CHAPTER 5 RADIOCHEMICAL MEASUREMENTS Gross decay, energy spectra, and radiochemical composition of material resulting from the various detonations were determined, Fission product yields and neutron induced radionuclides were measured, From this infor~ mation computations were made of the extent of fractionation of the bomb constituents and also the fraction of the bomb per unit area collected at several fallout stations, 51 RADIATION CHARACTERISTICS OF GROSS FALLOUT SAMPLES Beta and gamma decay were observed at the site as well as at USNRDL with geiger counters, proportional gas-flow counters, and scintillation counters. Gamma ionization decay was observed on Shot 4 in cooperation with Project 6.4. measurements were made, 5.1.1 a single sample fron Both absorption and gamma spectra Preparation of Counting Samples Counting sources for decay and absorption measurements were made by taking a measured amount of the fallout material from various collectors, These fallout samples were carefully aliquoted so that the total beta and gamma count of the fallout in the collector could be determined. Fallout in the form of solids, or slurries containing coral was dissolved with a minimum amount of HCl before the counting sample was taken. Liquid fallout was sampled directly. The source for the beta counting was prepared by pipetting an aliquot of the solution onto a piece of rubber hydrochloride plastic (2 x 2 x 0.00094 in.) which had been loosely spread over a glass planchet (1 in. o.d. x 1/4 im. deep), This arrangement confined the solution to an area about 2 cm in diameter. The solution was then evaporated under an infrared lamp placed at sufficient distance to prevent the rubber hydrochloride from melting. When the solution had completely evaporated, the sheet containing the dried contaminant was mounted on a stiff piece of cellulose acetate (3-5/16 x 2-1/2 x 1/32 in.) with a 1-3/6 in, hole in the center, The rubber hydrochloride sheet was sealed to the back of the cellulose acetate with scotch tape so that the contaminated area was centered in the hole. Krylon plastic was sprayed over the top of the counting sample. The Krylon tended to 100