligandkomplexen

Friebe, M.; Spies, H.; Johannsen, B.; Mohammed, A.; Eisenhut, M.

  • Lecture (Conference)
    DGN-Tagung, 36. Internationale Jahrestagung, Leipzig, 01.-04. April 1998
  • Abstract in refereed journal
    Nuklearmedizin 37 (1998) A49

Publ.-Id: 1035

Rezeptoraffine Oxorhenium(V)-Komplexe als Inhibitoren der Monoaminoxidase im Rattenhirn

Matys, S.; Brust, P.; Scheunemann, M.; Pietzsch, H.-J.; Johannsen, B.

In früheren Untersuchungen haben wir nachgewiesen, dass Oxorhenium(V)-Komplexe mit Ketanserin-, Cisaprid- und MDL72832-ähnlicher Struktur hohe Affinität zu Serotoninrezeptoren des Gehirns aufweisen, womit die analogen 99mTc-Verbindungen als potentielle Radiopharmaka von Interesse sind. Ihre Struktur ließ auch inhibitorische Wirkung auf die Serotonin abbauende Monoaminoxidase (MAO) vermuten. In Untersuchungen an Rattenhirnhomogenaten mit 1mM Tryptamin als Substrat beider Isoenzyme MAO A und MAO B, bzw. 1 mM Phenylethylamin als spezifisches Substrat für MAO B hemmt die Mehrheit der untersuchten Komplexe mit IC50 Werten zwischen 10-4 und 10-6 M das Enzym. Die höchste Affinität besitzt der abgebildete Komplex mit IC50=7*10-7±2 M.
Die räumliche Anordnung des protonierbaren Stickstoffs im Molekül ist dabei kritisch. Die Ergebnisse zeigen, daß bei der Bewertung von Radiotracern für das serotonerge System potentielle Wechselwirkungen mit der MAO berücksichtigt werden müssen.

  • Poster
    36. Intern. Jahrestagung DGN, Leipzig, 01.-04.04.1998
  • Abstract in refereed journal
    Nuklearmedizin 37 (1998) A51

Publ.-Id: 1034

Rheniumkomplexe von Steroidalen Estrogenen, Androgenen und Progestinen

Wüst, F.; Berger, R.; Katzenellenbogen, J. A.; Alberto, R.; Schubiger, P. A.; Spies, H.; Johannsen, B.

  • Lecture (Conference)
    36. Intern. Jahrestagung der DGN, Leipzig, 01.-04. April, 1998
  • Abstract in refereed journal
    Nuklearmedizin 37 (1998) A45

Publ.-Id: 1033

Beeinflussung der99mTc-MIBI- und [18F]FDG-Aufnahme durch Inhibitoren des P-Glycoproteins

Bergmann, R.; Brust, P.; Johannsen, B.

Das P-Glycoprotein (Pgp) ist ein energieabhängiges Efflux-Transportsystem für ein breites Pharmaka-Spektrum, welches in bestimmten Tumoren, aber auch in normalen Geweben, z.B. den Endothelzellen des Gehirns exprimiert wird. Die Pgp-Bewertung in Tumoren mit lipophilen Kationen (99mTc-MIBI, 99mTc-Tetrafosmin) wird durch verschiedene biochemische Veränderungen (z.B. des Energiestoffwechsels) erschwert. In Multitracerexperimenten an Hirnendothelzellen untersuchten wir die Veränderungen im Membranpotential (99mTc-MIBI, 99mTc-Tetrafosmin), des Glukoseumsatzes ([18F]FDG) und der Pgp-Aktivität ([3H]Vinblastin) unter dem Einfluß verschiedener Pgp-Inhibitoren (u.a. Verapamil, Vinblastin,Valinomycin). Die Zellaufnahme der Pgp-Substrate ([3H]Vinblastin, 99mTc-MIBI, 99mTc-Tetrafosmin) korrelliert unter Kontrollbedingungen mit dem Glucosemetabolismus ([18F]FDG). Bei Hemmung des Pgp zeigte sich allerdings in den meisten Fällen eine Verminderung der Akkumulation von FDG. Das Ionophor Valinonycin löst dagegen einen dramatischen Anstieg des Glucoseumsatzes aus, gleichzeitig ist die MIBI oder Tetrafosmin-Aufnahme verringert obwohl die [3H]Vinblasin-Akkumulation unverändert bleibt. Das zeigt, daß bei der Untersuchung von Pgp-Transportprozessen Sekundäreffekte auftreten können (hier Veränderungen des Energiestoffwechsels), die bei der Interpretation der Daten zu berücksichtigen sind.

  • Lecture (Conference)
    36. Intern. Jahrestagung DGN, Leipzig, 01.-04.04.1998
  • Abstract in refereed journal
    Nuklearmedizin 37 (1998) A17

Publ.-Id: 1032

Thermochromatography of Heavy Actinides - Adsorption of No-259 on Ti, V, Nb, Ta and Mo

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

  • Journal of Alloys and Compounds 271-273 (1998) 316-321
  • J. Less-Common Met. 271-273, 316 (1998)

Publ.-Id: 1030

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

Herbach, C.-M.; Ortlepp, H.-G.; Wagner, W.

The first series of experiments at the FOBOS detector, using beams of the U-400M cyclotron of the Flerov Laboratory of Nuclear Reactions, was devoted to few-fragment decays of equilibrated systems. To exclude deep inelastic collisions or quasifission as sources of massive fragments, hot heavy nuclei were produced in the very asymmetric reactions 7Li (43 AMeV) + 232Th, 14N (34 AMeV) + 197Au, and 14N (53 AMeV) + 197Au, 232Th. Two- and three-fragment events were analysed on the base of masses and velocity vectors measured independently for each fragment. The events were sorted into excitation energy bins according to the linear momentum transfer following the massive transfer approach. Binary events were treated as fission. Fragment mass distributions as well as total kinetic energies were studied for an excitation energy range of 100 - 500 MeV. A new TKE parametrisation is proposed extending the Viola systematics to large mass asymmetries. With rising excitation energy the mass dispersion develops unexpectedly. Two new effects have been fourid and are discussed as consquences of the cooling down during the slow fission process at moderate E*, and of a strong decrease of the fission time at large E*. Ternary events were analysed by comparing measured velocity correlations with results of Coulomb trajectory simulations. If one fragment has intermediate mass (A = 10...30), two components in the relative velocities and the Z/A ratios confirm a sequential and a neck mechanism. For events with three fragments of comperable size neither the assumption of two sequential independent fission acts nor a nlultifragnlentaion-like scenario can reproduce the data. Agreement is achieved if these three-fragment decays are characterized by a collinear intermediate state followed by two scissions separated by no more than 280 fm/c, a very short time scale compared with usual saddle-to-scission intervals.

  • Open Access Logo Forschungszentrum Rossendorf; FZR-198
    ISSN: 1436-3976
  • Other report
    Konferenzbeitrag HIPH '97


Publ.-Id: 1029

Metal Plasma Immersion Ion Implantation and Deposition (MPIIID): Chromium on Magnesium

Brückner, J.; Günzel, R.; Richter, E.; Möller, W.

  • Poster
    Konferenz SMMIB 97, Gatlinburg, TE, USA, Sept. 1997
  • Surface and Coatings Technology 103-104 (1998) 227-230

Publ.-Id: 1028

Complexation of Uranium(VI) with the Main Components of Mine-Wood Degradation. Part 1. Complexation with Protocatehuic Acid, Vanillic Acid and Vanillin

Baraniak, L.; Schmidt, M.; Bernhard, G.; Nitsche, H.

To consider the process of mine wood degradation and its concequences on the contaminant migration via aquatic path in risk assessments, e.g. for uranium mine restoration in the southern region of Saxony (Germany), the complexation of U(VI) with 3,4-dihydroxybenzoic acid (proto-catechuic acid), 4-hydroxy-3-methoxy-cinnamic acid (ferulic acid), 4-hydroxy-3-methoxybenzoic acid (vanillic acid) and 4-hydroxy-3-methoxybenzaldehyde (vanillin) was studied by potentiometric pH titration in carbonate-free solutions of 0.1 M NaClO4. These four complexants are reasonably stable monomeric intermediates in the microbial or hydrothermally driven spruce-wood lignin degradation and therefore play a role in natural water chemistry.

The evaluation of the pH titration curves was carried out with the classical theory of stepwise complex formation, analyzing Bjerrum’s formation function [1] and by non-linear fitting of the pH titration curve with Sayce’s multi-equilibria program "SCOGS" [2], considering hydrolysis and mixed-ligand complexation.

In the case of protocatechuic acid, a series of very stable (1:1) to (1:3) complexes are formed (log ß: 14.8/25.9/33.2). The constants calculated by Bjerrum’s formation function are in full agreement with the values of the SCOGS curve fitting, i.e. U(VI) hydrolysis is surpressed in the presence of this ligand. The complexes with ferulic acid and vanillic acid have a much lower stability: log ß11 values are to 6.88 and 7.16, respectively. In the case of ferulic acid, the assumption of the acidic species [UO2H(fer)]+ with log ß111 =11.9 improves the pH curve fit. Vanillin as complexant leads to pH curves that can be best fitted with the species [UO2(van)]+ and [UO2(van)2(OH)2]2- with log ß values of 4.47 and -3.95, respectively.

Using these data speciation calculations for some calcite-rich mine waters show that the strong U(VI)-carbonato complexes predominate. Under certain conditions only protocatechuic acid complexes can be formed.

  • Poster
    6th International Conference on Chemistry and Migration Behaviour of Actinides and Fission Products in the Geosphere: MIGRATION '97, Sendai, Japan, October 26-31, 1997

Publ.-Id: 1027

Characterization of the Redox Behaviour of Spruce-Wood Lignin and Humic Acid

Mack, B.; Abraham, A.; Baraniak, L.; Bernhard, G.; Nitsche, H.

The redox behaviour of spruce lignin and humic acid was characterized by their redox potential and redox capacity. Such polyelectrolytes are formed in natural degradation processes including wood decomposition. They influence the redox situation in water of flooded uranium mines.

The first approach to the standard potential using a platinum electrode in combination with a silver-siver chloride electrode (3 M KCl) in a cell with liquid junction [1] was done in two ways: (1) by direct redox potential measurements [2] and (2) by redox titration with potassium hexacyanoferrate(III) [3], both in dependence on the pH. The redox potential of spruce lignin at pH 0 determined in that way was found to be 580±20 mV. That represents a rough E0 which can be arranged in the series of redox couples with decreasing E0. The reduction capacity determined from the titration at pH 9 amounts to 15±0.5 meq/g. Iron(III) in non-complexing solution (0.1 M KCl) was completely reduced by lignin with a maximum capacity of 6.5±0.8 meq/g in the pH range 2 to 2.5. Humic acids of different origin are characterized in the same way.

In addition, the iron(III) reduction by lignin and humic acid was examined in the pH range 3 to 5 by sqare-wave voltammetric analysis after a four weeks equilibration under inert gas at 25 °C. The iron(III) waves at -1.40 V and -1.60 V disappeared and the typical iron(II) signal was found at -1.33 V (all potentials were measured vs. Ag/AgCl, 3 M KCl). Changing the iron(III)-lignin ratio at pH 4.7±0.2 the maximum iron(III) quantity that can be reduced by a given lignin amount could be determined to 4.0 meq/g. At higher ratios the wave of the unreduced iron(III) was detected at -1.6 V (pH 4). At ratios below 4 meq/g iron(III) is quantitatively reduced and there is a linear relationship between the introduced iron(III) concentration and the intensity of the found iron(II) signal.

The analytical proof of the formed iron(II) was carried out by spectrophotometric determination with o-phenantroline. This sensitive method with a detection limit of 0.01 ppm iron(II) was adapted in such a way that iron(II) could be determined in the presence of iron(III).

  • Poster
    13th Radiochemical Conference, Marianske Lazne - Jachymov, Czech Republic, April 20.-24.04.1998

Publ.-Id: 1026

Simultaneous Measurement of 18F-FDOPA Metabolism and Cerebral Blood Flow in Newborn Piglets

Brust, P.; Bauer, R.; Walter, B.; Bergmann, R.; Füchtner, F.; Vorwieger, G.; Steinbach, J.; Johannsen, B.; Zwiener, U.

  • Int. J. Devl. Neuroscience, Vol. 16, No. 5, pp 353-364, 1998

Publ.-Id: 1025

A Method for the Intrinsic Calibration of CsI(Tl) Detectors

Kamanin, D. V.; Wagner, W.; Ortlepp, H.-G.

A method for the intrinsic energy calibration of photomultiplier-coupled CsI(Tl) detectors is described. A simple empirical model of the scintillation light pulse-shape of CsI(Tl) crystals for light charged particles has been applied to simulate the particle identification matrix as it follows from the pulse-shape analysis method. The calibration procedure for the large-area CsI(Tl) detectors of the scintillator shell of the 4 π - array FOBOS for ions with Z < 4 at energies below 100 AMeV is based on the energies of the particle punch-through points.

  • Open Access Logo Forschungszentrum Rossendorf; FZR-197
    ISSN: 1436-3976
  • Nuclear Instruments and Methods in Physics Research A 413 (1998) 127-137


Publ.-Id: 1023

RBS and Channeling Analysis of Cobalt Disilicide Layers Produced by Focused Ion Beam Implantation

Teichert, J.; Voelskow, M.; Bischoff, L.; Hausmann, S.

Cobalt disilicide layers were formed by ion beam synthesis using 35 keV Co+ focused ion beam (FIB) implantation into silicon. A strong influence of the pixel dwell time on the layer formation was found. Only for short pixel dwell-times (about 1µs) closed layers with sufficient quality for device application could be formed. To understand the dwell-time effect the as-implanted samples were examined by Rutherford backscattering (RBS) and channeling analysis. A method is presented which allows quantitative measurements of samples where the implanted areas are smaller than the diameter of the RBS beam. Evidence has been obtained that the silicon crystal damage is less for short dwell-times.

  • Vacuum, Volume 51, Number 2, Pages 261-266, 1998
  • Lecture (Conference)
    10th Int. School on Vacuum, Electron and Ion Technologies, Varna, Bulgaria, Sept. 22 - 27, 1997

Publ.-Id: 1022

Elastic Proton-Deuteron Backward Scattering: Relativistic Effets and Polarization Observables

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

The elastic proton-deuteron backward reaction is analyzed within a covariant approach based on the Bethe-Salpeter equation with realistic meson-exchange interaction. Lorentz boost and other relativistic effects in the cross section and spin correlation observables, like tensor analyzing power and polarization transfer etc., are investigated in explicit form. Results of numerical calculations for a compbte set of polarization observables are presented.

  • Open Access Logo Forschungszentrum Rossendorf; FZR-194
    ISSN: 1436-3976
  • Physical Review C Vol. 57 (1998) 1097-1111


Publ.-Id: 1021

Verification of the Code DYN3D/R with the Help of International Benchmarks

Grundmann, U.; Rohde, U.

Different benchmarks for reactors with quadratic fuel assemblies were calculated with the code DYN3D/R. In this report comparisons with the results of the reference solutions are carried out. The results of DYN3D/R and the reference calculation for the eigenvalue keff and the power distribution are shown for the steady-state 3-dimensional IAEA-Benchmark. The results of NEACRP-Benchmarks on control rod ejections in a standard PWR were compared with the reference solutions published by the NEA Data Bank. For assessing the accuracy of DYN3D/R results in comparison to other codes the deviations to the reference solutions are considered. Detailed comparisons with the published reference solutions of the NEA-NSC Benchmarks on uncontrolled withdrawal of control rods are made. The influence of the axial nodalization is also investigated. All in all, a good agreement of the DYN3D/R results with the reference solutions can be seen for the considered benchmark problems.

  • Open Access Logo Forschungszentrum Rossendorf; FZR-195 October 1997
    ISSN: 1436-3976


Publ.-Id: 1020

Entwicklung von theoretischen Schwingungsmodellen für WWER-Reaktoren auf der Grundlage der Finite-Elemente-Methode

Altstadt, E.; Weiß, F.-P.; Werner, M.; Bulavin, V.; Pavelko, V.; Gutsev, D.; Anikin, G.; Usanov, A.; Dodonov, V.

In diesem Abschlußbericht wird ein Fördervorhaben beschrieben, welches auf die Unterstützung von 6 russischen Wissenschaftlern aus drei unterschiedlichen Institutionen abzielte. Ihre Arbeiten zur Anlagendiagnostik / Schadensfrüherkennung dienen der Erhöhung der Sicherheit von WWER-Reaktoren.
Das Vorhaben leistet einen Beitrag zur verbesserten Beurteilung der mechanischen Integrität von Reaktoren der russischen WWER-440 und WWER-1000 Baureihe, insbesondere zur empfindlichen Früherkennung und Lokalisation mechanischer Schädigungen an Reaktorkomponenten mit Hilfe schwingungsdiagnostischer Methoden. Zu diesem Zweck wurde das Finite-Element-Modell zur Simulation des mechanischen Schwingungsverhaltens aller Primärkreiskomponenten eines WWER-1000 erstellt. Dafür wurde das Programmpaket ANSYS® genutzt.
Das Berechnungsmodell zum WWER-440 wurde mit neueren Ergebnissen experimenteller Schwingungsuntersuchungen weiter justiert. Das Modell kann in der Hauptsache genutzt werden, um zu klären, wie sich unterstellte mechanische Defekte von Reaktoreinbauten auf die Schwingungen der Gesamtanlage auswirken. Diese Schadenssimulation ist besonders geeignet, empfindliche Meßpositionen für die on-line Überwachung zu finden und physikalisch fundierte Grenzwerte zu definieren.

  • Open Access Logo Forschungszentrum Rossendorf; FZR-196 Oktober 1997
    ISSN: 1436-3976


Publ.-Id: 1019

Ellipsometric Investigation of Damage Distribution in Low Energy Boron Implantation of Silicon

Fukarek, W.; Möller, W.; Hatzopoulos, N.; Armour, D. G.; van den Berg, J. A.

As the scaling of silicon devices to 100 nm channel length requires the formation of ultra-shallow (< 60 nm) junctions, high depth resolution analytical techniques become necessary for the characterization of the dopant and damage distributions. In situ single wavelength Ellipsometric
Etch Depth Profiling (EEDP) and non-destructive Variable Angle of incidence Spectroscopic Ellipsometry (VASE) have been used to obtain accurate and quantitative information on the depth profiles of radiation damage produced by low energy, room temperature ion implantation of B+ into Si.

  • Nuclear Instruments and Methods in Physics Research B 127/128 (1997) 879-883

Publ.-Id: 1018

Verhalten des Radiums im Flutungsprozeß des Uranbergwerks Königstein

Baraniak, L.; Thieme, M.; Funke, H.; Bernhard, G.; Nitsche, H.

The interaction of radium with characteristic sediments of the upper Saxon Elbe river valley was investigated with the
aim to provide key data for transport modelling within the framework of mining site restoration. Adsorption
measurements therefore were carried out on site-specific sediments (different kinds of sandstone, claystone and lime
marl) using (1) acidic mine water coming from sulfuric acid residues of the former in-situ leaching process, (2)
groundwater that is inflowing into the mine and (3) mixtures of both which simulates certain stages of the mine flooding process. The distribution ratios were determined by batch experiments using an eight-week equilibration at aquifer temperature (14 °C). Radium adsorption from acidic mine water onto different kinds of sandstone is characterized by high distribution ratios (3400 mL/g). When contacted with groundwater, the sorption is decreased more than 20-fold (60-180 mL/g). For claystone and lime marl the distribution ratios amount to 130 and 480 mL/g, respectively, and they are nearly constant in the mine flooding process. The main adsorption mechanisms on the leached sandstone and the clayey sediments were identified as coprecipitation and ion exchange, respectively. The long-term migration behaviour in the aquifers of the south-east Saxon Elbe basin was calculated on the basis of Hadermanns' equation, considering retardation, dispersion and radioactive decay.

  • Wissenschaftliche Zeitschrift der TU-Dresden 46 (1997) Heft 6, S. 90-94

Publ.-Id: 1016

Interaction of Uranium(VI) with Arsenate in Aqueous Solution Studied by Time-Resolved Laser-Induced Fluorescence Spectroscopy (TRLFS)

Rutsch, M.; Geipel, G.; Bernhard, G.; Nitsche, H.

  • Poster
    13th Radiochemical Conference, Marianske Lasne-Jachymov, Czech Republik, 20.-24.04.1998
  • Radiochimica Acta 86(1999), 135-141

Publ.-Id: 1014

Methods for Colloid Characterization in Environmental Waters Rich in Humic Substances

Zänker, H.; Richter, W.; Hüttig, G.; Schmeide, K.; Nitsche, H.

  • Poster
    13th Radiochemical Conference, Marianske Lazne, 19-24.4.1998

Publ.-Id: 1013

Fine Structure of the E1 Response in 140Ce Below the Particle Threshold*

Herzberg, R.-D.; von Brentano, P.; Eberth, J.; Enders, J.; Fischer, R.; Huxel, N.; Klemme, T.; von Neumann-Cosel, P.; Nicolay, N.; Pietralla, N.; Ponomarev, V. Y.; Reif, J.; Richter, A.; Schlegel, C.; Schwengner, R.; Skoda, S.; Thomas, H. G.; Wiedenhöver, I.; Winter, G.; Zilges, A.

The E1 response of the semi-magic nucleus 140Ce below the particle
threshold was measured in a (gamma, gamma') experiment utilizing the new
Euroball Cluster detector at the S-DALINAC. While the energy averaged data
are in good agreement with the tagged photon results, here they are resolved
for the first time into 54 individual transitions. A quasiparticle-phonon
model calculation including up to three-phonon configurations compares
well to the extracted strength distribution. The interference between one-
and two-phonon contributions is essential for a quantitative reproduction.

  • Physics Letters B 390 (1997) 49-54

Publ.-Id: 1011

Tilted Rotation of Weakly Deformed and Triaxial Nuclei

Frauendorf, S.

  • Zeitschrift für Physik A 358, 163-167 (1997)

Publ.-Id: 1010

Dipole excitations in 122Te, 126Te and 130Te

Schwengner, R.; Schauer, W.; Winter, G.; von Brentano, P.; Eberth, J.; Enders, J.; von Egidy, T.; Grinberg, M.; 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.; Stoyanov, C.; Thomas, H. G.; Wiedenhöver, I.; Zilges, A.

Excited states of the nuclei 122Te, 126Te and 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 detector. In all nuclei several
dipole transitions were identified at energies around 3 MeV. The lowest
corresponding J = 1 states are interpreted as two-phonon excitations. Quasiparticle-phonon-model
calculations predict one 1- state arising from the coupling
of the first quadrupole and the first octupole phonon and one 1+
state arising from the coupling of the first and the isovector second quadrupole
phonon at about 3 MeV. The calculated transition strengths are compatible
with experimental one.

  • Zeitschrift für Physik A 358, H.2, 197-198 (1997)

Publ.-Id: 1008

Particle-hole Induced Intruder Bands in117Sb and 119Sb

Lafosse, D. R.; Fossan, D. B.; Hughes, J. R.; Liang, Y.; Schnare, H.; Vaska, P.; Waring, M. P.; Zhang, J. Y.

  • Physical Review C Volume 56, Number 2, 760-771

Publ.-Id: 1007

Fragmentation of the Yrast Band in 186Os at Ipi=18+ and Disappearance of the Collective Minimum

Balabanski, D. L.; Hristov, D. H.; Lieder, R. M.; Rzaca-Urban, T.; Gast, W.; Hebbinghaus, G.; Krämer-Flecken, A.; Schnare, H.; Urban, W.; Wyss, R.

  • Zeitschrift für Physik A 356, 393-397 (1997)

Publ.-Id: 1006

The application of PET to quality assurance of heavy-ion tumour therapy.

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

At the new heavy ion tumor therapy facility of the Gesellschaft für Schwerionenforschung at Darmstadt positron emission tomography (PET) has been implemented for in-beam and in-situ therapy control, i.e. during the tumor irradiation. The components necessary for this dedicated PET-imaging and their integration into the framework of therapy planning and quality assurance of heavy ion cancer treatments are presented. Results of the first application of this PET-method to patient treatments are reported.

Keywords: heavy-ion therapy; positron emission tomography; treatment planning; quality assurance

  • Strahlentherapie und Onkologie, Vol. 175, Suppl. II (1999) 33-36

Publ.-Id: 1005

Solution of the 4th AER Dynamic Benchmark by Use of the Code DYN3D with a Particle-in-Cell Method for the Description of Boron Transport

Rohde, U.; Lucas, D.

The results of the 4th AER dynamic benchmark obtained by the use of the code DYN3D in the Research Centre Rossendorf are presented. The benchmark comprises the modeling of a boron dilution transient caused by switching on the first main coolant pump of a loop containing a plug of partially undiluted water. Therefore, the course of the transient is significantly affected by correct modeling of the boron transport. The results of studies on the influence of numerical diffusion during boron transport are presented. Consequently, a new numerical model based on the particle­in­cell method has been developed and implemented into DYN3D. The basic features of this model are described. It allows the complete suppression of numerical diffusion and to take into account the effect of boron enrichment in the liquid water phase in the case of boiling in a simple manner. Another important feature of the benchmark task was that each participant had to use his own macroscopic cross section library. In our analysis the MAGRU library for VVER­440 was used. A few reactor­physical key parameters had been given in the benchmark definition for optional adoptation of the cross section data. The presented analysis was carried out with a minimum amount of adoptations. Finally, only the static supercriticality of the boron dilution was given an the Doppler feedback was adopted. Some interesting thermo­hydraulic effects are discussed, which can be used for a deeper comparative analysis of the thermo­hydraulics models of the codes. Due to the low mass flow rate and high heat flux densities occuring, vapour generation during the transient is significantly affected by subcooled boiling under thermodynamic non­equlibrium conditions.

  • Lecture (Conference)
    7th Symposium of Atomic Energy Research, Hörnitz, 23. - 26. 09. 1997
  • Contribution to proceedings
    Proceedings of the 7th Symposium of Atomic Energy Research, p. 387, Hörnitz, 23. - 26. 09. 1997

Publ.-Id: 1004

Strong Blue and Violet Photo- and Electroluminescence from Germanium- and Silicon-Implanted Silicon Dioxide Layers

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

  • Applied Physics Letters, Vol. 71, Nr. 19, S. 2809-2811

Publ.-Id: 1002

MARS: A Start Detector System for the Cosy Time-of-Flight Spectrometer TOF

Michel, P.; Möller, K.; Naumann, B.; Naumann, L.; Schamlott, A.; Schmidt, G.; Schülke, A.

  • Nuclear Instruments and Methods in Physics Research A 408 (1998) 453-467

Publ.-Id: 1001

11C-Labelling of Heterocyclic Aromatic Compounds in Ring Positions: Synthesis of 2-11C Indole

Zessin, J.; Steinbach, J.

  • Journal of Labelled Compounds and Radiopharmaceuticals XLI, 669-676 (1998)

Publ.-Id: 1000

Synthesis of Oxorhenium(V) Complexes Derived from 7-alpha-Functionalized Testosterone: First Rhenium-Containing Testosterone Derivatives

Wüst, F.; Scheller, D.; Spies, H.; Johannsen, B.

  • Eur. J. Inorg. Chem. 1998, 789-793

Publ.-Id: 999

In-beam PET imaging for the control of heavy-ion tumour therapy.

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

A method for the in-situ control of the heavy-ion tumour therapy by means of positron emission tomography is introduced. This method is founded on the measurement of the dynamic spatial distributions of beta+-emitters generated by nuclear fragmentation during the irradiation and their relation to the dose. In order to study this relationship and to derive the dose distribution from the measured beta+-activity distribution, a framework of model calculations is used. Results of phantom experiments with 12C ion beams will be presented, demonstrating good agreement between experiment and calculation as well as the possibilities and limits of the PET-technique for treatment plan verification and beam monitoring.

  • IEEE Transactions on Nuclear Science, Vol. 44, No. 4 (1997) 1492-1498
  • Lecture (Conference)
    IEEE Nuclear Science Symposium, 2-9 Nov, 1996, Anaheim, California, USA
    Conference Record, Vol. 2 (1996) 1099-1103
  • Contribution to proceedings
    IEEE Nuclear Science Symposium, 2-9 Nov, 1996, Anaheim, California, USA
    Conference Record, Vol. 2 (1996) 1099-1103

Publ.-Id: 998

Tilted Rotation and Backbending in an Odd-Proton Nucleus

Pearson, C. J.; Walker, P. M.; Purry, C. S.; Dracoulis, G. D.; Bayer, S.; Byrne, A. P.; Kibedi, T.; Kondev, F. G.; Shizuma, T.; Bark, R. A.; Sletten, G.; Frauendorf, S.

  • Physical Review Letters, Volume 79, Number 4

Publ.-Id: 997

Fission of Metal Clusters

Näher, U.; Bjornholm, S.; Frauendorf, S.; Garcias, F.; Guet, C.

  • Physics Reports 285 (1997) 245-320

Publ.-Id: 996

Identification of Excited States in Doubly Odd 110Sb: Smooth Band Termination

Lane, G. J.; Fossan, D. B.; Thorslund, I.; Vaska, P.; Allatt, R. G.; Paul, E. S.; Käubler, L.; Schnare, H.; Hibbert, I. M.; O'Brien, N.; Wadsworth, R.; Andrejtscheff, W.; de Graaf, J.; Simpson, J.; Lee, I. Y.; Macchiavelli, A. O.; Blumenthal, D. J.; Davids, C. N.; Lister, C. J.; Seweryniak, D.; Afanasjev, A. V.; Ragnarsson, I.

Excited states in 110Sb have been identified for the first time
in a series of gamma-spectroscopy experiments using both thin and backed
targets, including neutron-fold and recoil-mass measurements to provide
unambiguous channel identification. The three decoupled intruder bands
observed in 110Sb are based upon configurations involving 2p-2h
excitations across the Z=50 shell gap and show the features of smooth band
termination. The yrast intruder band, which has been connected to the low-spin
levels, is tentatively identified up to its predicted termination at IPi=45+.
Excellent agreement with configuration-dependent cranked Nilsson-Strutinsky
calculations is obtained for the high-spin states near termination.

  • Physical Review C, Nuclear Physics, 3rd Series, Volume 55, Number 5

Publ.-Id: 995

Influence of the Ion Irradiation on the Properties of ß-FeSi2 Layers Prepared by Ion Beam Assisted Deposition

Barradas, N.; Panknin, D.; Wieser, E.; Schmidt, B.; Betzl, M.; Mücklich, A.; Skorupa, W.

ß-FeSi2 was produced by ion beam assisted deposition
(IBAD). The influence of the deposition parameters on the structure was
studied by Rutherford backscattering, X-ray diffraction, cross section
transmission electron microscopy, and scanning electron microscopy. The
samples grow in a columnar way with pin-holes and their surface is rough.
A soft IBAD process with low Ar energy (EAr = 200 eV) and low Ar ion to
Fe atom ratio (IAr/AFe = 0.16) improves the layer structure in comparison
to samples prepared without Ar irradiation. Less pin-holes are formed,
and the roughness shows a minimum. The roughness increases for larger EAr
and larger IAr/AFe. All samples are polycrystalline but with a pronounced
texture. The preferential orientation is also enhanced by the IBAD process.
The electrical properties of the layers were characterized by Hall effect
measurements and measurements of the I-V characteristics of simple diode
structures. The results are discussed in relation with the influence of
the ion beam.

  • Nuclear Instruments and Methods in Physics Research B 127/128(1997) 316-320

Publ.-Id: 994

Pion Production in Mass-Symmetric Heavy Ion Collisions at 0.8-1.8 AGeV

Müntz, C.; Baltes, P.; Oeschler, H.; Sartorius, C.; Sturm, C.; Wagner, A.; Bormann, C.; Brill, D.; Shin, Y.; Stein, J.; Ströbele, H.; Ahner, W.; Barth, R.; Cieslak, M.; Debowski, M.; Grosse, E.; Henning, W.; Koczon, P.; Mang, M.; Miskowiec, D.; Schicker, R.; Senger, P.; Kohlmeyer, B.; Pöppl, H.; Pühlhofer, F.; Speer, J.; Völkel, K.; Walus, W.

  • Zeitschrift für Physik A 357, 399-409 (1997)

Publ.-Id: 993

Jahresbericht 1995/1996 Abteilung Kommunikation und Datenverarbeitung

Fülle, R.

  • Open Access Logo Forschungszentrum Rossendorf; FZR-187
    ISSN: 1436-3976


Publ.-Id: 992

In-situ Investigation of Ion Drift Processes in Glass During Anodic Bonding

Schmidt, B.; Nitzsche, P.; Lange, K.; Grigull, S.; Kreißig, U.; Thomas, B.; Herzog, K.

  • Lecture (Conference)
    EUROSENSORS XI, The 11th European Conference on Solid-State Transducers , Warzaw, Poland, Sept. 21-24, 1997
  • Sensors and Actuators A 67 (1998) 191-198

Publ.-Id: 991

Elektroenergieerzeugung aus erneuerbaren Energiequellen in Sachsen

Hackstein, G.; Riedel, J.; Rindelhardt, U.; Schwanitz, M.

Im Bericht werden die Potentiale zur Elektroenergieerzeugung aus verschiedenen erneuerbaren Energiequellen in Sachsen zusammengestellt. Dabei werden natürliche Potentiale und - wo möglich - technische Potentiale sowie wirtschaftliche Potentiale unterschieden. Das ermittelte technische Potential (ohne Biomasse) entspricht etwa einer Elektroenergieproduktion von 7400 GWh jährlich. Davon entfallen etwa 2/3 auf die Windenergie und der Rest zu gleichen Teilen auf die Wasserkraft und die Photovoltaik.
Die Erschließung der Potentiale seit 1990 wird im Einzelnen dargestellt. Neben der seit langem genutzten Wasserkraft entwickelt sich insbesondere die Windenergie sehr dynamisch. Die Windenergie wird noch 1997 die Wasserkraft als bedeutendste erneuerbare Energie in Sachsen ablösen. Die weitere Nutzung dieser beiden Energiequellen stößt allerdings auf zunehmende ökologische Bedenken bzw. Widerstände.
Der Anteil der erneuerbaren Energiequellen am Elektroenergieverbrauch in Sachsen erreichte 1996 etwa 1,3 %. Bis zum Jahr 2000 erscheint eine Vergrößerung dieses Anteils auf ca. 5 % möglich.

  • Open Access Logo Forschungszentrum Rossendorf; FZR-193 August 1997
    ISSN: 1436-3976


Publ.-Id: 989

Pre- and post-scission light charged particle multiplicities in incomplete fusion reactions

Yanez, R.

In this article we present results concerning the extraction of light charged particle multiplicities in incomplete fusion-fission reactions with a moving source fitting procedure. To demonstrate the feasibility and reliability of the procedure we have used simulated events of known multiplicity to construct kinetic energy distributions at different angles that are fitted assuming several pre- and post-scission sources. In particular, we show that it is necessary to include at least two pre-equilibrium sources in order to extract correctly the known pre-equilibrium proton multiplicity. These two sources are characterized by high ernission temperatures, low emission barriers and high velocities, having ~ 70% and ~ 25% of the beam velocity along the beam axis, respectively The former source is naturally dominant at forward angles due to the strong focusing effect of its high velocity, Contrary to normal expectations, however, the slower pre-equilibrium source is present with considerable yield at the most backward angles θ ~ 145° where it is normally assumed only evaporative components are present. The estracted proton multiplicities are well reproduced by the moving source procedure, as well as fitting parameters with physical relevance.

  • Open Access Logo Forschungszentrum Rossendorf; FZR-192
    ISSN: 1436-3976


Publ.-Id: 988

Test und Berechnung des passiven Notkondensators

Schaffrath, A.; Hicken, E. F.; Jaegers, H.; Prasser, H.-M.

The Siemens AG is developing the new innovative boiling water
reactor concept SWR1000. New features are the passive safety
systems (e.g. emergency condensers, building condensers, passive
pressure pulse transmitters).
For the experimental investigation of the emergency condenser
effectiveness, the NOKO test facility has been constructed at
the Forschungszentrum Jülich in cooperation with Siemens. The
facility has an operating pressure of 10 MPa and a maximum power
of 4 MW for steam production. The condenser bundle consists of 8
tubes and is fabricated with the geometry and material as planned
for the SWR. In more than 200 experiments, the emergency condenser
capacity was tested as a function of pressure, water level and
concentration of noncondensables in the pressure vessel as well as
pressure, water level and temperature in the condenser.
Posttest calculations of NOKO experiments were performed with an
improved version of ATHLET. To calculate the heat transfer coefficients
during condensation in horizontal tubes the module KONWAR has been
developed and implemented in ATHLET. KONWAR is based on the flow regime
map of Tandon and includes several semiempirical correlations for the
determination of the heat transfer coefficients. The presented comparison
between calculations and experiments shows a good agreement

  • Atomwirtschaft-Atomtechnik 42 (1997), Nr. 11, S. 697-700

Publ.-Id: 986

Analysis and Calculation of an Accident with Delayed Scram on NPP Greifswald Using the Coupled Code DYN3D/ATHLET

Kliem, S.

Analysis and calculation of an abnormal event which occurred in 1989 at the NPP Greifswald (VVER-440/213) are reported about. This event was a scram failure at about 50% nominal power with two of six working main coolant pumps (MCP). The analysis revealed remarkable differences between the active and passive loops due to non-homogeneous coolant mixing in the downcomer and lower plenum in the initial state before the accident. An existing input data deck for the coupled code DYN3D/ATHLET was modified to carry out calculations of this accident. On account of the absence of a mixing model considering loops with forward and loops with backward flow at the same time, the six reactor loops were modeled by a 3-fold (passive), a 2-fold (active) and a single (with the MCP to be switched-off at the beginning of the transient) loop. The comparison of the stationary calculation with the reported data shows a good agreement taking into account the mentioned deviations between the loops. Most of the calculated thermohydraulic parameters during the accident are very close to the measured data. Deviations in the loop temperatures can be explained by the differences in the measured stationary data and by the fact of non-homogeneous coolant mixing in the downcomer and the lower plenum. A small, but continuous power increase was observed during the whole time in the calculation while the measured power was remaining nearly constant. The power behaviour was brought into agreement with the measured data by a correction of the moderator temperature coefficient within the accuracy recommendations of the Atomic Energy Research (AER).
The calculation of this accident is an important contribution to the validation of the coupled code DYN3D/ATHLET. It demonstrated problems of the analysis of real abnormal events on NPP`s.

  • Contribution to proceedings
    Proc. 7th Symposium of AER, pp.457-468, KFKI Atomic Energy Research Institute, Budapest (1997)
  • Lecture (Conference)
    7th Symposium of AER

Publ.-Id: 985

Experimentelle Ergebnisse mit der NOKO-Versuchsanlage

Schaffrath, A.; Hicken, E. F.; Jaegers, H.; Prasser, H.-M.

On the NOKO (emergency condenser) test station constructed at Jülich Research Centre, the operating performance and effectiveness of the emergency condenser of the boiling water reactor 1000 have been determined in well over 200 tests. It has been possible to check that the tests were in close agreement with a modified version of ATHLET

  • VGB-Kraftwerkstechnik 78 (1998), Heft 5, ISSN 0372-5715, S. 90-96

Publ.-Id: 984

SANS Investigations of the Microstructure of VVER-440-Type RPV Steel after Low Temperature Irradiation at 60 grd C

Grosse, M.; Böhmert, J.; Gilles, R.

  • Poster
    Annuals User's Meeting, Hahn-Meitner-Institut, Berlin, November 1997, Posterbeitrag

Publ.-Id: 983

Perspektiven der Windenergienutzung in den neuen Bundesländern

Rindelhardt, U.

Der Stand und die Perspektiven der Windenergienutzung in den neuen Bundesländern unterscheidet sich nicht grundsätzlich von der Situation in den alten Ländern. In einigen Fragen (flächendeckende Potentialerhebungen, durchschnittliche WEA-Größe) ist der Stand sogar höher zu bewerten. Die weitere Entwicklung der Windenergienutzung wird bestimmt durch
- die mittelfristig mögliche Senkung der Stromgestehungskosten (Anforderungen an die Standortwahl und Standortnutzung),
- den praktischen Nachweis von Zuverlässigkeit und Lebensdauer der eingesetzten Anlagen,
- den künftigen ordnungspolitischen Rahmen für die Windenergienutzung (Zielkonflikt Liberalisierung der Strommärkte und Reduktion CO2-Ausstoß) sowie
- die politische und soziale Akzeptanz der Windenergienutzung.
Neben Wissenschaftlern und Technikern steht hier auch die Politik vor einer großen Herausforderung.

  • Lecture (Conference)
    Tagungsband "Windenergienutzung im Binnenland", S. 168 -178 Kassel, 8./ 9. Oktober 1997
  • Contribution to proceedings
    Tagungsband "Windenergienutzung im Binnenland", S. 168 -178 Kassel, 8./ 9. Oktober 1997

Publ.-Id: 982

Definition of the Fifth Dynamic AER Benchmark Problem - A Benchmark for Coupled Thermohydraulic/ Three-Dimensional Hexagonal Neutron Kinetic Codes

Kliem, S.

The fifth dynamic benchmark defined in this paper is the first benchmark for coupled thermohydraulic system/three-dimensional neutron kinetic core models. In this benchmark the interaction between the components of a VVER-440 NPP with the reactor core should be investigated.

The initiating event is a symmetrical break of the main steam header (MSH) at the end of the first fuel cycle and hot shutdown conditions with one stuck out control rod group. The main purpose is the investigation of recriticality. For this reason, the calculation should be continued until the power excursion is eventually terminated by high-borated water from the high pressure injection system.

The participants of the benchmark should use own input data decks developed according to the needs of their own codes. The main geometrical parameters and characteristics of control and safety systems to be considered in this benchmark will be given to bring into agreement the data decks. Own best estimate nuclear cross section data should be used in the calculation. Only the initial subcriticality at the beginning of the transient will be given to made the results more comparable.

  • Contribution to proceedings
    Proc. 7th Symposium of AER, pp.429-438 , KFKI Atomic Energy Research Institute, Budapest (1997)
  • Lecture (Conference)
    7th Symposium of AER

Publ.-Id: 981

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

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

  • Poster
    Migration '97 Konferenz, 26.-31. Oktober, Sendai, Japan
  • Radiochim. Acta 82, 103 (1998)

Publ.-Id: 980

Bremsstrahlung in intermediate-energy nucleon reactions within an effective one-beson exchange model

Shklyar, V.; Kämpfer, B.; Reznik, B. L.; Titov, A. I.

Within a covariant effective one-boson exchange model for the T matrix of NN interactions we present detailed calculations of bremsstrahlung cross sections for proton - proton and proton - neutron reactions at beam energies in the 1 GeV region. Besides pure bremsstrahlung processes we consider photons from ∆ decays and contributions from the η → γγ process. At beam energies above 700 MeV the ∆ decay channel dominates the spectra at large photon energies, where the interference between non-resonance processes and the ∆ decay channel becomes also important. Low energy photons stem from pure bremsstrahlung processes. The available experimental data at 730 MeV beam energy is well described. We extrapolate the model down to 280 MeV, where more detailed experimental data exist, and find agreement with angular distributions.

  • Open Access Logo Forschungszentrum Rossendorf; FZR-191
    ISSN: 1436-3976
  • Nuclear Physics A 628 (1998) 255-274


Publ.-Id: 979

Precipitation Studies in Oxygen- and Nitrogen Rich Silicon Formed by High Dose Implantation

Weber, R.; Müller, R.; Skorupa, W.

  • Other report
    E-MRS 1993 Spring Meeting, Strasbourg, May 4-7, 1993

Publ.-Id: 978

CdS Nanocrystals Entrapped in Thin SiO2 Films

Pham, M. T.; Matz, W.; Möller, D.; Mücklich, A.; Oswald, S.

  • Journal of Physical Chemistry B Vol. 102, Number 21, Pages 4081-4088, 1998

Publ.-Id: 977

Correlation Between the Powder Structure and Microstructure of Tetragonal ZrO2 Ceramics

Haase, I.; Müller, R.

  • Poster
    European Ceramic Society, Third Conference, Madrid, September 12-17, 1993, P04-05 (Poster)

Publ.-Id: 976

Untersuchung der Wechselwirkungen zwischen ZrNb1 und austenitischem Stahl bei hohen Temperaturen

Müller, R.; Gleisberg, O.

  • Poster
    29. Kolloquium des Arbeitskreises für Elektronenmikroskopische Direktabbildung und Analyse von Oberflächen (EDO) 8.-11. Oktober 1996 in Münster
  • Elektronenmikroskop. Direktabb. und Analyse v. Oberfl., 29 (1996)

Publ.-Id: 975

Laserspektroskopie zur Bestimmung der chemischen Speziation von Uranylkomplexen

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

  • Poster
    Poster bei der Hauptjahrestagung der GDCh, Wien, Sept. 1997

Publ.-Id: 974

In-situ Laser Reflectometry Study of the Amorphization of Silicon Carbide by MeV Ion Implantation

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

  • Journal of Applied Physics,Vol 84, No. 6, Seite 3090-3097

Publ.-Id: 972

Institute of Safety Research; Annual Report 1996

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

The report gives an overview on the scientific work of the Institute of Safety Research in 1996.

  • Open Access Logo Forschungszentrum Rossendorf; FZR-190 August 1997
    ISSN: 1436-3976


Publ.-Id: 971

Estimats of Dilepton Spectra from Open Charm and Bottom Decays in Relativistic Heavy-Ion Collisions

Kämpfer, B.; Pavlenko, O. P.

The spectra of lepton pairs from correlated open charm and bottom decays in ultrarelativistic heavy-ion collisions are calculated. Our approach includes energy loss effects of the fast heavy quarks in deconfined matter which are determined by temperature and density of the expanding parton medium. We find a strong suppression of the initial transverse momentum spectrum of heavy quarks due to the energy lass at LHC conditions. Within the central rapidity covered by the ALICE detector system, the dominant contribution from bottom decays to the high invariant mass dielectron spectrum is predicted.

  • Open Access Logo Forschungszentrum Rossendorf; FZR-188
    ISSN: 1436-3976


Publ.-Id: 970

Thermal Open Charm Signals Versus Hard Initial Yields in ultrarelativistic Heavy-Ion Collisions

Kämpfer, B.; Pavlenko, O. P.; Peshier, A.; Hentschel, M.; Soff, G.


Exploiting a unique set of parton distribution functions we estimate hard processes for open charm, dilepton and mini-jet production. Assuming rapid thermalization within the mini-jet plasma we follow the evolution (expansion and chemical equilibration) of the parton matter and calculate the energy loss of charm quarks in this environment. A substantial part of charm is espected to thermalize. We try to estimate the thermalized open charm component in the final hadron spectra.

  • Journal of Physics G: Nucl. Part. Phys. 23 (1997) 2001-2011
  • Open Access Logo Forschungszentrum Rossendorf; FZR-189
    ISSN: 1436-3976


Publ.-Id: 969

Investigation of Oxidation Resistance of Carbon Based First-Wall Liner Material Aerolor AO5

Krüssenberg, A.-K.; Moormann, R.; Hinssen, H.-K.; Hofmann, M.; Wu, C. H.

Minimizing the consequences of loss of vacuum and loss of coolant into vacuum accidents with respect to fusion reactor design requires the choice of materials as oxidation resistant as possible. In continuation to the testing of carbon candidate materials under oxidizing conditions (oxygen and steam) in collaboration with NET the carbon compound Aerolor AO5 of Carbone Lorraine has been examined in detail in the test facilities INDEX 2 and SPALEX at Forschungszentrum Jülich. The parameters for these oxidation experiments in the in-pore diffusion controlled regime are temperature (from 973 K up to 1173 K for oxygen, from 1173 K up to 1423 K for steam) and reaction gas concentration (1 vol.-% - 20 vol.% oxygen in argon, 5 vol.% - 100 vol.% steam in argon). The deducted equations for the primary oxidation reactions consider the dependence of the reaction rate on temperature, partial pressure and burn-off of the material.

  • Journal of Nuclear Materials 258-263 (1998) 770-776
  • Poster
    Posterbeitrag während 8th International Conference Fusion Reactor Materials, 26.10 - 31.10.1997, Sendai, Japan

Publ.-Id: 968

Studies of Liquid-Gaseous Two-Phase Systems by Positron Emitting Radiotracers

Hensel, F.

For a more detailed knowledge and understanding of various industrial processes an in-situ visualization is required. Positron Emission Tomography is an imaging technique used in medical research as a tool to study brain and heart diseases, allowing a non-invasive in-vivo concentration measurement of labeled substances. The mentioned features got us to carry out feasibility investigations for PET-like radiotracer applications in the field of two-phase flow systems. The main aim was to observe mixing and flow phenomena in efficient spatial and time resolution.

Typical values for the stopping ranges of positrons produced by common PET isotopes in water are approximately 2mm. Typical densities of the liquid-gaseous two phase systems that were to investigate are below 10% of the density of water under normal conditions. So the positron range effect becomes very important. Therefore as a first step the spatial annihilation distribution of a solid positron source has been measured using a Ti-45 source and solid blocks of polystyrene and polyurethane foam. The experiments have been carried out using a double head spherical PET-scanner for treatment plan verification of 3D conformable radiation therapy [1]. The foam density amounted from 15 kg/m3 to 38 kg/m3. The feasibility of a range based density measuring technique using the positron range was successfully shown. The next steps in this field could be the setup of a density measurement system for foams, including a detector optimization that results in an easy to handle low cost experimental assembly. It should comprise an encapsulated positron source and 2-4 pairs of detectors to cover an enlarged density range.

Liquid positron emitting tracers were used for monitoring phenomena in bubbly flows. PET experiments often require high activities and quite long integration times for an image reconstruction. Due to activity limitations it has been tried to optimize the experimental setup. Good results were achieved using a nearly two-dimensional geometry in combination with a midplane backprojection. In the experiments mixing processes in bubbly flows were observed using a F-18 solution. The bubbly flows were created by air injection. The event data were collected in list mode. The time resolution for these experiments was below 1s (integration time for the data evaluation). Best choice was a time step value of 500ms. In a further experiment the drainage of a surfactant stabilized foam was investigated.

Transport processes in bubbly flows and foams seem to be adequate topics for investigation using a PET technique. Time resolutions of about 1 s and below can be achieved, depending on the problem. The main advantage of PET tracers is the fact that many organic substances can be labeled with positron emitting isotopes which is important for the component sensitive investigation of many industrial processes.

  • Contribution to proceedings
    3rd Topical Meeting on Industrial Radiation and Radioisotope Measurements and Applications, Conference Program and Abstracts, Raleigh, NC (USA), October 6-9, 1996, p. 101, ISBN 0-89448-645-2
  • Applied Radiation and Isotopes 48 (1997), 1485 - 1492
  • Lecture (Conference)
    3rd Topical Meeting on Industrial Radiation and Radioisotope Measurements and Applications, Raleigh, NC (USA), October 6-9, 1996

Publ.-Id: 967

A numerical three-dimensional stability analysis of the MHD cylinder wake flow

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

  • Lecture (Conference)
    3rd Int. Conference Transfer Phenomena in Magnetohydrodynamic and Electroconducting Flows; September 22-26, 1997 (Assois, France), Vol. 2, pp. 323 - 328
  • Contribution to proceedings
    3rd Int. Conference Transfer Phenomena in Magnetohydrodynamic and Electroconducting Flows; September 22-26, 1997 (Assois, France), Vol. 2, pp. 323 - 328

Publ.-Id: 965

Investigation of the Atomic Interdiffusion and Phase Formation in Ion Beam Irradiated Thin Cu-Al and Ag-Al Multilayers by In-situ RBS and XRD

Markwitz, A.; Matz, W.; Waldschmidt, U.; Demortier, G.

  • Surface and Interface Analysis, Vol. 26, 160-174 (1998)

Publ.-Id: 964

Test and Calculation of the Emergency Condenser of the SWR 1000

Schaffrath, A.; Prasser, H.-M.; Hicken, E. F.; Jaegers, H.

The Siemens AG is developing the new innovative boiling water reactor
concept SWR1000. New features are the passive safety systems (e.g.
emergency condensers, building condensers, passive pressure pulse
transmitters, gravitydriven core flooding lines).

For the experimental investigation of the emergency condenser effectiveness,
the NOKO test facility has been constructed at the Forschungszentrum Jülich
in cooperation with Siemens. This test facility has an operating pressure of
10 MPa and a maximum power of 4 MW for steam production. The emergency
condenser bundle consists of eight tubes and is fabricated with planned
geometry and material of the SWR1000. In more than 200 experiments, the
emergency condenser capacity was tested as a function of pressure, water
level and concentration of noncondensables in the pressure vessel as well
of pressure, water level and temperature in the condenser.

Post test calculations of NOKO experiments were performed with an improved
version of ATHLET. To calculate the heat transfer coefficients during
condensation in horizontal tubes the module KONWAR has been developed
and implemented in ATHLET. KONWAR is based on the flow regime map of
Tandon and includes several semiempirical correlations for the determination
of the heat transfer coefficients. The comparison between calculations and
experiments shows a good agreement.

  • Lecture (Conference)
    Post-SMIRT 14 International Seminar "Passive Safety Features in Nuclear Installations", S B2.27-B2.35, 25.-27. August 1997, Pisa, Italien
  • Contribution to proceedings
    Post-SMIRT 14 International Seminar "Passive Safety Features in Nuclear Installations", S B2.27-B2.35, 25.-27. August 1997, Pisa, Italien

Publ.-Id: 963

Non-destructive Evaluation of Glass Corrosion States

Mäder, M.; Grambole, D.; Herrmann, F.; Neelmeijer, C.; Schreiner, M.; Woisetschläger, G.

  • Nuclear Instruments and Methods in Physics Research B, 136-138 (1998) 863-868
  • Lecture (Conference)
    13th Int. Conf. on Ion Beam Analysis (IBA-13), Lisboa, Portugal, July 27-Aug. 1, 1997

Publ.-Id: 962

Modelling of boron nitride: atomic scale simulations on thin film growth

Albe, K.; Möller, W.

Molecular-dynamics simulations on ion-beam deposition
of boron nitride are presented. A realistic Tersoff-like potential energy
function for boron nitride, which was specially fitted to ab initio-data,
has been used. The impact of energetic boron and nitrogen atoms on a c-BN
target is simulated with energies ranging from 10 to 600 eV. The structural
analysis of the grown films shows, that a loose, dominantly sp2-bonded
structure arises at high ion flux. In no case the formation of a sp3-bonded
phase is observed, but the obtained films partially reveal textured basal
planes as found in experiment. Two different growth regimes are identified
for ion energies above and below 100 eV.

  • Computational Materials Science 10 (1998) 111
  • Invited lecture (Conferences)
    E-MRS Spring Meeting, Symp. D: Computational Modeling of Issues in Materials Science, Strasbourg, France, June 16 - 20, 1997 (invited lecture)

Publ.-Id: 961

Preparation of SiO2 Films with embedded Si Nanocrystals by Reactive RF-Magnetron Sputtering

Seifarth, H.; Grötzschel, R.; Markwitz, A.; Matz, W.; Nitzsche, P.; Rebohle, L.

  • Thin Solid Films 330 (1998) 202-205

Publ.-Id: 960

Increased Tool Cutling Life of Drills by Ion Implantation

Hilke, R.; Mändl, S.

  • Other report
    8th International DAAAM Symposium: Intelligent Manufacturing & Automation, Dubrovnik, Croatia, Oct. 28-25, 1997

Publ.-Id: 959

Strömungsformen bei Kondensationsvorgängen im Notkondensator-Versuchsstand

Prasser, H.-M.; Böttger, A.; Schaffrath, A.

Im Rahmen des Forschungsvorhabens "Berechnung des passiven Notkondensators eines mit Naturumlauf arbeitenden innovativen Siedewasserreaktors (SWR600) mit ATHLET", das eng mit dem Forschungsvorhaben 15 NU 9050 "Notkondensator für einen Siedewasserreaktor mittlerer Leitung - Versuche zur Ermittlung der Leistung" verknüpft ist, wurden seitens des Forschungszentrums Rossendorf (FZR) e.V. im Rahmen eines F&E-Vertrages Auswertungen und Interpretationen von Messungen zu Strömungsformen und Kondensationsvorgängen im NOKO-Versuchsstand durchgeführt. Neben den Bündelversuchen wurden im NOKO-Versuchsstand mehrere Experimente im einem separaten, seitlich vom Bündel angeordneten und umfangreich instrumentierten Einzelrohr durchgeführt, um die Aussagesicherheit der Notkondensatorexperimente zu erhöhen und zusätzlich experimentelle Daten für die Validierung von Thermohydraulikprogrammsystemen (u.a. den ATHLET-Code) bereitzustellen. Hierbei geht es speziell um die Untersuchung der transienten Zweiphasenströmung innerhalb der Notkondensatorrohre hinsichtlich der dort anzutreffenden Strömungsformen, sowie die Bestimmung des volumentrischen Gasgehaltes an verschiedenen Stellen auf der Sekundärseite im Bündel bei unterkühltem und gesättigtem Sieden. Das NOKO-Einzelrohr wurde hierzu mit nadelförmigen Voidsonden ausgestattet. Durch die Nutzung von jeweils mehreren Sonden in zwei ausgewählten Strömungsquerschnitten wurde die Phasenverteilung während der Füllstandsabsenkung, d.h. beim Durchgang des Flüssigkeitsspiegels an den Sondenpositionen, in-stationär gemessen. Daraus läßt sich die Form der Phasengrenzfläche rekonstruieren. Neben den Messungen im Einzelrohr fanden, ebenfalls mit Nadelsonden, Messungen auf der Sekundärseite des NOKO-Bündels statt. Die Einzelrohr-Versuche an der NOKO-Anlage in Jülich haben gezeigt daß bei entsprechend geringer Konzentration von nichtkondensierbaren Gasen Schwälle und Pfropfen im Ansatz zu beobachten sind, die Vorhersagen bekannter Strömungskarten jedoch nicht zutreffen. Dort werden Schwälle und Pfropfen in wesentlich größerem Aumaß vorhergesagt. Die Aufstellung und Validierung eines einfachen Modells zur Berechnung des Druckverlustes im Wärmeübertragerrohr ist gelungen. Damit kann der Differenzdruck zwischen den Kollektoren ober besser ein an den Wärmeübertragerrohren direkt gemessener Differenzdruck zur Füllstandsmessung auf der Primärseite des Notkondensators herangezogen werden. Bei der Validierung mußten jedoch die experimentell ermittelten Volumina des nichtkondensierbaren Gases in die Berechnung einfließen. Der Mechanismus der Kondensationsbehinderung durch das nichtkondensierbare Gas wurde durch Gegenüberstellung der Sondendaten mit den Meßwerten der Thermoelemente im Einzelrohr im Detail untersucht.

  • Open Access Logo Wissenschaftlich-Technische Berichte / Forschungszentrum Rossendorf; FZR-186 Juli 1997
    ISSN: 1436-3976


Publ.-Id: 958

Analysis of deuterium induced nuclear reactions giving criteria for the formation process of expanded austenite

Parascandola, S.; Günzel, R.; Grötzschel, R.; Richter, E.; Möller, W.

High current ion nitriding of austenitic stainless steel at temperatures of about 400°C leads to the formation of a surface layer, called expanded austenite. The formation of this layer is not well understood. Deuterium induced nuclear reaction analyses have been performed on austenitic stainless steel samples that were subsequently high current ion nitrided with low energy ion implantation of 15 N and 14 N. The obtained depth profiles yield criteria for the formation process of the expanded austenite. A trapping mechanism cannot be confirmed.

  • Nuclear Instruments and Methods in Physics Research B, 136-138 (1998) 1281
  • Poster und Beitrag zu Sammelwerken / Proceedings of the Thirteenth International Conference on Ion Beam Analysis, Lisbon, Portugal, 27 July - 1 August 1997

Publ.-Id: 956

Comment on "On the Relation Between Unimolekular Reaction Rates and Overlapping Resonances"

Rotter, I.

  • J. Chem. Phys. 106(11), 4810, 15 March 1997

Publ.-Id: 955

Initial Inter-Laboratory Testing of the Rossendorf-Oxford (ROX97) Secondary Standard for X-ray Analysis

Neelmeijer, C.; Mäder, M.; Jarjis, R.; Calligaro, T.; Salomon, J.; Schreiner, M.; Gantz, T.

  • Nuclear Instruments and Methods in Physics Research B, 136-138 (1998) 902-907
  • Lecture (Conference)
    13. Int. Conf. on Ion Beam Analysis (IBA-13), Lisboa, Portugal, July 27 - Aug. 1, 1997

Publ.-Id: 954

Estimates of Dilepton Spectra from Open Charm and Bottom Decays in Relativistic Heavy-Ions Collisions

Kämpfer, B.; Pavlenko, O. P.; Gallmeister, K.

  • Physics Letters B 419 (1998) 412-418

Publ.-Id: 953

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