Speaker
Description
The Laser Interferometer Space Antenna (LISA) will be the first space-based gravitational-wave observatory sensitive in the 0.1 mHz-1 Hz band. Background radiation can limit LISA sensitivity at the lower frequencies. To monitor and characterize this environment, a compact Radiation Monitor (RM) has been developed for the LISA mission. The RM is designed to measure the integral cosmic-ray proton flux with a statistical precision of about 1% in approximately one hour, while satisfying strict constraints on mass, volume, and power consumption. The detector is based on plastic scintillators read out by silicon photomultipliers, combined with tungsten absorbers and copper shielding to reject low-energy protons. Signal processing is performed using a low-power ASIC, custom developed for space applications. An FPGA controls the ASIC, the trigger logic and processes the digitized data. The flux and energy information is obtained from the coincidence counts for the four scintillators. We evaluated the performance of the RM, assessed through Monte Carlo simulations and dedicated experiments performed with a proton beam at TRIUMF (up to 480 MeV) and 160 GeV/c muons at SPS (CERN). We will present results of the detector acceptance, angular response and discuss the capabilities for spectrum and direction reconstruction.