The Performance of the Micro Time Projection Chamber Based on /spl mu/-PIC

We have been developing a micro-TPC (mu-TPC) based on a micro pixel chamber (mu-PIC) with a real-time readout system. The mu-PIC has micro-pixel electrodes with a pitch of 400 mum in an area of 10times10 cm². The mu-TPC has high performances for tracking charged particles and measuring their energy deposition so that there are various developing applications such as an advanced Compton camera, a neutron detector, a dark matter search detector and so on. A prototype model of the mu-TPC with a size of 10times10times8 cm with an Ar-based gas mixture was developed and its performance was evaluated. Furthermore a flight model of the mu-TPC for a balloon experiment was developed with a size of 10times10times15 cm with a Xe-based gas mixture. We carried out a balloon-borne experiment in September, 2006. The operation of mu-TPC at an altitude of 30 km was successful without any trouble and any damage.