Initial Tests Of The Pion Beta Decay Detector - 3.3.3 Multi-wire proportional chambers

3.3.3 Multi-wire proportional chambers

The pibeta detector will incorporate two cylindrically shaped multi-wire proportional chambers (MWPCs) to obtain accurate position information for particles passing between the target and the CsI calorimeter. This will be most useful in identifying

Figure 3.9: CsI crystals, half-length plastic veto, target, degrader, target veto from 1996 GEANT simulation

accidental coincidences occurring when two muons decay simultaneously in the target. These coincidences might otherwise be misinterpreted as p -> e n events which would compromise the accuracy of the normalization used in the pion beta decay measurement. The wires are located at a radius of 60.15mm (120.1mm) for the inner (outer) chamber from the beam axis. They both have wire spacings of 1.96 mm and have a resolution of 0.2 mm.