Performances of linseed oil-free bakelite RPC prototypes with cosmic ray muons

TL;DR

This study compares the performance of bakelite RPC prototypes made from different Indian grades of bakelite, demonstrating that a specific grade with silicone coating achieves stable high efficiency over extended periods using cosmic ray muons.

Contribution

It presents a comparative analysis of bakelite RPCs with different grades, highlighting the importance of silicone coating for stable operation in cosmic ray detection.

Findings

Bakelite grade P-120 yields >96% efficiency for over 130 days.

Silicone coating on inner surfaces is essential for stable operation.

RPCs operated in streamer mode with specified gas mixture.

Abstract

A comparative study has been performed on Resistive Plate Chambers (RPC) made of two different grades of bakelite paper laminates, produced and commercially available in India. The chambers, operated in the streamer mode using argon, tetrafluroethane and isobutane in 34:59:7 mixing ratio, are tested for the efficiency and the stability with cosmic rays. A particular grade of bakelite (P-120, NEMA LI-1989 Grade XXX), used for high voltage insulation in humid conditions, was found to give satisfactory performance with stable efficiency of > 96% continuously for more than 130 days. A thin coating of silicone fluid on the inner surfaces of the bakelite RPC is found to be necessary for operation of the detector.