Ionisation quenching factors from W-values in pure gases for rare event searches

Abstract

The effect of ionisation quenching for ions is critical for experiments relying on the measurement of low energy recoils, such as direct Dark Matter searches. We present ionisation quenching factor estimates over a range of energies for protons, α-particles, and heavier ions in H2, CH4, N2, Ar, CO2, and C3H8 gases, estimated from the respective reference W-value measurements. The resulting ionisation quenching factors are compared with predictions from SRIM.