Cross-section measurement and analysis for the 149Sm(n,alpha)146Nd reaction at 6.0 MeV

Journal Article · Fri Jan 01 04:00:00 EST 2010 · Physical Review C

DOI:https://doi.org/10.1103/PhysRevC.82.014601· OSTI ID:1023339

Gledenov, Yu. M. ^[1]; Zhang, Guohui ^[2]; Khuukhenkhuu, G ^[3]; Sedysheva, M. V. ^[1]; Szalanski, P. ^[4]; Koehler, Paul Edward ^[5]; Liu, Jiaming ^[2]; Wu, Hao ^[2]; Liu, Xiang ^[2]; Chen, Jinxiang ^[2]

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1. Joint Institute for Nuclear Research, Dubna, Russia
2. Peking University
3. National University of Mongolia
4. University of Lodz
5. ORNL

We have measured the {sup 149}Sm(n,{alpha}){sup 146}Nd cross section at 6.0 MeV to be 0.12 {+-} 0.018 mb. This is the first reported result for this cross section in the MeV region and so should be helpful for constraining nuclear data evaluations (which differ by a factor of 40 for this reaction at this energy) and for testing and improving nuclear models. The experiment was performed at the at the 4.5-MV Van de Graaff accelerator of Peking University. Neutrons were produced via the {sup 2}H(d,n){sup 3}He reaction using a deuterium gas target, and absolute neutron flux was determined with a small {sup 238}U fission chamber. Alpha particles were detected using a two-section gridded ionization chamber in which two large-area {sup 149}Sm{sub 2}O{sub 3} samples were placed back-to-back so that the cross section and forward/backward ratio were measured for nearly the entire 4{pi} solid angle. The data were compared to statistical-model predictions using the code talys. Good agreement between the measured and theoretical cross sections could be obtained with a small modification of the {alpha}-optical potential parameters from their default values in talys. However, we were not able to reproduce the measured forward/backward ratio. In addition, using the previously reported {sup 147}Sm(n,{alpha}){sup 144}Nd cross section at 6.0 MeV together with our new result, good agreement was found between the measured and predicted cross-section ratio for these two isotopes. Finally, none of the existing evaluated data libraries are in agreement with our new data to within the experimental uncertainties.

• Research Organization: Oak Ridge National Laboratory (ORNL)
• Sponsoring Organization: SC USDOE - Office of Science (SC)
• DOE Contract Number: AC05-00OR22725
• OSTI ID: 1023339
• Journal Information: Physical Review C, Journal Name: Physical Review C Journal Issue: 1 Vol. 82; ISSN 0556-2813
• Country of Publication: United States
• Language: English

Related Subjects

43 PARTICLE ACCELERATORS
ALPHA PARTICLES
CROSS SECTIONS
DEUTERIUM
FISSION CHAMBERS
IONIZATION CHAMBERS
MODIFICATIONS
NEUTRON FLUX
NEUTRONS
NUCLEAR MODELS
TESTING
VAN DE GRAAFF ACCELERATORS