为准确测量上海光源软X射线谱学显微光束线采用的变包含角平面光栅单色仪的转角重复精度,提出了一种新的基于相位板衍射准直技术的测量方法。该方法将半导体激光单模光纤和相位板衍射准直技术结合起来,利用面阵CCD采集图像,通过测量光斑的位移变化确定平面镜和光栅的角度变化。实验表明,该方法可以测量掠入射情况下单色仪联动时的转角重复精度,测量精度可达±0.1″,此测量精度优于同等实验条件下的商用ELCOMAT 3000自准直仪的测量精度。

In order to measure the mechanical angle repeatability of the variable-included-angle plane-grating-monochromator used in soft X-ray spectro-microscopy beamline at Shanghai Synchrotron Radiation Facility,a new method was proposed based on the phase plate diffraction collimation. This system was designed combining laser diode fiber with phase plate diffraction collimation technique. A 2-dimension CCD was adopted to collect the images,which was used to measure the displacement of the light spot,thus the angle repeatability of the plane mirror and the grating could be determined. The results show that this method could be used to measure the monochromator′s angle repeatability in a higher precision estimated to be ±0.1″,which is better than that measured by the commercial ELCOMAT 3000 auto collimator used in the same condition.