PoS - Proceedings of Science
Volume 398 - The European Physical Society Conference on High Energy Physics (EPS-HEP2021) - T04: Neutrino Physics
OSIRIS – An online scintillator radiopurity monitor for the JUNO experiment
M.C. Vollbrecht
Full text: pdf
Pre-published on: January 12, 2022
Published on:
Abstract
The Jiangmen Underground Neutrino Observatory (JUNO), currently under construction in China, will be the first multi-kton liquid scintillator detector and has a vast potential for new insights into several fields of neutrino and astroparticle physics. To reach its design sensitivity for detecting reactor and solar neutrinos, a radiopure liquid scintillator is required. For IBD measurements, a radiopurity of $10^{-15}$ g/g is needed for both $^{238}$U and $^{232}$Th, $10^{-16}$ g/g for solar measurements.
The Online Scintillator Internal Radioactivity Investigation System (OSIRIS) allows an on-line radiopurity evaluation of the scintillator during the JUNO detector filling over several months. The design of OSIRIS is optimized for tagging $^{214}$Bi-$^{214}$Po and $^{212}$Bi-$^{212}$Po coincidence decays in the decay chains of $^{238}$U and $^{232}$Th, respectively. OSIRIS will also be able to monitor the $^{14}$C and $^{210}$Po levels in the scintillator.

To achieve its goals, OSIRIS features a 20 ton liquid scintillator target monitored by 76 intelligent photomultiplier tubes (iPMTs). In this novel design, each iPMT consists of a PMT and its readout electronics mounted on its back. Each hit causing these electronics to trigger is sent to the DAQ as a digitized PMT pulse. A single computer (EventBuilder) is sufficient to combine the data stream into events for further analysis.

For the timing and charge calibration of the detector, two optical systems (LED- and LASER-based) are employed. The energy and position calibration of OSIRIS is performed with height-adjustable radioactive sources within the liquid scintillator. These sources cover the crucial energy range for the detection of Bi-Po signals between 0.66 MeV to 2.5 MeV.
DOI: https://doi.org/10.22323/1.398.0212
How to cite

Metadata are provided both in "article" format (very similar to INSPIRE) as this helps creating very compact bibliographies which can be beneficial to authors and readers, and in "proceeding" format which is more detailed and complete.

Open Access
Creative Commons LicenseCopyright owned by the author(s) under the term of the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.