180 Teo 9 ° OIAMETER (MICRONS) 140 100 80 60 40 20 ! 2 3 10 2 30 © SO 60 70 80 90 39 39.9 PERCENTAGE LESS THAN INDICATED DIAMETER Pig. 4.2 Size Distribution or Active Aerosol Particles from Shot 1 appeared to have errived at the filter in the form of liquid droplete, as shown by Fig. 4.3, @ reproduction of an autograph of the filter on type K X-ray film. Examination of these active areas of the filter under the optical microscope revesled simply a deep tangled deposit of crystalline forms, with no specific resolvable source of activity other than the whole generalized mass covering the autograph. On the other hand, pillipores exposed topside on YAG 40 were free from radioactive drop indications, as shown by the X-ray autograph also reproduced in Fig. 4.3 Microscopic examination of these filters autoradiographed with Eastman type NTB stripping film by a slightly modified technique developed mterial at this Laboratoryl0/definitely associated the activity with flaky or ash- hardly deseribable as particles or crystals, They were like, quite large (~ 10 p to 70,,) and generally distributed or smeared few out in nebulous patches, as iliustrated in Fig. 4.4. coral grains, There were a In some areas of high concentration, the active material 85