Reduction of Dead Times in Geiger–Müller Counters

Abstract

THE significance of the positive ion sheath, formed in the immediate vicinity of the wire in a Geiger – Müller counter during a discharge, has been discussed by the Montgomeries¹ and by Stever². According to them, the positive ion sheath is directly responsible for the dead time occurring in the counter after each discharge; the dead time is identified with the time necessary for the sheath to move sufficiently far from the wire for the field to be restored to a value at which the next event can be detected. Following this, Simpson³ and Hodson⁴ investigated the possibility of reducing the dead time by bringing the ion sheath back to the central wire and collecting it there. For this purpose they employed circuits by means of which the wire potential could be switched about 100 volts negative with respect to the cathode for a few microseconds after each discharge. Dead times as low as 20–30 microsec. were obtained in this way.