Measurements of Rayleigh, Compton and resonant Raman scattering cross-sections for 59.536 keV γ-rays

The K-L and K-M resonant Raman scattering (RRS) cross-sections have been measured for the first time at the 59.536 keV photon energy in the Yb-70 (B-K = 61.332 keV), Lu-71 (B-K = 63.316 keV) and 72HF (B-K = 65.345 keV) elements; B-K being the K-shell binding energy. The K-L and K-M RRS measurements have been performed at the 59degrees and 133degrees angles, respectively, to avoid interference of the Compton-scatter peak. The Rayleigh and Compton scattering cross-sections for the 59.536 keV gamma-rays have also been measured at both the angles in the atomic region 1 less than or equal to Z less than or equal to 92. Measurements were performed using the reflection-mode geometrical arrangements involving the Am-241 radioisotope as photon source and planar Si(Li) and HPGe detectors. Ratios of the K-M and K-L RRS cross-sections in Yb, Lu and Hf are in general lower than that of the fluorescent Kbeta(1,3,5) (K-M) and Kalpha (K-L) X-ray transition probabilities. Theoretical Rayleigh scattering cross-sections based on the modified form-factors (MFs) corrected for the anomalous scattering factors (ASFs) and the S-matrix calculations are on an average similar to15% and similar to6% higher, respectively, at the 133degrees angle and exhibit good agreement with the measured data at the 59degrees angle. Larger deviations similar to30% and similar to20%, respectively, are observed at the 133degrees angle for the Gd-64, Dy-66, Ho-67 and Yb-70 elements having the K-shell binding energy in vicinity of the incident photon energy. The measured Compton scattering cross-sections are in general agreement with those calculated using the Klein-Nishina cross-sections and the incoherent scattering function. (C) 2004 Elsevier B.V. All rights reserved.