Toward Scintillator High-Gain Avalanche Rushing Photoconductor Active Matrix Flat Panel Imager (SHARP-AMFPI): Initial fabrication and characterization.
Toward Scintillator High-Gain Avalanche Rushing Photoconductor Active Matrix Flat Panel Imager (SHARP-AMFPI): Initial fabrication and characterization.
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DOI：
10.1002/mp.12693
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发表时间：
2018-03
期刊：
影响因子：
3.8
通讯作者：
Zhao W
中科院分区：
文献类型：
--
作者：
Scheuermann JR;Howansky A;Hansroul M;Léveillé S;Tanioka K;Zhao W
我们提出了第一个原型闪烁体高增益雪崩光电导体有源矩阵平板成像器（SHARP AMFPI）。该检测器包括雪崩非晶硒（a-Se）（HARP）层作为间接检测器中的光电导体，以放大信号并降低电子噪声的影响，从而获得用于低剂量应用的量子噪声限制图像。这是第一次雪崩a-Se已被用于固态成像设备，并构成一个可能的解决方案，以消除电子噪声的影响，这是至关重要的低剂量成像性能的AMFPI。我们成功地在像素间距为85 μm的24 × 30 cm 2薄膜晶体管阵列（TFT阵列）上沉积了固态HARP结构。HARP层由16 μm的a-Se组成，具有空穴阻挡层和电子阻挡层，以分别防止来自高压偏压和像素电极的电荷注入。在a-Se层上施加高达105 Vμm−1的电场（ESe）而没有击穿。使用150 μm厚的结构化CsI：Tl闪烁体形成SHARP-AMFPI。使用30 kVp Mo/Mo束表征X射线成像性能。我们评估的空间分辨率，噪声功率，和检测量子效率在零频率的系统和没有雪崩增益。采用级联线性系统模型（CLSM）对结果进行了分析。在ESe = 105 Vμm−1时测得雪崩增益为76 ± 5。我们证明了雪崩增益可以放大信号，以克服电子噪声。随着雪崩增益的增加，图像质量提高了恒定（0.76 mR）曝光，直到电子噪声被克服。我们的系统目前受到我们的高压电极的光学透明度差和导致暗电流噪声的长积分时间的限制。这两种效应导致高空间频率噪声主导成像性能。我们证明了固态HARP X射线成像仪的可行性，并制造了迄今为止最大的有源区HARP传感器。程序，以减少次级量子和暗噪声的概述。未来的工作将改善光耦合和电荷传输，从而获得频率DQE和时间指标。
We present the first prototype Scintillator High Gain Avalanche Rushing Photoconductor Active Matrix Flat Panel Imager (SHARP-AMFPI). This detector includes a layer of avalanche amorphous Selenium (a-Se) (HARP) as the photoconductor in an indirect detector to amplify the signal and reduce the effects of electronic noise to obtain quantum noise limited images for low dose applications. It is the first time avalanche a-Se has been used in a solid-state imaging device and poses as a possible solution to eliminate the effects of electronic noise, which is crucial for low-dose imaging performance of AMFPI. We successfully deposited a solid-state HARP structure onto a 24 × 30 cm2 array of thin film transistors (TFT array) with a pixel pitch of 85 μm. The HARP layer consists of 16 μm of a-Se with a hole blocking and electron blocking layer to prevent charge injection from the high voltage bias and pixel electrodes, respectively. An electric field (ESe) up to 105 Vμm−1 was applied across the a-Se layer without breakdown. A 150 μm thick structured CsI:Tl scintillator was used to form SHARP-AMFPI. The x-ray imaging performance is characterized using a 30 kVp Mo/Mo beam. We evaluate the spatial resolution, noise power, and detective quantum efficiency at zero frequency of the system with and without avalanche gain. The results are analyzed using cascaded linear system model (CLSM). An avalanche gain of 76 ± 5 was measured at ESe = 105 Vμm−1. We demonstrate that avalanche gain can amplify the signal to overcome electronic noise. As avalanche gain is increased, image quality improves for a constant (0.76 mR) exposure until electronic noise is overcome. Our system is currently limited by poor optical transparency of our high voltage electrode and long integrating time which results in dark current noise. These two effects cause high spatial frequency noise to dominate imaging performance. We demonstrate the feasibility of a solid-state HARP X-ray imager and have fabricated the largest active area HARP sensor to date. Procedures to reduce secondary quantum and dark noise are outlined. Future work will improve optical coupling and charge transport which will allow for frequency DQE and temporal metrics to be obtained.
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影响因子：
10.6
作者：
FUJITA, H;TSAI, DY;OHTSUKA, A
通讯作者：
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影响因子：
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