A measurement of (n, xn gamma) cross sections for Pb-208 from threshold up to 20 MeV RID A-4094-2011

Author:

Mihailescu, L. C.  Borcea, C.  Baumann, P.  Dessagne, Ph.  Jericha, E.  Karam, H.  Kerveno, M.  Koning, A. J.  Leveque, N.  Pavlik, A.  Plompen, A. J. M.  Quetel, C.  Rudolf, G.  Tresl, I.  

Journal:

NUCLEAR PHYSICS A

Issue Date:

2008

Abstract(summary):

Gamma production cross sections for neutron inelastic scattering, (n,2n gamma) and (n, 3n gamma) reactions on Pb-208 were measured at the Geel Electron Linear Accelerator (GELINA) from the respective thresholds up to at most 20 MeV. An unprecedented neutron energy resolution of 1.1 keV at 1 MeV (35 keV at 10 MeV) and a total uncertainty of about 5% was achieved for the integral gamma production cross section of the most intense transition in Pb-208. The gamma production cross section was measured for 29 transitions of the inelastic channel, 5 transitions of the (n, 2n gamma) channel and one transition of the (n, any) channel. Based on the evaluated level scheme of Pb-208, the total neutron inelastic scattering cross section and the level cross sections were deduced. Four large volume HPGe (high purity germanium) detectors were used for the detection of the gamma-rays. The 88.11% enriched Pb-208 sample was placed at a flight path length of 198.551 m. The cross sections were measured relative to the U-235(n, f) standard cross section by continuously monitoring the neutron flux with a fission chamber containing U-235. The results are compared with the existing experimental data from the literature and with model estimates obtained with the recent TALYS 1.00 code. A good agreement of the present data is found with both the existing experimental data and with the calculations. The present work greatly expands the number of measured gamma production cross sections and the level cross sections derived for this nucleus. (C) 2008 Elsevier B.V. All rights reserved.

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