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Title: An array of low-background 3He proportional counters for theSudbury Neutrino Observatory

Abstract

An array of Neutral-Current Detectors (NCDs) has been builtin order to make a unique measurement of the total active ux of solarneutrinos in the Sudbury Neutrino Observatory (SNO). Data in the thirdphase of the SNO experiment were collected between November 2004 andNovember 2006, after the NCD array was added to improve theneutral-current sensitivity of the SNO detector. This array consisted of36 strings of proportional counters lled with a mixture of 3He and CF4gas capable of detecting the neutrons liberated by the neutrino-deuteronneutral current reaction in the D2O, and four strings lled with a mixtureof 4He and CF4 gas for background measurements. The proportional counterdiameter is 5 cm. The total deployed array length was 398 m. The SNO NCDarray is the lowest-radioactivity large array of proportional countersever produced. This article describes the design, construction,deployment, and characterization of the NCD array, discusses theelectronics and data acquisition system, and considers event signaturesand backgrounds.

Authors:
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Publication Date:
Research Org.:
COLLABORATION - Sudbury NeutrinoObservatory
OSTI Identifier:
929668
Report Number(s):
LBNL-63390
Journal ID: ISSN 0167-5087; NIMRD9; TRN: US0803507
DOE Contract Number:
DE-AC02-05CH11231
Resource Type:
Journal Article
Resource Relation:
Journal Name: Nuclear Instruments and Methods in PhysicsResearch; Journal Volume: A 579; Related Information: Journal Publication Date: 2007
Country of Publication:
United States
Language:
English
Subject:
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; CONSTRUCTION; DATA ACQUISITION SYSTEMS; DESIGN; MIXTURES; NEUTRAL CURRENTS; NEUTRONS; PROPORTIONAL COUNTERS; SENSITIVITY; SOLAR NEUTRINOS; SUDBURY NEUTRINO OBSERVATORY

Citation Formats

Amsbaugh, J.F., Anaya, J.M., Banar, J., Bowles, T.J., Browne,M.C., Bullard, T.V., Burritt, T.H., Cox-Mobrand, G.A., Dai, X., H.Deng,X., Di Marco, M., Doe, P.J., Dragowsky, M.R., Duba, C.A., Duncan, F.A., Earle, E.D., Elliott, S.R., Esch, E.-I., Fergani, H., Formaggio, J.A., Fowler, M.M., Franklin, J.E., Geissbuehler, P., Germani, J.V., Goldschmidt, A., Guillian, E., Hallin, A.L., Harper, G., Harvey, P.J., Hazama, R., Heeger, K.M., Heise, J., Hime, A., Howe, M.A., Huang, M., Kormos, L.L., Kraus, C., Krauss, C.B., Law, J., Lawson, I.T., Lesko,K.T., Loach, J.C., Majerus, S., Manor, J., McGee, S., Miknaitis, K.K.S., Miller, G.G., Morissette, B., Myers, A., Oblath, N.S., O'Kee, H.M., Ollerhead, R.W., Peeters, S.J.M., Poon, A.W.P., Prior, G., Reitzner,S.D., Rielage, K., Robertson, R.G.H., Skensved, P., Smith, A.R., Smith,M.W.E., Steiger, T.D., Stonehill,L.C., Thornewell, P.M., Tolich, N., VanDevender, B.A., VanWechel, T.D., Wall, B.L., Tseung, H.W.C., Wendland,J., West, N., Wilhelmy, J.B., Wilkerson, J.F., and Wouters, J.M. An array of low-background 3He proportional counters for theSudbury Neutrino Observatory. United States: N. p., 2007. Web.
Amsbaugh, J.F., Anaya, J.M., Banar, J., Bowles, T.J., Browne,M.C., Bullard, T.V., Burritt, T.H., Cox-Mobrand, G.A., Dai, X., H.Deng,X., Di Marco, M., Doe, P.J., Dragowsky, M.R., Duba, C.A., Duncan, F.A., Earle, E.D., Elliott, S.R., Esch, E.-I., Fergani, H., Formaggio, J.A., Fowler, M.M., Franklin, J.E., Geissbuehler, P., Germani, J.V., Goldschmidt, A., Guillian, E., Hallin, A.L., Harper, G., Harvey, P.J., Hazama, R., Heeger, K.M., Heise, J., Hime, A., Howe, M.A., Huang, M., Kormos, L.L., Kraus, C., Krauss, C.B., Law, J., Lawson, I.T., Lesko,K.T., Loach, J.C., Majerus, S., Manor, J., McGee, S., Miknaitis, K.K.S., Miller, G.G., Morissette, B., Myers, A., Oblath, N.S., O'Kee, H.M., Ollerhead, R.W., Peeters, S.J.M., Poon, A.W.P., Prior, G., Reitzner,S.D., Rielage, K., Robertson, R.G.H., Skensved, P., Smith, A.R., Smith,M.W.E., Steiger, T.D., Stonehill,L.C., Thornewell, P.M., Tolich, N., VanDevender, B.A., VanWechel, T.D., Wall, B.L., Tseung, H.W.C., Wendland,J., West, N., Wilhelmy, J.B., Wilkerson, J.F., & Wouters, J.M. An array of low-background 3He proportional counters for theSudbury Neutrino Observatory. United States.
Amsbaugh, J.F., Anaya, J.M., Banar, J., Bowles, T.J., Browne,M.C., Bullard, T.V., Burritt, T.H., Cox-Mobrand, G.A., Dai, X., H.Deng,X., Di Marco, M., Doe, P.J., Dragowsky, M.R., Duba, C.A., Duncan, F.A., Earle, E.D., Elliott, S.R., Esch, E.-I., Fergani, H., Formaggio, J.A., Fowler, M.M., Franklin, J.E., Geissbuehler, P., Germani, J.V., Goldschmidt, A., Guillian, E., Hallin, A.L., Harper, G., Harvey, P.J., Hazama, R., Heeger, K.M., Heise, J., Hime, A., Howe, M.A., Huang, M., Kormos, L.L., Kraus, C., Krauss, C.B., Law, J., Lawson, I.T., Lesko,K.T., Loach, J.C., Majerus, S., Manor, J., McGee, S., Miknaitis, K.K.S., Miller, G.G., Morissette, B., Myers, A., Oblath, N.S., O'Kee, H.M., Ollerhead, R.W., Peeters, S.J.M., Poon, A.W.P., Prior, G., Reitzner,S.D., Rielage, K., Robertson, R.G.H., Skensved, P., Smith, A.R., Smith,M.W.E., Steiger, T.D., Stonehill,L.C., Thornewell, P.M., Tolich, N., VanDevender, B.A., VanWechel, T.D., Wall, B.L., Tseung, H.W.C., Wendland,J., West, N., Wilhelmy, J.B., Wilkerson, J.F., and Wouters, J.M. Thu . "An array of low-background 3He proportional counters for theSudbury Neutrino Observatory". United States. doi:. https://www.osti.gov/servlets/purl/929668.
@article{osti_929668,
title = {An array of low-background 3He proportional counters for theSudbury Neutrino Observatory},
author = {Amsbaugh, J.F. and Anaya, J.M. and Banar, J. and Bowles, T.J. and Browne,M.C. and Bullard, T.V. and Burritt, T.H. and Cox-Mobrand, G.A. and Dai, X. and H.Deng,X. and Di Marco, M. and Doe, P.J. and Dragowsky, M.R. and Duba, C.A. and Duncan, F.A. and Earle, E.D. and Elliott, S.R. and Esch, E.-I. and Fergani, H. and Formaggio, J.A. and Fowler, M.M. and Franklin, J.E. and Geissbuehler, P. and Germani, J.V. and Goldschmidt, A. and Guillian, E. and Hallin, A.L. and Harper, G. and Harvey, P.J. and Hazama, R. and Heeger, K.M. and Heise, J. and Hime, A. and Howe, M.A. and Huang, M. and Kormos, L.L. and Kraus, C. and Krauss, C.B. and Law, J. and Lawson, I.T. and Lesko,K.T. and Loach, J.C. and Majerus, S. and Manor, J. and McGee, S. and Miknaitis, K.K.S. and Miller, G.G. and Morissette, B. and Myers, A. and Oblath, N.S. and O'Kee, H.M. and Ollerhead, R.W. and Peeters, S.J.M. and Poon, A.W.P. and Prior, G. and Reitzner,S.D. and Rielage, K. and Robertson, R.G.H. and Skensved, P. and Smith, A.R. and Smith,M.W.E. and Steiger, T.D. and Stonehill,L.C. and Thornewell, P.M. and Tolich, N. and VanDevender, B.A. and VanWechel, T.D. and Wall, B.L. and Tseung, H.W.C. and Wendland,J. and West, N. and Wilhelmy, J.B. and Wilkerson, J.F. and Wouters, J.M.},
abstractNote = {An array of Neutral-Current Detectors (NCDs) has been builtin order to make a unique measurement of the total active ux of solarneutrinos in the Sudbury Neutrino Observatory (SNO). Data in the thirdphase of the SNO experiment were collected between November 2004 andNovember 2006, after the NCD array was added to improve theneutral-current sensitivity of the SNO detector. This array consisted of36 strings of proportional counters lled with a mixture of 3He and CF4gas capable of detecting the neutrons liberated by the neutrino-deuteronneutral current reaction in the D2O, and four strings lled with a mixtureof 4He and CF4 gas for background measurements. The proportional counterdiameter is 5 cm. The total deployed array length was 398 m. The SNO NCDarray is the lowest-radioactivity large array of proportional countersever produced. This article describes the design, construction,deployment, and characterization of the NCD array, discusses theelectronics and data acquisition system, and considers event signaturesand backgrounds.},
doi = {},
journal = {Nuclear Instruments and Methods in PhysicsResearch},
number = ,
volume = A 579,
place = {United States},
year = {Thu Feb 01 00:00:00 EST 2007},
month = {Thu Feb 01 00:00:00 EST 2007}
}
  • The Sudbury Neutrino Observatory (SNO) used an array of {sup 3}He proportional counters to measure the rate of neutral-current interactions in heavy water and precisely determined the total active ({nu}{sub x}) {sup 8}B solar neutrino flux. This technique is independent of previous methods employed by SNO. The total flux is found to be 5.54{sub -0.31}{sup +0.33}(stat){sub -0.34}{sup +0.36}(syst) x 10{sup 6} cm{sup -2}s{sup -1}, in agreement with previous measurements and standard solar models. A global analysis of solar and reactor neutrino results yields {Delta}m{sup 2} = 7.94{sub -0.26}{sup +0.42} x 10{sup -5} eV{sup 2} and {theta} = 33.8{sub -1.3}{sup +1.4}more » degrees. The uncertainty on the mixing angle has been reduced from SNO's previous results.« less
  • Current solar neutrino detectors measure a considerably lower flux of electron-flavor neutrinos than predicted by solar models. This could be an indication of neutrino oscillations, which would provide direct evidence that neutrinos have mass. The Sudbury Neutrino Observatory (SNO) was designed to detect all flavors of neutrinos, and will provide a rigorous test of this theory. The SNO detector`s heavy water target gives it the unique ability to detect all non-sterile neutrino flavors via the neutral-current (NC) break-up of the deuteron. This NC interaction liberates a neutron which may be detected with an array of discrete {sup 3}He proportional counters.more » The strict radioactivity requirements imposed by the need for low backgrounds dictate the use of ultra-pure materials and processes in building these counters. Additionally, they must survive in the heavy water environment for several years. The design, construction, and testing of these unique counters are described.« less
  • The Sudbury Neutrino Observatory (SNO) used an array of {sup 3}He proportional counters to measure the rate of neutral-current interactions in heavy water and precisely determined the total active ({nu}{sub x}) {sup 8}B solar neutrino flux. This technique is independent of previous methods employed by SNO. The total flux is found to be 5.54{sub -0.31}{sup +0.33}(stat){sub -0.34}{sup +0.36}(syst)x10{sup 6} cm{sup -2} s{sup -1}, in agreement with previous measurements and standard solar models. A global analysis of solar and reactor neutrino results yields {delta}m{sup 2}=7.59{sub -0.21}{sup +0.19}x10{sup -5} eV{sup 2} and {theta}=34.4{sub -1.2}{sup +1.3} degrees. The uncertainty on the mixing anglemore » has been reduced from SNO's previous results.« less
  • Age dating groundwater and seawater using 39Ar/Ar ratios is an important tool to understand water mass flow rates and mean residence time. For modern or contemporary argon, the 39Ar activity is 1.8 mBq per liter of argon. Radiation measurements at these activity levels require ultra low-background detectors. Low-background proportional counters have been developed at Pacific Northwest National Laboratory. These detectors use traditional mixtures of argon and methane as counting gas, and the residual 39Ar from commercial argon has become a predominant source of background activity in these detectors. We demonstrated sensitivity to 39Ar by using geological or ancient argon frommore » gas wells in place of commercial argon. The low level counting performance of these proportional counters is then demonstrated for sensitivities to 39Ar/Ar ratios sufficient to date water masses as old as 1000 years.« less