This report summarizes in somewhat more detail than the monthly H.I. Environs reports the extent and magnitude of the radioactive contamination detected in the environs of the Hanford Works. Radioactive contamination resulting from the operation of the Hanford Works as well as that found occurring in natural quantities is included. This belated report is being issued merely for the records to serve as a composite summary of measurements already reported in the monthly H.I. Environs reports and covers the quarterly period January, February, and March, 1949.

Discussions included the aluminum nitrate recovery process; specifications for process pumps; a review of the safety of the Redox process; plans for the proposed Waste Tank Farm, retention basin, diversion box, and cribs; and a request from the US AEC for a concise summary of the entire Redox program.

Topics discussed include gang valve substitute devices; cost of lining cell bottom with stainless steel; and the pump development program. [The Redox plant used a reduction-oxidation process for fuel separation that allowed recovery of uranium as well as plutonium for the first time. It succeeded earlier plants (T and B) that had used methods based on the bismuth phosphate process that recovered only plutonium.]

The cloud chamber is a means of observing the path of ionizing radiation. It does not reveal the radiation directly, but gives a visible trail of the path along which the radiation has traveled. The trail is formed by vapor condensing upon pairs of ions remaining after an ionizing particle has passed through the medium. The mutual interaction among rays, atoms, nuclei, and particles, can be studied and measured with the aid of vapor trails. Measurements of changes in direction and range as recorded on the photographs may be interpreted in terms of changes in momentum and energy of the particles in these reactions. To obtain a precision measurement is difficult with a cloud chamber. The dependence of the apparatus upon a sudden gas expansion is certain to create distortions resulting from turbulence. Furthermore, since any radiation is subject to variations, precision measurements can be obtained only be the collection of numerous observations for statistical analysis. This document details the design, operation, and limitations of cloud chambers.