Far-ultraviolet signatures of the 3He(n,tp) reaction in noble gas mixtures

TL;DR

This study demonstrates that adding noble gases to 3He cells amplifies far-ultraviolet signals from neutron reactions, enabling high-efficiency detection with potential advantages over traditional counters.

Contribution

It reveals that noble gases significantly enhance far-ultraviolet emission from 3He neutron reactions, achieving up to 30% energy conversion efficiency.

Findings

Signal amplification by factors of 1000 with noble gases

Emission due to noble-gas excimers confirmed

Potential for high-efficiency neutron detection

Abstract

Previous work showed that the 3He(n,tp) reaction in a cell of 3He at atmospheric pressure generated tens of far-ultraviolet photons per reacted neutron. Here we report amplification of that signal by factors of 1000 and more when noble gases are added to the cell. Calibrated filter-detector measurements show that this large signal is due to noble-gas excimer emissions, and that the nuclear reaction energy is converted to far-ultraviolet radiation with efficiencies of up to 30%. The results have been placed on an absolute scale through calibrations at the NIST SURF III synchrotron. They suggest possibilities for high-efficiency neutron detectors as an alternative to existing proportional counters.