The PATHWAY model results were used, in conjunction with a hypothetical major nuclear attack on the U.S., to arrive at the ratio of internal to external dose for humans from early (48 h) fallout. Considered were the four nuclides (137Cs, 89Sr, 90Sr, 131I) that account for most of the reconstructed whole-body committed equivalent dose from internal radiation in people who lived downwind of the Nevada Test Site during atmospheric tests. Effects of climate perturbations (the "nuclear winter" effect) on food crops were considered. These could increase internal dose estimates, depending on the severity of the climate perturbations. Internal and external doses to humans for 10 locations within the U.S. have been calculated, with varying local conditions and varying assumption about their shelters. The estimated 50-y internal dose commitment ranged from 0.0-0.17 Sv, the 48-h external dose from 0.15-4.6 Sv. The resultant ratios of internal to external committed dose received in the first months (until food transport was restored) varied from less than 0.01 to about 0.2. In all cases examined, the total dose from early fallout was found to be dominated by the external dose.

Fallout distributions are calculated for nuclear attacks on the contiguous United States. Four attack scenarios are treated, including counterforce and counterforce-countervalue attacks, for meteorological conditions associated with a typical day in summer and one in winter. The countervalue attacks contain mostly airbursts. To determine fallout effects, the population surviving the prompt effects is first calculated. For the prompt effects, a "conflagration-type" model is used. The counterforce attack produces about 8 million prompt deaths, and the counterforce-countervalue case projects 98 million prompt deaths. Partial relocation before attack to low-risk fallout areas at least 15 km from potential strategic targets would result in a decrease in projections of deaths by tens of millions. For fallout risk calculations, only the dose received in the first 48 h (the early or local fallout) is considered. Populations are assumed to be sheltered, with a shelter protection factor profile that varies for a large urban area, a small urban area, or a rural area. With these profiles, without relocation, the fallout fatalities for all four attack scenarios are calculated to be less than one million people. This can be compared to fallout fatalities of about 10 million for a hypothetical unsheltered "phantom" population.

The magnetic dipole gamma-ray strength function for some strongly deformed heavy nuclei is computed on the basis of the Nilsson model, pairing, and a residual spin-spin interaction. The strength of the spin-spin interaction is adjusted to give average agreement with experiment of effective spin g factors for low-energy M1 transitions and moments. Predictions are made for average Ml widths of primary transitions following neutron capture; the predictions are in reasonable agreement with recent data.Existing experimental data on the reduced widths of primary magnetic dipole transitions in the (n, y) reaction have recently been summarized by Bollinger. 1 The reduced widths for yray transitions of 4-to 9-MeV energy are found to be, on the average, some 10 to 20 times larger than "single-particle" estimates. 2 ' 3 It is the purpose of this note to present some results of a simple computation, with no ad hoc assumptions, which can account for some of these results.By reduced width we mean the quantity 3

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