Robust Signal Extraction Methods and Monte Carlo Sensitivity Studies for the Sudbury Neutrino Observatory and SNO+ Experiments
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Authors
Wright, Alexander
Date
2009-09-15T23:01:54Z
Type
thesis
Language
eng
Keyword
Sudbury Neutrino Observatory , SNO+ , neutrino , neutrinoless double beta decay
Alternative Title
Abstract
The third and final phase of the Sudbury Neutrino Observatory (SNO)
experiment utilized a series of 3He proportional counters called
Neutral Current Detectors (NCDs) to detect the neutrons produced by
the neutral current interactions of solar neutrinos in the
detector. The number of neutrons detected by the NCDs, and hence the
total flux of 8B solar neutrinos, has been determined using two
novel signal extraction techniques which were designed to be robust
against potential unexpected behaviour in the NCD background. These
techniques yield total 8B solar neutrino flux measurements of
5.04(+0.42-0.40(stat))(+/-0.28(syst))x10E6/cm2/s
and (4.40 - 6.43)x10E6/cm2/s, which are in good agreement
with previous SNO results and with solar model
predictions, and which confirm that previous NCD analyses were not
unduly affected by unexpected background behaviour.
The majority of the hardware from the now-completed SNO experiment
will be reused to create a new liquid scintillator based neutrino
experiment called SNO+. An important part of the SNO+ physics
program will be a search for neutrinoless double beta decay, carried
out by dissolving 150Nd into the scintillator. The sensitivity of
the SNO+ experiment to neutrinoless double beta decay has been
evaluated. If loaded at 0.1% (w/w) with natural neodymium, after
1 kTa of data taking SNO+ would
have a 90%C.L. sensitivity equivalent to a neutrinoless double beta decay half life of 8.0x10E24a or better 50%
of the time; if the experiment were run with neodymium enriched to 50% in 150Nd this
limit improves to 57x10E24a. Under a reasonable choice for the
150Nd neutrinoless double beta decay matrix element, these half lives correspond
to upper limits on the effective Majorana neutrino mass of 112 meV and
42 meV, respectively. These limits are competitive with those expected from all other
near-term neutrinoless double beta decay experiments.
Description
Thesis (Ph.D, Physics, Engineering Physics and Astronomy) -- Queen's University, 2009-09-10 21:07:00.25
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