China Jinping Underground Laboratory

China Jinping Underground Laboratory
Name	China Jinping Underground Laboratory
Native name	紫金山地下实验室
Established	2009
Location	Jinping Mountains, Sichuan Province, People's Republic of China
Depth	~2400 m
Operator	Chinese Academy of Sciences; Tsinghua University; Institute of High Energy Physics

China Jinping Underground Laboratory is a deep-underground research facility located beneath the Jinping Mountains in Sichuan Province, People's Republic of China. Built to exploit exceptional overburden for low-background experiments, the laboratory supports particle physics, nuclear astrophysics, and geoscience programs requiring extreme shielding from cosmic radiation. The site has grown from an initial cavern into a multi-hall complex hosting international collaborations and national institutes.

Overview

The laboratory was conceived to provide an ultra-low cosmic-ray muon flux environment for experiments probing neutrino properties, dark matter candidates, and rare-event searches. Its development aligns with priorities of the Chinese Academy of Sciences and major research universities such as Tsinghua University and Peking University for large-scale underground science. The facility's depth, access via hydropower tunnel infrastructure associated with the Yalong River hydropower projects, and proximity to national laboratories enabled rapid deployment of detectors. Scientific goals include sensitivity to weakly interacting massive particles, neutrinoless double beta decay, and measurements relevant to solar neutrino flux and geoneutrino signals.

Location and Geology

The laboratory lies beneath the Jinping Mountains in Sichuan Province, inside the Jinping-II hydropower tunnel complex near the Yalong River valley. The rock cover provides an overburden of approximately 2400 metres water equivalent, yielding one of the lowest muon fluxes of any underground site. Host rock is primarily hard gneiss and granite, with local shear zones and fault structures mapped by teams from the China University of Geosciences and the Institute of Geology and Geophysics, Chinese Academy of Sciences. Geological surveys and borehole logging characterized hydrogeology, in-situ stress, and radiogenic background from uranium and thorium series isotopes, informing cavern siting and shielding design. Seismicity in the region is monitored in coordination with the China Earthquake Administration due to proximity to tectonic features associated with the Indian Plate–Eurasian Plate collision.

Facilities and Infrastructure

The complex comprises multiple experimental halls, service caverns, cleanrooms, and a surface support campus. Hall A, Hall B, and Hall C were excavated sequentially to accommodate experiments with varying size and background needs; Hall A hosted early dark matter detectors, while Hall C was designed for next-generation large-mass setups. Utility systems include low-radon air handling, deionized water systems, cryogenic plants, and power conditioning tied to regional grids serving the China Southern Power Grid operations. Logistics use the Jinping hydropower tunnel access routes constructed for the Jinping Hydropower Station projects. Onsite laboratories support materials assay using high-purity germanium detectors, low-background counting facilities run by the Institute of High Energy Physics, and mechanical workshops affiliated with Tsinghua University and Shanghai Jiao Tong University for detector assembly.

Research Programs and Experiments

Major physics programs target dark matter direct detection, neutrinoless double beta decay, low-energy solar neutrino spectroscopy, and nuclear astrophysics cross-section measurements. Prominent experiments hosted include the Jinping Neutrino Experiment, the PandaX dark matter series, and prototype cryogenic detectors developed by consortia involving the Institute of High Energy Physics, the Shanghai Institute of Applied Physics, and international partners from CERN-linked collaborations. R&D on low-background techniques, such as ultraclean materials processing, radon suppression, and active veto systems, is conducted with expertise from Lawrence Berkeley National Laboratory cooperative projects and instrumentation groups at Caltech and MIT. Geoscience and multidisciplinary programs exploit the deep site for studies of deep biosphere microbial communities, rock mechanics under high confining stress, and underground fluid migration, often in collaboration with the China University of Mining and Technology.

Safety and Environmental Management

Safety systems address geotechnical stability, ventilation, fire suppression, and emergency egress linked to the hydropower tunnel network. Engineering teams from the China National Nuclear Corporation standards groups and the Ministry of Natural Resources (China) guidelines oversaw risk assessments, seismic design criteria, and long-term monitoring. Radon mitigation and radiopurity screening reduce backgrounds for sensitive detectors; radiopurity campaigns work with the Chinese Academy of Medical Sciences and materials science departments at Peking University to certify construction and detector materials. Environmental stewardship coordinates with local authorities in Yanyuan County and provincial agencies to manage groundwater impacts and pipeline routing for utilities, while community liaison programs maintain communication with regional stakeholders involved in the Sichuan-Tibet Railway corridor planning and hydropower operations.

Collaboration and Funding

The laboratory operates through a matrix of national institutes, university consortia, and international scientific partners. Core funding and oversight come from the Chinese Academy of Sciences, the Ministry of Science and Technology (China), and participating universities including Tsinghua University, Peking University, and Shanghai Jiao Tong University. Project-specific grants and instrument funding are provided by national funding bodies such as the National Natural Science Foundation of China and cooperative agreements with foreign agencies and laboratories. Collaborative frameworks have brought in expertise and resources from institutions including CERN, Lawrence Berkeley National Laboratory, TRIUMF, and university groups across Europe, North America, and Asia, facilitating joint experiments, data analysis, and technology transfer.

Category:Underground laboratories Category:Particle physics facilities in China