Past, Present, and Future of Solar Neutrino Detection: SNO, SNO+, and Theia
Bibliographic record
Abstract
This thesis represents a comprehensive study of solar neutrinos spanning three generations of solar neutrino detection techniques. Data from the Sudbury Neutrino Observatory (SNO), a heavy water detector instrumental in demonstrating flavor change in the neutrino sector, is used to set a limit on the lifetime of massive neutrino states within a model where said states can decay. The analysis of SNO data finds a limit of $k_2>8.08 \\times 10^{-5}$~s/eV at 90\\% confidence for the lifetime of $\\nu_2$. Combining this limit with constraints from all other solar neutrino experiments, a new global best limit is found at $k_2>1.92 \\times 10^{-3}$~s/eV at 90\\% confidence for the lifetime of $\\nu_2$.The upgrade of the SNO detector, SNO+, is currently in the process of migrating to a liquid scintillator target material. Prior to this, SNO+ produced a physics dataset with light water as the target, which was analyzed to extract the flux of $^8$B solar neutrinos. This analysis resulted in a measured flux of $\\Phi_{\\mathrm{^8B}} = 5.95^{+0.75}_{-0.71}\\mathrm{(stat.)}^{+0.28}_{-0.20}\\mathrm{(syst.)} \\times 10^6\\,\\,\\mathrm{cm}^{-2}\\mathrm{s}^{-1}$. Further, this analysis demonstrated SNO+ has achieved very low backgrounds above 6.0~MeV visible energy. To aid in detector calibrations as SNO+ moves from water to scintillator, the design and evaluation of a Cherenkov optical calibration source is presented.With an eye on the future, the capabilities of the proposed Theia experiment are discussed, with particular attention to the novel water-based liquid scintillator target being evaluated for use by that experiment. A small scale experiment to evaluate the prospects of distinguishing scintillation and Cherenkov light in this target is described. Results are presented demonstrating the potential for identification of Cherenkov photons by timing and intensity information for this water-based liquid scintillator, and for a more traditional scintillator, LAB+PPO.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.011 | 0.010 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.002 | 0.003 |
| Science and technology studies | 0.001 | 0.003 |
| Scholarly communication | 0.007 | 0.006 |
| Open science | 0.001 | 0.003 |
| Research integrity | 0.001 | 0.003 |
| Insufficient payload (model declined to judge) | 0.003 | 0.001 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".