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Design and Fabricating Diagnostic X-Ray Spectrum Unfolding Systems Based On HPGe Detector and CR Film

A Mahjoob1, S Sina2*, R Faghihi1, (1)Nuclear Engineering department, School of Mechanical Engineering, Shiraz University, Shiraz, Iran(2) Radiation Research Center, Shiraz University, Shiraz, Iran


(Sunday, 7/12/2020)   [Eastern Time (GMT-4)]

Room: AAPM ePoster Library

Purpose: spectroscopy in various radiological centers is important for the quality control of the device. X-ray spectroscopy is not possible with simple methods because of the high flux of X-ray and the occurrence of Pile-up phenomenon. Therefore indirect methods should be used. The purpose of this study is to unfold the X ray spectrum using two indirect methods.

Methods: the first method, which is done with wedge and flat panel detectors or CR, the film is exposed to X-rays, with the wedge located between film and the source. Another way is Compton method, in which the collimated beam collides a PMMA rod, and the beam scattered at 90 degree angle is detected by the HPGe detector. A large number of monochromatic beams was simulated with MCNPX to obtain the response matrix, R, which is used to unfold the spectrum after exposing the wedge-CR, and the compton system constructed in this study. The regularization methods, like, TSVD, MTSVD and Tikhonov were used to retrieve the initial spectrum.

Results: unfolding the initial spectrum, the results were compared with the spectrum obtained by the SPEKTR toolbox in MATLAB software and then we validate our responses with calculating the 1’Th and 2’Th HVL in simulation and experiment.

Conclusion: results indicate that the regularization methods used in this study, could be effectively used in unfolding X- ray spectra.


X Rays, Spectrometry, Quality Control


IM- X-Ray: Monte Carlo modeling

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