Inelastic scattering of 59.5 keV photons by elements with 13 <= Z <= 82

Inelastic scattering differential cross-sections for 59.5 keV photons at an angle of 121 degrees have been measured in 18 elements with 13 less than o r equal to Z less than or equal to 82. The measurements were performed usin g an annular source of Am-241 radioisotope as photon source and a planar Si (Li) detector. The measurements were performed under vacuum similar to 10(- 2) Torr. The contribution due to photons scattered from the surroundings wa s minimized by placing the target and annular source assembly in a Pb housi ng, and using a vacuum chamber made of glass lined inside with Pb. Thin tar gets have been used to minimize the contribution of multiple scattered phot ons to the inelastic scattered peak. The product of the intensity of incide nt photons, detector efficiency, and other geometrical factors was determin ed by measuring the K X-ray yields from targets of different elements with 30 less than or equal to Z less than or equal to 69 excited by the 59.5 keV photons from Am-241 source and from the knowledge of K X-ray fluorescence cross-sections. A calibrated Am-241 radioactive point source was also used for this purpose. The measured inelastic scattering cross-sections are foun d to be in good agreement with those calculated using the Klein-Nishina cro ss-section for Compton scattering by stationary free electrons and the nonr elativistic Hartree-Fock incoherent scattering function S(chi, Z). (C) 2001 Elsevier Science B.V. All rights reserved.