DOSEFIELD DAY #2:Fragmentation is now in the live app. Until today the web dosimeter only ran the primary-only transport — the most interesting result, that breaking up heavy ions is why hydrogen-rich shielding wins, was buried in a console script. Now there’s a “Primaries only ⇄ + Fragmentation” toggle, and flipping it visibly bends the curves: polyethylene pulls away from aluminium and the mean quality factor drops. Concretely, at solar minimum behind 20 g/cm², polyethylene’s edge over aluminium jumps from 12% to 34% the moment fragmentation turns on — the same figure the validation script prints, read from the same function, not hardcoded. Mean ⟨Q⟩ behind 16 g/cm² of aluminium falls 4.47 → 4.14. Nothing was tuned; the toggle just calls the existing Bradt–Peters model. And the honest ceiling stays put: still no secondary neutrons, so the absorbed-dose gap vs the real MSL/RAD measurement (~0.31 vs 0.46 mGy/day) remains — and the UI footnote says so out loud. 76/76 tests green, build clean. Next: surface the NIST + RAD validation inside the app itself.