Performance of the gamma-ray camera based on GSO(Ce) scintillator array and PSPMT with the ASIC readout system
Performance of the gamma-ray camera based on GSO(Ce) scintillator array and PSPMT with the ASIC readout system
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DOI：
10.1016/j.nima.2008.03.071
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发表时间：
2008-06
影响因子：
1.4
通讯作者：
K. Ueno;K. Hattori;C. Ida;S. Iwaki;S. Kabuki;H. Kubo;S. Kurosawa;K. Miuchi;T. Nagayoshi;H. Nishimura;R. Orito;A. Takada;T. Tanimori
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文献类型：
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作者：
K. Ueno;K. Hattori;C. Ida;S. Iwaki;S. Kabuki;H. Kubo;S. Kurosawa;K. Miuchi;T. Nagayoshi;H. Nishimura;R. Orito;A. Takada;T. Tanimori
我们研究了基于GSO(Ce)闪烁体阵列的通道多阳极PSPMT(滨松平板H8500)的伽马相机专用集成电路读出系统的性能。GSO阵列由8×8像素的6×6×13 mm 3像素组成，像素间距与H8500的阳极相同。这款相机旨在用作电子跟踪康普顿伽马射线相机的吸收器，该相机测量的伽马射线最高可达∼1 MeV。由于气球载实验需要一个低功耗的读出系统，所以我们采用了32通道ASIC芯片IDEAS VA32_HDR11，它是商用芯片中动态范围最大的芯片之一。然而，在使用GSO(Ce)晶体和H8500的情况下，VA32_HDR11的动态范围很窄，因此H8500必须以大约105的低增益操作。如果H8500在低增益下运行，则相机的入射能量动态范围从100到700keV很窄，在662 keV时的能量分辨率较差，为13.0%(半高宽)。因此，我们开发了一块衰减板，用于操作H8500，典型增益为106，可测量高达∼1 MeV的伽马射线。该电路板使阳极增益变化均匀，扩大了H8500的动态范围。采用新型衰减板的系统具有良好的均匀性，最小：最大∼为1：1.6，入射能量动态范围为30~900keV，位置分辨率小于6 mm，在662 keV处的典型能量分辨率为10.6%(半高宽)，低功耗约为1.7W/64ch。
We have studied the performance of a readout system with ASIC chips for a gamma-ray camera based on a 64-channel multi-anode PSPMT (Hamamatsu flat-panel H8500) coupled to a GSO(Ce) scintillator array. The GSO array consists of 8×8 pixels of 6×6×13mm3with the same pixel pitch as the anode of the H8500. This camera is intended to serve as an absorber of an electron tracking Compton gamma-ray camera that measures gamma rays up to ∼1MeV. Because we need a readout system with low power consumption for a balloon-borne experiment, we adopted a 32-channel ASIC chip, IDEAS VA32_HDR11, which has one of the widest dynamic range among commercial chips. However, in the case of using a GSO(Ce) crystal and the H8500, the dynamic range of VA32_HDR11 is narrow, and therefore the H8500 has to be operated with a low gain of about 105. If the H8500 is operated with a low gain, the camera has a narrow incident-energy dynamic range from 100 to 700keV, and a bad energy resolution of 13.0% (FWHM) at 662keV. We have therefore developed an attenuator board in order to operate the H8500 with the typical gain of 106, which can measure up to ∼1MeV gamma ray. The board makes the variation of the anode gain uniform and widens the dynamic range of the H8500. The system using the new attenuator board has a good uniformity of min:max∼1:1.6, an incident-energy dynamic range from 30 to 900keV, a position resolution of less than 6mm, and a typical energy resolution of 10.6% (FWHM) at 662keV with a low power consumption of about 1.7W/64ch.