DNA 1240H-2 detectars(not on a radial line} and the device characteristics (shielding inherent in the weapon configurations). A plot of neutron dose versus distance, calculated from the flux data, showed agreement within a factor of 2 to 2.5 with values predicted according to Reference 2. Estimates of total neutron dose vs distance from burst are derived from two sources, RadiationHandbo k” and A Study of the Sulfur Neutrons From Fission Weapons. “5 Doses at given ranges from unboosted fission weapons, calculated according to Ref. 25, are higher by a factor of 1.5 to 2 than those calculated according to Reference 24. Since the conclusions of Ref. 25 are based on more extensive data than were available when Ref.24 was prepared, the results of Ref. 25 are recommended for use. The main conclusions of the Ref. 25 analysis are as follows: (1) The neutron dose closely follows the sulfur neutron fluence (nvt) for both boosted and unboosted fission weapons. The ratio of the sulfur neutron fluence intercept to the biological dose intercept is about a factor of 2 higher for boosted than unboosted weapons. However, boosting also increases the sulfur neutron fluence by about the same factor. Since these factors are compensating, there is no net effect on dose. (2) The sulfur neutron intercept fluence per kiloton is an inverse function of the thickness of the weapon's high explosive component for thickness greater than about 10 cm, but appears relatively insensitive to changes in HE thickness below this value. Plots of neutron dose vs distance for the probable range of atmospheric density are given in Fig. 17-4. One pair of curves gives values for a “typical fission weapon,” the other pair for_a fusion weapon. The “average value" of intercept fluence per 1 Say< in Ref.25 was used to calculate the values o ion e@. Furthermore, the correlation of sulfur neutron flux with - biological dose given was adjusted to provide results in terms of rads (absorbed dose). The values for the fusion curves are calculated from Ref. 24, since no more recent methods are available. It must be noted that because of variations in, and paucity of, data, dose estimates at best should be considered reliable only to + 200%. It has been found that neutron radiation for ylelds under 1 MT can increase the total F.P.C. radiation dose by as much as 6 factor of 2, at close-in ranges. For yields of over 1 MT at ranges where measurements have been possible, the neutron dose is relatively insignificant compared to the gamma dose. a 17-24 mM 1 wee a ae ee eee ee ee eee ns