The W-chair whole body counter: a Monte Carlo investigation
Bibliographic record
Abstract
The W-chair whole body counting geometry, a derivative of the meter-arc counting geometry, has been examined using Monte Carlo simulations to investigate the effect of phantom size on the counting efficiency. Three detector positions were simulated (42 cm, 71 cm, and 100 cm from the chair), with one being very close to the physical counting geometry in use at the Whiteshell Laboratories, to investigate the effects of detector-chair distance. The agreement of the simulations with observed counting efficiencies was within 7% over the energy region of 122 keV to 1,173 keV. The optimum counting geometry was found to be the 71-cm detector-chair distance as this balances both sensitivity and counting efficiency. The range of relative counting efficiencies is 0.94 to 1.13 for all energies studied (126 keV to 2,754 keV) and selected phantom sizes relative to the Reference Man phantom. This range also represents the extent of the activity estimate's uncertainty if no size correction factors are applied during routine counting and shows the W-chair counting geometry to be relatively subject-size independent.
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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 | 0.002 | 0.006 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.001 | 0.002 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.001 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
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".