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Effects of in‐target Compton‐scattering in lanthanum fluorescence spectra
Author(s) -
Uroić M.,
Majer M.,
Pašić S.,
Vuković B.,
Ilakovac K.
Publication year - 2006
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/xrs.888
Subject(s) - spectral line , compton scattering , scattering , photon , detector , physics , atomic physics , collimator , scintillator , lanthanum , elastic scattering , optics , chemistry , nuclear physics , astronomy
A study was made of the continuum adjacent to the Kα 1 and Kα 2 peaks (the ‘shoulder’) in lanthanum fluorescence spectra. The fluorescence was induced by 59.537 keV γ‐rays from a 241 Am source. The spectra were observed with an La 2 O 3 ‐loaded paraffin target (the ‘La target’). To limit the observations to the scattering in the target, a collimator was used in front of the germanium detector, which strongly reduced the near‐detector scattering. Changes in the shoulder spectra were observed on attaching additional mass to the La target and on changing its orientation with respect to the detector‐to‐target centre‐line. The measurements clearly show that the main cause of the shoulder spectra is the in‐target Compton scattering. A different distribution of mass in the vicinity of the fluorescing atoms with respect to the detector‐to‐target centre‐line results in different probabilities of the observed scattering at all angles. Since the energy of secondary Compton photons is directly related to the scattering angles, different distributions of mass cause changes in the shoulder spectra. Comparison of the calculated and measured shoulder spectra shows good agreement on an absolute scale. Copyright © 2006 John Wiley & Sons, Ltd.