None

Despite the fact the adequate data from long-term, chronic experiments on the effects of Po{sup 210} are not available, some sort of a working figure for the maximum permissible body content of polonium is desirable. As described herein, calculations involved in determining the permissible body content of polonium generally fall into three classes. 1. Comparison of X-ray and polonium toxicity and application of an acceptable X-ray tolerance figure. 2. Assumption of a most sensitive organ and computation of the critical concentration of radioactive material present in this organ under conditions such that the organ received an assumed maximum permissible exposure over an indefinitely long period of time. 3. Comparison of radium and polonium toxicity with application of an acceptable maximal content of radium.

This report provides information on reactivity, temperature coefficients and energy storage to the Reactor Safeguard Committee with regard to contemplated increases in power levels.

Work of the pile physics and experimental physics groups is reported. Theoretical work is also reported.

The extension of the passband of wideband amplifiers is a highly important problem to the designer of electronic circuits. Throughout the electronics industry and in many research programs in physics and allied fields where extensive use is made of video amplifiers, the foremost requirement is a passband of maximum width. This is necessary if it is desired to achieve a more faithful reproduction of transient wave forms, a btter time resolution in physical measurements, or perhaps just a wider band gain-frequency response to sine wave signals. The art of electronics is continually faced with this omnipresent amplifier problem. In particular, the instrumentation techniques of nuclear physics require amplifiers with short rise times, a high degree of gain stability, and a linear response to high signal levels. While the distributed amplifier{sup 1} may solve the problems of those seeking only a wide passband, the requirements of stability and linearity necessitate using feedback circuits. This paper considers feedback amplifiers from the standpoint of high-frequency performance. The circuit conditions for optimum steady-state (sinusoidal) and transient response are derived and practical circuits (both interstage and output) are presented which fulfill these conditions. In general, the results obtained may be applied to the low-frequency end. …

Exploratory tests are reported which indicate the feasibility of a one-step reduction process for the preparation of uranium metal from the hexafluoride by the action of calcium metal and iodine.