A practical design of a cylindrical tissue equivalent Proportional counter for microdosimetry

A 12-mm cylindrical tissue equivalent proportional counter was designed and constructed for microdosimetric measurements. It can be used in radiation therapy and radiation protection applications in many radiation fields such as gamma, neutrons and heavy ions. This detector achieves common to others TEPC features, but it does not use field shaping electrodes and it is able to work at higher bias voltages which make it capable to measure full energy deposition spectra for gamma rays. The main considerations regarding mechanical and electrical design depend on the practical application and the availability of materials. The following ideas were taken into account in order to make the design: first of all the use of a cylindrical shape detector featured as simple as possible but keeping its performance as well, the next point is to avoid the use of field shaping tubes and the last one is to make the preamplifier small and as close as possible to the detector. Its construction is based on a cylindrical proportional counter with A-150 tissue equivalent material as cathode, TE-methane gas as a proportional gas and a 20-mm diameter wire as anode