Shielding and Handling of Targets for a High Intensity Radioactive Ion Beam Facility
Bibliographic record
Abstract
There has been a steadily growing worldwide interest in generating accelerated beams of unstable nuclei for use in a variety of applications such as nuclear physics, nuclear astrophysics, atomic and condensed matter physics, and medicine. A number of facilities, either planned or under construction, will couple an intense production source of unstable elements to an efficient accelerator in order to produce accelerated ion beams of a wide range of nuclei far from stability. We describe here the production targets and their shielding as designed and constructed for ISAC, the high-intensity accelerated radioactive ion beam facility at TRIUMF.The shielding for the targets is integrated into each target module so that all services and radiation-sensitive connections are made outside the shielding and the vacuum enclosure. This allows the use of, for example, elastomer seals for the vacuum connections. Including the weight of the steel shielding, each target module weighs approximately 15 tonnes. For servicing, the target modules are removed vertically by a remotely operated crane. The modules may then be transported either to one of two hot cells for maintenance or to a storage silo. The remotely controlled transport takes place in the Target Maintenance Hall. This is a shielded, ventilated building that allows the target modules to be transported without shielding for the induced radioactivity.We also present some observations of experience during the initial commissioning at low and medium proton beam intensities.
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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 | 0.001 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.000 |
| Science and technology studies | 0.001 | 0.000 |
| Scholarly communication | 0.000 | 0.001 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.005 | 0.002 |
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.
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".