无谐波软X射线单色仪设计

Highly Monochromatic Soft X-ray Beam Source Design

能量在0.1～1keV范围的软X射线辐射在空间科学任务中具有重要应用.飞行前的辐射定标试验及地面辐射定标系统采用传统单色仪分光时,由于波长的整数倍关系带来的高次谐波污染问题非常严重.高次谐波在光束中的占比严重影响了软X射线探测仪器的定标数据精度.本文探讨了无谐波单极衍射技术在产生具有高单色性能的软X射线光束中的应用,基于单极衍射光栅技术实现软X射线无谐波单色仪设计.软X射线无谐波单色仪应用于空间辐射定标系统时能够将高次谐波占比抑制到0.3%以下,满足空间软X射线科学仪器高精度辐射定标试验对高次谐波抑制的要求.

The soft X-ray radiation in the range from 100 eV to 1 keV consists of rich significant emission lines and the blackbody continuum. It is commonly used in X-ray instruments for space scientific missions, and the instruments should be well calibrated for spectral response before the flight. Because of the obvious spectra contamination from higher orders of diffraction, X-ray source used traditional gratings is difficult to get highly monochromatic X-ray beam. A new monochromator based on single-order diffraction grating is designed in patterns of zigzag or photon sieves, which has excellent diffraction characteristics of suppressing all higher orders of diffraction from shorter wavelength. The monochromator can keep the percent of the higher order contamination below 0.3%. The results can bring great advantages in preflight calibration of X-ray instruments for space science purposes.