The Sudbury Neutrino Observatory

The Sudbury Neutrino Observatory is a second generation water Cherenkov detector designed to determine whether the currently observed solar neutrino deficit is a result of neutrino oscillations. The detector is unique in its use of D2O as a detection medium, permitting it to make a solar model-independent test of the neutrino oscillation hypothesis by comparison of the charged- and neutral-current interaction rates. In this paper the physical properties, construction, and preliminary operation of the Sudbury Neutrino Observatory are described. Data and predicted operating parameters are provided whenever possible.Comment: 58 pages, 12 figures, submitted to Nucl. Inst. Meth. Uses elsart and epsf style files. For additional information about SNO see http://www.sno.phy.queensu.ca . This version has some new reference

Measurement of the νe and total 8B solar neutrino fluxes with the Sudbury Neutrino Observatory phase-III data set

This paper details the solar neutrino analysis of the 385.17-day phase-III data set acquired by the Sudbury Neutrino Observatory (SNO). An array of 3He proportional counters was installed in the heavy-water target to measure precisely the rate of neutrino-deuteron neutral-current interactions. This technique to determine the total active 8B solar neutrino flux was largely independent of the methods employed in previous phases. The total flux of active neutrinos was measured to be 5.54-0.31+0.33(stat.)-0.34+0.36(syst.)×106 cm-2 s-1, consistent with previous measurements and standard solar models. A global analysis of solar and reactor neutrino mixing parameters yielded the best-fit values of Δm2=7.59-0.21+0.19×10 -5eV2 and θ=34.4-1.2+1.3degrees

First neutrino observations from the sudbury neutrino observatory

The first neutrino observations from the Sudbury Neutrino Observatory are presented from preliminary analyses. Based on energy, direction and location, the data in the region of interest appear to be dominated by 8B solar neutrinos, detected by the charged current reaction on deuterium and elastic scattering from electrons, with very little background. Measurements of radioactive backgrounds indicate that the measurement of all active neutrino types via the neutral current reaction on deuterium will be possible with small systematic uncertainties. Quantitative results for the fluxes observed with these reactions will be provided when further calibrations have been completed

Measurement of CC interactions produced by8B solar neutrinos at SNO

The Sudbury Neutrino Observatory (SNO) is a 1000 tonne heavy water Cherenkov detector placed 2 km underground in Ontario, Canada. Its main purpose is the detection of solar neutrinos, but it is also sensitive to atmospheric and supernova neutrinos. In this paper we report our first measurement of the solar electron-type neutrino flux using the charged current interaction on deuterium, above an electron kinetic energy threshold of 6.75 MeV. This measurement, when compared with an electron scattering measurement from Super Kamiokande, provides the first evidence for non-electron neutrino types from the Sun implying flavor change of solar electron neutrinos. We also present an initial angular distribution of through-going muons, which shows that we can detect neutrino-induced muons from well above the horizontal. This will give us good sensitivity to neutrino oscillations in the atmospheric sector

Measurement of the nue and Total 8B Solar Neutrino Fluxes with the Sudbury Neutrino Observatory Phase I Data Set

This article provides the complete description of results from the Phase I data set of the Sudbury Neutrino Observatory (SNO). The Phase I data set is based on a 0.65 kt-year exposure of heavy water to the solar 8B neutrino flux. Included here are details of the SNO physics and detector model, evaluations of systematic uncertainties, and estimates of backgrounds. Also discussed are SNO's approach to statistical extraction of the signals from the three neutrino reactions (charged current, neutral current, and elastic scattering) and the results of a search for a day-night asymmetry in the ?e flux. Under the assumption that the 8B spectrum is undistorted, the measurements from this phase yield a solar ?e flux of ?(?e) = 1.76+0.05?0.05(stat.)+0.09?0.09 (syst.) x 106 cm?2 s?1, and a non-?e component ?(? mu) = 3.41+0.45?0.45(stat.)+0.48?0.45 (syst.) x 106 cm?2 s?1. The sum of these components provides a total flux in excellent agreement with the predictions of Standard Solar Models. The day-night asymmetry in the ?e flux is found to be Ae = 7.0 +- 4.9 (stat.)+1.3?1.2 percent (sys.), when the asymmetry in the total flux is constrained to be zero