Detection of photoabsorption point with capillary imaging gas proportional counter

We have successfully detected the images of photoelectron tracks of 2.7 keV and 5.9 keV X-rays utilizing a Capillary Imaging Gas Proportional Counter (CIGC). This is an important technique to detect X-ray polarization employing photoelectron track. The images of the tracks contain at most two clusters composed of pixels for 2.7 keV photoelectron and 5.9 keV X-ray, respectively. The images of the events were extracted with systematic analysis based on clustering of the tracks removing the spurious noise cluster due to I.I. CCD. The extent of the cluster spreading was approximately 1.2 mm on average for 5.9 keV X-ray. The light yield was distributed at 95% FWHM around a peak for 5.9 keV X-ray. The light yield and the extent of the clusters for 2.7 keV photoelectrons were approximately a half of them for 5.9 keV, respectively. Therefore, the result encourages us to detect the photoabsorption point due to X-ray above 10 keV