column would be of the order of 500 to 100 meters therefore we would not expect to poison an area of more than a few square kilometers ."° Professor Hirschfielder also proposed that FAT MAN be fired during weather conditions "conducive to thunderstorms," which would reduce the radioactive fallout from the "smoke column," Possible dangers from the radioactive cloud following the shot were unknown. Therefore, ‘precautions were taken to protect the unsuspecting population near the test site, On Sunday evening, 15 July 1915, a convoy of Army trucks parked alonga road just outside the small town of Carrizozo, New Mexico, northeast-of the test site, The convoy commander was in contact with the test operations by radio and, if the nuclear cloud drifted over the little town, the truck convoy was to enter Carrizozo and evacuate the citizens.’ Just before daylight on Monday, 16 July 195, the first atomic bomb detonated with an energy release of approximately 23.8 ictlotons,° Two Sherman medium tanks, with Army crews approached the crater following detonation and measured the radiation, They had been modified for sampling; a scoop operated from the interior of the tank and the interiors were lined with lead. Professor Enrico Fermi was in one of these sampling tanks, supervising the operation, the scoops and 6Btained dirt for laboratory analysis, sampling mission for Operation TRINITY.” satisfied with the TRINITY test. Crews lowered This constituted But the scientists were well The bomb ", , , was as powerful as any had dared hope and it was a practical weapon "10 2 APWALHO SWEH~2~003),