SuperK-Gd: The Gd future of Super-Kamiokande.
2019 July 22
Water Cherenkov detectors are notable for their large masses and their charge particle detection capabilities. These two properties have been exploited in depth in many searches with outstanding results at Super-Kamiokande. On the other hand, neutrons are usually captured on protons and produce a single 2.2 MeV gamma. The Compton scattered electron that is being produced does not yield enough Cherenkov light for the PMT coverage (40\%) of Super-Kamiokande to be efficiently detected. However, detecting neutrons would be an important improvement in most of our analyses to either improve our signal event selection (for processes that produce neutrons) or background event rejection (for processes that do not produce any neutron). Gadolinium (Gd) has the largest thermal neutron capture cross section. In this process, it emits a gamma cascade with a total energy of about 8 MeV which would be possible to detect with high efficiency. The EGADS project demonstrated that it is possible to safely add Gd to Super-Kamiokande and the collaboration approved in June 2015 the SuperK-Gd project. The necessary refurbishment of the Super-Kamiokande detector started in June 2018 and finished in early 2019. In this talk, we will report about this work and the project outlook.