Development of linseed oil-free bakelite resistive plate chambers

TL;DR

This paper reports on the development and testing of bakelite resistive plate chambers made from a specific Indian-grade bakelite, exploring the effects of silicone coating and surface finish on their performance in cosmic ray detection.

Contribution

It introduces a new bakelite grade for RPCs and compares performance with and without silicone coating, highlighting improvements with better surface finish.

Findings

Silicone coating ensures >90% efficiency over time.

Better surface finish allows operation without silicone coating.

RPCs show stable performance in cosmic ray detection.

Abstract

In this paper we would like to present a few characteristics of the Resistive Plate Chambers (RPC) made of a particular grade of bakelite paper laminates (P-120, NEMA LI-1989 Grade XXX), produced and commercially available in India. This particular grade is used for high voltage insulation in humid conditions. The chambers are tested with cosmic rays in the streamer mode using argon, tetrafluroethane and isobutane in 34:59:7 mixing ratio. In the first set of detectors made with such grade, a thin coating of silicone fluid on the inner surfaces of the bakelite was found to be necessary for operation of the detector. Those silicone coated RPCs were found to give satisfactory performance with stable efficiency of >90% continuously for a long period as reported earlier. Results of the crosstalk measurement of these silicone coated RPC will be presented in this paper. Very recently RPCs made with the same grade of bakelite but having better surface finish, are found to give equivalent performance even without any coating inside. Preliminary results of this type of RPCs are also being presented.