The Study Of The Fluorescence Of Cable Sheath For JUNO

The Jiangmen Underground Neutrino Observatory(JUNO)will set up a huge and precise experimental station.Its major goal is determining neutrino mass hierarchy by precisely measuring the energy spectrum of reactor electron antineutrino.addition,JUNO is going to improve the precision of neutrinooscillation parameters and it can also detect the supernovae neutrinos,the atmospheric neutrinos,and the earth neutrino.The experiment of JUNO requires Twenty thousand of 20 inches of photo multiplier tube(PMT)and Thirty-six thousand of 3 inches of photomultiplier tube(PMT).This several tens of thousands of PMTs need cables to supply power and transmit signals.So many cables are likely to be excited by light and then produce fluorescence which will bring background noise to the experiment.The selection of the cables depends on the property of signal transmission,mechanical performance,life span,etc.,as well as the photoelectric property of the epidermal material after excited.This paper studies the performance of various cable epidermis excited by light,and the results provide reference for the final cable selection of JUNO.The article studies two methods to the performance of various cable epidermis excited by light.Both the photomultiplier tubes respectively the use of single photoelectron spectra and fluorescence spectrometer in order to develop the nine different alternative cable skin material is the study of fluorescence analysis.single photoelectron spectra photomultiplier tubes and fluorescence spectrometer were used to characterize the fluorescence effect of nine different cable epidermis.The study found that:(1)Numbers for 1,2,6 cable epidermis after excitation by the light of the weak fluorescence,and the number of Y2,Y3,Y4 cable skin produce strong fluorescence peak at 360 nm;(2)The absolute yield of three types of high-emitting fluorescence cable were 4.80%,4.35%,3%,and fluorescence life was 20ns.All these results provide theoretical support and technical basis for the selection of JUNO cables.In addition,the paper analyses the work gas score of the gas detector in the BESIII,The main drift chamber(MDC),the μ detector,and the upgraded TOF terminals(ETOF)are gas detectors,which are important detectors for the BESIII.The gas detector’s working gas is a mixture of various gases,which affect the performance of the detector.Therefore,the real-time monitoring and stability of the gas scores is of great significance to the normal operation of the BESIII.This paper also designs a set of automatic analysis system,realize to the probe’s gas quality Mass flow ratio analysis,and is able to automatically switch in the three kinds of gas detector.A small amount of mixed gas was extracted in the mixing cylinder of the front end,and the quality score of mixed gas was monitored and analyzed by gas chromatography of The GC7890A.The GC7890A through its stability testing,monitoring and analysis of mixed gas quality score for a long time,and set mass flow rate and mass flow meter score than found both before and after the difference is very small.Results showed that the mass flow meter work in normal state,the score does not affect the gas detector(MRPC)performance,monitoring and analysis system of this design is feasible.