Performance of the CAT-TPC based on two-dimensional readout strips

A gas detector 140 × 140 × 140 mm 3 in size, termed the compact active target time projection chamber (CAT-TPC), was developed in this study to measure resonant scattering associated with cluster structures in unstable nuclei. The CAT-TPC consists of an electronic field cage, double-thick gas-electron-multiplier foils, a general-purpose digital data acquisition system, and a newly developed two-dimensional strip-readout structure. The CAT-TPC was operated using a 4 He (96%) + CO 2 (4%) gas mixture at 400 mbar. The working gas also serves as an active target for tracking charged particles. The overall performance of the CAT-TPC was evaluated using a collimated α -particle source. A time resolution of less than 20 ns and a position resolution of less than 0.2 mm were observed along the electron drift direction. Three-dimensional images of incident trajectories and scattering events can be clearly reconstructed under an angular resolution of approximately 0.45 degree.