Ph.D. Proposal Presentation by Marat Seidaliev
Friday, May 6, 2005

(Dr. Chris Wang, Chair)

"Development and Test of a High-Efficiency GEM-Based TEPC for Neutron Protection Dosimetry"

Abstract

The effective dose equivalent, H E (or the effective dose, E ) to an individual is the primary limiting quantity in radiation protection. However, techniques for measuring H E for neutrons have not been fully developed. The proposed study is to develop and test a t issue e quivalent p roportional c ounter (TEPC) based on a g as e lectron m ultiplier (GEM) for measuring H E for neutrons.

The study includes five major tasks. The first task of the proposed research is to design and build the new GEM-based TEPC. The second task is to use the new TEPC to measure the absorbed dose, D , and the frequency distribution of lineal energy, , for two different neutron sources (a 252 Cf source and a Am-Be source), and then to combine D and f ( y ) to obtain H E . The third task is to perform the computer simulation of the new TEPC to obtain the pulse height distributions for the two neutron sources and then compare the results with the measured results. The fourth task is to perform Monte Carlo calculations to obtain H E for the 252 Cf source and for the Am-Be source, and then to examine how well agree the measured results and the calculated results. The fifth task is to experimentally study the new TEPC's response with respect to the directions of incident neutrons, i.e. the angular dependencies.

Some of the tasks stated above have already been completed. These include: design and construction of the new TEPC, pulse-height-spectrum measurement of a 252 Cf source with the new TEPC, and computer simulation of the pulse-height-spectrum measurement of a 252 Cf source with the new TEPC. These results will be presented. Completion of the proposed project should have significant impact on radiation protection dosimetry for neutrons.