The design and sensitivity of JUNO’s scintillator radiopurity pre-detector OSIRIS
Angel Abusleme, Thomas Adam, S. Ahmad, Rizwan Ahmed, S. Aiello, M. Akram, Fengpeng An, Guangpeng An, Qi An, Giuseppe Andronico, Н. Анфимов, V. Antonelli, Tatiana Antoshkina, Burin Asavapibhop, J. P. A. M. de André, Didier Auguste, Andrej Babič, W. Baldini, Andrea Barresi, D. Basilico, E. Baussan, Marco Bellato, Antonio Bergnoli, Thilo Birkenfeld, Sylvie Blin, David Blum, S.C. Blyth, Anastasia Bolshakova, M. Bongrand, Clément Bordereau, D. Breton, A. Brigatti, R. Brugnera, Riccardo Bruno, A. Budano, Mario Buscemi, José Busto, Ilya Butorov, J. Busenitz, Hao Cai, X. Cai, Yanke Cai, Zhiyan Cai, Antonio Cammi, Agustín Campeny, Chuanya Cao, Guofu Cao, Jun Cao, R. Caruso, C. Cerna, J. F. Chang, Yun Chang, Pingping Chen, Po-An Chen, Shaomin Chen, Xurong Chen, Yiwen Chen, Yixue Chen, Yu Chen, Zhang Chen, Jie Cheng, Yaping Cheng, Alexey Chetverikov, D. Chiesa, P. Chimenti, A. Chukanov, Gérard Claverie, Catia Clementi, Barbara Clerbaux, Selma Conforti Di Lorenzo, Daniele Corti, S. Costa, F. Dal Corso, Olivia Dalager, C. De La Taille, Jiawei Deng, Zhi Deng, Ziyan Deng, Wilfried Depnering, M. A. Díaz, Xuefeng Ding, Yayun Ding, Bayu Dirgantara, Sergey Dmitrievsky, Tadeáš Dohnal, Dmitry Dolzhikov, Georgy Donchenko, J. Dong, E. Doroshkevich, M. Dracos, Frédéric Druillole, Shuxian Du, S. Dusini, Martin Dvořák, T. Enqvist, Heike Enzmann, Andrea Fabbri, L. Fajt, Donghua Fan, Lei Fan
Abstract
Abstract The OSIRIS detector is a subsystem of the liquid scintillator filling chain of the JUNO reactor neutrino experiment. Its purpose is to validate the radiopurity of the scintillator to assure that all components of the JUNO scintillator system work to specifications and only neutrino-grade scintillator is filled into the JUNO Central Detector. The aspired sensitivity level of $$10^{-16}\hbox { g/g}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:msup> <mml:mn>10</mml:mn> <mml:mrow> <mml:mo>-</mml:mo> <mml:mn>16</mml:mn> </mml:mrow> </mml:msup> <mml:mspace/> <mml:mtext>g/g</mml:mtext> </mml:mrow> </mml:math> of $$^{238}\hbox {U}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:msup> <mml:mrow/> <mml:mn>238</mml:mn> </mml:msup> <mml:mtext>U</mml:mtext> </mml:mrow> </mml:math> and $$^{232}\hbox {Th}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:msup> <mml:mrow/> <mml:mn>232</mml:mn> </mml:msup> <mml:mtext>Th</mml:mtext> </mml:mrow> </mml:math> requires a large ( $$\sim 20\,\hbox {m}^3$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:mo>∼</mml:mo> <mml:mn>20</mml:mn> <mml:mspace/> <mml:msup> <mml:mtext>m</mml:mtext> <mml:mn>3</mml:mn> </mml:msup> </mml:mrow> </mml:math> ) detection volume and ultralow background levels. The present paper reports on the design and major components of the OSIRIS detector, the detector simulation as well as the measuring strategies foreseen and the sensitivity levels to U/Th that can be reached in this setup.