Feasibility Study for Large Water-Based Neutron and Neutrino Detection

C.Svoboda, R ; Bernstein, A ; Coleman, W ; Dazeley, S A

Lawrence Livermore National Laboratory

关键词: Materials Testing;    46 Instrumentation Related To Nuclear Science And Technology;    Attenuation;    Wavelengths;    National Security;   

DOI  :  10.2172/1036852
RP-ID  :  UCRL-TR-229205
RP-ID  :  W-7405-ENG-48
RP-ID  :  1036852

美国|英语

来源: UNT Digital Library

【 摘 要 】

The possibility of neutron and neutrino detection using water Cerenkov 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 addressed two major concerns about the feasibility of such detectors: (1) the transparency of the doped water to the ultraviolet Cerenkov light, and (2) the effect of the doped water on detector materials. We report on the construction of a 19-meter water transparency measuring instrument and associated materials test tank. The first sensitive measurement of the transparency of doped water at 337nm has been made using this instrument (> 35 meters). This transparency is sufficient to proceed to the next stage of building a prototype detector. Materials testing is not yet complete, as materials must be soaked for a year or more to assess the effects. We have measured a 30% decrease in the attenuation length of 337 nm laser light after the addition of GdCl3 to pure water. The capability to measure at other wavelengths exists, and this will be done over the next few months by William Coleman, a student from LSU who will use this experiment as the topic for his Ph.D. thesis. This will provide crucial information needed to predict the behavior of gadolinium-doped water detectors vis-a-vis pure water ones. Final results will be also published in Nuclear Instrumentation and Methods (NIM) A after completion of his thesis. Our preliminary conclusion (assuming that longer wavelengths are no worse than the 337 nm measurement) is that small detectors of length scales 10 meters or less will not suffer significant light loss due to gadolinium chloride doping. Long-term effects, however, are still to be measured.