Exploiting area detectors to reduce measured Compton scattering via energy selection

摘要

A technique to improve the ratio of diffraction signal to Compton background has been examined in the context of diamond anvil cell crystallography carried out using imaging plates. Specifically, imaging plates exhibit an abrupt discontinuity in absorption as a function of energy due to barium, the primary compositional element of the imaging plate phosphor. By carrying out diffraction at some energy just above the Ba k-edge, coherent scattering is efficiently absorbed by the detector while less-energetic Compton scattering is less efficiently absorbed. This yields an improvement in the signal-to-background ratio of approximately 33%. Data are presented detailing the absorption characteristics of imaging plates over a broad energy range of the continuous synchrotron radiation spectrum. Diffraction data are presented for Si powder contained in a diamond anvil cell. Diffraction images taken with incident radiation at three distinct energies near the Ba k-edge are analyzed to evaluate the effectiveness of the technique.