Transparency of 0.2% GdCl3 doped water in a stainless steel test environment

The possibility of neutron and neutrino detection using water Cherenkov detectors doped with gadolinium holds the promise of constructing very large high-efficiency detectors with wide-ranging application in basic science and national security. This study addresses a major concern regarding the feasibility of such detectors: the transparency of the doped water to the ultraviolet Cherenkov light. We report on experiments conducted using a 19-m water transparency measuring instrument and associated material test tank. Sensitive measurements of the transparency of water doped with 0.2% GdCl3 at 337, 400 and 420 nm were made using this instrument. These measurements indicate that the use of GdCl3 in stainless steel constructed water Cherenkov detectors is problematic.