A NEW PROPORTIONAL COUNTER FOR INDIVIDUAL NEUTRON DOSIMETRY

This paper presents the design and the optimisation of a special propo rtional counter made of two flat multichannel cathodes and a set of an ode wire. First, the multicellular geometry is discussed. The increase of internal surface area of the cathode, the chord length distributio n and the simulated volume are emphasized. Subsequently, a special gas mixture, based on propane, argon, nitrogen and carbon dioxide, is pro posed to fill the counter; the assumptions on its composition are disc ussed and a first experimental evaluation of the gas gain is presented . Finally the response of the first prototype 'multicellular counter' to monoenergetic neutrons, in the range of 0.144-2.5 MeV, is presented according to ICRP-21 and ICRP-60 recommendations.