Pixellated thallium bromide detectors for gamma-ray spectroscopy and imaging
Pixellated thallium bromide detectors for gamma-ray spectroscopy and imaging
复制标题
用于伽马射线光谱和成像的像素化溴化铊探测器
DOI：
10.1016/j.nima.2004.03.046
复制
发表时间：
2004
影响因子：
1.4
通讯作者：
Y. Hiratate
中科院分区：
文献类型：
--
作者：
T. Onodera;K. Hitomi;T. Shoji;Y. Hiratate
近年来，由CZT、CZT、HgI2等材料制成的像素化半导体探测器具有较高的能量分辨率。溴化铊是一种高原子序数(Tl=81，Br=35)和高密度(7.56g/cm~3)的化合物半导体。因此，与用于辐射探测器制造的其他半导体材料如CdTe、CZT和HgI2相比，TlBr显示出更高的光子阻止能力。TlBr2的宽带隙(2.68 eV)使探测器可以在室温附近低噪声工作。我们的研究致力于制备具有足够的探测效率和良好的电荷收集效率的像素化TlBr光探测器。在本研究中，用水平移动熔融区(TMZ)法生长的多道区提纯的晶体制成像素化的TlBr光探测器。TlBr探测器在一个晶体表面上有一个连续的阴极和3×3个像素化的阳极(每个0.57×0.57mm2)，在相反的表面上有一个保护环。电极是通过荫罩真空蒸发钯实现的。探测器的典型厚度为2 mm。用241Am(59.5keV)、57Co(122keV)和137Cs(662 KeV)的伽马源在-20℃下照射TlBr探测器，测试了探测器的能谱性能。对于59.5、122和662 keV的伽马射线，能量分辨率分别为4.0、6.0和9.7keV。
Recently, pixellated semiconductor detectors exhibit high-energy resolution, which have been studied actively and fabricated from CdTe, CZT and HgI2. Thallium bromide (TlBr) is a compound semiconductor characterized with its high atomic numbers (Tl=81, Br=35) and high density (7.56g/cm3). Thus, TlBr exhibits higher photon stopping power than other semiconductor materials used for radiation detector fabrication such as CdTe, CZT and HgI2. The wide band gap of TlBr (2.68eV) permits the detectors low-noise operation at around room temperature. Our studies made an effort to fabricate pixellated TlBr detectors had sufficient detection efficiency and good charge collection efficiency. In this study, pixellated TlBr detectors were fabricated from the crystals purified by the multipass zone-refining method and grown by the horizontal traveling molten zone (TMZ) method. The TlBr detector has a continuous cathode over one crystal surface and 3×3 pixellated anodes (0.57×0.57mm2each) surrounded by a guard ring on the opposite surface. The electrodes were realized by vacuum evaporation of palladium through a shadow mask. Typical thickness of the detector was 2mm. Spectrometric performance of the TlBr detectors was tested by irradiating them with241Am (59.5keV),57Co (122keV) and137Cs (662keV) gamma-ray sources at temperature of –20°C. Energy resolutions (FWHM) were measured to be 4.0, 6.0 and 9.7keV for 59.5, 122 and 662keV gamma-rays, respectively.