# Neutron activation and prompt gamma intensity in Ar/CO$_{2}$-filled neutron detectors at the European Spallation Source

## TL;DR

This study uses Monte Carlo simulations to analyze neutron activation effects in Ar/CO₂ neutron detectors at the European Spallation Source, finding that only argon-40 activation significantly impacts the detector environment.

## Contribution

The paper presents a validated MCNP6.1 model to quantify neutron activation effects in Ar/CO₂ detectors, highlighting the limited impact of gamma emissions and argon-41 activity.

## Key findings

- $^{40}$Ar activation is the primary concern among neutron activation effects.
- Prompt gamma emissions from $^{40}$Ar neutron capture do not significantly affect background levels.
- $^{41}$Ar activity does not impact gamma dose rates around the detector.

## Abstract

Monte Carlo simulations using MCNP6.1 were performed to study the effect of neutron activation in Ar/CO$_{2}$ neutron detector counting gas. A general MCNP model was built and validated with simple analytical calculations. Simulations and calculations agree that only the $^{40}$Ar activation can have a considerable effect. It was shown that neither the prompt gamma intensity from the $^{40}$Ar neutron capture nor the produced $^{41}$Ar activity have an impact in terms of gamma dose rate around the detector and background level.