Source Position Determination Method Of Multiplexing Lobster-Eye Optics

The source position determination method of the multiplexing lobster-eye optics (MuLE), which is a newly proposed configuration of the Lobster-Eye (LE) optics to reduce the number of focal plane detectors significantly, was developed. In the MuLE configuration, X-rays came from different field-of-views (FoVs) were focused on a single imager. To separate the multiplexed FoVs, the optics was designed so that cross-like responses of LE mirror in different FoVs had different azimuthal rotation angles. In this paper, we show the method to determine the rotation angles and verify the FoV discrimination power by using a ray tracing simulation. The configuration we assumed in the simulation was nine multiplexed FoVs projecting onto a single imager (nine-segment MuLE optics) with a 30 cm focal length and a 9x9 cm(2) effective area of each LE segment. One LE segment covers 9.6 degrees x 9.6 degrees FoV and the total FoV of the nine-segment MuLE configuration was 9 times of that. Our method provided 100% correct FoV discrimination at the 5 sigma detection limit flux (35-70 mCrab) for a transient source with a duration of 100 s except for the edge of the FoV.