弱谐波情况下透射光栅衍射效率标定方法

同步辐射光源中的高次谐波会使透射光栅衍射效率标定精度变差。为了校正光源中的高次谐波对透射光栅衍射效率标定的影响,提出了一种光源存在弱谐波情况下的透射光栅衍射效率标定方法,通过使用谐波X射线的衍射效率修正基波衍射效率标定中谐波的影响,从而得到更为准确的透射光栅衍射效率。使用该标定方法在北京同步辐射光源上开展了透射光栅相对衍射效率标定工作。实验结果表明:在100~800eV存在高次谐波能段,修正后透射光栅一级与零级的相对衍射效率与理论模拟结果吻合较好,修正后光栅二级与一级的相对衍射效率更接近理论模拟结果,但与理论模拟结果仍有较大偏差,该偏差主要来源光栅较弱的二级衍射。

Calibration method of transmission grating diffraction efficiency with weak high-order harmonics

The accuracy of transmission grating calibration on synchrotron radiation could be worsened by high-order harmonics. In order to correct this influence, a calibration method was proposed for the light source with weak high-order harmonics. This method corrected the fundamental wave diffraction efficiency using the high-order harmonics diffraction efficiencies which were obtained in calibration too. This verifying experiment was carried out on Beijing Synchrotron Radiation Facility. The experimental results show that the corrected ratio of first-zero order diffraction efficiency to zero-order agreed well with the calculated results between 100-800 eV where high-order harmonics existed. The ratio of second-order diffraction efficiency to first-order was more closed to the calculated results though some difference still existed. This difference came from the weak two-order diffraction.