  A novel gaseous two-dimensional imaging detector "Micro Pixel Chamber
(micro-PIC)" has been developed. This detector is based on double sided printed
circuit board (PCB). We have developed large area (10cm x 10cm) micro-PICs with
65536 pixel anodes of 400um pitch on a 100um thick insulating substrate.
Achieved energy resolution was 30% (FWHM) at 5.9keV, and a gas gain of 7000 was
obtained with argon ethane (8:2) gas mixture. This gain is high enough to
detect minimum ionizing particles with such a small electrode pitch. Although
several discharges occurred during 65 hours continuous operation, the detectors
have kept stable operation with high gain. The micro-PIC is a useful detector
for many applications e.g. X-ray, gamma ray, and charged particle imaging. The
micro electrode structure allows us to measure directions of primary electrons
due to incident X-rays or gamma rays, which provide a strong method for X-ray
polarimetry and gamma-ray imaging.
