NINJA experiment measures neutrino interactions with various nuclei using a high-intensity neutrino beam of J-PARC and nuclear emulsion. The nuclear emulsion is a high-resolution 3D tracking device that has contributed to many scenes of fundamental physics such as the detection of charm particles, the direct observation of ντ in DONUT, and the discovery of the ντ appearance in OPERA. Our main detector is an alternating structure of nuclear emulsion films and target material. It allows us to measure very short tracks from neutrino interactions and give insights into the understanding of neutrino interactions. A precise measurement of neutrino interactions on water especially plays an important role in neutrino oscillation experiments using water Cherenkov detectors. Moreover, our detector is suited for the measurement of electron neutrinos which inspect the existence of a sterile neutrino.
NINJA started our detector test runs since 2014, and the first physics run measuring neutrino interactions on water (J-PARC E71) has carried out in 2019.
