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Title: Feasibility Study for Large Water-Based Neutron and Neutrino Detection

Abstract

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.more » 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.« less

Authors:
; ; ;
Publication Date:
Research Org.:
Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
1036852
Report Number(s):
UCRL-TR-229205
TRN: US1201527
DOE Contract Number:
W-7405-ENG-48
Resource Type:
Technical Report
Country of Publication:
United States
Language:
English
Subject:
46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND TECHNOLOGY; ATTENUATION; CHERENKOV COUNTERS; DOPED MATERIALS; GADOLINIUM; GADOLINIUM CHLORIDES; LASERS; MATERIALS TESTING; MEASURING INSTRUMENTS; METERS; NATIONAL SECURITY; NEUTRINO DETECTION; NEUTRON DETECTION; WATER; WAVELENGTHS

Citation Formats

C.Svoboda, R, Bernstein, A, Coleman, W, and Dazeley, S A. Feasibility Study for Large Water-Based Neutron and Neutrino Detection. United States: N. p., 2007. Web. doi:10.2172/1036852.
C.Svoboda, R, Bernstein, A, Coleman, W, & Dazeley, S A. Feasibility Study for Large Water-Based Neutron and Neutrino Detection. United States. doi:10.2172/1036852.
C.Svoboda, R, Bernstein, A, Coleman, W, and Dazeley, S A. Tue . "Feasibility Study for Large Water-Based Neutron and Neutrino Detection". United States. doi:10.2172/1036852. https://www.osti.gov/servlets/purl/1036852.
@article{osti_1036852,
title = {Feasibility Study for Large Water-Based Neutron and Neutrino Detection},
author = {C.Svoboda, R and Bernstein, A and Coleman, W and Dazeley, S A},
abstractNote = {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.},
doi = {10.2172/1036852},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Tue Mar 13 00:00:00 EDT 2007},
month = {Tue Mar 13 00:00:00 EDT 2007}
}

Technical Report:

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  • No abstract prepared.
  • Water Cherenkov detectors have been used for many years as inexpensive, effective detectors for neutrino interactions and nucleon decay searches. While many important measurements have been made with these detectors a major drawback has been their inability to detect the absorption of thermal neutrons. We believe an inexpensive, effective technique could be developed to overcome this situation via the addition to water of a solute with a large neutron cross section and energetic gamma daughters which would make neutrons detectable. Gadolinium seems an excellent candidate especially since in recent years it has become very inexpensive, now less than $8 permore » kilogram in the form of commercially-available gadolinium trichloride, GdCl{sub 3}. This non-toxic, non-reactive substance is highly soluble in water. Neutron capture on gadolinium yields a gamma cascade which would be easily seen in detectors like Super-Kamiokande. We have begun to investigate the use of GdCl{sub 3} as a possible upgrade for the Super-Kamiokande detector with a view toward improving its performance as a detector for atmospheric neutrinos, supernova neutrinos, wrong-sign solar neutrinos, reactor neutrinos, proton decay, and also as a target for the coming T2K long-baseline neutrino experiment. This large-scale investigation, conducted in the one kiloton water Cherenkov detector built for the K2K long-baseline experiment, follows up on highly promising benchtop-scale work previously carried out with the assistance of a 2003 Advanced Detector Research Program grant.« less
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