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."

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: 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)."