Demonstration of a solid deuterium source of ultra-cold neutrons

Ultra-cold neutrons (UCN), neutrons with energies low enough to be confined by the Fermi potential in material bottles, are playing an increasing role in measurements of fundamental properties of the neutron. The ability to manipulate UCN with material guides and bottles, magnetic fields, and gravity can lead to experiments with lower systematic errors than have been obtained in experiments with cold neutron beams. The UCN densities provided by existing reactor sources limit these experiments. The promise of much higher densities from solid deuterium sources has led to proposed facilities coupled to both reactor and spallation neutron sources. In this paper we report on the performance of a prototype spallation neutron-driven solid deuterium source. This source produced bottled UCN densities of 145 +/-7 UCN/cm3, about three times greater than the largest bottled UCN densities previously reported. These results indicate that a production UCN source with substantially higher densities should be possible

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

Supernova neutrino detection in NOvA

The NOvA long-baseline neutrino experiment uses a pair of large, segmented, liquid-scintillator calorimeters to study neutrino oscillations, using GeV-scale neutrinos from the Fermilab NuMI beam. These detectors are also sensitive to the flux of neutrinos which are emitted during a core-collapse supernova through inverse beta decay interactions on carbon at energies of O(10 MeV). This signature provides a means to study the dominant mode of energy release for a core-collapse supernova occurring in our galaxy. We describe the data-driven software trigger system developed and employed by the NOvA experiment to identify and record neutrino data from nearby galactic supernovae. This technique has been used by NOvA to self-trigger on potential core-collapse supernovae in our galaxy, with an estimated sensitivity reaching out to 10 kpc distance while achieving a detection efficiency of 23% to 49% for supernovae from progenitor stars with masses of 9.6 M☉ to 27 M☉, respectively

Experiment to study the. beta. -decay of free atomic and molecular tritium. [For determining antineutrino mass]

An apparatus is described which will allow the measurement of the ..beta..-decay of free tritium atoms and molecules for determining antineutrino mass. It consists of an RF dissociator, a long cylindrical decay region open at both ends, a guide field, and a magnetic spectrometer