# High efficiency cyclotron trap assisted positron moderator

## TL;DR

This paper presents a novel cyclotron trap assisted positron tungsten moderator that significantly improves efficiency in converting broad-spectrum positrons into mono-energetic eV beams, with potential for even higher performance.

## Contribution

It introduces a new moderator design achieving nearly 100-fold higher efficiency than previous tungsten moderators, validated by simulation and experiment.

## Key findings

- Achieved 1.8% efficiency in converting positrons to eV beams.
- Demonstrated almost two orders of magnitude improvement over previous methods.
- Simulations suggest further efficiency enhancements are possible with optimization.

## Abstract

We report the realisation of a cyclotron trap assisted positron tungsten moderator for the conversion of positrons with a broad keV- few MeV energy spectrum to a mono-energetic eV beam with an efficiency of 1.8(2)% defined as the ratio of the slow positrons divided by the $\beta^+$ activity of the radioactive source. This is an improvement of almost two orders of magnitude compared to the state of the art of tungsten moderators. The simulation validated with this measurement suggests that using an optimised setup even higher efficiencies are achievable.