M.D. Shah, C. Marianno, S.P. Khatri, and D.R. Boyle,
"Simulation Analysis of Scintillation in Sodium Iodide Detector,"
55th Annual Meeting of the Institute of Nuclear Materials Management, Atlanta, Georgia, 20-14 July 2014.
This work investigates using a new type of integrated circuit
(IC) as a replacement for photomultiplier tubes (PMT) used for
interdiction scenarios. Existing PMTs for such missions can be
large, fragile, and have complex power delivery requirements and
high-energy consumption. While IC technology has advanced, circuits
on these chips are becoming increasingly sensitive to radiation
damage and therefore may fail to function properly. Researchers at
A&M have designed ICs that contain both radiation sensitive and
radiation resistant sectors on the same IC. These chips are
extremely sensitive to charge particles (such as betas) that are
produced at the photocathode. To effectively use these ICs as a PMT
replacement, it is essential that an understanding is developed
regarding the location and amount of betas produced on a
photocathode. To better understand this process, the transport of
visible photons was modeled in a 2" x 4" x 16" NaI detector using
Geant4. Simulation results were obtained using a pencil-beam of
gammas at 70 keV and 1 MeV. It was observed that optical photons
are denser on the surface through which the gammas enter the NaI.
Future work will include an analysis of the photoelectrons produced
by these optical photons, to accurately assess the capability of
replacing PMTs with ICs.
Associated Project(s):Radiation Detection Using Integrated Circuits