The design and technology development of the JUNO central detector
Angel Abusleme, Thomas Adam, S. Ahmad, Rizwan Ahmed, S. Aiello, Muhammad Akram, Abid Aleem, Tsagkarakis Alexandros, Fengpeng An, Qi An, Giuseppe Andronico, Н. Анфимов, V. Antonelli, Tatiana Antoshkina, Burin Asavapibhop, J. P. A. M. de André, Didier Auguste, Weidong Bai, N. Balashov, W. Baldini, Andrea Barresi, D. Basilico, E. Baussan, M. Bellato, Marco Beretta, Antonio Bergnoli, D. Bick, Thilo Birkenfeld, David Blum, S.C. Blyth, Anastasia Bolshakova, Mathieu Bongrand, Clément Bordereau, D. Breton, A. Brigatti, R. Brugnera, Riccardo Bruno, A. Budano, José Busto, J. Busenitz, Barbara Caccianiga, Hao Cai, X. Cai, Yanke Cai, Zhiyan Cai, S. Callier, Antonio Cammi, Agustín Campeny, Chuanya Cao, Guofu Cao, Jun Cao, R. Caruso, C. Cerna, Vanessa Cerrone, Chi Kuen Chan, J. F. Chang, Yun Chang, Guoming Chen, Pingping Chen, Shaomin Chen, Yixue Chen, Yu Chen, Zhiyuan Chen, Zikang Chen, Jie Cheng, Yaping Cheng, Yu Cheng, A. Chepurnov, Alexey Chetverikov, D. Chiesa, P. Chimenti, Ziliang Chu, A. Chukanov, Gérard Claverie, Catia Clementi, B. Clerbaux, Marta Colomer Molla, Selma Conforti Di Lorenzo, Alberto Coppi, Daniele Corti, Flavio Dal Corso, Olivia Dalager, C. De La Taille, Zhi Deng, Ziyan Deng, Wilfried Depnering, Marco Diaz, Xuefeng Ding, Yayun Ding, Bayu Dirgantara, Sergey Dmitrievsky, Tadeáš Dohnal, Dmitry Dolzhikov, Georgy Donchenko, J. Dong, E. Doroshkevich, Wei Dou, M. Dracos, F. Druillole, Ran Du
Abstract
Abstract The Jiangmen Underground Neutrino Observatory (JUNO) is a large-scale neutrino experiment with multiple physics goals including determining the neutrino mass hierarchy, the accurate measurement of neutrino oscillation parameters, the neutrino detection from supernovae, the Sun, and the Earth, etc. JUNO puts forward physically and technologically stringent requirements for its central detector (CD), including a large volume and target mass (20 kt liquid scintillator, LS), a high-energy resolution (3% at 1 MeV), a high light transmittance, the largest possible photomultiplier (PMT) coverage, the lowest possible radioactive background, etc. The CD design, using a spherical acrylic vessel with a diameter of 35.4 m to contain the LS and a stainless steel structure to support the acrylic vessel and PMTs, was chosen and optimized. The acrylic vessel and the stainless steel structure will be immersed in pure water to shield the radioactive background and bear great buoyancy. The challenging requirements of the acrylic sphere have been achieved, such as a low intrinsic radioactivity and high transmittance of the manufactured acrylic panels, the tensile and compressive acrylic node design with embedded stainless steel pad, and one-time polymerization for multiple bonding lines. Moreover, several technical challenges of the stainless steel structure have been solved: the production of low radioactivity stainless steel material, the deformation and precision control during production and assembly, and the usage of high-strength stainless steel rivet bolt and of high friction efficient linkage plate. Finally, the design of the ancillary equipment such as the LS filling, overflowing, and circulating system was done.