Study on the performance of a resistive Micromegas in a controlled O2 environment

Abstract

Abstract Being the state of the art, the Micro-Pattern Gaseous Detectors (MPGD) are widely accepted in almost every particle collider experiment. Micromegas is a type of MPGD which is famous for its simple single-stage amplification, high and stable gain, low ion feedback, and excellent spatial and temporal resolutions. The chance of O2 contamination in a gaseous detector is not negligible as the abundance of O2 in air is nearly 21%. Contamination of detector-gas by O2 may occur due to insufficient gas-tightness or the use of long plastic pipes. Being an electronegative gas, O2 attach with the electrons inside a gaseous detector and influence the performance. The concern is higher when the detector has a large scale extension. We are reporting our measurements on the diffusion of O2 through a couple of commonly used plastic pipes. Then, in a hermetic gas system, by infusing O2 in a controlled and precise way, we have measured the effects of O2 on the performance of a resistive Micromegas. In pure Ar-CO2 mixture, we have also compared the gas-gain of the Micromegas with simulation to better estimate the gas-gap. The effects of temperature and pressure fluctuations on our study have also been investigated.