Analysis of the Po-210 Alpha-Decay Peak to Support the Search for Neutrinoless Double Beta Decay
Bibliographic record
Abstract
Neutrinos are among the most mysterious particles in physics, and one of the most important open questions is whether they are their own antiparticles. The discovery of a process called neutrinoless double beta decay would answer this question and provide direct insight into the origin of neutrino mass. The SNO+ experiment is designed to search for this process by observing rare signals in a large volume of liquid scintillator deep underground. For such a search to be successful, the detector’s energy calibration must be extremely precise, since even small instabilities can obscure or mimic the rare signals of interest. One key calibration point comes from the natural alpha decay of polonium-210 (Po-210), which produces a peak in the energy spectrum. By carefully studying this peak under different conditions, we can test the stability of the detector response and improve background modelling. In my work, I analyzed data from the scintillator phase of SNO+, focusing on how consistently the Po-210 peak could be reconstructed. Candidate neutrino interactions known as inverse beta decays were used as reference points, and distance cuts of 2.5 m around events were applied to probe spatial uniformity across the detector. The resulting energy distributions were then fit with Gaussian functions to extract the peak position, width, and uncertainties under varying selections. I found that the Po-210 peak was consistently reconstructed at 0.455 +/- 0.005 MeV across different regions and data-taking periods, confirming the stability of the analysis method. At later times, however, the peak shifted toward higher energy (~0.75 MeV), suggesting potential changes in the detector environment following the bis-MSB fill period. This work demonstrates a reliable framework for monitoring natural radioactivity in SNO+. Analysis of the Po-210 peak directly strengthens the sensitivity of the experiment to neutrinoless double beta decay, helping SNO+ probe fundamental questions in particle physics.
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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 | 0.001 | 0.002 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.001 |
| Bibliometrics | 0.002 | 0.002 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.002 | 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".