The Low Polonium Field of Borexino and its significance for the CNO neutrino detection

Borexino collaboration

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

Borexino is a liquid scintillator detector located at the Laboratori Nazionale del Gran Sasso, Italy with the main goal to measure solar neutrinos. The experiment recently provided the first direct experimental evidence of CNO-cycle neutrinos in the Sun, rejecting the no-CNO signal hypothesis with a significance greater than 5σ at 99%C.L. The intrinsic210Bi is an important background for this analysis due to its similar spectral shape to that of CNO neutrinos.210Bi can be measured through its daughter210Po which can be distinguished through an event-by-event basis via pulse shape discrimination. However, this required reducing the convective motions in the scintillator that brought additional210Po from peripheral sources. This was made possible through the thermal insulation and stabilization campaign performed between 2015 and 2016. This article will explain the strategy and the different methods performed to extract the210Bi upper limit in Phase-III (Jul 2016- Feb 2020) of the experiment through the analysis of210Po in the cleanest region of the detector called the Low Polonium Field.

Original languageEnglish (US)
Title of host publicationProceedings of the 55th Rencontres de Moriond - 2021 Electroweak Interactions and Unified Theories, EW 2021
EditorsEtienne Auge, Jacques Dumarchez, Jean Tran Thanh Van
PublisherARISF
Pages441-444
Number of pages4
ISBN (Electronic)9791096879137
StatePublished - 2021
Event55th Rencontres de Moriond on Electroweak Interactions and Unified Theories, EW 2021 - Virtual, Online
Duration: Mar 20 2021Mar 27 2021

Publication series

NameProceedings of the 55th Rencontres de Moriond - 2021 Electroweak Interactions and Unified Theories, EW 2021

Conference

Conference55th Rencontres de Moriond on Electroweak Interactions and Unified Theories, EW 2021
CityVirtual, Online
Period3/20/213/27/21

All Science Journal Classification (ASJC) codes

  • Astronomy and Astrophysics
  • Atomic and Molecular Physics, and Optics

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