Scott Christopher C, Farrier Michael, Li Yunzhe, Laxer Sam, Ravi Parmesh, Kenesei Peter, Wojcik Michael J, Miceli Antonino, Karim Karim S
KA Imaging Inc., 560 Parkside Drive, Unit 3, Waterloo, Ontario, Canada N2L 5Z4.
Farrier Microengineering LLC, 616 Petoskey Street, Unit 004, Petoskey, MI 49770, USA.
J Synchrotron Radiat. 2021 Jul 1;28(Pt 4):1081-1089. doi: 10.1107/S1600577521004835. Epub 2021 Jun 2.
The objective of this work was to fabricate and characterize a new X-ray imaging detector with micrometre-scale pixel dimensions (7.8 µm) and high detection efficiency for hard X-ray energies above 20 keV. A key technology component consists of a monolithic hybrid detector built by direct deposition of an amorphous selenium film on a custom designed CMOS readout integrated circuit. Characterization was carried out at the synchrotron beamline 1-BM-B at the Advanced Photon Source of Argonne National Laboratory. The direct conversion detector demonstrated micrometre-scale spatial resolution with a 63 keV modulation transfer function of 10% at Nyquist frequency. In addition, spatial resolving power down to 8 µm was determined by imaging a transmission bar target at 21 keV. X-ray signal linearity, responsivity and lag were also characterized in the same energy range. Finally, phase contrast edge enhancement was observed in a phase object placed in the beam path. This amorphous selenium/CMOS detector technology can address gaps in commercially available X-ray detectors which limit their usefulness for existing synchrotron applications at energies greater than 50 keV; for example, phase contrast tomography and high-resolution imaging of nanoscale lattice distortions in bulk crystalline materials using Bragg coherent diffraction imaging. The technology will also facilitate the creation of novel synchrotron imaging applications for X-ray energies at or above 20 keV.
这项工作的目标是制造并表征一种新型的X射线成像探测器，其像素尺寸为微米级（7.8 µm），对能量高于20 keV的硬X射线具有高探测效率。一个关键的技术组件是通过在定制设计的CMOS读出集成电路上直接沉积非晶硒膜构建的单片混合探测器。表征工作在阿贡国家实验室先进光子源的同步加速器光束线1-BM-B上进行。该直接转换探测器在奈奎斯特频率下展示了微米级空间分辨率，63 keV的调制传递函数为10%。此外，通过对21 keV下的透射条形靶进行成像，确定了低至8 µm的空间分辨能力。还在相同能量范围内对X射线信号的线性度、响应度和滞后进行了表征。最后，在光束路径中放置的相位物体中观察到了相位对比边缘增强。这种非晶硒/CMOS探测器技术可以填补市售X射线探测器的空白，这些空白限制了它们在能量大于50 keV的现有同步加速器应用中的实用性；例如，相位对比断层扫描以及使用布拉格相干衍射成像对块状晶体材料中的纳米级晶格畸变进行高分辨率成像。该技术还将促进为能量在20 keV及以上的X射线创建新型同步加速器成像应用。
