Chapter 2 PROCEDURE 2.1 INSTRUMENTATION A preliminary resum of the operational techniques, aircraft instru- mentation and procedures used in the collection of gaseous debris from Castle have been briefly described in References l, 2, 7, 8, 18, and 19. Close~in particulate and gaseous samples were obtained by F-84 and B-36 aircraft penetrating the cloud resulting from each detonation. The Air Weather Service WB-29 aircraft equipped with particulate and gaseous sampling devices collected samples at remote distances from the detona- tion site. Five F-84G aircraft utilized the method of snap gas-sampling, which was the primary collection method for obtaining close-in samples during Operations Ivyand Upshot-Knothole (Reference 7). This consisted of an exterior stainless-steel probe in the nose of the aircraft which fed into a deflated polyethylene bag installed in the gun deck portion of the aircraft. Samples were taken by activating a valve and filling the poly- ethylene bag by ram pressure. On return of the aircraft to the ground, the sample was transferred from the bag by evacuation, using a diaphragm pump, and stored in a G-l cylinder. The radioactive gases of interest were measured and the results compared with similar analyses of gases collected by the technique described in the following paragraph. Ten F-84G's were equipped with a dual electrical compressor system feeding into two 500-in? compression cylinders (3,000 psi). All of the air sampled was bled from an intermediate stage of the axial compressor of the aircraft and fed into the dual compressors located in the gun- deck section. This method of collection---called the Squeegee method--- had been tried experimentally during the Upshot~-Knothole tests. Operation Castle provided the first full-scale operational test of this highpressure system. In addition, several B-36's equipped with the Squeegee system were utilized. In these cases, intake air was bled from the upstream side of the large cabin pressurization filter to six compressors located in the bomb bay. Each compressor pumped into its individual 900- in? high-compression cylinder (3,000 psi). Longer-range samples were obtained using WB-29 aircraft with associated C-1 foils for particulate samples, and a B-31 gas-sampling device for the gaseous debris (Reference 7). The collection of all close-in particulate samples was under the technical direction of the los Alamos Scientific Laboratory (LASL), and the collection of gas samples was supervised by Headquarters, United RINEMAEM oo States Air Force » The University of California Radiation Laboratory (UCRL)”wasrésponsible for gas separation and analyses of some samples at the test site. The instrumentation, techniques, and procedures in the processing, separation, and assay of the nuclear particulate and gaseous debris---both 12