Cheap as CHIPS: A Cost Effective Approach to Larger Neutrino Detectors

In the current landscape of neutrino oscillation physics most of the PMNS parameters have been measured to a precision of a few percent. Two of the lingering questions that the field is focused on answering are: 1) What is the mass ordering (normal or inverted)? and 2) Is there CP violation in neutrino mixing (is delta-CP conclusively non-zero)? While answering these question is the focus of the next generation experiments such as Hyper-K and DUNE, even larger next-next generation experiments will be needed to make super-precise measurements of delta-CP or to shed light on possible new physics that may be hinted at by the new experiments. The traditional approaches to scaling up detector mass however, are prohibitively expensive. This is where CHIPS comes in as an R&D program focused on developing techniques for cost-effective, very large water Cherenkov detectors (WCDs). In the short term, a 7 kiloton CHIPS detector is being built to further exploit the NuMI beam line neutrinos while simultaneously demonstrating procedures for building WCDs in the price range of $200k-$300k/kiloton and mass range around 100 kilotons. In the long term, the CHIPS methodologies could be scaled to an array of detectors in the LNBE beam line with a combined mass on the order of 1 Megaton.