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Title: Thermal Neutron Capture Cross Sections Of The Palladium Isotopes

Abstract

We have measured precise thermal neutron capture {gamma}-ray cross sections cry for all stable Palladium isotopes with the guided thermal neutron beam from the Budapest Reactor. The data were compared with other data from the literature and have been evaluated into the Evaluated Gamma-ray Activation File (EGAF). Total radiative neutron capture cross-sections {sigma}{gamma} can be deduced from the sum of transition cross sections feeding the ground state of each isotope if the decay scheme is complete. The Palladium isotope decay schemes are incomplete, although transitions deexciting low-lying levels are known for each isotope. We have performed Monte Carlo simulations of the Palladium thermal neutron capture deexcitation schemes using the computer code DICEBOX. This program generates level schemes where levels below a critical energy Ecrit are taken from experiment, and those above Ecrit are calculated by a random discretization of an a priori known level density formula {rho}(E,J{pi}). Level de-excitation branching intensities are taken from experiment for levels below Ecrit the capture state, or calculated for levels above Ecrit assuming an a priori photon strength function and applying allowed selection rules and a Porter-Thomas distribution of widths. The advantage of this method is that calculational uncertainties can be investigated systematically. Calculatedmore » feeding to levels below Ecrit can be normalized to the measured cross section deexciting those levels to determine the total radiative neutron cross-section {sigma}{gamma}. In this paper we report the cross section measurements {sigma}{gamma}[102Pd(n,{gamma})]=0.9{+-}0.3 b, {sigma}{gamma}[104Pd(n,{gamma})=0.61{+-}0.11 b, {sigma}{gamma}[105Pd(n,{gamma})]=2.1.1{+-}1.5 b, {sigma}{gamma}[106Pd(n,{gamma})]=0.36{+-}0.05 b, {sigma}{gamma}[108Pd(n,{gamma})(0)]=7.6{+-}0.6 b, {sigma}{gamma}[108Pd(n,{gamma})(189)]=0.185{+-}0.011 b, and {sigma}{gamma}[110Pd(n,{gamma})]=0.10{+-}0.03 b. We have also determined from our statistical calculations that the neutron capture states in 107Pd are best described as 2+[59(4)%]+3+[41(4)%]. Agreement with literature values was excellent in most cases. We found significant discrepancies between our results for 102Pd and 110Pd and earlier values that could be resolved by re-evaluation of the earlier results.« less

Authors:
 [1];  [2]; ; ;  [3]; ;  [4]
  1. Lawrence Berkeley National Laboratory Berkeley CA 94720 (United States)
  2. Faculty of Mathematics and Physics, Charles University V Holesovickach 2, CZ-180 00 Prague 8 (Czech Republic)
  3. Lawrence Livermore National Laboratory, Livermore, California 94551 (United States)
  4. Institute of Isotope and Surface Chemistry H-1525, Budapest (Hungary)
Publication Date:
OSTI Identifier:
20798322
Resource Type:
Journal Article
Journal Name:
AIP Conference Proceedings
Additional Journal Information:
Journal Volume: 819; Journal Issue: 1; Conference: 12. international symposium on capture gamma-ray spectroscopy and related topics, Notre Dame, IN (United States), 4-9 Sep 2005; Other Information: DOI: 10.1063/1.2187890; (c) 2006 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 0094-243X
Country of Publication:
United States
Language:
English
Subject:
73 NUCLEAR PHYSICS AND RADIATION PHYSICS; BRANCHING RATIO; CAPTURE; COMPUTERIZED SIMULATION; CROSS SECTIONS; DE-EXCITATION; ENERGY-LEVEL DENSITY; GAMMA RADIATION; GROUND STATES; MONTE CARLO METHOD; NEUTRON REACTIONS; NUCLEAR DECAY; PALLADIUM 102; PALLADIUM 104; PALLADIUM 105; PALLADIUM 106; PALLADIUM 107; PALLADIUM 108; PALLADIUM 110; PHOTONS; PORTER-THOMAS DISTRIBUTION; SELECTION RULES; STRENGTH FUNCTIONS; THERMAL NEUTRONS

Citation Formats

Firestone, R B, Krtiaka, M, McNabb, D P, Sleaford, B, Agvaanluvsan, U, Belgya, T, and Revay, Zs. Thermal Neutron Capture Cross Sections Of The Palladium Isotopes. United States: N. p., 2006. Web. doi:10.1063/1.2187890.
Firestone, R B, Krtiaka, M, McNabb, D P, Sleaford, B, Agvaanluvsan, U, Belgya, T, & Revay, Zs. Thermal Neutron Capture Cross Sections Of The Palladium Isotopes. United States. doi:10.1063/1.2187890.
Firestone, R B, Krtiaka, M, McNabb, D P, Sleaford, B, Agvaanluvsan, U, Belgya, T, and Revay, Zs. Mon . "Thermal Neutron Capture Cross Sections Of The Palladium Isotopes". United States. doi:10.1063/1.2187890.
@article{osti_20798322,
title = {Thermal Neutron Capture Cross Sections Of The Palladium Isotopes},
author = {Firestone, R B and Krtiaka, M and McNabb, D P and Sleaford, B and Agvaanluvsan, U and Belgya, T and Revay, Zs},
abstractNote = {We have measured precise thermal neutron capture {gamma}-ray cross sections cry for all stable Palladium isotopes with the guided thermal neutron beam from the Budapest Reactor. The data were compared with other data from the literature and have been evaluated into the Evaluated Gamma-ray Activation File (EGAF). Total radiative neutron capture cross-sections {sigma}{gamma} can be deduced from the sum of transition cross sections feeding the ground state of each isotope if the decay scheme is complete. The Palladium isotope decay schemes are incomplete, although transitions deexciting low-lying levels are known for each isotope. We have performed Monte Carlo simulations of the Palladium thermal neutron capture deexcitation schemes using the computer code DICEBOX. This program generates level schemes where levels below a critical energy Ecrit are taken from experiment, and those above Ecrit are calculated by a random discretization of an a priori known level density formula {rho}(E,J{pi}). Level de-excitation branching intensities are taken from experiment for levels below Ecrit the capture state, or calculated for levels above Ecrit assuming an a priori photon strength function and applying allowed selection rules and a Porter-Thomas distribution of widths. The advantage of this method is that calculational uncertainties can be investigated systematically. Calculated feeding to levels below Ecrit can be normalized to the measured cross section deexciting those levels to determine the total radiative neutron cross-section {sigma}{gamma}. In this paper we report the cross section measurements {sigma}{gamma}[102Pd(n,{gamma})]=0.9{+-}0.3 b, {sigma}{gamma}[104Pd(n,{gamma})=0.61{+-}0.11 b, {sigma}{gamma}[105Pd(n,{gamma})]=2.1.1{+-}1.5 b, {sigma}{gamma}[106Pd(n,{gamma})]=0.36{+-}0.05 b, {sigma}{gamma}[108Pd(n,{gamma})(0)]=7.6{+-}0.6 b, {sigma}{gamma}[108Pd(n,{gamma})(189)]=0.185{+-}0.011 b, and {sigma}{gamma}[110Pd(n,{gamma})]=0.10{+-}0.03 b. We have also determined from our statistical calculations that the neutron capture states in 107Pd are best described as 2+[59(4)%]+3+[41(4)%]. Agreement with literature values was excellent in most cases. We found significant discrepancies between our results for 102Pd and 110Pd and earlier values that could be resolved by re-evaluation of the earlier results.},
doi = {10.1063/1.2187890},
journal = {AIP Conference Proceedings},
issn = {0094-243X},
number = 1,
volume = 819,
place = {United States},
year = {2006},
month = {3}
}