Speaker
Description
We demonstrate that a CMOS pixel sensor with a pixel size of 2.5 μm can work as a photo-electron tracking X-ray polarimeter. Although it is designed for visible light by GPixel Inc., we succeed in detecting X-ray photons with an energy res- olution of 176 eV @5.9 keV (FWHM) at room temperature. This performance is remarkable considering that conventional X-ray CCD detectors need to be cooled down to −100◦C to detect X-rays in the photon counting mode. We irradiate a polarized X-ray beam to this CMOS sensor with various rotation angles in SPring-8, the synchrotron radiation facility in Japan, to evaluate its polarimetry sensitivity. Modulation factors obtained from the number ratio of the double pixel events with different split directions are 7.63 ± 0.07% and 15.5 ± 0.4% at 12.4 keV and 24.8keV, respectively. These results show this CMOS sensor can measure X-ray polarization with the highest spatial resolution ever. We discuss possible applica- tions for future missions of this type of sensors.
| Affiliation | Osaka University |
|---|---|
| Topic | Future missions |
