Quenching factor for heavy ions in liquid argon

A few years ago, Hitachi, Doke and Mozumder (1992) estimated "quenching factors" for scintillation yield produced by various heavy ions in liquid argon. However, these quenching factors could not clearly explain our new experimental results obtained by an allene-doped liquid argon calorimeter with multi-parallel plate electrodes for 650 MeV/n Ni ions, including the data of various low energy fragments. We found that the quenching factor of the new results can be expressed by 1.4 QF/sub HDM//sup 2/, where QF/sub HDM/ is the quenching factor estimated by Hitachi et al. This new "quenching factor" is considered as that including the charge collection efficiency for high energy density along the heavy ion tracks.