PERFORMANCE OF TEPCS AT LOW-PRESSURES - SOME ATTEMPTS TO IMPROVE THEIR DOSE-EQUIVALENT RESPONSE IN THE NEUTRON ENERGY-RANGE FROM 10 KEV TO 1 MEV

A TEPC, from its operation principle, fulfils reasonably well the requ irements of an area monitor with a dose equivalent response nearly ind ependent of neutron energy to be used for radiation protection dosimet ry at various work places. However, between neutron energies from 10 k eV to 1 MeV, which are of relevance for environments with strongly mod erated neutron fields, the response of TEPCs with thin walls is too lo w. Attempts to increase the response in this energy region by modifyin g gas pressure, gas composition and wall thickness show that significa nt improvement first requires operation of the TEPC at lower simulated diameters compared with the 2 mum diameter commonly used. Preliminary investigations to improve the operational properties of TEPCs at low pressures are presented.