Abstract :
Geiger Muller tubes are simple, easy to use detectors of radiation and have been used by the nuclear industry for many years. Their characteristics are well understood and they are unlikely to be replaced by solid state detectors for some years, and in many applications, may never be replaced. One disadvantage of the Geiger Muller tube is that its energy response will vary considerably over the range of energies likely to be encountered in health physics environments. To improve this situation a series of Geiger Muller tubes has been produced with energy compensation to meet the stringent demands of regulations laid down by I.E.C., P.T.B., ANSI and J.I.S. In all cases, this is combined with a good polar response which makes an instrument less dependent on orientation, and provides the user with a safer instrument. As an example, it is now possible to provide energy compensated tubes for health physics application which do not vary by more than ± 20 percent over the range 40 keV to 1.25 MeV coupled with a good polar response.