Low Radioactivity Techniques (LRT2022)

Background measurements for Jinping Neutrino 1-t prototype at CJPL

Jun 16, 2022, 8:30 AM

15m

EEP 252 (South Dakota Mines)

Oral Presentation Experiment Backgrounds, Models, Simulations LRT 2022 - presentations

Speaker

Yiyang Wu (Tsinghua University)

Description

In 2017-2020, Jinping Neutrino 1-t prototype has detected numerous MeV radioactive background events, 343 high energy muon events and muon induced neutrons. By Bi-Po coincidence, the U238 contamination of liquid scintillator (LS) is measured as $(6.98\pm 0.73)\times 10-13$ g/g, and Th232 upperlimit is $3.7\times 10-13$ g/g (95% C.L., preliminary). On PMT glass, K40 contamination is $(5.73\pm 0.79stat.\pm 1.49sys.)\times 10-8$ g/g and Tl208 event rate is $(3.86\pm 0.26stat.\pm 0.85sys.)\times 10-3$ Bq/g, indicating $(2.64\pm 0.18stat.\pm 0.58sys.)\times 10-6g/g$ Th232. The radioactivity of LS will be further suppressed after the distillation system is online. The muon flux is $(3.61\pm 0.19stat.\pm 0.10sys.)\times 10-10{\mathrm{cm}}^{-2}{\mathrm{s}}^{-1}$ with an average energy of 340 GeV, and its neutron yield is $(3.44\pm 1.86stat.\pm 0.76syst.)\times 10-4\mu -1g-1cm2$. Those results indicates that CJPL is an ideal place for low background experiments. We are making steady progresses on lowering radioactive isotopes of detector materials.

Presentation materials

LRT2022JinpingNeutrino.pdf