A high-pressure hydrogen time projection chamber for the MuCap experiment

Abstract

The MuCap experiment at the Paul Scherrer Institute performed a high-precision measurement of the rate of the basic electroweak process of nuclear muon capture by the proton, ${\mu }^{-}+p\to n+{\nu }_{\mu }$. The experimental approach was based on the use of a time projection chamber (TPC) that operated in pure hydrogen gas at a pressure of 10 bar and functioned as an active muon stopping target. The TPC detected the tracks of individual muon arrivals in three dimensions, while the trajectories of outgoing decay (Michel) electrons were measured by two surrounding wire chambers and a plastic scintillation hodoscope. The muon and electron detectors together enabled a precise measurement of the $\mu p$ atom's lifetime, from which the nuclear muon capture rate was deduced. The TPC was also used to monitor the purity of the hydrogen gas by detecting the nuclear recoils that follow muon capture by elemental impurities. This paper describes the TPC design and performance in detail.

15 pages, 13 figures, to be submitted to Eur. Phys. J. A; clarified section 3.1.2 and made minor stylistic corrections for Eur. Phys. J. A requirements

References in corpus (5)

• Measurement of the Rate of Muon Capture in Hydrogen Gas and Determination of the Proton's Pseudoscalar Coupling $g_P$
• Measurement of Muon Capture on the Proton to 1% Precision and Determination of the Pseudoscalar Coupling g_P
• Electroweak Radiative Corrections to Muon Capture
• Simulation of Three Dimensional Electrostatic Field Configuration in Wire Chambers : A Novel Approach
• A Circulating Hydrogen Ultra-High Purification System for the MuCap Experiment

Cited by in corpus (2)

• Measurement of the Formation Rate of Muonic Hydrogen Molecules
• HydroX, a light dark matter search with hydrogen-doped liquid xenon time projection chambers