The XRISM X-ray Mirror Assemblies

The X-ray astronomy satellite XRISM (X-Ray Imaging and Spectroscopy Mission), developed in collaboration between the United States and Japan, was launched on September 7, 2023, from the Tanegashima Space Center in Japan. Two complementary X-ray telescopes, Resolve and Xtend are onboard XRISM. Resolve is an ultra-high resolution spectrometer using an X-ray calorimeter, while Xtend has a wide field of view using an X-ray CCD camera. Both telescopes use the same type of X-ray Mirror Assembly (XMA), which is a multi-nested thin-foil optics using aluminum X-ray reflectors. The surface of the reflector is coated with replicated gold and the energy band is extended up to 12 keV. Ground calibration of these XMAs was performed at the X-ray beamline at NASA/GSFC. Their performance, including the PSF, the effective area, and the vignetting, was measured in detail before they were onboard XRISM. In this presentation, the in-orbit performance of the XMAs will be reported. The wide field of view of the Xtend make it possible to obtain a detailed PSF. The energy-dependent effective area of Xtend-XMA can also be obtained using the energy resolution of the X-ray CCD camera. The effective area of Resolve-XMA will be also measured at different energies. The PSF of Resolve-XMA will be measured in the Resolve’s 3′x3′ FoV with its 35 pixels and will be compared to the PSF obtained in the ground calibration. The aim point determination of both telescopes and the accuracy of determination will also be presented. We can verify that these performances meet the mission requirements and that the launch did not affected the performance of XMAs.