月船2号太阳X射线监测仪（XSM）与INSPIRESat-1卫星双孔径太阳X射线光谱仪（DAXSS）及GOES-16卫星X射线传感器（XRS）的交叉定标
Cross-Calibration of Chandrayaan-2 XSM with INSPIRESat-1 DAXSS and GOES-16 XRS
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中文总结 AI 辅助
本文通过将月船2号XSM的铍窗厚度修正为25微米，完成其与INSPIRESat-1卫星DAXSS及GOES-16 XRS的交叉定标，使XSM在1-8埃波段的流量测量与DAXSS吻合度达~10%内，与GOES-16 XRS中值流量差小于10%。
中文摘要 AI 辅助
太阳日冕和耀斑的X射线光谱观测可为等离子体性质提供关键诊断，对理解日冕加热和太阳爆发活动的物理过程至关重要。月船2号太阳X射线监测仪（XSM）可获取1-15 keV软X射线波段内的太阳盘积分光谱，用于建模从宁静期到强太阳耀斑期间日冕的热X射线辐射；XSM已运行约7年，始于上一个太阳活动极小期，覆盖了当前太阳活动周的极大期。INSPIRESat-1卫星搭载的双孔径太阳X射线光谱仪（DAXSS）覆盖与XSM相似的太阳X射线光谱能量范围，运行时段为2022-2026年。多台X射线仪器同时观测太阳为跨仪器测量对比提供了可能，本文开展了XSM与DAXSS及宽带X射线流量监测仪GOES-16卫星X射线传感器（XRS）的交叉定标。XSM与DAXSS的光谱对比显示，XSM低能响应存在未被解释的衰减；结合实验室测量结果，该差异源于探测器铍窗有效厚度为25微米，而非此前假设的8微米。将此修正纳入XSM校准后，两台仪器的一致性显著提升，在1-8埃波段内流量测量的吻合度优于~10%；与GOES-16 XRS在不同太阳活动水平下的测量对比进一步验证了一致性，其中值流量差小于10%。
英文摘要
X-ray spectroscopic observations of the solar corona and flares provide crucial diagnostics of plasma properties and are essential for understanding the physical processes responsible for coronal heating and solar eruptive activity. The Chandrayaan-2 Solar X-ray Monitor (XSM) provides disk-integrated spectra of the Sun in the 1--15~keV soft X-ray band, enabling modeling of the thermal X-ray emission from the corona across quiet phases to intense solar flares. XSM has been operational for about seven years, starting from the last solar minimum and covering the maximum of the current Solar Cycle. The Dual-zone Aperture X-ray Solar Spectrometer (DAXSS) instrument on board INSPIRESat-1 covers the solar X-ray spectra in a similar energy range as XSM and was operational during 2022--2026. With multiple instruments simultaneously observing the Sun in X-rays, there is scope to compare measurements across instruments. Here, we present the cross-calibration of XSM with DAXSS and a broadband X-ray flux monitor, the GOES-16 X-ray Sensor (XRS). Comparisons of XSM and DAXSS spectra reveal an unaccounted attenuation in the XSM low-energy response. Supported by laboratory measurements, we attribute this difference to the effective detector beryllium window thickness being 25 microns rather than the previously assumed 8 microns. Incorporating this revision into the XSM calibration significantly improves the agreement between the two instruments, with flux measurements agreeing within ~10% in the 1--8 Angstrom band. Comparison with GOES-16 XRS measurements over a broad range of solar activity levels further demonstrates consistency, with a median flux difference of less than 10%.
