Speaker
Description
Usual RPC readout is made with long strips a few centimeters wide which behave like signal transmission lines of quite good quality that inject the signal in the front-end electronics circuit located at the strips ends. We present here an alternative readout made with 40x40 cm2 square pads which strongly reduce the number of channels required to cover large sensitive areas.
The signal pickup point, which is located at the center of the pad, reduces the signal path length to the front-end electronics and strongly improves the external noise shielding. We show here that, despite large pad capacitance, charge signals as low as 300 fC can easily be detected by front-end electronics and the typical time resolution of a 2mm gas gap RPC is preserved. We present here a full test of a chamber 80x280 cm2 equipped with 16 readout pads and powered by a DC-DC high voltage supply integrated on the chamber Faraday cage. The test results show time resolution, detection efficiency, cluster size, external noise and spontaneous sparking as a function of high voltage and front-end electronic threshold.