Effects of linseed oil treatment on the forward resistive plate chamber for compact muon solenoid in the high-η region

We present the beam test results of a real-sized prototype resistive plate chamber (RPC) for the high-eta region of the Compact Muon Solenoid (CMS) experiment at the Large Hadron Collider (LHC) under a high-radiation environment up to 2 kHz/cm(2). Particularly, we emphasize the effects of a linseed oil treatment on the surfaces of bakelite plates for avalanche-mode operation. The improved quality of the bakelite surface due to the linseed oil coating results in a significant reduction in the intrinsic noise rate and the dark current without affecting the muon detection efficiency. At the same time, the noise cluster size is somewhat increased by the linseed oil treatment, especially, under no radiation background.