Study the effect of humidity on the RPC performance

The effect of water vapor on the performance of a resistive plate chamber (RPC) has been studied by simulating the dependency of avalanche multiplication on the amount of humidity in the RPC gas mixture. Also, the change of plates’ resistivity with humidity has been considered in the simulation. The results of simulation show that at the room temperature, the addition of water vapor to the gas mixture even up to 100% relative humidity (RH), has no practical influence on the avalanche multiplication process inside the RPC gap. The humidity effect on the avalanche multiplication appears for high-temperature operation where the induced signal increases with humidifying the gas mixture. The simulation was also performed for high-particles flux densities and the results show that the degradation of plates’ resistivity with humidity improves the efficiency as well as rate capability of the detector in agreement with experimental reports.