Erlangen 2026 – wissenschaftliches Programm
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T: Fachverband Teilchenphysik
T 53: Scintillator Detectors II
T 53.4: Vortrag
Mittwoch, 18. März 2026, 17:00–17:15, KH 01.014
Characterisation of internal backgrounds in JUNO using BiPo-214 decays — •Ujwal Santhosh1,2 and Livia Ludhova1,2 — 1GSI Helmholtzzentrum für Schwerionenforschung, 64291 Darmstadt, Germany — 2Institute of Physics and EC PRISMA+, Johannes Gutenberg Universität Mainz, Mainz, Germany
The Jiangmen Underground Neutrino Observatory (JUNO) operates at a depth of 700 m underground in South China. The detector has multiple ambitious physics goals, but to achieve them, JUNO must maintain the radiopurity of the scintillator at very high levels. This work focuses on the 238U decay chain, which is assumed to be in secular equilibrium because of its long lifetime and can therefore be determined by measuring 214BiPo coincidences. 214Bi decays into 214Po with a characteristic prompt-delayed signature that can be isolated using spatial and temporal coincidence. However, the secular equilibrium of isotopes below 222Rn in the 238U chain can be disturbed by radon influx from the surrounding air. This is characterised by an increase in the BiPo-214 rate, as they are the decay products of radon. Such contamination can typically occur during detector filling in the presence of small leaks. In a closed system, the broken equilibrium is then restored in weeks due to the relatively short lifetime of radon. This study follows the 214BiPo rate during filling to search for radon leaks and later in a stable data-taking period to extract the 238U level.
Keywords: 238U; 214BiPo; JUNO