Poster - Thur Eve - 66: Investigation of Shielding Property Changes in Curing High Density Concrete
Bibliographic record
Abstract
Our centre is currently undergoing a major expansion, including the construction of two new linear accelerator radiotherapy bunkers and the addition of extra shielding to existing bunkers. While shielding material is typically specified by Tenth-Value Layer (TVL) at the design stage, the concrete supplier will specify the (wet) densities of the concrete constituents, and the concrete testing lab will verify the as-cast material by its dry (cured) density. Thus, the relationship between the intended TVL and the actual performance of the shielding material might not be entirely clear. In this study, cylindrical samples of the high-density shielding concrete were taken as each section was poured. The shielding performance of the samples (measured by beam attenuation and TVL) was evaluated for 15 MV and 6 MV X-ray beams, and for the 1.25 MeV monoenergetic gamma beam from a Cobalt-60 (Co-60) source. The samples were also imaged and analyzed using Cobalt-60 Cone Beam Computed Tomography (CoCBCT). Results indicate no significant change in the TVL of high-density concrete samples as they cure. The minor fluctuations in shielding properties observed are explained by the heterogeneous structure of the samples as indicated in the CoCBCT images.
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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 | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.002 | 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".