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A sensitive assay technique for <sup>210</sup>Pb in water

2020· article· en· W3000650568 on OpenAlexaffabout
D. Chauhan, O. Chkvorets

Bibliographic record

VenueJournal of Physics Conference Series · 2020
Typearticle
Languageen
FieldPhysics and Astronomy
TopicNeutrino Physics Research
Canadian institutionsLaurentian UniversitySnolabQueen's University
Fundersnot available
KeywordsScintillatorUltrapure waterRadiochemistryElectromagnetic shieldingContaminationLiquid scintillation countingShieldsSeawaterChemistryNuclear physicsNuclear chemistryAnalytical Chemistry (journal)PhysicsEnvironmental chemistryEnvironmental scienceDetectorGeologyEnvironmental engineering

Abstract

fetched live from OpenAlex

Abstract SNO+ is a multipurpose neutrino physics experiment, located 2 kilometers underground in the SNOLAB facility in Sudbury, Canada. It is the successor of the SNO experiment, replacing the heavy water in the Acrylic vessel (AV) with 780 tons of liquid scintillator, Linear Alkyl Benzene (LAB). The AV is surrounded by 7000 tons of ultrapure light water, which shields the detector from naturally occurring radioactivity in the surrounding rock, PMTs, and PSUP. To achieve the radiopurity requirements, the water should be very clean and levels of U and Th contamination in the shielding water must be carefully controlled. A water assay technique, based on the capture of Ra and Th radioisotopes using Hydrous Titanium Oxide (HTiO), was developed by the SNO experiment. Ra sensitivities equivalent to 232Th: 4×10−16 gTh/D2O and 238U: 3×10−16 gU/g D2O were achieved with this technique [1]. The HTiO technique will be used in SNO+ to monitor 238U and 232Th contamination levels in the shielding water and the performance of the water purification system. For the lower energy measurements of interest to SNO+, radon daughter radioisotopes, especially 210Po and 210Bi supported by 210Pb, are also important. Since water will be used in the purification of both the liquid scintillator and tellurium that will be chemically loaded in SNO+ to search for neutrinoless double beta decay, a technique to assay for 210Pb in water was desirable. The SNO+ collaboration has extended the HTiO assay technique to allow measurement of 210Pb in the water. This technique is capable of measuring 0.4 +/- 0.13 mBq/m3 of 210Pb for a 10 tonne assay. The method developed and results of initial 210Pb measurements are presented.

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 imitation

Not 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.

metaresearch head score (Codex)0.000
metaresearch head score (Gemma)0.001
Version: metacan-v3-hybrid-931329e0061cValidation status: machine_predicted_unvalidated
Candidate categoriesnone
Consensus categoriesnone
DomainCandidate signal: none · Consensus signal: none
Study designCandidate signal: Bench or experimental · Consensus signal: Bench or experimental
GenreCandidate signal: Methods · Consensus signal: Methods
Teacher disagreement score0.002
Threshold uncertainty score0.006

Distilled classifier scores by category (both heads)

CategoryCodexGemma
Metaresearch0.0000.001
Meta-epidemiology (narrow)0.0010.000
Meta-epidemiology (broad)0.0000.000
Bibliometrics0.0010.000
Science and technology studies0.0000.000
Scholarly communication0.0000.000
Open science0.0010.000
Research integrity0.0000.000
Insufficient payload (model declined to judge)0.0020.002

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.

Opus teacher head0.036
GPT teacher head0.291
Teacher spread0.255 · how far apart the two teachers sit on this one work
Validation statusscore_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from it

Classification

machine, unvalidated

Machine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.

The models applied no category: nothing in the taxonomy fit this work.
Study designBench or experimental
Domainnot available
GenreMethods

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".

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Citations1
Published2020
Admission routes2
Has abstractyes

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