Measurements have been made to determine the scattered radiation to be expected from typical multicurie Cs13' installations. For the cesium pellet sources investigated the scattered intensity ranged from 12 to 21 per cent of the total incident radiation intensity. The source capsule is responsible for scattered intensity of about 8 per cent with the source material contributing the bulk of the balance. The source material scatter, for a source diameter of 3.6 cm, is about 5 per cent per centimeter for source thicknesses of up to about 1.5 cm.

A brief description of the theory of operation of Geiger-Milller counters is presented, with special emphasis on the deadtime and recovery characteristics. An electronic gating instrument is described that has been developed for the determination of deadtime and recovery characteristics to an accuracy of 1 percent or 2 microseconds. Experimental data are presented showing variation of dead time and recovery time with counter pressure and overvoltage.

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Work on this project is continuing under Interagency Agreement Number DE-AI02-93ER40778.A0001. I. Objective Development and maintenance of fast and flexible modular data acquisition and control systems by the NIM Committee to meet the needs of the high energy physics community.