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."

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.

"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 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.