GAMMA-RAY PRODUCTION CROSS SECTIONS FOR Bi-209

Authors & Affiliations

Zolotarev K.I., Tertychnyj G.Ya., Lunev V.P.
Institute of Physics and Power Engineering, Obninsk, Russia

Abstract

At the present time the available evaluated data on neutron induced gamma-ray production cross sections for 209Bi are very discrepant. The discrepancy in the data from the libraries ENDF/B-VI and JENDL-3.2 at neutron energies above 4 MeV reaches 40-50%. In the same time the relative energy dependence of cross sections in these libraries differs considerably in all neutron energy region above 2 MeV. The new evaluation described in this work of gamma-ray production cross section for 209Bi in the neutron incident energy region of 0.5-20 MeV was made on the basis of the calculations using GNASH code. The choice of input data for calculations - discrete level parameters of residual nuclei, level density parameters and optical parameters - was based on the consistent description of three competitive reactions leading to the gamma-ray production in the incident neutron energy region of 0.5-20 MeV - (n,n'), (n,2n) and (n,3n). The agreement between calculations and experiments observed in the data on gamma-ray spectra, (n,n'), (n,2n), (n,3n) reactions and total gamma-ray yields proves that the new evaluation was made quite correctly. This permits to say that new evaluation gave possibility to make more precise the gamma-ray production cross sections for 209Bi in the neutron energy range from 0.5 to 20 MeV.

Keywords
cross section, gamma-rays, bismuth, parameters of the discrete levels, residual nuclei, excited nuclear levels, optical parameters

Article Text (in Russian, PDF)

References

UDC 539.17

Problems of Atomic Science and Technology. Series: Nuclear Constants", issue 2, 1998