Optimisation and fabrication of a composite pyrolytic graphite monochromator for the Pelican instrument at the ANSTO OPAL reactor
Optimisation and fabrication of a composite pyrolytic graphite monochromator for the Pelican instrument at the ANSTO OPAL reactor
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ANSTO OPAL 反应堆 Pelican 仪器复合热解石墨单色仪的优化和制造
DOI：
10.1016/j.nima.2010.05.052
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发表时间：
2011
影响因子：
1.4
通讯作者：
D. H. Yu
中科院分区：
文献类型：
--
作者：
A. Freund;D. H. Yu
ANSTO的TOF中子谱仪鹈鹕的三重单色仪已经在整体性能方面进行了全面优化，包括测定热解石墨晶体的厚度。设计并制备了24个复合晶体。单色器晶体的计算最佳厚度为1.3 mm，长度为15 cm，这是商业上没有的。在解理和结合过程前后，使用X射线和中子衍射对晶体进行了广泛的表征。结果表明，在制造过程中没有出现损伤，完全达到了设计目标。测量的峰值反射率和摇摆曲线宽度确实与理论符合得很好。除了这种新方法实现的三重单色器的优越效率外，所需的晶体材料的量可以减少三分之一。
The triple monochromator for the TOF neutron spectrometer Pelican at ANSTO has been fully optimised in terms of overall performance, including the determination of the thickness of the pyrolytic graphite crystals. A total of 24 composite crystals were designed and fabricated. The calculated optimum thickness of 1.3mm and the length of 15cm of the monochromator crystals, that are not available commercially, were obtained by cleaving and soldering with indium. An extensive characterisation of the crystals using X-ray and neutron diffraction was conducted before and after the cleaving and bonding processes. The results proved that no damage was introduced during fabrication and showed that the design goals were fully met. The measured peak reflectivity and rocking curve widths were indeed in an excellent agreement with theory. In addition to the superior efficiency of the triple monochromator achieved by this novel approach, the amount of the crystal material required could be reduced by 1/3.