{
  "$schema": "https://themachinepress.com/schemas/story-v1.schema.json",
  "schema_version": "1.0.0",
  "document_type": "machine_press_story",
  "story": {
    "story_id": "mp-2026-07-29-009",
    "source_story_id": "tmp-story-greta-first-beam-commissioning",
    "edition_id": "mp-2026-07-29-morning-0020",
    "edition_url": "https://themachinepress.com/edition/2026-07-29",
    "position": 9,
    "story_type": "dispatch",
    "section": "infrastructure",
    "editorial_classification": "editorial",
    "headline": "GRETA Saw Its First Beam",
    "slug": "greta-saw-its-first-beam",
    "dek": "The gamma-ray tracking spectrometer completed commissioning at the Facility for Rare Isotope Beams.",
    "summary": "The gamma-ray tracking spectrometer completed commissioning at the Facility for Rare Isotope Beams.",
    "body_text": "The Gamma-Ray Energy Tracking Array, or GRETA, has completed first-beam commissioning at Michigan State University's Facility for Rare Isotope Beams. The instrument uses highly segmented germanium detectors and signal processing to reconstruct gamma-ray interactions from short-lived nuclei, with performance reported as anticipated during commissioning. The milestone opens a new experimental tool; it is not itself a nuclear-structure discovery.",
    "why_it_matters": "The gamma-ray tracking spectrometer completed commissioning at the Facility for Rare Isotope Beams.",
    "limitations": [
      "The milestone opens a new experimental tool; it is not itself a nuclear-structure discovery."
    ],
    "importance": 8,
    "canonical_url": "https://themachinepress.com/story/mp-2026-07-29-009/greta-saw-its-first-beam",
    "json_url": "https://themachinepress.com/story/mp-2026-07-29-009.json",
    "first_published_at": "2026-07-29T09:00:00.000-04:00",
    "modified_at": "2026-07-29T09:00:00.000-04:00",
    "content_status": "new",
    "is_carryover": false,
    "carryover_reason": null,
    "key_claims": [
      {
        "claim_id": "claim-mp-2026-07-29-009-001",
        "text": "The gamma-ray tracking spectrometer completed commissioning at the Facility for Rare Isotope Beams.",
        "source_ids": [
          "source-2026-07-29-009"
        ],
        "qualification": "The milestone opens a new experimental tool; it is not itself a nuclear-structure discovery."
      }
    ],
    "source_ids": [
      "source-2026-07-29-009"
    ],
    "tags": [
      "GRETA",
      "gamma rays",
      "FRIB",
      "nuclear science"
    ],
    "image_url": null,
    "corrections": []
  },
  "sources": [
    {
      "source_id": "source-2026-07-29-009",
      "title": "Lawrence Berkeley National Laboratory via Newswise: GRETA commissioning at FRIB",
      "publisher": "Lawrence Berkeley National Laboratory via Newswise",
      "url": "https://www.newswise.com/articles/greta-comes-online-for-a-new-era-of-nuclear-science",
      "canonical_url": "https://www.newswise.com/articles/greta-comes-online-for-a-new-era-of-nuclear-science",
      "source_type": "secondary_reporting",
      "is_primary_source": false,
      "published_at": null,
      "accessed_at": "2026-07-29T08:25:00.000-04:00",
      "supports_claim_ids": [
        "claim-mp-2026-07-29-009-001"
      ]
    }
  ],
  "corrections": [],
  "publisher": {
    "name": "The Machine Press",
    "url": "https://themachinepress.com",
    "description": "A daily newspaper for the age of artificial intelligence."
  },
  "cite_this_report": {
    "title": "GRETA Saw Its First Beam",
    "publisher": "The Machine Press",
    "published_at": "2026-07-29T09:00:00.000-04:00",
    "canonical_url": "https://themachinepress.com/story/mp-2026-07-29-009/greta-saw-its-first-beam"
  }
}