Author/Authors :
Rochman، نويسنده , , D. and Haight، نويسنده , , R.C. and O’ Donnell، نويسنده , , J.M. and Michaudon، نويسنده , , A. and Wender، نويسنده , , S.A. and Vieira، نويسنده , , D.J. and Bond، نويسنده , , E.M. and Bredeweg، نويسنده , , T.A. and Kronenberg، نويسنده , , A. and Wilhelmy، نويسنده , , J.B. and Ethvignot، نويسنده , , T. and Granier، نويسنده , , T. and Petit، نويسنده , , M. and Danon، نويسنده , , Y.، نويسنده ,
Abstract :
A description is given of a lead slowing-down spectrometer (LSDS) installed at the 800-MeV proton accelerator of the Los Alamos Neutron Science Center (LANSCE). The LSDS is designed to study neutron-induced fission on actinides that can only be obtained or used in small quantities. The characteristics of this LSDS (energy–time relation, energy resolution, neutron flux) are presented through simulations with MCNPX and measurements with several different methods. Results on neutron-induced fission of 235U and 239Pu with tens of micrograms and tens of nanograms, respectively, are presented. Finally, additional MCNPX calculations have been performed to simulate the measurement of the cross-section for U 235 m ( n , f ) using different target quantities and different initial isomer-to-ground state compositions.
Keywords :
Neutron-induced reaction , Lead slowing-down spectrometer , Fission cross-section , MCNPX , Spallation neutron source
