Photoelectron track image of capillary gas proportional counter

The segmented pixel gas detector has been developed with an optical imaging capillary gas proportional counter (CGPC) to obtain an image of an X-ray photoelectron track. The pixel signal is read out with an image-intensified CCD camera combined with the CGPC through the optical system of mirrors. Using the optical imaging CGPC with a penning gas mixture of Ar+8% CH4+2% TMA at 1 atm, we have successfully detected clear images of photoelectron tracks for 22 keV X-rays. The detection efficiency of the photoelectron track was approximately 95% for the images. The evaluated range of 5.2 mm for 22 keV X-ray photoelectron was consistent to the published ranges. The optical imaging CGPC with the high-resolution capability is available for an imaging type of X-ray polarimeter and for the field of medical science.