— This report describes the co® source (1.1 to 1.3 Mev, half- amina- life 5.3 yr) developed to meet this need. The design of the capsule was such that readings taken at points equidistant from the capsule, whether from any side or the bottom, are uniform. The radioactive cobalt slug is enclosed in a sealed stainless steel capsule, the lead shield for which is contained in a plywood carrying case. An approved remote- - an accurate calibration of the source, complete with date of calibration, ity Z handling device is supplied with this shielded source. - ination Also supplied is the strength (in mr/ hr) at calibration, and suitable equations, tables, and graphs for computing its strength at later dates. CRLIR - 170 - RADIOCHEMICAL STUDIES ON SIZE-GRADED FALLOUT AND FILTER SAMPLES. (Operation JANGLE) Robert C. Tompkins and Phillip W. Krey, 7 August 1952. SECRET-RESTRICTED DATA phic ast Fission product activity was shown to vary with particle size. A study of the data obtained in these tests leads to @ plausible hypothesis je from which have been derived equations that fit the data within experiment- al error. It may reasonably be assumed that an atomic cloud initially comprises a complete spectrum of particle sizes. Particles grown by agglomeration and/or condensation of other matter on the particle surfaces. During this growth process, fission-product atoms are adsorbed on the surfaces of these particles, with simultaneous reduction of concentration io- of free sorbable fission-product atoms in the cloud. Consequently the distribution of fission-product activity in the radioactive fallout w particles is nonhomogeneous. ID. A formula was derived for the calculation of activity per unit mass, of particle, and graphs have been plotted of the activities of zr?, BaltO, and Cel? ys particle size. On the basis of the gaseous precursors of the nuclides analyzed, equations were derived indicating the distribution of these nuclides in the particles. The sr89 activity was ess distributed throughout the agglomerate shell of the particle. found on the surface of the particles, whereas the ar7? , Bal40, and Celhh were fa CRLIR - 1¢5 ssary -~- EFFECTS OF IMPACT UPON CANDIDATE PELLETS, ROOFING SURFACES, AND SOILS. Manfred Morgenthau, Albert H. Ferguson, and Harold Avrouchenko, October 1952. SECRET-RESTRICTED DATA uit Because the value of the disintegrating type of RW pellet depends in part on the difficulty of decontaminating a target area, it is REST ATO GY TA 954 19 ac we ZO