Progress on a Novel 7BA Lattice for a 196-m Circumference Diffraction-Limited Soft X-Ray Storage Ring
Bibliographic record
Abstract
The ALS Upgrade to a diffraction-limited soft x-ray storage ring calls for ultralow emittance in a very limited circumference. In this paper we report on progress with a lattice based on a 7BA with distributed chromatic correction. This lattice relies heavily on longitudinal gradient bends and reverse bending in order to suppress the emittance, so that, despite having only seven bends, ultralow emittance can be achieved in addition to large dynamic aperture and momentum acceptance. An initial alternate 7BA lattice has been revised to relax magnet requirements as well as further increase off-energy performance and resilience to machine imperfections. We now demonstrate ±2.5 mm dynamic aperture including errors and calculate the effect of IBS to show that this lattice achieves 6 hours Touschek lifetime (at 500 mA, including errors) and a brightness of roughly 3x10²¹ ph/s/mm²/mrad²/0.1%BW at 1 keV.
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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 | 0.001 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 0.001 |
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".