A new generation γ-ray camera for planetary science applications: High pressure xenon time projection chamber

A new γ-ray imaging camera based on High-pressure Xe Time-Projection-Chamber (HPXe-TPC) allows us to simultaneously determine arrival direction and its energy of individual incident γ rays. HPXe-TPC is a promising γ-ray detector for planetary science which provides means of global mapping of elemental composition in planetary surface as the remote sensing spectrometer. The simulation study by Geant4 and numerical calculation show that the angular resolution is mostly affected by multiple scattering of the recoil electron, and position resolution of electrodes of TPC. It is found that the angular resolution is 9° (50%) at 2 MeV for γ rays. The feasibility of HPXe-TPC is discussed as a γ-ray imaging camera for future planetary mission.