This paper describes a pixel imaging array consisting in 400 um x 400 um photodiodes fabricated in CMOS technology. Above the photodiodes, an array of scintillating CsI:Tl crystals are placed. The scintillating crystals are encapsulated in aluminum walls forming a light path to guide the produced visible light into the photodiodes. So, the x-ray energy is first converted into visible light which is then detected by the photodiode at the end of each light guide. The scintillator is 800 um thick, absorbing almost all of 20 keV x-ray photons. Usually, the spatial resolution of the scintillating x-rays detectors is identical to the scintillator thickness. By using the light guides, the scintillator thickness can be increased, without decreasing the spatial resolution. The increase of the scintillator thickness is desirable in order to increase the x-rays absorption efficiency. Tests carried out on the system show very promising results near 20 keV.
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机译:本文介绍了一个像素成像阵列,该阵列由以CMOS技术制造的400 um x 400 um光电二极管组成。在光电二极管上方,放置了闪烁的CsI:Tl晶体阵列。闪烁晶体封装在铝壁中,形成一条光路,将产生的可见光引导到光电二极管中。因此,X射线能量首先转换为可见光,然后由每个光导末端的光电二极管检测到。闪烁体的厚度为800 um,吸收了几乎所有的20 keV X射线光子。通常,闪烁X射线探测器的空间分辨率与闪烁体的厚度相同。通过使用光导,可以增加闪烁体的厚度,而不会降低空间分辨率。为了增加X射线吸收效率,期望增加闪烁体的厚度。在系统上进行的测试显示,在20 keV附近,结果非常可观。
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