DNA 1240H-2 In the theoretical method developed at NEDL, it was found possible to express the results of Goldstein and Wilkins©* for the dose buildup factor, B, of Equation 17-13 for any given medium and quantum energy, expression of the form given in Equation 17-19 of 17.5.5: B -| 1+ a(pux} + b(we)?]er(ux) by an (17-19) The constants a, b, and c can be related to quantum energy E and evaluated for various media. Further, since the expression for the buildup factor is analytic, it ie possible to integrate Eq. 17-13 over & source region. The integrated expreesion for dose rate due to sources distributed over the top of a circular slab of radius Ry is given in Ref.55. For simplicity and abbreviation of notation, the integral form wili be employed in this discussion. The ship-shielding factor for deposit radiation is evaluated by using three dose-rate ratios similar to those used to calculate the shielding factor for transit radiation: dhR Shoe dn 43R SF agp" }do * Theol * do (17-30) where dip = exposure dose rate (at a given below-decke location) Gue to activity deposited on the weather-deck of the ship. Q3R = exposure dose rate at 3 ft above the weather-deck, over the below-decks location. Gnoo = exposure dose rate at a location considered to be a given distance below an infinite slab of shielding, with radioactive sources distributed uniformly over the top surface of the slab. a," 8 symbolic dose-rate measure of source strength. For the plane source case, @, has the units r/hr. It is e quantity equivalent to that given by Eq.17-14 or Eq.17-17 of Section 17.5.5, but with ann whose units are photons/cm@ - sec. See Note after Eq. 17-17, and footnote after Equation 17-24 of Section 17.6.4. Since the individual dose rates on the right hand eide of Eq.17- 30 are initially unknown, it was found possible to obtain the desired shielding factor by substituting equivalent ratios into the calculations. BEST AVAILABLE copy 17-82