成像光谱仪辐射测量一致性校正中插值方法选择

谱线弯曲破坏了色散型成像光谱仪光谱辐射能量采集的一致性,采用插值的办法对系统采集到的辐射能量数据依据无偏离波长定标数据重新采样,可以提高光谱辐射测量的一致性。选择恰当的插值采样方法尤为重要,直接影响校正后辐射能量偏差的剩余量,决定了校正效果的好坏。采用常用的线性、三点二次多项式、四点三次Lagrange、五点四次Lagrange、三次Hermite和三次样条插值方法对存在光谱偏离的像元采集到的辐射能量数据进行重新采样,比较采样后辐射能量剩余偏差,结果表明:四点三次Lagrange插值和三次样条插值的校正效果明显好于其他四种方法。对于系统光谱偏离量10%Δλ(Δλ=5 nm),辐射能量归一化偏差PV=0.06,插值校正后PV<0.022,采用其他四种方法校正后PV均大于0.035。另外,光谱分辨率较低时(Δλ>5 nm),四点三次Lagrange插值略优;光谱分辨率较高时(Δλ<5 nm),三次样条插值略优。

The Effects of Spherical Surface and Laser Polarization on the Photodetachment Cross Section of H^-

We report the combined effects of laser polarization and curvature of the spherical surface on the detached electron spectra from H-. The Theoretical imaging method is used as a tool of investigation. The photodetachment cross sections for various polaxization angles, radii of curvatures and inter ion surface distances axe displayed. The analysis of the spectra reveals that the laser polarization angle θL, curvature of the surface τc and inter ion surface distance d strongly affect oscillations in the spectra. Therefore, a fine control on the laser polaxization and that of curvature in the surface can be used to control oscillations in the photodetachment of negative ions.