Fluorocarbon paint on Daya Bay antineutrino detectors

The aim of the Daya Bay reactor antineutrino experiment is to determine the neutrino mixing angle ϕ13 with a sensitivity of 0.01 or better at 90% confidence level. In order to improve the position resolution of both the positron interaction and the neutron capture, the inside of the antineutrino detectors should be as unreflecting as possible. A black matt fluorocarbon paint is coated on the inner surface of the detectors made of 304L stainless steel to meet the physical requirement. This paint is compatible with mineral oil, has low radioactivity, is easy to spray and fast curing at normal temperatures. The coating has excellent performance such as good adhesive force, uniformity, compact, scratch and wear resistance, and so on. It is the first application of such paint to large physical devices.