SAPHIRE (scintillator avalanche photoconductor with high resolution emitter readout) for low dose x-ray imaging: spatial resolution.
SAPHIRE (scintillator avalanche photoconductor with high resolution emitter readout) for low dose x-ray imaging: spatial resolution.
复制标题
SAPHIRE（具有高分辨率发射器读数的闪烁体雪崩光电导体），用于低剂量 X 射线成像：空间分辨率。
DOI：
10.1118/1.2937652
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发表时间：
2008
期刊：
影响因子：
3.8
通讯作者：
Zhao,Wei
中科院分区：
文献类型：
--
作者：
Li,Dan;Zhao,Wei
正在研究一种具有可编程雪崩增益和场发射阵列（FEA）读出的间接平板成像仪（FPI），用于低剂量和高分辨率X射线成像。其通过光学耦合结构化X射线闪烁体制成，例如，铊（Tl）掺杂的碘化铯（CsI）转化为无定形硒雪崩光电导体，称为高增益雪崩冲击无定形光电导体（HARP）。闪烁体/HARP（SHARP）组合产生的电荷图像由FEA发射的电子束读出。拟议的探测器称为具有高分辨率发射极读出的闪烁体雪崩光电导体（SAPHIRE）。HARP的可编程雪崩增益可以改善间接FPI的低剂量性能，而FEA可以在像素尺寸小到的情况下进行。由于雪崩增益，高分辨率类型的CsI（Tl）（其由于其较低的光输出而未被广泛用于间接FPI）可以用于改善高空间频率性能。本文的目的是研究影响SAPHIRE空间分辨率的因素。由于SHARP组合的分辨率性能已经得到了很好的研究，目前工作的重点是FEA读出方法的固有分辨率。使用两种不同的电子光学设计研究了从像素FEA发射的电子束的横向扩展：仅网状电极和静电聚焦。我们的结果显示静电聚焦可以将电子束的横向扩展限制在像素尺寸之内。由于静电聚焦基本上与信号强度无关，因此它将提供优异的空间均匀性。
An indirect flat panel imager (FPI) with programmable avalanche gain and field emitter array (FEA) readout is being investigated for low‐dose and high resolution x‐ray imaging. It is made by optically coupling a structured x‐ray scintillator, e.g., thallium (Tl) doped cesium iodide (CsI), to an amorphous selenium avalanche photoconductor called high‐gain avalanche rushing amorphous photoconductor (HARP). The charge image created by the scintillator/HARP (SHARP) combination is read out by the electron beams emitted from the FEA. The proposed detector is called scintillator avalanche photoconductor with high resolution emitter readout (SAPHIRE). The programmable avalanche gain of HARP can improve the low dose performance of indirect FPI while the FEA can be made with pixel sizes down to . Because of the avalanche gain, a high resolution type of CsI (Tl), which has not been widely used in indirect FPI due to its lower light output, can be used to improve the high spatial frequency performance. The purpose of the present article is to investigate the factors affecting the spatial resolution of SAPHIRE. Since the resolution performance of the SHARP combination has been well studied, the focus of the present work is on the inherent resolution of the FEA readout method. The lateral spread of the electron beam emitted from a pixel FEA was investigated with two different electron‐optical designs: mesh‐electrode‐only and electrostatic focusing. Our results showed that electrostatic focusing can limit the lateral spread of electron beams to within the pixel size of down to . Since electrostatic focusing is essentially independent of signal intensity, it will provide excellent spatial uniformity.