Speaker
Description
The second phase of J-PARC Sterile Neutrino Search at J-PARC Spallation Neutron Source(JSNS^2-II) experiment aims at searching for the sterile neutrinos using a neutrino beam produced by a 3 GeV proton accelerator via muon decay at rest. This experiment has entered its second phase, employing two liquid scintillator detectors located at near and far positions from the neutrino source. Recently, the far detector of the experiment has been completed and is currently in the calibration phase.
To achieve good energy resolution for physics events, the gains of the PMTs must be matched within 10% of the supplied high voltages, making it essential to acquire the accurate gain curves for each PMT as a function of high voltage. A lower gain is necessary to avoid PMT non-linearity and FADC saturation, which makes it crucial to obtain accurate gain curves. The LED system of the far detector uses two Ultra-Violet(UV) LEDs, which can provide pseudo-isotropic light inside the liquid scintillator. The UV light is converted into visible light wavelengths inside the liquid scintillator via the wavelength shifters, providing pseudo-isotropic light. This LED system was used to measure single photoelectron (SPE) signals and to extract information about the PMT gain and signal timing.
In this poster, we present the results of the PMT calibration using the embedded LEDs.
