Measurement of 232Th(n,5n γ) cross sections from 29 MeV to 42 MeV

The excitation function of the reaction 232Th(n, 5nγ)228Th from 29 to 42 MeV has been measured for the first time at the quasi-monoenergetic neutron beam of the UCL cyclotron CYCLONE employing the 7Li(p,n) source reaction. Taking advantage of the good energy resolution of the planar High-Purity Germanium (HPGe) detectors, prompt γ-ray spectroscopy was used to detect the γ-rays resulting from the decay of excited states of nuclei created by the (n,xn) reactions. The neutron beam was characterized by a combination of time of flight measurements carried out using a liquid scintillation detector and a 238U fission ionization chamber. Fluence measurements were performed using a proton recoil telescope. The results are compared with TALYS-1.4 code calculations.

[1]  P. Leleux,et al.  Study of a Collimated Fast-neutron Beam , 1987 .

[2]  Osamu Iwamoto,et al.  Global coupled-channel optical potential for nucleon-actinide interaction from 1 keV to 200 MeV , 2004 .

[3]  T. Kawano,et al.  Production of isomers by neutron-induced inelastic scattering on 193Ir and influence of spin distribution in the pre-equilibrium process , 2006 .

[4]  J. M. Salome,et al.  Neutron producing targets at GELINA , 1981 .

[5]  M. Kerveno,et al.  (n,xn γ) reaction cross section measurements for (n,xn) reaction studies , 2013 .

[6]  Arjan J. Koning,et al.  Measurement of (n,xng) Reactions of Interest for the New Nuclear Reactors , 2011 .

[7]  F. D. Brooks,et al.  High-energy neutron reference fields for the calibration of detectors used in neutron spectrometry , 2002 .

[8]  M. Weyrauch,et al.  Proton recoil telescopes for fluence measurement in neutron beams of 20-200MeV energy , 2001 .

[9]  Andy Buffler,et al.  Cross Sections for Neutron-Induced Fission of 235U, 238U, 209Bi, and natPb in the Energy Range from 33 to 200 MeV Measured Relative to n-p Scattering , 2007 .

[10]  T. W. Burrows,et al.  Evaluation of theoretical conversion coefficients using BrIcc , 2008 .

[11]  T. Udagawa,et al.  Multistep direct reaction analysis of continuum spectra in reactions induced by light ions , 1982 .

[12]  Herman Feshbach,et al.  The statistical theory of multi-step compound and direct reactions , 1980 .

[13]  L. Oláh,et al.  A new HPGe setup at Gelina for measurement of gamma-ray production cross-sections from inelastic neutron scattering , 2004 .

[14]  M. Kerveno,et al.  Measurement of 235U(n,n'g) and 235U(n,2n) reaction cross sections , 2013 .

[15]  Andrew Thomas,et al.  WinBUGS - A Bayesian modelling framework: Concepts, structure, and extensibility , 2000, Stat. Comput..

[16]  D. B. Gayther.  International Intercomparison of Fast Neutron Fluence-Rate Measurements Using Fission Chamber Transfer Instruments , 1990 .

[17]  A. Hogenbirk,et al.  New Nuclear Data Libraries for Lead and Bismuth and Their Impact on Accelerator-Driven Systems Design , 2007 .

[18]  A.J.M. Plompen,et al.  Global characterisation of the GELINA facility for high-resolution neutron time-of-flight measurements by Monte Carlo simulations , 2010 .

[19]  C. Brune.  Gaussian quadrature applied to experimental /γ-ray yields , 2002 .

[20]  S. Kailas,et al.  RIPL – Reference Input Parameter Library for Calculation of Nuclear Reactions and Nuclear Data Evaluations , 2009 .