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.