# Beam induced space-charge effects in Time Projection Chambers in low-energy nuclear physics experiments

## TL;DR

This paper investigates how beam-induced space-charge effects from primary ionization in low-energy nuclear physics experiments affect the drift field homogeneity in Time Projection Chambers, emphasizing the importance of gas property optimization.

## Contribution

It provides the first detailed analysis of primary ionization induced space-charge effects in TPCs for low-energy nuclear physics, supported by electron transport simulations.

## Key findings

- Beam-induced space-charge effects cause drift field distortions.
- Gas property optimization is crucial to mitigate space-charge effects.
- Track distortion impacts tracking algorithm performance.

## Abstract

Tracking capabilities in Time Projection Chambers (TPCs) are strongly dictated by the homogeneity of the drift field. Ion back-flow in various gas detectors, mainly induced by the secondary ionization processes during amplification, has long been known as a source of drift field distortion. Here, we report on beam-induced space-charge effects from the primary ionization process in the drift region in low-energy nuclear physics experiment with Active Target Time Projection Chamber (AT-TPC). A qualitative explanation of the observed effects is provided using detailed electron transport simulations. As ion mobility is a crucial factor in the space-charge effects, the need for a careful optimization of gas properties is highlighted. The impact of track distortion on tracking algorithm performance is also discussed.