Xtend is a soft X-ray imaging telescope developed for the X-Ray Imaging and Spectroscopy Mission (XRISM). XRISM is scheduled to be launched in the Japanese fiscal year 2022. Xtend consists of the Soft X-ray Imager (SXI), an X-ray CCD camera, and the X-ray Mirror Assembly (XMA), a thin-foil-nested conically approximated Wolter-I optics. The SXI uses the P-channel, back-illuminated type CCD with an imaging area size of 31 mm on a side. The four CCD chips are arranged in a 2$\times$2 grid and can be cooled down to $-120$ $^{\circ}$C with a single-stage Stirling cooler. The XMA nests thin aluminum foils coated with gold in a confocal way with an outer diameter of 45~cm. A pre-collimator is installed in front of the X-ray mirror for the reduction of the stray light. Combining the SXI and XMA with a focal length of 5.6m, a field of view of $38^{\prime}\times38^{\prime}$ over the energy range from 0.4 to 13 keV is realized. We have completed the fabrication of the flight model of both SXI and XMA. The performance verification has been successfully conducted in a series of sub-system level tests. We also carried out on-ground calibration measurements and the data analysis is ongoing.
Pile-up simulator for XRISM/Xtend onboard the X-ray Imaging and Spectroscopy Mission (XRISM)
Japan Aerospace Exploration Agency, Institute of Space and Astronautical Science（日本宇宙航空研究开发机构 宇宙科学研究所）；Osaka University, Department of Earth and Space Science（大阪大学 地球行星科学系）；University of Tokyo, School of Science（东京大学 理学部）；Tohoku Gakuin University, Faculty of Informatics（东北学院大学 情报学部）；University of Miyazaki, Faculty of Engineering（宫崎大学 工学部）；Saitama University, Graduate School of Science and Engineering（埼玉大学 理工学研究科）；Nara University of Education, Faculty of Education（奈良教育大学 教育学部）；Hiroshima University, School of Science（广岛大学 理学部）
