{"paper":{"title":"On the nuclear halo of a proton pencil beam stopping in water","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","headline":"","cross_cats":["physics.ins-det"],"primary_cat":"physics.med-ph","authors_text":"Bernard Gottschalk, Ethan W. Cascio, Juliane Daartz, Miles S. Wagner","submitted_at":"2014-11-28T22:35:32Z","abstract_excerpt":"The dose distribution of a pencil beam in water consists of a core, a halo, an aura and (possibly) spray. The core is due to primary protons which suffer multiple Coulomb scattering (MCS) and slow down by multiple collisions with atomic electrons (Bethe-Bloch theory). The halo is due to charged secondaries, many of them protons, from elastic interactions with H, elastic and inelastic interactions with O, and nonelastic interactions with O. We show that the halo radius is roughly one third of the beam range. The aura is due to neutral secondaries (neutrons and gamma rays). Spray denotes dose, a"},"claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"1412.0045","kind":"arxiv","version":3},"verdict":{"id":null,"model_set":{},"created_at":null,"strongest_claim":"","one_line_summary":"","pipeline_version":null,"weakest_assumption":"","pith_extraction_headline":""},"references":{"count":0,"sample":[],"resolved_work":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57","internal_anchors":0},"formal_canon":{"evidence_count":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"author_claims":{"count":0,"strong_count":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"builder_version":"pith-number-builder-2026-05-17-v1"}