Performance of a time-projection chamber with a large-area micro-pixel-chamber readout

A micro-time-projection chamber (micro-TPC) with a detection volume of 23×28×31 cm3 was developed, and its fundamental performance was examined. The micro-TPC consists of a micro-pixel chamber with a detection area of 31×31 cm2 as a two-dimensional imaging device and a gas electron multiplier (GEM) with an effective area of 23×28 cm2 as a pre-gas-multiplier. The micro-TPC was operated at a gas gain of 50,000, and energy resolutions and spatial resolutions were measured.