Mechanical and Optical Design of the HIRAX Radio Telescope
Bibliographic record
Abstract
The Hydrogen Intensity and Real-time Analysis eXperiment (HIRAX) is a planned\ninterferometric radio telescope array that will ultimately consist of 1024\nclose packed 6 m dishes that will be deployed at the SKA South Africa site.\nHIRAX will survey the majority of the southern sky to measure baryon acoustic\noscillations (BAO) using the 21 cm hyperfine transition of neutral hydrogen. It\nwill operate between 400-800 MHz with 391 kHz resolution, corresponding to a\nredshift range of $0.8 < z < 2.5$ and a minimum $\\Delta z/z$ of ~0.003. One of\nthe primary science goals of HIRAX is to constrain the dark energy equation of\nstate by measuring the BAO scale as a function of redshift over a\ncosmologically significant range. Achieving this goal places stringent\nrequirements on the mechanical and optical design of the HIRAX instrument which\nare described in this paper. This includes the simulations used to optimize the\ninstrument, including the dish focal ratio, receiver support mechanism, and\ninstrument cabling. As a result of these simulations, the dish focal ratio has\nbeen reduced to 0.23 to reduce inter-dish crosstalk, the feed support mechanism\nhas been redesigned as a wide (35 cm diam.) central column, and the feed design\nhas been modified to allow the cabling for the receiver to pass directly along\nthe symmetry axis of the feed and dish in order to eliminate beam asymmetries\nand reduce sidelobe amplitudes. The beams from these full-instrument\nsimulations are also used in an astrophysical m-mode analysis pipeline which is\nused to evaluate cosmological constraints and determine potential systematic\ncontamination due to physical non-redundancies of the array elements. This\nend-to-end simulation pipeline was used to inform the dish manufacturing and\nassembly specifications which will guide the production and construction of the\nfirst-stage HIRAX 256-element array.\n
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| 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 | 0.001 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 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 teacher head, 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".