# Modelling radiation damage to pixel sensors in the ATLAS detector

## TL;DR

This paper develops a detailed digitization model to simulate radiation damage effects in ATLAS pixel sensors, validated against collision data, to improve understanding of sensor performance under high radiation.

## Contribution

It introduces a novel digitization model that incorporates radiation damage effects, validated with real collision data for the first time.

## Key findings

- Model accurately predicts charge collection efficiency.
- Model reproduces Lorentz angle variations.
- Validated against data up to $10^{15}$ 1 MeV ${n}_{eq}/{cm}^2$.

## Abstract

Silicon pixel detectors are at the core of the current and planned upgrade of the ATLAS experiment at the LHC. Given their close proximity to the interaction point, these detectors will be exposed to an unprecedented amount of radiation over their lifetime. The current pixel detector will receive damage from non-ionizing radiation in excess of $10^{15}$ 1 MeV ${n}_{eq}/{cm}^2$, while the pixel detector designed for the high-luminosity LHC must cope with an order of magnitude larger fluence. This paper presents a digitization model incorporating effects of radiation damage to the pixel sensors. The model is described in detail and predictions for the charge collection efficiency and Lorentz angle are compared with collision data collected between 2015 and 2017 ($\leq 10^{15}$ 1 MeV ${n}_{eq}/{cm}^2$).