Initial operations of the Soft X-ray Imager onboard XRISM

XRISM (X-Ray Imaging and Spectroscopy Mission) is an astronomical satellite launched successfully on September 7th, 2023 (JST). One of the mission instruments, SXI (Soft X-ray Imager) consists of CCDs, analog and digital electronics, and a mechanical cooler and cooler driver. During the initial operation phase, we verified our operation procedure, stability of the cooling system, performance of all the observation options with different imaging areas and/or timing resolutions, and operations for protection against South Atlantic Anomaly and day-earth occultation. We optimized the operation procedure and observation parameters including the cooler power, imaging areas for specific modes with high timing resolutions, and X-ray-event selection algorithm. In this presentation, we summarize our policy and procedure of the initial operations of the SXI. We also report on a couple of unexpected issues we faced during the initial operations and how we dealt with them.