Equation 1.6 indicates that a ray originating in the center of the sphere would traverse only y, of the mass in the shell model that it would in the homogeneous model. The result would be an enhancementof radiation. Once the shell of material in the shock front passes the detector, an even greater enhancémentresults. As previously stated, the N' (n, y) N'° componentofinitial radiation is essentially emitted within 0.2 second. Since it takes at least 1 second for the shock front to reach a detector ata distance of 7,000 feet (even for devices in the order of 6 Mt), the N* (n, y) N® componentis not significantly enhanced. The fission-product gammas continue to contribute for the first 30 seconds. Therefore, this radiation is strongly enhanced by the shock wave. 13