Aging Studies of Large Area Proportional Chambers under High-Rate Irradiation with $CF_4$-based Mixtures (Part 2)

TL;DR

This study investigates the aging effects on large-area proportional chambers under high-rate irradiation with various $CF_4$-based gas mixtures, providing insights for their use in high-radiation environments like HERA-B and LHC.

Contribution

It presents new experimental data on aging of proportional chambers with different gas mixtures under high-rate irradiation, highlighting factors influencing aging.

Findings

Aging rate depends on total charge and irradiation mode.

Different gas mixtures show varying aging behaviors.

Results inform design of large-area detectors for high-rate environments.

Abstract

Experimental conditions at the HERA-B experiment impose very strong requirements for gaseous detectors. The charged particle fluxes through the HERA-B tracking system, varying with the radial distance R from the beam line, are about $2 \times 10^{7}/R^{2}$ particles per second, and comparable to those that will be encountered by LHC experiments. The severe radiation environment of the HERA-B experiment leads to a maximum charge deposit on a wire, within the muon detector, of 200 mC/cm per year. We report recent results of aging studies performed by irradiating proportional wire chambers filled with $Ar/CF_4/CH_4$ (74:20:6), $Ar/CF_4/CH_4$ (67:30:3), $Ar/CF_4/CO_2$ (65:30:5), $Ar/CF_4$ (70:30), $CF_4/CH_4$ (90:10), $CF_4/CH_4$ (80:20) mixtures in a three different experimental setups. The size of the irradiation zone varied in the tests from 1 cm up to 500 cm. Our experience shows that the aging rate depends not only on the total collected charge, but, in addition, on the mode of operation and area of irradiation. The possible application of these results to the construction of a large area gaseous detectors for operation in high rate environments is presented.