An Innovative 2-Dimension Grating for Solar Soft X-ray and EUV Spectrometer

The solar X-EUV irradiance is a dominant energy source inputting to the Earth’s upper atmosphere from the outer space. Variability of the solar X-EUV irradiance drives disturbance of the ionosphere, thermosphere and density of the upper atmosphere. Accurate measurement of the solar X-EUV spectra is essential to learn how the solar activities change the Earth’s upper atmosphere vertically and globally, and further impacts to the global space weather or ever the global weather changes. Since the solar X-EUV spectra coming from the super-hot coronal plasma is composited with rich emission lines and continuum, higher-order diffractions introduced by a traditional grating make spectral data severely contaminated in the X-EUV region. It greatly challenges precise measurement of the solar X-EUV irradiance. In this paper we propose an innovative 2-dimension grating designed in a pattern of zigzag or photon sieve, to be used for future solar X-EUV spectrometers that could have capability to deeply suppress higher-order diffractions, whose magnitude is deeply suppressed to be four orders lower comparing to that measured by a traditional instrument based on black-white grating.