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Remembering ANS member Gil Brown
Brown
The nuclear community is mourning the loss of Gilbert Brown, who passed away on July 11 at the age of 77 following a battle with cancer.
Brown, an American Nuclear Society Fellow and an ANS member for nearly 50 years, joined the faculty at Lowell Technological Institute—now the University of Massachusetts–Lowell—in 1973 and remained there for the rest of his career. He eventually became director of the UMass Lowell nuclear engineering program. After his retirement, he remained an emeritus professor at the university.
Sukesh Aghara, chair of the Nuclear Engineering Department Heads Organization, noted in an email to NEDHO members and others that “Gil was a relentless advocate for nuclear energy and a deeply respected member of our professional community. He was also a kind and generous friend—and one of the reasons I ended up at UMass Lowell. He served the university with great dedication. . . . Within NEDHO, Gil was a steady presence and served for many years as our treasurer. His contributions to nuclear engineering education and to this community will be dearly missed.”
A. Kargar, E. Ariesanti, D. S. McGregor
Nuclear Technology | Volume 175 | Number 1 | July 2011 | Pages 131-137
Technical Paper | Special Issue on the 16th Biennial Topical Meeting of the Radiation Protection and Shielding Division / Materials for Nuclear Systems | doi.org/10.13182/NT11-A12281
Articles are hosted by Taylor and Francis Online.
In this study, the charge collection efficiencies (CCEs) of a 7.8- × 7.8- × 15.6-mm3 CdZnTe Frisch collar detector and a 2.1- × 2.1- × 4.1-mm3 HgI2 Frisch collar detector were measured and compared. Two Frisch collar devices were designed and fabricated to have identical aspect ratios of 2.0 to maintain similar weighting potential distributions. Pulse-height spectra were acquired from both Frisch collar devices with a standard calibration gamma-ray source of 137Cs, and the results are presented. As known, the Frisch collar alters the weighting potential within the planar device and enhances the CCE distributions. Thus, the parameters affecting these distributions have great impact on the pulse-height spectrum. The device length and mobility-lifetime product have great impacts on CCE. Primarily, crystal (device) length L directly affects CCE because more charge carriers are trapped in longer devices with longer traveling distances. Alternatively, the better mobility-lifetime product of the charge carriers enhances CCE of the fabricated device. It is shown in this study that as a result of similarity in shape for both devices (equal aspect ratio), the weighting potential distributions resemble each other. However, as a result of the trapping effect (due to both length and ), the CCE profiles are not the same, and the CdZnTe detector shows more uniform response to gamma rays and, therefore, better spectroscopic performance (even with a longer device length), which is confirmed through CCE simulations. Finally, by applying the CCE model to the HgI2 Frisch collar device, the mobility-lifetime products e, h e, h of electrons and holes were estimated to be 0.0008 and 0.00003 cm2V-1 , respectively, for the HgI2 crystal.
