Measurement of Fusion Neutrons and Capture Neutrons From Muon Stops in Deuterium for MuSun

The MuSun experiment at PSI will determine the $\mu^-$ capture rate in ultra-pure deuterium gas, $\Lambda_d$, to a precision of 1.5\% by measuring the time distribution of decay electrons. MuSun uses an array of eight liquid scintillator detectors to detect neutrons. Muons in deuterium produce neutrons by two processes: muon capture, $\mu + d \rightarrow n + n + \nu_\mu$, and muon catalyzed fusion, $dd \mu \rightarrow {}^{3}He + n + \mu$. Furthermore, neutrons from high-Z captures indicate the occurrence of muon stops in either gas impurities or chamber walls and may be used as a quality check. I will discuss particle identification and discrimination, as well as what may be inferred about $\mu d$ atomic kinetic parameters.