Li$_2$MnCl$_4$ single crystal: new candidate for red-emitting neutron scintillator

TL;DR

This paper proposes Li$_2$MnCl$_4$ as a new red-emitting scintillator for thermal neutron detection, highlighting its unique properties and exploring doping strategies to enhance scintillation efficiency.

Contribution

It introduces Li$_2$MnCl$_4$ as a novel candidate for neutron scintillators and investigates its luminescence mechanisms and doping effects.

Findings

Li$_2$MnCl$_4$ has suitable properties for neutron detection.

Doping with Eu$^{2+}$ and Ce$^{3+}$ enhances luminescence.

Energy transfer from dopants to Mn$^{2+}$ is key to scintillation.

Abstract

Novel red-emitting scintillator Li$_2$MnCl$_4$ is proposed as a candidate for thermal neutron detection. It features high Li content, low density, low effective atomic number, and emission in red-NIR region. These characteristics make it an interesting candidate for long distance neutron detection in harsh enviroments e. g. decomisioning of nuclear powerplants. The absorption spectrum is thoroughly investigated in the scope of Tanabe-Sugano diagram. Luminescence mechanism in the undoped Li$_2$MnCl$_4$ is studied in depth. Doping by Eu$^{2+}$ and Ce$^{3+}$ is introduced as a trial to improve the scintillation efficiency. We show in the Eu$^{2+}$ and Ce$^{3+}$ doped Li$_2$MnCl$_4$ that luminescence mechanism involves energy transfer from the dopants to Mn$^{2+}$, and propose the local lattice distortion around the dopant and a possible charge compensation mechanisms.