Extracting the net O(K) X-ray peak from Si(Li)-detector spectra

Abstract

The shape of the O(K) X-ray peak has been extracted from spectra taken using a cryogenically cooled Si(Li) detector with an ice layer on the crystal. The spectrum stripping method consists of subtracting a PIXE spectrum of beryllium taken with the BeO surface layer removed from that taken with the BeO surface layer intact. The method relies on the fact that the background spectrum is not affected by the removal of the thin layer containing surface oxygen. The resulting O(K) peak shape corresponds to that measurable with a de-iced detector and can be used to determine the shape of the bremsstrahlung background in the vicinity of the O(K) edge. With proper normalizations, the net O(K) integral can be determined using these two shapes. These results help explain the apparently varied O(K) X-ray peak shapes previously reported in the literature.