Super-Kamiokande (SK) is a 50 kton water Cherenkov detector
located approximately 1 km beneath mount Ikenoyama, Gifu, Japan. While
SK can reconstruct charged particle tracks over a wide energy range, the
detection efficiency of neutrons is very low. Achieving efficient
neutron tagging is useful in all analyses, from the observation of the
diffuse supernova neutrino background for the first time, to proton
decay studies and oscillation analyses.
SK gadolinium (SK-Gd) is the upgrade project to make neutron tagging
efficient. After extensive studies, the SK collaboration approved the
SK-Gd project on June 27 2015. In the second half of 2018 we refurbished
the detector and in the first half of 2020 we will add gadolinium to the
SK tank for the first time. This talk will report the preparations that
led to SK-Gd and its current status.