Speaker
Description
Ionization chambers are widely used for particle identification of heavy ions
through energy-deposit measurements. In the TRIP-S3CAN 2025 experimental
campaign at the RIBF facility at RIKEN, four ionization chambers were used to
determine the atomic number Z by measuring energy deposition in gas for a wide
range of heavy ions. Previous performance studies suggested that the Z resolution
can be affected by charge-state fluctuations within the ionization chambers and
motivating further investigation on charge-state fluctuations is needed. Therefore, in this study, we investigate the effects of charge-state fluctuations
using Geant4 simulations. We focus on their effects on δ-ray production and
energy-deposit straggling and evaluate how these processes affect energy-deposit
resolution. By comparing experimental data from our previous measurements with
simulation results, we aim to clarify how charge-state fluctuations and δ-ray
production influence the energy-deposit and its fluctuations in ionization chambers. Preliminary results show that the Geant4 simulations incorporating charge-state
fluctuations reproduce the degradation of the energy-deposit resolution observed in
our previous experimental data. This agreement suggests that charge-state
fluctuations play an important role in determining the energy-deposit resolution of
ionization chambers.