Abstract The risk of radiation-induced cancer to space travelers outside the earth's magnetosphere will be of concern on missions to the Moon and beyond to Mars. High energy galactic cosmic rays with high charge (HZE particles) will penetrate the spacecraft and the bodies of the astronauts, sometimes fragmenting into nuclear secondary species of lower charge but always ionizing densely, thus causing cellular damage which may lead to malignant transformation. To quantitate this risk, the concept of dose equivalent (in which a quality factor Q as a function of LET is assumed) may not be adequate, since different particles of the same LET may have different efficiencies for tumor induction. Also, RBE values on which quality factors are based depend on response to low-LET radiation at low doses, a very difficult region for which to obtain reliable experimental data. Thus, we introduce a new concept, a fluence-related risk coefficient (F), which is the risk of a cancer per unit particle fluence and which we call the risk cross section. The total risk is the sum of the risk from each particle type: i F i (L i ) ϕ i (L i ) dL i , where Li is the LET and ϕi(Li) is the fluence-LET spectrum of the ith particle type. As an example, tumor prevalence data in mice are used to estimate the probability of mouse Harderian gland tumor induction per year on an extra-magnetospheric mission inside an idealized shielding configuration of a spherical aluminum shell 1 g/cm2 thick. The combined shielding code BRYNTRN/GCR is used to generate the LET spectra at the center of the sphere. Results indicate a yearly prevalence at solar minimum conditions of 0.06, with 60% of this arising from charge components with Z between 10 and 28, and two-thirds of the contribution arising from LET components between 10 and 200 keV/μm.


    Access

    Check access

    Check availability in my library

    Order at Subito €


    Export, share and cite



    Title :

    Fluence-related risk coefficients using the Harderian gland data as an example


    Contributors:

    Published in:

    Advances in Space Research ; 12 , 2-3 ; 407-416


    Publication date :

    1991-01-01


    Size :

    10 pages




    Type of media :

    Article (Journal)


    Type of material :

    Electronic Resource


    Language :

    English



    Fluence-related risk coefficients using the Harderian gland data as an example

    Curtis, S. B. / Powers-Risius, P. / Alpen, E. L. et al. | NTRS | 1992





    Renault Fluence

    Perini,G. / Renault,FR | Automotive engineering | 2004