Si1−xGex gradient crystals: a new monochromator material for hard X-rays
Si1−xGex gradient crystals: a new monochromator material for hard X-rays
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Si1−xGex 梯度晶体：一种新型硬 X 射线单色仪材料
DOI：
10.1016/s0168-9002(98)00542-7
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发表时间：
1998
影响因子：
1.4
通讯作者：
H. Riemann
中科院分区：
文献类型：
--
作者：
S. Keitel;C. C. Retsch;T. Niemöller;J. Schneider;N. Abrosimov;S. Rossolenko;H. Riemann
采用三晶衍射仪，采用120keV同步辐射，研究了Si1−xGex（0.02≤x≤0.07）梯度大Czochralski晶体的衍射特性。在晶体长度为40mm时，观察到晶格参数的均匀变化1.7×10−3。在低锗含量的透射几何结构中测量的衍射图显示，在不考虑吸收的情况下，FWHM为14.8arcsec，峰值反射率为96%。随着锗含量的增加，衍射图的波峰宽增大到49arcsec，峰值反射率减小到72%。考虑到吸收，120keV光子的有效反射率在68%到50%之间变化，这是惊人的高。这种材料为同步辐射仪器的光学优化开辟了新的机会，预计它也将在中子散射实验中具有优势。
The diffraction properties of a large Czochralski grown Si1−xGex(0.02≤x≤0.07) gradient crystal have been studied by means of a triple-crystal diffractometer using 120keV synchrotron radiation. Over a crystal length of 40mm a homogeneous variation of the lattice parameter by 1.7×10−3has been observed. The diffraction pattern measured in transmission geometry at low Ge content showed a FWHM of 14.8arcsec at a peak reflectivity of 96% disregarding absorption. With increasing Ge content the FWHM of the diffraction pattern increases up to 49arcsec with the peak reflectivity decreasing to a value of 72%. Taking absorption into account the effective reflectivity for 120keV photons varies between 68% and 50%, which is surprisingly high. This material opens up new opportunities of optimising optics in synchrotron radiation instrumentation, it is expected that it will also be of advantage in neutron scattering experiments.