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

Abstract

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 70Yb ( B K=61.332 keV), 71Lu ( 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 59° and 133° angles, respectively, to avoid interference of the Compton-scatter peak. The Rayleigh and Compton scattering cross-sections for the 59.536 keV γ-rays have also been measured at both the angles in the atomic region 1⩽ Z⩽92. Measurements were performed using the reflection-mode geometrical arrangements involving the 241Am 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 Kβ 1,3,5 (K–M) and Kα (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 ∼15% and ∼6% higher, respectively, at the 133° angle and exhibit good agreement with the measured data at the 59° angle. Larger deviations ∼30% and ∼20%, respectively, are observed at the 133° angle for the 64Gd, 66Dy, 67Ho and 70Yb 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.