Two dimensional localization of electrons and positrons under high counting rate

The construction of two wire chambers for high counting rate application is reported. Each chamber includes three wire planes – one anode and two orthogonal cathodes – in which the wires operate as independent proportional counters. One of the chambers is rotated with respect to the other, so that four position coordinates may be encoded for a charged particle crossing both chambers. Spatial resolution is determined by the wire pitch: 1 mm for cathodes, 2 mm for anodes. 320 electronic channels are involved in the detection system readout. Global counting rates in excess of 107 events per second have been measured, while the average electron–positron beam intensity may be as high as 3×107 events per second.