The first activities of the Canfranc Underground Laboratory ("Laboratorio Subterr\'aneo de Canfranc", LSC) started in the mid-eighties in a railway tunnel located under the Spanish Pyrenees; since then, it has become an international multidisciplinary facility equipped with different services for underground science. The research activity at LSC is about Astroparticle Physics, dark matter searches and neutrino Physics; but also activities in Nuclear Astrophysics, Geophysics, and Biology are carried out. The investigation of the neutrinoless double beta decay has been one of the main research lines of LSC since the beginning. Many unknowns remain in the characterization of the basic neutrino properties and the study of this rare decay process requiring Physics beyond the Standard Model of Particle Physics can shed light on the lepton number conservation, the nature of the neutrinos as Dirac or Majorana particles and the absolute scale and ordering of the masses of the three generations. Here, the double beta decay searches performed at LSC for different emitters and following very different experimental approaches will be reviewed: from the very first experiments in the laboratory including the successful IGEX for $^{76}$Ge, which released very stringent limits to the effective neutrino mass at the time, to the present NEXT experiment for $^{136}$Xe and future project CROSS ("Cryogenic Rare-event Observatory with Surface Sensitivity") for $^{130}$Te and $^{100}$Mo, both implementing innovative detector technologies to discriminate backgrounds. For the neutrinoless double beta decay channel and at 90% C.L., IGEX derived a limit to the half-life of $^{76}$Ge of $T_{1/2}^{0\nu} > 1.57 \times 10^{25}$ y while the corresponding expected limits are $T_{1/2}^{0\nu} > 1.0\times 10^{26}$ y for $^{136}$Xe from NEXT-100 (for an exposure of 500 kg.y) and $T_{1/2}^{0\nu} > 2.8 \times 10^{25}$ y for $^{100}$Mo from CROSS (for 5 y and 4.7 kg of isotope). Activities related to double beta decays searches carried out in other underground laboratories have also been developed at LSC and will be presented too, like the operation of the BiPo-3 detector for radiopurity measurements of thin sheets with very high sensitivity. For each one of these experiments, the concept, the experimental set-ups and relevant results will be discussed.

中文翻译：

---

Canfranc 地下实验室的双β衰变实验

Canfranc 地下实验室（“Laboratorio Subterr\'aneo de Canfranc”，LSC）的第一项活动于 80 年代中期在西班牙比利牛斯山脉下方的一条铁路隧道中开始；从那时起，它已成为一个国际多学科设施，为地下科学提供不同的服务。LSC 的研究活动是关于天体粒子物理学、暗物质搜索和中微子物理学；但也开展了核天体物理学、地球物理学和生物学方面的活动。无中微子双β衰变的研究从一开始就是LSC的主要研究方向之一。在基本中微子特性的表征中仍有许多未知数，而对这种需要超越粒子物理学标准模型的物理学的罕见衰变过程的研究可以阐明轻子数守恒、中微子作为狄拉克或马约拉纳粒子的性质以及绝对值三代人的规模和秩序。在这里，将回顾在 LSC 对不同发射器和遵循非常不同的实验方法进行的双 β 衰变搜索：从实验室的第一个实验开始，包括成功的 $^{76}$Ge IGEX，它发布了非常严格的限制当时的有效中微子质量，到现在的 $^{136}$Xe 的 NEXT 实验和未来的项目 CROSS（“具有表面敏感性的低温稀有事件天文台”）) 用于 $^{130}$Te 和 $^{100}$Mo，两者均采用创新的检测器技术来区分背景。对于中微子双β衰变通道和 90% CL，IGEX 推导出 $T_{1/2}^{0\nu} > 1.57 \times 10^ $^{76}$Ge 的半衰期极限{25}$ y 而相应的预期限制为 $T_{1/2}^{0\nu} > 1.0\times 10^{26}$ y for $^{136}$Xe from NEXT-100（对于500 kg.y) 和 $T_{1/2}^{0\nu} > 2.8 \times 10^{25}$ y for $^{100}$Mo from CROSS（5 y 和 4.7 kg同位素）。LSC 还开发了与在其他地下实验室进行的双 β 衰变搜索相关的活动，并将展示这些活动，例如 BiPo-3 探测器的操作，用于以非常高的灵敏度对薄片进行放射性纯度测量。对于这些实验中的每一个，概念，