Study of photon strength functions of Pu-241 and Cm-245 from neutron capture measurements

Abstract

We have measured the gamma-rays following neutron capture on Pu-240 and (CM)-C-244 at the n_TOF facility at CERN with the Total Absorption Calorimeter (TAC) and with C6D6 organic scintillators. The TAC is made of 40 BaF2 crystals operating in coincidence and covering almost the entire solid angle. This allows to obtain information concerning the energy spectra and the multiplicity of the measured capture gamma-ray cascades. Additional information is also obtained from the C6D6 detectors. We have analyzed the measured data in order to draw conclusions about the Photon Strength Functions (PSFs) of Pu-241 and (CM)-C-245 below their neutron separation energies. The analysis has been performed by fitting the PSFs to the experimental results, using the differential evolution method, in order to find neutron capture cascades capable of reproducing at the same time a great variety of deposited energy spectra.