The 10 bar hydrogen time projection chamber of the MuCap experiment

The experimental goal of the MuCap experiment at the Paul Scherrer Institute (PSI) is a high-precision measurement of the singlet capture rate of the nuclear muon capture on the free proton in the reaction μ − + p → n + ν μ . The measuring principle is a lifetime measurement whereas the experimental approach is based on a specially developed Time Projection Chamber (TPC) operating with ultra-pure and deuterium-depleted hydrogen gas at a pressure of 10 bar. The TPC acts as an active muon stop detector and the 10 bar hydrogen operates as target and detector. Design, construction and operation of the Time Projection Chamber are presented.