This report is the final in a series of preliminary reports that follow the studies of scavenging systems related to radioactive fallout. The project consisted of two phases: preliminary experiments to relate the sizes of particles in air to specific radioisotopes, and preliminary laboratory studies of scavenging of particles by liquid drops, including studies of sticking probability and effects of Brownian motion and water vapor diffusion.

Introduction: "This is the seventh letter report on ARF Project C 127, entitled "Preliminary Studies of Scavenging Systems Related to Radioactive Fallout." This report covers the period from April 1 to May 31, 1959."

Introduction: "This is the eighth letter report on ARF Project C 127, entitled "Preliminary Studies of Scavenging Systems Related to Radioactive Fallout." This report covers the period from June 1 to August 1, 1959."

Introduction: "This is the ninth letter report on ARF Project C 127, entitled "Preliminary Studies of Scavenging Systems Related to Radioactive Fallout." This report covers the period from August 1 to October 1, 1959."

Introduction: "This is the tenth letter report on ARF Project C 127, entitled "Preliminary Studies of Scavenging Systems Related to Radioactive Fallout." This report covers the period from October 1 to December 1, 1959."

This document is the third in a series of progress report that records investigations of graphite bodies. Along with the report, two appendices are given to describe the different graphite bodies: "Synthetic Binders for Carbon and Graphite" and "High Temperature Physical Properties of Molded Graphites".

A report which explores areas in the vicinity of the intermetallic compounds of the sirconium-iron-tin system were studied in detail between the temperatures 500° and 1100ºC.

Abstract: "The niobium-oxygen equilibrium has been determined by metallographic examination of arc-cast alloys made of electron-gun-refined niobium metal and special purity niobium pentoxide. Two intermediate oxides, NbO and NbO2, melt without decomposition at 1945 C and 1915 C, respectively. Eutectic reactions exist between niobium and NbO and 1915 C and between NbO and NbO2 at 1810 C. Experimental supports a peritectic reaction between NbO2 and Nb2O5 1510 C. The maximum solid solubility of oxygen in niobium metal is 0.72 weight per cent."

Abstract: "The niobium-carbon system has been determined by X-ray and metallographic examination of sintered and arc-cast alloys. Two carbides exist: hexagonal Nb2C with a limited range of homogeneity, and cubic NbC with a solubility range from 8.25 to 10.25 weight per cent carbon. Dilute alloys freeze by eutectic reaction at 2230 C. The solubility of carbon in niobium is 0.80 at the eutectic temperature, but this decreases rapidly with temperature. Metallographic evidence indicates a peritectic reaction between melt, Nb2C, and NbC; alloys richer in carbon than NbC freeze by eutectic reaction."

Abstract: "Tungsten-rich alloys, developed for use at temperatures up to 2000F, exhibit ductility, fabricability and joinability not found in commercially-available materials. An envelope type of microstructure was produced in compositions containing at least 90 wt% tungsten by liquid-phase sintering of cold-pressed powders in hydrogen. At room temperature the alloys could be rolled extensively, and tensile elongations up to 25% were noted. Strength properties of a W-Ni-Fe base were improved by small quaternary additions. The ultimate tensile strength of a 90W-4.8Ni-3.2Fe-2Ru alloy was 46,700 psi at 2000F, compared to 30,000 - 35,000 psi for unalloyed tungsten or W-Ni-Fe; the 100-hour stress-rupture strength at 1600F was 15,000 psi. Excellent joints were produced by spot welding and localized induction heating. The oxidation resistance of unprotected 90 wt% tungsten compositions was not significantly affected by alloying."

The following document is a note describing the process of building a nuclear density gauge and its improved features in comparison to previously reported density gauges.

This is the final report on the progress, "A Wide-Range Neutron Detector and Monitoring Instrument," ARF 1118-6. This report covers activities from May 8, 1958 to May 8, 1959. This report describes the basic design principles of a proportional counter that has been constructed whose cathode diameter increases towards one end.

Summary. During the past year the work carried out in this program has included experiments on the x-ray output produced by the separated fission product beta sources, the interpretation of such experiments for the effective design of high level secondary x-ray sources, and the design and testing of prototype sources of secondary radiation for specific industrial applications. In this report results of work carried out during the past fours months are reported: (1) analysis of beta-excited x-rays; (2) performance of Kr85 prototype x-ray source; and (3) design of high level Pm147 x-ray sources.

Quarterly progress report describing work related to a study of radiation physics problems involved in the design of high-level cesium-137 gamma sources. It outlines work completed and ongoing goals for the project.

"Abstract: The advantages of storing nuclear pulse height information on tape for later use with an analyzer are pointed out. Experiments with a magnetic modulator playback head which would offset inaccuracies due to tape speed variation are described. (T.R.H.)."

The following report discusses direct recording of nuclear pulse height data on magnetic tape that represents an inexpensive method of data storage where some degradation of the original energy resolution can be tolerated.

"Abstract: Data on analog magnetic tape characteristics are presented along with results from conventional and modulator playback system operational tests. Theoretical considerations imply that the modulator head should be loss sensitive to short term variations in record and playback tape speed. It is also pointed out that although a tape recorder operating at 7.5 in./sec has only 12 kcs bandwidth for sinusoidal wave forms. the record and play-back amplifiers for pulse recording can operate with other bandwidths. These amplifiers must be capable of passing a square wave with a frequency of 1.5 kcs. A square wave of such frequency represents the condition of 350 microsecond pulses with a 700 microsecond period. (J.R.D)."

The following document is a note describing the building process of an improved nuclear density gauge in comparison to previous gauges, within the interval of June 1 to July 1, 1959.

The following document is a note describing the building process of an improved nuclear density gauge in comparison to previous gauges, within the interval of July 1 to August 1, 1959.

This report discusses the concept of an improved mass gauging technique with a scintillation counter as the radiation detector in order to meet industrial requirements.

The following document is an updated note on the process of building an improved nuclear density gauge within the time interval of September 2 to October 1, 1959.

This report is the second in a series of quarterly reports on the discussion and progression of an improved nuclear density gauge, covering techniques measuring detector sensitivity to result in improved stability.