Relative Timing Calibration of the Resolve X-Ray Microcalorimeter Onboard XRISM Using the Modulated X-Ray Source

The Resolve instrument onboard the X-Ray Imaging and Spectroscopy Mission (XRISM) hosts an x-ray microcalorimeter that consists of 36 pixels in an array operated at 50 mK. It is currently under development and will be launched in 2022. X-ray microcalorimeters are known for their high spectral resolution, but they also excel in timing resolution for the necessity of cross-correlating event signals with templates in the time domain for accurate energy derivation. Primary and redundant modulated x-ray sources (MXS) are installed in Resolve for the purpose of correcting changes in the energy scale of the microcalorimeters while minimizing additional background; each source is switched on for intervals of O (1 ms) with a duty cycle of similar to 1 %. The MXS can also be utilized for calibrating relative timing as a function of pixel, event grade, and energy. We had a week-long run in 2022 June using the flight model hardware during the spacecraft level test with several different settings. We describe the method and the result of the relative timing calibration using this data set.