The recent disaster of Fukushima in Japan combined with the high demand to enhance nuclear safety and to minimize personal exposure to radioactive materials has a significant impact on research and development of radiation detection instrumentation. Currently, there is ample effort worldwide in the pursuit of radiation detection to maximize the accuracy and meet international standards in terms of size and specifications to enable radiation protection decision making. Among the requirements is the development of a portable, light-weight gamma-ray isotope identifier to be used by first responders in nuclear accidents as well as for radiation security and identification of illicit material isotopes. From nuclear security perspective, research into advanced screening technologies has become a high priority in all aspects, while for occupational safety, and environmental radiation protection, the regulatory authorities are requiring specific performance of radiation detection and measuring devices. At the applied radiation laboratory of the University of Ontario Institute of Technology, UOIT, the development of a high resolution spectrometer for medium and high energy gamma ray has been conducted. The spectrometer used a newly developed scintillator based on a LaBr3(Ce) crystal. The detector has been modeled using advanced Monte Carlo code (MCNP/X code) for the response function simulation and parameter characterization. The simulation results have been validated by experimental investigations using a wide range of gamma radiation energies. The developed spectrometer has been characterized in terms of resolution and response in different fields. It has also been compared with other crystals such as NaI(TI) and LiI(Eu). / UOIT

There has been a great deal of interest in the use of LaBr3 (Ce) detectors for fast timing measurements. Due to their excellent energy resolution, ≈ 3% at 1MeV, they offer an improved signal to background over BaF2 which has ≈ 9% energy resolution. Many groups are planning arrays of LaBr3 detectors. The 8π collaboration has recently acquired a small array of 6 2”x 2” cylindrical LaBr3 detectors to replace its BaF2 detectors. We have been investigating the effects of detector-to-detector scattering on timing resolution. We have further investigated the use of Compton-suppression shields with LaBr3 detectors. This will also be the first testing of the DANTE acquisition system in the 8π. A summary of the results of our optimization, scattering studies, and Compton-suppression tests will be presented.

京都大学 / 新制・課程博士 / 博士(工学) / 甲第25284号 / 工博第5243号 / 新制||工||1998(附属図書館) / 京都大学大学院工学研究科原子核工学専攻 / (主査)教授 田中 浩基, 教授 堀 順一, 准教授 土田 秀次 / 学位規則第4条第1項該当 / Doctor of Agricultural Science / Kyoto University / DFAM