Design and Development of a Cryogenic Preamplifier for the MuSun Experiment

The MuSun Collaboration is working to measure the rate of muon capture on the deuteron with high precision. A pad plane TPC filled with cryogenic deuterium gas detects muons and nuclear recoils. In previous experimental runs the preamplifiers for the TPC were located outside its vacuum chamber at a distance of 80 cm. This additional cable added interference, capacitance and noise, which decreased the energy resolution. A design for a preamplifier was developed that could be placed inside the vacuum at low temperatures. Components for the preamplifier were tested and characterized, and a prototype was constructed. Measurements of energy resolution as a function of detector capacitance are in progress, and they will be presented along with the design of the preamplifier.