{
  "abstract": "We show that the APS-U could support a hard X-ray storage ring free electron laser oscillator, providing a promising avenue toward high repetition rate, narrow bandwidth coherent light sources. The results of our numerical simulations demonstrate that a transverse gradient undulator yields ~8% and ~6% single-pass gain at 8.05 keV and 10 keV respectively. We further identify a configuration at 5 keV that does not require a TGU but still exceeds a 5% gain threshold despite the relatively short 5-meter long insertion device. All cases presented retain spectral purity on the order of meV and reach a steady-state output whose equilibrium is consistent with the Renieri Saturation Limit. We have calculated the 5 keV case to have an average brightness of ~10^26 photons/(s * mm2 * mrad2 * 0.1% BW), representing an increase in more than four orders of magnitude from the standard APS-U undulator. These results indicate that a storage ring free electron laser oscillator at multi-keV photon energies is feasible with nominal APS-U parameters and standard x-ray cavity optics.",
  "abstract_shown": true,
  "affiliations": [],
  "article_type": null,
  "arxiv": "2608.10419",
  "author_total": 4,
  "authors": [
    {
      "name": "Emmanuel Aneke"
    },
    {
      "name": "Kent Wootton"
    },
    {
      "name": "Ryan Lindberg"
    },
    {
      "name": "Chris Jacobsen"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/ee9vf7nf8svfc.bib",
  "cited_by": 0,
  "doi": "10.48550/arxiv.2608.10419",
  "fulltext_url": null,
  "id": "ee9vf7nf8svfc",
  "issns": [],
  "landing_url": "https://arxiv.org/abs/2608.10419",
  "language": null,
  "licence": "CC-BY-4.0",
  "licence_label": "CC BY 4.0",
  "licence_source": "article",
  "licence_url": "http://creativecommons.org/licenses/by/4.0/",
  "metadata_licence": "CC0-1.0",
  "native_subjects": [
    [
      "arxiv",
      "physics.acc-ph"
    ],
    [
      "openalex",
      "2208|Particle Accelerators and Free-Electron Lasers"
    ]
  ],
  "openalex": "W7202299115",
  "pdf_url": "https://arxiv.org/pdf/2608.10419",
  "pmcid": null,
  "pmid": null,
  "published": "2026-09-21",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/ee9vf7nf8svfc.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:23:39Z",
      "native_id": "2608.10419",
      "source": "arxiv",
      "url": "https://arxiv.org/abs/2608.10419"
    }
  ],
  "subjects": [
    {
      "field": "physics",
      "origin": "arxiv:physics.acc-ph",
      "subfield": "applied-instrumentation"
    }
  ],
  "title": "Realizing A Hard X-Ray Storage Ring Free Electron Laser Oscillator at the APS-U",
  "title_text": "Realizing A Hard X-Ray Storage Ring Free Electron Laser Oscillator at the APS-U",
  "type": "preprint",
  "updated_at": "2026-10-30T12:23:39Z",
  "url": "https://research.draconitic.com/paper/ee9vf7nf8svfc",
  "venue": "arXiv",
  "versions": []
}