Long Term Performance Studies of Large Oil-Free Bakelite Resistive Plate Chamber

TL;DR

This study evaluates the long-term stability and performance of a large, oil-free bakelite resistive plate chamber over more than a year, demonstrating consistent efficiency, low noise, and stable operational parameters for high-energy physics applications.

Contribution

It provides comprehensive long-term performance data of a large oil-free bakelite RPC, highlighting its stability and suitability for large-scale physics experiments.

Findings

Efficiency remained above 95% throughout the testing period.

Time resolution was consistently around 0.83 ns.

Operational parameters like leakage current and noise rate remained stable.

Abstract

Several high energy physics and neutrino physics experiments worldwide require large-size RPCs to cover wide acceptances. The muon tracking systems in the Iron calorimeter (ICAL) in the INO experiment, India and the near detector in DUNE at Fermilab are two such examples. A (240 cm $\times$ 120 cm $\times$ 0.2 cm) bakelite RPC has been built and tested at Variable Energy Cyclotron Centre, Kolkata, using indigenous materials procured from the local market. No additional lubricant, like oil has been used on the electrode surfaces for smoothening. The chamber is in operation for $>$ 365 days. We have tested the chamber for its long term operation. The leakage current, bulk resistivity, efficiency, noise rate and time resolution of the chamber have been found to be quite stable during the testing peroid. It showed an efficiency $>$ 95$\%$ with an average time resolution of $\sim$0.83 ns at the point of measurement at 9000 V throughout the testing period. Details of the long term performance of the chamber have been discussed.