An attenuation length measurement device was constructed using an oscilloscope and LabVIEW for signal acquisition and processing. The performance of the device has been tested in a variety of ways. The test results show that the set-up has a good stability and high precision （sigma/mean reached 0.4 percent）. Besides, the accuracy of the measurement system will decrease by about 17 percent if a filter is used. The attenuation length of a gadolinium-loaded liquid scintillator （Gd-LS） was measured as 15.1±0.35 m where Gd-LS was heavily used in the Daya Bay Neutrino Experiment. In addition, one method based on the Beer-Lambert law was proposed to investigate the reliability of the measurement device, the R-square reached 0.9995. Moreover, three purification methods for Linear Alkyl Benzene （LAB） production were compared in the experiment.
Types 316 and 304 stainless steel are two candidates for the storage vessels and piping systems of LABbased liquid scintillator（LS） in the JUNO experiment. LS aging experiments are carried out at temperatures of 40 and 25. After 192 days aging at 40, the attenuation length of LS was reduced by 6% in a glass container, 12%in a type 304 stainless steel tank, and 10% in a type 316 stainless steel tank. At 25 in 304 and 316 stainless steel tanks, the attenuation length was reduced by 6% after 307 days. The light yield and the absorption spectrum were practically the same as that of the unaged sample. The concentration of element Fe in the LAB-based LS did not show a clear change. Type 316 and 304 stainless steel can be used as vessels and transportation pipeline material for LAB-based LS.
The aim of the Daya Bay reactor antineutrino experiment is to determine the neutrino mixing angle 813 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 neu- tron 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 com- patible with mineral oil, has low radioactivity, is easy to spray and fast curing at normal temperatures. The coating has excel- lent performance such as good adhesive force, uniformity, compact, scratch and wear resistance, and so on. It is the first appli- cation of such paint to large physical devices.
WANG RuiGuangHENG YueKunWANG LanDING YaYunCAO JunWANG YiFangYANG ChangGen
