Ion counting efficiencies at the IGISOL facility

TL;DR

This study uses simulations to analyze how different properties of fission fragments and experimental parameters affect ion stopping efficiency at the IGISOL facility, aiming to optimize detection performance.

Contribution

It provides a detailed simulation-based analysis of how fragment properties and experimental conditions influence ion stopping efficiency, offering insights for optimization.

Findings

Heavy fragments are stopped about 9% less efficiently than light fragments.

U, Ni, and He gas properties significantly influence stopping efficiency.

Efficiency variation depends on fragment properties and experimental parameters.

Abstract

At the IGISOL-JYFLTRAP facility, fission mass yields can be studied at high precision. Fission fragments from a U target are passing through a Ni foil and entering a gas filled chamber. The collected fragments are guided through a mass separator to a Penning trap where their masses are identified. This simulation work focuses on how different fission fragment properties (mass, charge and energy) affect the stopping efficiency in the gas cell. In addition, different experimental parameters are varied (e. g. U and Ni thickness and He gas pressure) to study their impact on the stopping efficiency. The simulations were performed using the Geant4 package and the SRIM code. The main results suggest a small variation in the stopping efficiency as a function of mass, charge and kinetic energy. It is predicted that heavy fragments are stopped about 9% less efficiently than the light fragments. However it was found that the properties of the U, Ni and the He gas influences this behavior. Hence it could be possible to optimize the efficiency.