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    "story_id": "mp-2026-07-16-010",
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    "headline": "A Small Crystal Measures a Fusion-Scale Field",
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    "dek": "Sandia's compact optical sensor tracks intense magnetic fields through light rotation in rare-earth garnet.",
    "summary": "Sandia's compact optical sensor tracks intense magnetic fields through light rotation in rare-earth garnet.",
    "body_text": "Sandia National Laboratories researchers are developing rare-earth garnet crystals as magnetic-field sensors for fusion and pulsed-power experiments. A laser passes through the crystal, and the field rotates the light's polarization; measuring that rotation provides a reading without placing a conventional electrical probe inside the harshest part of an experiment. The team has also reduced the size of the supporting optics, a practical step toward use where space and survivability are limited. The work is a diagnostic technology under development, not evidence of a new fusion-energy gain or reactor milestone.",
    "why_it_matters": "Sandia's compact optical sensor tracks intense magnetic fields through light rotation in rare-earth garnet.",
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      "The work is a diagnostic technology under development, not evidence of a new fusion-energy gain or reactor milestone."
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    "first_published_at": "2026-07-16T09:00:00.000-04:00",
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        "qualification": "The work is a diagnostic technology under development, not evidence of a new fusion-energy gain or reactor milestone."
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    "tags": [
      "fusion",
      "magnetic fields",
      "rare-earth garnet",
      "diagnostics"
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      "source_id": "source-2026-07-16-010",
      "title": "Sandia National Laboratories via Newswise: Crystal power for fusion research",
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      "published_at": "2026-07-15T19:20:00.000-04:00",
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    "title": "A Small Crystal Measures a Fusion-Scale Field",
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