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Si(Li) Detector Lineshapes: Contributions from Atomic Physics and Detector Properties
Author(s) -
Campbell J. L.,
Maxwell J. A.,
Papp T.,
White G.
Publication year - 1997
Publication title -
x‐ray spectrometry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.447
H-Index - 45
eISSN - 1097-4539
pISSN - 0049-8246
DOI - 10.1002/(sici)1097-4539(199707)26:4<223::aid-xrs224>3.0.co;2-8
Subject(s) - physics , detector , atomic physics , spectrometer , multiplet , photon energy , radiative transfer , spectral line , optics , photon , astronomy
The detailed response of an Si(Li) detector to the manganese K x‐rays from a 55 Fe source was studied by least‐squares fitting various spectrum models using a generalized variant of the GUPIX code. The peak‐to‐background ratio (>10 6 ) observed for the manganese Kα x‐rays is superior in the detector used here to that observed in a crystal spectrometer, and very large spectrum intensities are recorded. In addition to well recognized effects such as the intrinsic Lorentzian distribution of an x‐ray line and the approximately Gaussian detector response function, the Kα and Kβ peak shapes are influenced by multiplet structure. The Kβ shape is affected by 3p3d exchange coupling, and both Kα and Kβ are influenced by 3d spectator vacancy satellites. The flat shelf‐like features below the peaks appear to be associated with escape of Auger and photoelectrons, and show a step‐like structure that has not hitherto been discussed. Using an accurate energy calibration provided by simultaneously recorded rubidium K x‐rays, the escape peak energy shift was shown to have the theoretical value of 1.74 keV. The escape peak width was significantly augmented, relative to the value expected for a diagram line at 4.2 keV energy, by shake‐off satellites and by an additional component on its low‐energy side; this observation explains the widely reported escape energy values in excess of 1.75 keV. Approximate determinations were made of the shape and intensity of the KLL radiative Auger feature and of the intensity of the KMM feature. © 1997 John Wiley & Sons, Ltd.