Development of an MeV gamma-ray imaging detector
Development of an MeV gamma-ray imaging detector
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DOI：
10.1109/nssmic.2003.1352045
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发表时间：
2003
期刊：
影响因子：
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通讯作者：
A. Takeda;H. Kubo;K. Miuchi;T. Nagayoshi;Y. Okada;R. Orito;A. Takada;T. Tanimori;Masaru Ueno;O. Bouianov;M. Bouianov
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文献类型：
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作者：
A. Takeda;H. Kubo;K. Miuchi;T. Nagayoshi;Y. Okada;R. Orito;A. Takada;T. Tanimori;Masaru Ueno;O. Bouianov;M. Bouianov
已经开发出一种兆电子伏伽马射线成像探测器，可以实现逐事件重建。该 MeV 伽马射线探测器是微型 TPC 的混合探测器，微型 TPC 是具有气态微像素室 (/spl mu/-PIC) 读出装置的时间投影室 (TPC) 和封闭式闪烁相机。我们开发了MeV伽马射线成像探测器原型，其微型TPC体积为10 /spl times/ 10 /spl times/ 8 cm/sup 3/，NaI闪烁体为10 /spl times/ 10 /spl times/ 2.5 cm/sup 3/尺寸，由25个直径为3/4"的单阳极PMTS读取，并成功地用放射源重建了伽马射线事件。原型探测器的角分辨率主要受到微型TPC对最小电离粒子（MIP）的跟踪灵敏度的限制，而该灵敏度由/spl mu/-PIC的气体增益决定。因此，我们采用新的制造技术开发了/spl mu/-PIC的电极结构，从而获得了比以前的/spl mu/-PIC高出三倍的气体增益。由于电极结构的改进，不仅实现了高气体增益，而且还实现了良好的增益均匀性。此外，新型/spl mu/-PIC作为X射线探测器还证实了低离子反馈和长期稳定性。
An MeV gamma-ray imaging detector which makes an event-by-event reconstruction possible has been developed. This MeV gamma-ray detector is a hybrid detector of a micro-TPC which is a time projection chamber (TPC) with a gaseous micro pixel chamber (/spl mu/-PIC) readout and an enclosing scintillation camera. We developed a prototype of the MeV gamma-ray imaging detector with the micro-TPC of 10 /spl times/ 10 /spl times/ 8 cm/sup 3/ volume and an NaI scintillator of 10 /spl times/ 10 /spl times/ 2.5 cm/sup 3/ size read by 25 single anode PMTS of 3/4" diameters, and succeeded in reconstructing the gamma-ray events with a radioactive source. Angular resolutions of the prototype detector were restricted mainly by the tracking sensitivity of the micro-TPC for minimum ionizing particles (MIPs) which is determined by the gas gain of the/spl mu/-PIC. We have, then, developed an electrode structure of the/spl mu/-PIC using a new manufacture technology in order to improve the gas gain. As a result, a gas gain three times higher than that of the former/spl mu/-PIC has been obtained. This result is in good agreement with the simulation. Owing to this improvement of the electrode structure, not only the high gas gain but also a good gain uniformity has been achieved. In addition, a low ion-feedback and long term stability have been confirmed by the new/spl mu/-PIC as an X-ray detector.