Analog read - out of the RPCs in the ARGO - YBJ experi - ment

The ARGO-YBJ experiment, currently under construction at the Yang-baijing Laboratory (4300 m a.s.l.), consists of a single layer of ∼ 2000 Resistive Plate Chambers (RPCs) for a total instrumented area of ∼ 6700 m 2. The digital read-out, performed by means of pickup electrodes 6.7 × 62 cm 2 ('strips'), allows one to measure the particle number of small size showers. To extend the size range up to the knee region it is necessary to implement the charge read-out of the detector chambers. In order to achieve this goal each RPC has been instru-mented with two large size pads of dimensions 140× 125 cm 2. In this paper the performance of the prototype circuit devoted to the charge read-out is reported.