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arXiv · 2312.07915

2-mm-Thick Large-Area CdTe Double-sided Strip Detectors for High-Resolution Spectroscopic Imaging of X-ray and Gamma-ray with Depth-Of-Interaction Sensing

Takahiro Minami·Miho Katsuragawa·Shunsaku Nagasawa·Shin'ichiro Takeda·Shin Watanabe·Yutaka Tsuzuki·Tadayuki Takahashi
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Abstract

We developed a 2-mm-thick CdTe double-sided strip detector (CdTe-DSD) with a 250 um strip pitch, which has high spatial resolution with a uniform large imaging area of 10 cm$^2$ and high energy resolution with high detection efficiency in tens to hundreds keV. The detector can be employed in a wide variety of fields for quantitative observations of hard X-ray and soft gamma-ray with spectroscopic imaging, for example, space observation, nuclear medicine, and non-destructive elemental analysis. This detector is thicker than the 0.75-mm-thick one previously developed by a factor of $\sim$2.7, thus providing better detection efficiency for hard X-rays and soft gamma rays. The increased thickness could potentially enhance bias-induced polarization if we do not apply sufficient bias and if we do not operate at a low temperature, but the polarization is not evident in our detector when a high voltage of 500 V is applied to the CdTe diode and the temperature is maintained at -20 $^\circ$C during one-day experiments. The ''Depth Of Interaction'' (DOI) dependence due to the CdTe diode's poor carrier-transport property is also more significant, resulting in much DOI information while complicated detector responses such as charge sharings or low-energy tails that exacerbate the loss in the energy resolution. In this paper, we developed 2-mm-thick CdTe-DSDs, studied their response, and evaluated their energy resolution, spatial resolution, and uniformity. We also constructed a theoretical model to understand the detector response theoretically, resulting in reconstructing the DOI with an accuracy of 100 um while estimating the carrier-transport property. We realized the detector that has high energy resolution and high 3D spatial resolution with a uniform large imaging area.

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Takahiro Minami, Miho Katsuragawa, Shunsaku Nagasawa, Shin'ichiro Takeda, Shin Watanabe, Yutaka Tsuzuki, Tadayuki Takahashi. 2023-12-13. 2-mm-Thick Large-Area CdTe Double-sided Strip Detectors for High-Resolution Spectroscopic Imaging of X-ray and Gamma-ray with Depth-Of-Interaction Sensing. https://doi.org/10.1016/j.nima.2023.169024

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