Wysokinski Tomasz W, Renier Michel, Suortti Pekka, Belev George, Rousset Léo, Adam Madison, Miller Denise, Huber Norman, Chapman L Dean
Science Projects, Canadian Light Source Inc., 44 Innovation Boulevard, Saskatoon, SK, Canada S7N 2V3.
European Synchrotron Radiation Facility, Grenoble, France.
J Synchrotron Radiat. 2018 Sep 1;25(Pt 5):1548-1555. doi: 10.1107/S1600577518008639. Epub 2018 Aug 2.
The research program at the biomedical imaging facility requires a high-flux hard-X-ray monochromator that can also provide a wide beam. A wide energy range is needed for standard radiography, phase-contrast imaging, K-edge subtraction imaging and monochromatic beam therapy modalities. The double-crystal Laue monochromator, developed for the BioMedical Imaging and Therapy facility, is optimized for the imaging of medium- and large-scale samples at high energies with the resolution reaching 4 µm. A pair of 2 mm-thick Si(111) bent Laue-type crystals were used in fixed-exit beam mode with a 16 mm vertical beam offset and the first crystal water-cooled. The monochromator operates at energies from 25 to 150 keV, and the measured size of the beam is 189 mm (H) × 8.6 mm (V) at 55 m from the source. This paper presents our approach in developing a complete focusing model of the monochromator. The model uses mechanical properties of crystals and benders to obtain a finite-element analysis of the complete assembly. The modeling results are compared and calibrated with experimental measurements. Using the developed analysis, a rough estimate of the bending radius and virtual focus (image) position of the first crystal can be made, which is also the real source for the second crystal. On the other hand, by measuring the beam height in several points in the SOE-1 hutch, the virtual focus of the second crystal can be estimated. The focusing model was then calibrated with measured mechanical properties, the values for the force and torque applied to the crystals were corrected, and the actual operating parameters of the monochromator for fine-tuning were provided.
生物医学成像设施的研究项目需要一台高通量硬X射线单色仪，该单色仪还能提供宽光束。标准射线照相、相衬成像、K边减影成像和单色束治疗模式需要宽能量范围。为生物医学成像与治疗设施开发的双晶劳厄单色仪，针对中大型样本在高能量下的成像进行了优化，分辨率达到4 µm。一对2 mm厚的Si(111)弯曲劳厄型晶体用于固定出射光束模式，垂直光束偏移16 mm，第一块晶体水冷。该单色仪在25至150 keV的能量下运行，在距光源55 m处测得的光束尺寸为189 mm（水平）×8.6 mm（垂直）。本文介绍了我们开发该单色仪完整聚焦模型的方法。该模型利用晶体和弯曲器的力学性能对整个组件进行有限元分析。将建模结果与实验测量结果进行比较和校准。利用所开发的分析方法，可以对第一块晶体的弯曲半径和虚拟焦点（图像）位置进行粗略估计，而这也是第二块晶体的实际光源。另一方面，通过在SOE-1实验室内的几个点测量光束高度，可以估计第二块晶体的虚拟焦点。然后根据测量的力学性能对聚焦模型进行校准，校正施加在晶体上的力和扭矩值，并提供用于微调的单色仪实际运行参数。
