LDMX Trigger Scintillator system

      New theoretical developments have motivated “hidden sector” dark matter with mass below the proton mass. The Light Dark Matter Experiment (LDMX) will use an electron beam to produce dark matter in fixed-target collisions. A low current, high repetition rate (37.2MHz) electron beam extracted from SLAC’s LCLS-II will provide LDMX with sufficient luminosity to explore many dark matter candidates. Using a novel detector design, LDMX is expected to definitively search for thermal relic dark matter with masses between 1 MeV and several hundred MeV.

      A missing energy trigger will be used to identify the signal events. Such a trigger requires precise knowledge of the number of incoming electrons. The LDMX trigger scintillator system will use an array of fast scintillators and SiPMs to count the number of electrons.

      A strategy for the missing energy trigger will be described. An overview of the LDMX trigger scintillators and the recent developments in the detector commissioning will be presented.