An RCA 7046 photomultiplier tube. This tube, with a nominal diameter of 12.5 cm, was a 14-stage unit that operated at a cathode-anode voltage of 3400 V. The device is approximately 25 cm tall and had an amplification of about three million. These photomultipliers were often coupled to scintillators (plastic or sodium-iodide based) which produced light pulses when struck by gamma rays. The signals, proportional to the gamma ray energy, provided much of the early data on nuclear decay. This particular unit was used in nuclear physics measurement at the University of Toronto.
