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

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*10²0 cm^ (-3). In addition, SrF2 crystal will not be irradiated-colored under strong 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.