Jiangmen Underground Neutrino Observatory

Jiangmen Underground Neutrino Observatory
Name	Jiangmen Underground Neutrino Observatory
Location	Jiangmen, Guangdong, China
Type	Research facility
Established	2016 (groundbreaking)
Affiliation	Institute of High Energy Physics, Chinese Academy of Sciences

Jiangmen Underground Neutrino Observatory

The Jiangmen Underground Neutrino Observatory is a large-scale particle physics experiment designed to study neutrino properties using a deep underground detector complex in southern China. It is designed and built by a consortium of international institutions including the Institute of High Energy Physics (China), various universities such as Tsinghua University, Peking University, University of Tokyo, Massachusetts Institute of Technology, and national laboratories such as Brookhaven National Laboratory, Lawrence Berkeley National Laboratory, and CERN. The project interacts with global programs like Super-Kamiokande, Sudbury Neutrino Observatory, Daya Bay Reactor Neutrino Experiment, KamLAND, and NOvA.

Overview

The observatory aims to measure neutrino oscillation parameters, probe the neutrino mass hierarchy, and search for rare processes by deploying a kiloton-scale liquid scintillator detector. The effort builds on predecessors and contemporaries including Borexino, SNO+, IceCube, Hyper-Kamiokande, DUNE, and RENO. It involves major Chinese research bodies such as the Chinese Academy of Sciences and international partners from institutions like Imperial College London, University of Oxford, University of California, Berkeley, University of Chicago, Stanford University, University of Michigan, and Princeton University.

Scientific Goals

Primary goals include precision measurement of the neutrino mixing angle theta13 legacy parameters and determination of the neutrino mass ordering through reactor antineutrino spectroscopy, complementing measurements by Daya Bay, RENO, and Double Chooz. Secondary goals encompass measurements of solar neutrinos alongside experiments such as Homestake Experiment and GALLEX, searches for neutrinoless double beta decay similar to GERDA and EXO-200, and studies of geoneutrinos in the tradition of KamLAND and Borexino. The observatory also targets supernova neutrino bursts with networks including Super-Kamiokande and SNEWS, and aims to contribute to multimessenger campaigns with observatories like LIGO, VIRGO, IceCube, Fermi Gamma-ray Space Telescope, and Swift Observatory.

Detector Design and Technology

The central detector concept uses a spherical acrylic vessel filled with linear alkylbenzene-based liquid scintillator and photomultiplier tubes (PMTs) including high quantum efficiency models from manufacturers tied to groups such as Hamamatsu, paralleling developments in Daya Bay and Borexino. The design incorporates a water Cherenkov muon veto surrounding the inner detector similar to SNO and Super-Kamiokande, plus calibration systems influenced by techniques at MINOS and NOvA. Readout and trigger electronics draw on designs tested at CERN and KEK, while simulation and reconstruction software integrate frameworks used at ROOT and collaborations connected to GEANT4. Cryogenic and purification technology builds on expertise from Gran Sasso National Laboratory and Los Alamos National Laboratory for low-background operation.

Site and Infrastructure

The underground site is located in the Jiangmen region of Guangdong province and employs horizontal access tunnels and hall caverns similar to those at Gran Sasso Laboratory and Boulby Mine. Surface and underground infrastructure coordinate with local authorities including Guangdong Provincial Government and municipal agencies, and require geotechnical work informed by practices at Sudbury Neutrino Observatory (SNOLAB) and BNO (Baksan Neutrino Observatory). Logistics involve transport links near Shenzhen, Guangzhou, and port facilities like Port of Shenzhen for international hardware shipments involving partners such as CERN and KEK. Environmental monitoring engages agencies analogous to Chinese Academy of Sciences institutes and provincial environmental bureaus.

Construction and Timeline

Initial proposal and concept studies involved meetings at institutions including Institute of High Energy Physics (China), Tsinghua University, and partner universities. Groundbreaking and civil construction phases began in the mid-2010s with involvement from engineering firms with experience at projects like Three Gorges Dam and tunneling contracts comparable to Beijing Subway contractors. Key milestones include detector vessel fabrication, PMT procurement comparable to procurement at Super-Kamiokande and JUNO scale projects, liquid scintillator production influenced by suppliers used by Borexino and Daya Bay, and staged commissioning phases mirroring schedules at KamLAND-Zen and SNO+. Funding pulls from national programs similar to National Natural Science Foundation of China and provincial allocations, with international contributions coordinated through memoranda of understanding with universities such as University of Tokyo, RWTH Aachen University, École Polytechnique, and University of Toronto.

Collaborations and Management

The collaboration comprises research groups from numerous institutions including Institute of High Energy Physics (China), Tsinghua University, Peking University, Shanghai Jiao Tong University, Fudan University, University of Science and Technology of China, Nankai University, Sun Yat-sen University, Tsukuba University, and international partners like University of Edinburgh, University of Geneva, Max Planck Society, Weizmann Institute of Science, CEA Saclay, and Lawrence Livermore National Laboratory. Governance structures echo those used by large collaborations such as CERN experiments and IceCube, with steering committees, technical boards, and publication policies influenced by standards at APS conferences and ICHEP proceedings. Training and outreach relate to university curricula at Tsinghua University and exchanges with laboratories like Brookhaven National Laboratory and SLAC National Accelerator Laboratory.

Research Programs and Results

Ongoing research programs include reactor antineutrino studies drawing on comparison datasets from Daya Bay and RENO, solar neutrino analyses referencing results from Borexino and Super-Kamiokande, and geoneutrino measurements in the context of work by KamLAND. Early commissioning runs and calibration campaigns follow strategies developed for SNO+ and Borexino, while planned data releases will be presented at conferences such as Neutrino 2024, ICHEP, and APS Division of Particles and Fields meetings. The collaboration publishes in journals frequented by groups from Physical Review Letters, Physical Review D, Journal of High Energy Physics, and Nature Physics, and contributes to global efforts on neutrino mass ordering alongside DUNE and Hyper-Kamiokande.

Category:Particle physics experiments Category:Neutrino observatories Category:Science and technology in China