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The Solar Neutrino Deficit -- Principle and Interest (a Modern Problem)
Sufficient data now exist that tests, independent of any solar model, can be made of whether solar neutrino experiment are consistent with the minimal Standard Model (stable, massless neutrinos). If the experimental uncertainties are correctly estimated and the sun is generating energy by light-element fusion in quasi-static equilibrium, the probability of a standard-physics solution is less than 1.2%. Even when the luminosity constraint is abandoned, the probability is not more than 5%. The sensitivity of the conclusions to input parameters is explored. New experiments nearing completion (SNO and SuperKamiokande) are expected to provide decisive evidence of neutrino oscillations, if they are indeed the explanation
Neutrino Detection using Lead Perchlorate
We discuss the possibility of using lead perchlorate as a neutrino detector.
The primary neutrino interactions are given along with some relevant properties
of the material.Comment: 2 pages, 2 figures, TAUP-99, TEX fil
Background Studies for the Neutral Current Detector Array in the Sudbury Neutrino Observatory
An array of 3He-filled proportional counters will be used in the Sudbury
Neutrino Observatory to measure the neutral-current interaction of neutrinos
and deuterium. We describe the backgrounds to this detection method.Comment: Accepted for publication in the proceedings of TAUP99. 2 page
Arrival time and magnitude of airborne fission products from the Fukushima, Japan, reactor incident as measured in Seattle, WA, USA
We report results of air monitoring started due to the recent natural
catastrophe on 11 March 2011 in Japan and the severe ensuing damage to the
Fukushima Dai-ichi nuclear reactor complex. On 17-18 March 2011, we registered
the first arrival of the airborne fission products 131-I, 132-I, 132-Te,
134-Cs, and 137-Cs in Seattle, WA, USA, by identifying their characteristic
gamma rays using a germanium detector. We measured the evolution of the
activities over a period of 23 days at the end of which the activities had
mostly fallen below our detection limit. The highest detected activity amounted
to 4.4 +/- 1.3 mBq/m^3 of 131-I on 19-20 March.Comment: 7 pages, 5 figures, published in Journal of Environmental
Radioactivit
Solubility, Light Output and Energy Resolution Studies of Molybdenum-Loaded Liquid Scintillators
The search for neutrinoless double-beta decay is an important part of the
global neutrino physics program. One double-beta decay isotope currently under
investigation is 100Mo. In this article, we discuss the results of a
feasibility study investigating the use of molybdenum-loaded liquid
scintillator. A large, molybdenum-loaded liquid scintillator detector is one
potential design for a low-background, internal-source neutrinoless double-beta
decay search with 100Mo. The program outlined in this article included the
selection of a solute containing molybdenum, a scintillating solvent and the
evaluation of the mixture's performance as a radiation detector.Comment: 8 pages, 3 figure
A Compact 3H(p,gamma)4He 19.8-MeV Gamma-Ray Source for Energy Calibration at the Sudbury Neutrino Observatory
The Sudbury Neutrino Observatory (SNO) is a new 1000-tonne D2O Cerenkov solar
neutrino detector. A high energy gamma-ray source is needed to calibrate SNO
beyond the 8B solar neutrino endpoint of 15 MeV. This paper describes the
design and construction of a source that generates 19.8-MeV gamma rays using
the 3H(p,gamma)4He reaction (``pt''), and demonstrates that the source meets
all the physical, operational and lifetime requirements for calibrating SNO. An
ion source was built into this unit to generate and to accelerate protons up to
30 keV, and a high purity scandium tritide target with a scandium-tritium
atomic ratio of 1:2.0+/-0.2 was included. This pt source is the first
self-contained, compact, and portable high energy gamma-ray source (E>10 MeV).Comment: 33 pages (including 2 table, 12 figures) This is the revised
manuscript, accepted for publication in NIM A. This revision relfects minor
editorial changes from the previous versio
Four methods for determining the composition of trace radioactive surface contamination of low-radioactivity metal
Four methods for determining the composition of low-level uranium- and
thorium-chain surface contamination are presented. One method is the
observation of Cherenkov light production in water. In two additional methods a
position-sensitive proportional counter surrounding the surface is used to make
both a measurement of the energy spectrum of alpha particle emissions and also
coincidence measurements to derive the thorium-chain content based on the
presence of short-lived isotopes in that decay chain. The fourth method is a
radiochemical technique in which the surface is eluted with a weak acid, the
eluate is concentrated, added to liquid scintillator and assayed by recording
beta-alpha coincidences. These methods were used to characterize two `hotspots'
on the outer surface of one of the He-3 proportional counters in the Neutral
Current Detection array of the Sudbury Neutrino Observatory experiment. The
methods have similar sensitivities, of order tens of ng, to both thorium- and
uranium-chain contamination.Comment: 22 pages, 19 figure
Solar Neutrinos
Experimental work with solar neutrinos has illuminated the properties of
neutrinos and tested models of how the sun produces its energy. Three
experiments continue to take data, and at least seven are in various stages of
planning or construction. In this review, the current experimental status is
summarized, and future directions explored with a focus on the effects of a
non-zero theta-13 and the interesting possibility of directly testing the
luminosity constraint. Such a confrontation at the few-percent level would
provide a prediction of the solar irradiance tens of thousands of years in the
future for comparison with the present-day irradiance. A model-independent
analysis of existing low-energy data shows good agreement between the neutrino
and electromagnetic luminosities at the +/- 20 % level.Comment: 16 pages, 8 figures. Proceedings of International School on Nuclear
Physics; 27th Course: "Neutrinos in Cosmology, in Astro, Particle and Nuclear
Physics" in Erice, Sicily, Italy; September 16 - 24, 2005. To be published in
Progress Part. Nucl. Phy
The calibration of the Sudbury Neutrino Observatory using uniformly distributed radioactive sources
The production and analysis of distributed sources of 24Na and 222Rn in the
Sudbury Neutrino Observatory (SNO) are described. These unique sources provided
accurate calibrations of the response to neutrons, produced through
photodisintegration of the deuterons in the heavy water target, and to low
energy betas and gammas. The application of these sources in determining the
neutron detection efficiency and response of the 3He proportional counter
array, and the characteristics of background Cherenkov light from trace amounts
of natural radioactivity is described.Comment: 24 pages, 13 figure
Localizability of Tachyonic Particles and Neutrinoless Double Beta Decay
The quantum field theory of superluminal (tachyonic) particles is plagued
with a number of problems, which include the Lorentz non-invariance of the
vacuum state, the ambiguous separation of the field operator into creation and
annihilation operators under Lorentz transformations, and the necessity of a
complex reinterpretation principle for quantum processes. Another unsolved
question concerns the treatment of subluminal components of a tachyonic wave
packets in the field-theoretical formalism, and the calculation of the
time-ordered propagator. After a brief discussion on related problems, we
conclude that rather painful choices have to be made in order to incorporate
tachyonic spin-1/2 particles into field theory. We argue that the field theory
needs to be formulated such as to allow for localizable tachyonic particles,
even if that means that a slight unitarity violation is introduced into the S
matrix, and we write down field operators with unrestricted momenta. We find
that once these choices have been made, the propagator for the neutrino field
can be given in a compact form, and the left-handedness of the neutrino as well
as the right-handedness of the antineutrino follow naturally. Consequences for
neutrinoless double beta decay and superluminal propagation of neutrinos are
briefly discussed.Comment: 12 pages, 5 figure
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