Compact Gamma Ray Source for On-Site Calibration of Radiation Detectors

This project develops a portable gamma ray source for on-site,high energy calibration of gamma ray and X-ray detectors. Scintillators and high purity germanium (HPGe) detectors are routinely calibrated at low energy using natural radioactive isotopes such as 137Cs (0.662 MeV) and 60Co (1.17,1.33 MeV). At high energies, however, there is no portable device for calibrating the energy and dose measurements of these detectors. The novel gamma ray source uses neutrons generated from the nuclear fusion reactions. Prompt gamma rays with a known energy spectrum are produced when some of the neutrons are captured in a suitably chosen moderator. The gamma ray source is used to calibrate other gamma ray detectors. Feasibility of the gamma ray source based on a compact neutron generator was demonstrated by design and simulations in Phase I. Moderator materials were selected for generation of monoenergetic gamma rays. Specifications for a compact neutron generator were prepared. In Phase II we will complete the final design of a compact gamma ray source and will f9bricate and test the device. CommercialAppHcations and Other Benefits The gamma ray source with discrete energy levels and known intensities can be used for on-site calibration of different types of radiation detectors, among themare radiation monitors for homeland security use at seaports, airports and other government facilities. Other users include universities, research institutions and astrophysical observatories,as well as industries. The neutron generator as a stand-alone product will have copious uses such as material science research, interrogation of special nuclear material and neutron radiography.