J. Howard Marshall

The Apollo gamma-ray spectrometer

Abstract A γ-ray spectrometer has been flown on the Apollo 15 and 16 spacecrafts to determine the lunar-surface composition and measure the cosmic γ- ay flux. The instrument included a Nal(Tl) scintillation crystal coupled to a 7.6 cm photomultiplier tube, a plastic mantle for anti-coincidence rejection of charged particles, and 511 channels of analysis. Boom-mounted operation permitted a significant reduction in the background. The data were transmitted on an event-by-event basis. About 22% of the lunar surface was mapped and spectra of the cosmic γ-ray flux over an energy range of 0.065–27.5 MeV have been obtained.

A nanosecond coincidence circuit using transistors

Abstract A transistor coincidence circuit is described which is intended to be used for scintillation counting of high energy particles. Details of the performance of the basic components are given both with test pulses and with photo-multiplier pulses in a counting arrangement. Resolving times as low as 2 nanoseconds were measured ††

50—Nanosecond Printed Circuit Linear Gate Using Transistors

A 50‐nsec linear gate with primary use in high energy physics experiments is described. The gate has a pedestal stability of 0.2% of the maximum output pulse height and a feedthrough of less than 0.2% over a pulse‐height range of 100 to 1. Design considerations, construction details, and performance are discussed.

A multifold coincidence-veto circuit using transistors ☆

A versatile coincidence-anticoincidence circuit in the 50 nsec time range is described capable of being used with large number of counters. Basic considerations with detailed circuits, operation and performance are given.