os UNCLASSIFIED The fall-out from TUMBLER/SNAPPER (Restricted) and UPSHOT/ENCTHOLE (Restricted) Test Operations is examined in some detail in this report. The radioactive contamination resulting from the tower shots of the above two test operations is plotted pictorially (see Figures 1 through 9). Both the air and ground radiological zonitoring data contained in the Radiological Safety Reports of the test operations have been utilized (1,2). IZ, RADIOACTIVE FALL-COT DUE TO SAND AND SOIL DEBRIS FROM TOWsR SHOTS OF TUMBLER/SNAPPER (R) AND UPSHOT/KNOTHOLS (R) TESST OPERATIONS A. Radioactive Fall-out as a Finctican of Yield and Height of Detonation Above Ground During high air drops of nominal bambs there is practically no stem formed to the atomic cloud. As the height of detonation is de- may or may not reach the rapidly rising mishroom, As the height of a itt intial ereased, or the yield of the bomb is increased, a stem is formed which bemb is reduced still further there appears a definite stem to the cloud which is continusus with the mushroom. Aswever, no extensive fall-out _occurs within immediate area of the test site unless the height of detonation is so low that the fireball touches the ground, An inspec tien of Table I brings out the fact that unless the zaximum fireball KADIUS diameter is greater than the height of burst there is practically no radieactive fall-eut within 200 miles of ground zere (fall-out being less than 1%). During the two test operations this factor was verified in a sufficient number of cases so that it is possible to put considerable “ta: GE | 26¢ so Ee cm petyALSob hrinn hip3am -