A tissue equivalent proportional counter filled with a mixture of tissue equivalent gas and 3He for neutron monitoring

Tissue equivalent proportional counters (TEPC) allow the measurement of the ambient dose equivalent H* (10) in mixed fields. IRSN has been studying the design and the response of a TEPC in terms of neutron H* (10). First, a cylindrical counter was filled with propane gas at a low pressure. H* (10) measured in monoenergetic neutron fields underestimated the reference (>50%) at low energies ( 40%) were not totally complying with the objectives (< 20%). Finally the choice was made to improve the analysis of the microdosimetric spectra y·d(y) in order to identify the energy of the incident neutrons. The analysis allows a better estimate of H* (10). The aim of this article is to describe the TEPC and the effect of these methods of optimisation. © 2006 Oxford University Press