[1M01-04] Dosimeter Development

[1M01] A novel dosimeter technique using quadruple-phoswich scintillator for beta/gamma simultaneous counting and discriminating.

(1)Concept and overall design

*Tatsuyuki Maekawa¹, Naoto Kume², Shunichiro Makino¹, Kentaro Kikuchi², Yuji Oshima¹, Eiichi Fujiwara¹ (1. Toshiba Power Systems Radiation Techno-Service, 2. Toshiba Energy Systems & Solutions Corporation)

Keywords:beta ray, gamma ray, phosich scintillator, quadruple, deisrimination, simultaneous, dose rate

At Fukushima-daiichi decommissioning site, β-ray management is extremely important. With the legislation of lowering the eye lens dose limit, more convenient and reliable measurement tools of β-ray dose rate is strongly required. For β-ray dose rate measurement, ionization chamber survey meters usually adopted, but the evaluation of β-ray requires two measurements with and without a β-ray cutoff filter and subtraction of these data. In this situation, error propagation of the γ-ray component is unavoidable in the dose rate subtraction and the measurement exposure should be minimized,too.
Against this background, we are developing a new measurement tool. Focusing on the continuous energy deposition of β-rays and the stochastic reaction of γ-rays, we proposed a new quadruple Phoswich scintillator. In this development, we are developing real-time pulse shape discrimination method and dose equivalent rate calculation method using digital signal processing. This time, we will give a series of presentation on the overall outline of this technology and the results of optimization and feasibility verification of the four-layer phoswich detector.