Status and progress of the JUNO liquid scintillator

The Jiangmen Underground Neutrino Observatory (JUNO) is a multi-purpose experiment designed to elucidate fundamental neutrino properties, study neutrinos with astrophysical or terrestrial origins, and search for rare processes beyond the Standard Model of particle physics. Its central detector is a 20 kton liquid scintillator (LS) located 650 m underground in Guangdong, China. To achieve its physics goals, the JUNO LS must have high transparency and very high radio-purity. To purify the LS, five plants were designed: alumina filtration, distillation, mixing, water extraction, and gas stripping. In addition, two corollary plants were designed to supply ultra-pure water and high pure nitrogen for the LS purification system. The installation of all seven plants has been thoroughly completed, and both self-commissioning and joint commissioning of the plants have been carried out. The commissioned samples are currently undergoing testing.