. gamitssc) Project 22,3 - S-Unit Monitoring and High Explosive Transit Time - C. E. Ingersoll E, C. Woodward The technique used for monitoring the S-unit consisted of telemetering signals from signal sources in the immediate neighborhood of _ (Apache) device by high frequency radiofrequency methods to a receiving and recording station located on Parry. The signals were then recorded on oscillographs. The signal sources were the load ring pulse of the X-unit and the output of a fluor - photomultiplier detector near the S-unit which measures both the S-unit output and the gamma rays from the nuclear reaction, The oscillograph displays consisted of a raster scope display containing all signals and a linear sweep display on a 517 oscillograph which showed greater detail of the load ring pulse signal and the S-unit signal, The results of the measurement are as follows: