title: Human exposure to large solar particle events in space.
abstract: Whenever energetic solar protons produced by solar particle events traverse bulk matter, they undergo various nuclear and atomic collision processes which significantly alter the physical characteristics and biologically important properties of their transported radiation fields.  These physical interactions and their effect on the resulting radiation field within matter are described within the context of a recently developed deterministic, coupled neutron-proton space radiation transport computer code (BRYNTRN).  Using this computer code, estimates of human exposure in interplanetary space, behind nominal (2 g/cm2) and storm shelter (20 g/cm2) thicknesses of aluminum shielding, are made for the large solar proton event of August 1972.  Included in these calculations are estimates of cumulative exposures to the skin, ocular lens, and bone marrow as a function of time during the event.  Risk assessment in terms of absorbed dose and dose equivalent is discussed for these organs.  Also presented are estimates of organ exposures for hypothetical, worst-case flare scenarios.  The rate of dose equivalent accumulation places this situation in an interesting region of dose rate between the very low values of usual concern in terrestrial radiation environments and the high dose rate values prevalent in radiation therapy.
authors.affiliation: National Aeronautics and Space Administration, Langley Research Center, Hampton, VA 23665-5225.
authors.forename: L W
authors.initials: LW
authors.lastname: Townsend
authors.forename: J W
authors.initials: JW
authors.lastname: Wilson
authors.forename: J L
authors.initials: JL
authors.lastname: Shinn
authors.forename: S B
authors.initials: SB
authors.lastname: Curtis
mesh_terms: D001853:Bone Marrow / Q000528:radiation effects; D003198:Computer Simulation; D003359:Cosmic Radiation; D004307:Dose-Response Relationship, Radiation; D006801:Humans; D007908:Lens, Crystalline / Q000528:radiation effects; D008954:Models, Biological; D009502:Neutrons / Q000009:adverse effects; D011522:Protons / Q000009:adverse effects; D011829:Radiation Dosage; D011834:Radiation Monitoring / Q000592:standards / Q000706:statistics & numerical data*; D011835:Radiation Protection / Q000295:instrumentation / Q000706:statistics & numerical data; D012306:Risk; D012867:Skin / Q000528:radiation effects; D016082:Solar System; D013026:Space Flight; D013997:Time Factors
chemical_list: D011522:Protons