Cryogenic Permanent Magnet Undulator Development at HZB/BESSY II
Bibliographic record
Abstract
The costs of a synchrotron radiation facility scales approximately linearly with the length (FEL) or the circumference (storage ring) of the machine. It is always beneficial for the reduction in overall expenses to utilize short period in-vacuum undulators (IVUs) for X-ray production. This is the reason for the success of the IVU development which was started almost 20 years ago in Japan [1 T. Hara, J. Synch. Rad., 5, 403–405 (1998).[Crossref], [PubMed], [Web of Science ®] , [Google Scholar]–3 T. Tanaka, Proc. FEL Conf., Stanford, CA, 370–377 (2005). [Google Scholar]]. Today, IVUs are implemented into nearly all third-generation storage rings. Ten years ago, the concept of cryogenically cooled permanent magnet undulators (CPMUs) was proposed [4 T. Hara, Phys. Rev. ST Accel. Beams, 7, 050702-1-6 (2004).[Crossref] , [Google Scholar]]. The magnetic properties of rare earth magnets (i.e., the remanence and the coercivity) improve substantially at low temperatures. The remanence increases by about 15%, whereas the coercivity grows by a factor of three to four. Due to the performance gain and the low technical risk of CPMUs, such devices are under development all over the world. The first generation of CPMUs, with period lengths well below 20 mm, is successfully operated at ESRF [5 J. Chavanne, AIP Conf. Proc., SRI 2009, Melbourne, Australia 1234, 25–28 (2010). [Google Scholar], 6 J. Chavanne, Proc. PAC, Vancouver, BC, Canada, 2414–2416 (2009). [Google Scholar]], PSI [7 T. Tanaka et al, Phys. Rev. ST Accel. Beams, 12, 120702-1-5 (2009).[Crossref] , [Google Scholar]], DIAMOND [8 C. Ostenfeld and M. Pedersen, Proc. IPAC, Kyoto, Japan, 3093–3095 (2010). [Google Scholar]], SOLEIL [9 C. Benabderrahmane, J. Phys., Conf. Ser., SRI 2012, Lyon, France 425, 032019-1-4 (2013). [Google Scholar]], and SPring-8 [10 T. Tanaka, Private communication (2015). [Google Scholar]].
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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 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.001 | 0.000 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.004 | 0.004 |
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".