An energy-independent albedo-dosimeter for neutrons

A small 3He-counting tube covered by a cadmium-layer within a polyethylene moderator of a wall thickness of 0.5'' is used as an albedo-dosimeter for neutrons. Only those pulses, which surmont an adjustable discriminator threshold are counted. By changing the discriminator threshold the energy-dependence of the device may be altered. Earlier measurements have shown that there is such a discriminator threshold which allows the energy-independent measurement of neutrons within an energy range between 0.5 eV up to about 10 MeV. Within this range the dose equivalent is proportional to the pulse rate within a deviation of the factor two. The device includes a small and little weight electronic, so that this dosimeter may be regarded as a prototyp of an albedo-dosimeter. The whole equipment will be described in detail and a review of measurements and practical experience with this device will be given