Caroline Kilbourne Stahle

Adapting calorimetric X-ray detectors for Compton scattering experiments performed at high energies

Abstract Motivated by the need for improved resolution in Compton scattering experiments performed with high energy X-rays, we have developed a high resolution spectrometer. We have adapted calorimetric X-ray detectors, produced at Goddard Space Flight Center for X-rays around 6 keV, to Compton scattering research using synchrotron radiation near 40 keV. Such a detector is operated below 0.1 K and determines X-ray energies by measuring the temperature increase which results from the absorption of a single X-ray photon. We have investigated a number of materials as candidates for the overlayer which is affixed to a device in order to absorb the X-rays and transfer their energy to phonons. Using Sn absorbers, we have achieved a resolution of 90 eV at 32 keV. The apparatus was brought to a wiggler beam line at the Stanford Synchrotron Radiation Laboratory, where we were able to measure Compton profiles of Si for the (100) and (111) directions. The difference reproduced the previously measured anisotropy, but the measurement was limited by the low number of total counts and by a degradation in resolution experienced during operation at the synchrotron. This experiment illustrates the feasibility of using such a system for Compton scattering research. We expect that future improvements to the detectors and to the supporting apparatus will make higher resolution measurements possible.