不同厚度Al滤片对17~33nm高次谐波抑制的定量研究

Quantitative research on higher order harmonic suppression in 17~33 nm with different thickness Al filters

利用840 l/mm的金膜透射光栅分光和AXUVl00G光电二极管(PD)探测器研究了不同厚度的Al滤片对光谱辐射标准和计量线(U27)球面光栅单色器(SGM)分支17～33 nm波段高次谐波的抑制情况.结果表明,A1滤片厚为400nm时,在17～33 nm波段有较好的抑制效果且能保证探测器的信号强度,高次谐波信号强度分量小于2%.经过探测器量子效率修正后,高次谐波分量小于0.6%,这对多层膜反射率的定标及探测器定标有着重要的意义.

With 840 l/mm transmission grating(made in house) behind the exit of Spherical Grating Monochromator(SGM) in Spectral Radiation Standard and Metrology(U27) beamline,the dispersion of exit beam and the contributions of different orders were analyzed.The results of higher order harmonics suppression by different thickness Al filters were given in the region of 17~33 nm.The results show that when the thickness of Al filter is 400 nm,and the wavelength between 17~33 nm,the contributions of higher orders to the detector signal are restricted to less than 2%,and the Photon Diode(PD) intensity is strong enough.After being corrected by quantum efficiency of the PD detector,the higher order contributions are less than 0.6%,which is important for calibration absolute reflectivities of multilayer and detector.