Thorium doped strontium fluoride crystal: a unique candidate for solid nuclear optical clock material

TL;DR

This paper introduces Th:SrF2 crystal as a promising solid-state nuclear optical clock material, highlighting its high doping efficiency, transparency, and radiation resistance, which are advantageous for precise timekeeping applications.

Contribution

The study presents a novel Th:SrF2 crystal with high doping concentration, excellent transmittance, and radiation stability, advancing solid nuclear clock technology.

Findings

High doping concentration (>6×10^20 cm^(-3)) achieved

Transmittance of ~69% at 150 nm maintained

Resistant to radiation-induced coloration

Abstract

We report a candidate with unique advantages in the cultivation of solid-state nuclear clock material, Th:SrF2 crystal. It not only has a segregation coefficient close to 1, which can achieve highly efficient and uniform doping of Th, but also ensures a high transmittance (~69% at 150 nm) while achieving extremely high doping concentration (232Th>6*10^20 cm^(-3). In addition, SrF2 crystal will not be irradiated-colored under strong {\alpha} radiation like CaF2 crystal, Th:SrF2 crystal is expected to fully unleash its high concentration doping characteristics while ensuring its transmission performance in nuclear transition band not be severely affected by 229Th radiation damage.