Abstract Scheelite related rare-earth double molybdate with the formula of NaLa(MoO4)2 is a promising scintillator for investigating the neutrinoless double beta decay process. In this study, NaLa(MoO4)2 crystal was grown by the vertical Bridgman method using spontaneous crystallization. The as-grown NaLa(MoO4)2 crystal exhibited yellow and dark blue in color (from top to the bottom). The powder x-ray diffraction and optical transmission spectra of the crystal were measured at room temperature. The temperature dependence of the luminescence and scintillation properties were measured under the excitations of 4.42 eV UV light from a LED source and β-particles from a 90Sr source in 10-300 K range, respectively. The transmittance of the annealed NaLa(MoO4)2 crystal sample with the thickness of 10 mm was about 65-72% above the fundamental absorption edge. The light yield under UV and β-particles excitations were found to be enhanced upon cooling and exhibited maximum intensity at 10 K. The luminescence light yield of NaLa(MoO4)2 crystal was estimated to be about half of that of CaMoO4 crystal and 18 times as much as that of Li2MoO4 crystal at 10 K. The scintillation light yield of NaLa(MoO4)2 crystal reached the maximum at 10 K and was 70% of Li2MoO4 crystal. The shortest average decay time of 6.12 μs was obtained at 250 K, which was further slowed down upon cooling of the crystal and the longest average decay time of 442.77 μs was found to be at 10 K. Considering the possibility of crystal growth with large volume and high quality, the luminescence and scintillation properties of NaLa(MoO4)2 crystal revealed that this scintillation material may be a promising candidate as a cryogenic detector for investigating the neutrinoless double beta decay (0νββ) search.

中文翻译：

---

垂直布里奇曼法生长的NaLa(MoO4)2晶体的低温发光和闪烁特性

摘要 分子式为NaLa(MoO4)2的白钨矿相关稀土双钼酸盐是一种很有前途的闪烁体，用于研究中微子双β衰变过程。在这项研究中，NaLa(MoO4)2 晶体是通过垂直布里奇曼方法使用自发结晶生长的。生长的 NaLa(MoO4)2 晶体呈黄色和深蓝色（从上到下）。在室温下测量晶体的粉末 X 射线衍射和光学透射光谱。发光和闪烁特性的温度依赖性分别在来自 LED 光源的 4.42 eV 紫外光和来自 90Sr 光源的 β 粒子在 10-300 K 范围内的激发下测量。10mm厚的退火NaLa(MoO4)2晶体样品的透光率比基本吸收边高约65-72%。发现紫外和 β 粒子激发下的光产额在冷却后增强，并在 10 K 时表现出最大强度。 NaLa(MoO4)2 晶体的发光光产额估计约为 CaMoO4 晶体的一半和 18 倍10 K 时与 Li2MoO4 晶体相同。NaLa(MoO4)2 晶体的闪烁光产额在 10 K 时达到最大值，为 Li2MoO4 晶体的 70%。在 250 K 下获得 6.12 μs 的最短平均衰减时间，在晶体冷却后进一步减慢，发现 10 K 处的最长平均衰减时间为 442.77 μs。考虑到大体积晶体生长的可能性和高品质，