A high-voltage test for the ATLAS RPC qualification

The RPC production sequence for the ATLAS experiment includes a specific test of current absorption at the operating point, which concerns the RPC “gas volumes”, namely the bare detectors not yet assembled with the read-out panels and the mechanical support structures. The test, which is carried out at the production site, consists of two phases. The gas volumes are initially conditioned with pure argon, keeping the voltage constant just above the breakdown value of about 2 kV. The final test, performed after the volumes have undergone inner surface varnishing with linseed oil, is based on the measurement of the current–voltage characteristics with the binary operating gas, C 2 H 2 F 4 / i - C 4 H 10 = 95 / 5 . The results presented here concern 45% of the total foreseen production.