Simulation of the measurement by primary cluster counting of the energy lost by a relativistic ionizing particle in argon

Abstract

Energy loss of charged particles in a gas has been estimated by a computer simulation technique with a view of studying primary cluster counting as a mean of the particle identification. Primary electron yield and secondary multiplication have been estimated through a detailed calculation of the atomic processes. Results are presented for pure argon in terms of cluster size distributions and relativistic rise of the number of clusters: the latter reaches a plateau at a γ of 200 and of level of 1.32 times minimum ionization. Limitations to detector resolution due to electronic dead time and longitudinal diffusion of the electrons drifting in the gas are presented. Such limitations are introduced in a comparison between the performance in particle separation of detectors based on energy loss, making use of pulse height measurement or cluster counting.