Itoga T, Ishikawa M, Baba M, Okuji T, Oishi T, Nakhostin M, Nishitani T
Cyclotron and Radioisotope Center, Tohoku University, Aoba 6-3, Aramaki, Aoba-ku, Sendai, Miyagi 980-8578, Japan.
Radiat Prot Dosimetry. 2007;126(1-4):380-3. doi: 10.1093/rpd/ncm141. Epub 2007 May 21.
The stilbene neutron detector which has been used for neutron emission profile monitoring in JT-60U has been improved, to respond to the requirement to observe the high-frequency phenomena in megahertz region such as toroidicity-induced Alfvén Eigen mode in burning plasma as well as the spatial profile and the energy spectrum. This high-frequency phenomenon is of great interest and one of the key issues in plasma physics in recent years. To achieve a fast response in the stilbene detector, a Flash-ADC is applied and the wave form of the anode signal stored directly, and neutron/gamma discrimination was carried out via software with a new scheme for data acquisition mode to extend the count rate limit to MHz region from 1.3 x 10(5) neutron/s in the past, and confirmed the adequacy of the method.
用于JT-60U装置中子发射剖面监测的芪中子探测器已得到改进，以满足在兆赫兹频段观测高频现象的需求，如燃烧等离子体中的环向阿尔文本征模以及空间剖面和能谱。这种高频现象备受关注，是近年来等离子体物理的关键问题之一。为使芪探测器实现快速响应，应用了闪存模数转换器（Flash-ADC），直接存储阳极信号的波形，并通过软件采用新的数据采集模式方案进行中子/伽马甄别，将计数率上限从过去的1.3×10⁵中子/秒扩展至兆赫兹频段，并证实了该方法的适用性。
