wan | residual activity of about 2 r/hr, which probably could not be tolerated by @ populace already considerably exposed in achieving this reduction in level. Using very optimistic assyuptions, it is estimated that the (U) cleaning up of the typical 20-sq mi urban area would take about 200 working hours or thirteen 16-hr days (limited by the number of trucks, an shovels, and water available), and perhaps would require the recruitment of personnel from surrounding areas to maintain minimum radiation exposures. CRLR - 369 - EXPERIMENTAL STUDIES OF GAMMA-RAY STRUCTURAL SCATTERING IN THE B-47 AIRCRAFT (U). Carl E. Heidt and Cecil R. Ward, 14 October 1955. SECRET-RESTRICTED DATA, Special Report One of the major problems associated with the RW program is he design of a mobile shield which will protect the flight crew of the delivery aircraft from the harmful effects of a 15-megacurie gamma (Zr95-Nb95) munition. It is of ¢tmost importance that the photon behavior within the aircraft be understood as thoroughly as possible due to the obvious weight limitations inherent in,such a design. The objectives are (1) to determine if structural scattering significantly increases the crew dose rate as observed in a simple air geometry and (2), if so, to determine an order of magnitude of this scattering. The conclusions drawn from this study are: (1) structural scattering does not significantly increase the crew dose rate observed in an air geometry. On the contrary, the inherent shielding provided by the aircraft, primarily in the form of fuel, results in a net decrease in dose rate, i.e., scattering; source with &ttenuation structural attenuation is far more significant than structural (2) allowing for the effects of replacing the test point the RW munition, there is every indication that this structural will decrease the expected dose rate by a factor of at least CRLR - ho2 - 2, or even 3; and (3) results clearly indicate that the aircraft structure can be safely ignored (i.e., air can be conservatively used as the sole scattering medium) in the programming of the in-flight shielding problem associated with the design of an RW aerial munition system. A GUIDE TO RADIOLOGICAL WARFARE COUNTERMEASURES, Stanford Research Institute. June 1954, SECRET-RESTRICTED DATA, Special Report. This report is a compilation of existing information on radio- ogical warfare countermeasures. Lacking data on enemy RW capabilities and plans, estimates are made of the most probable agents and types of REST . TA was 42 mac