~(13)C(α, n)~(16)O background in a liquid scintillator based neutrino experiment

α from natural radioactivity may interact with a nucleus and emit a neutron. The reaction introduces the background to the liquid scintillator(LS) based neutrino experiments. In the LS detector, α comes from 238 U,232Th,and 210 Po decay chains. For Gadolinium-doped LS(Gd-LS) detector, α also comes from 227 Ac. The nucleus 13 C is a natural component of Carbon which is rich in the LS. The background rate and spectrum should be subtracted carefully from the neutrino candidates. This paper describes the calculation of neutron yield and spectrum with uncertainty estimated. The results are relevant for many existing neutrino experiments and future LS or Gd-LS based experiments.     

Measurement of the liquid scintillator nonlinear energy response to electron

Nonlinearity of the liquid scintillator energy response is a key to measuring the neutrino energy spectrum in reactor neutrino experiments such as Daya Bay and JUNO. We measured the nonlinearity of the linear alkyl benzene based liquid scintillator in the laboratory, which is used in Daya Bay and will be used in JUNO, via the Compton scattering process. By tagging the scattered gamma from the liquid scintillator sample simultaneously at seven angles, the instability of the system was largely cancelled. The accurately measured nonlinearity will improve the precision of the θ₁₃, Δm², and reactor neutrino spectrum measurements at Daya Bay.