The MAPP Detector

The MAPP detector, depicted in the Figure below, is deployed in in the UA83 gallery consists of 400 scintillator bars of size 10 cm x 10 cm x 75 cm each of which is readout by a 3-inch low noise PMT. The bars are arranged in 4 equal sectors, each of size roughly 1m². Thus, for example, a milli-charged particle produced at IP8 would pass through 3m of scintillator readout by 4 PMTs in coincidence. MoEDAL’s threshold for detection is 10^-3e The MAPP-mQP detector is hermetically encased in a scintillator veto layer. The veto layer consists of scintillator tiles of size 25cm x 25cm and thickness 1cm. We will readout the tiles using 2 embedded wavelength shifting bres (WLS) of diameter 1mm readout by a SiPM (KETEK PM3225WB 3 x 3 mm²). We can monitor the performance of the CR veto system of the MAPP-mCP detector during data-taking and also when the beam is off. In the event that more VETO power is required we can utilize the outer layer of 10 cm x 10cm scintillator bars as an additional VETO layer. As we have a software trigger we can change existing VETO conditions and if necessary implement the extra VETO power offline using the recorded data.