Preliminary test of topmetal-II- sensor for X-ray polarization measurements

摘要

We present the assembly and preliminary results of a prototype detector, which was developed to evaluate the performance of the Topmetal-II- for application in Soft X-ray Polarimeter (SXP). SXP is used to measure the polarization of X-rays emitted from randomly occurring gamma-ray bursts (GRBs) and other specific dense celestial bodies. The Topmetal-II- is a silicon pixel sensor designed to directly track charged particles. The test was conducted on a gas mixture of Ne and DME at 0.8 atm pressure, and the Topmetal-II- sensor was used to image the photoelectron tracks. Typical real X-ray tracks obtained under four conditions are presented in this paper. The modulation factor derived from the tracks of 100% polarized 4.5 keV X-rays reached similar to 29% at similar to 53% signal efficiency, with a residual modulation of the order of similar to 2% for unpolarized 5.9 keV X-rays.

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