STUDY OF A SOLID-STATE MICRODOSIMETER BASED ON MICROMETRIC-SIZE DIODES COUPLED TO A RESIDUAL ENERGY MEASUREMENT STAGE

摘要

An array of micrometric diodes coupled to a residual energy measurement stage was proposed for solid-state microdosimetry. Each diode has a sensitive volume of a cylindrical shape (9 μm in nominal diameter) in order to reproduce that simulated by a cylindrical tissue-equivalent proportional counter (TEPC). The silicon microdosime-ter was irradiated coupled to a polyethylene converter with monoenergetic neutrons of several energies. The spectra of the energy imparted to the segmented telescope were corrected for tissue equivalence through an optimized procedure that exploits the information fromrnthe residual energy stage. A geometrical correction was also applied. The dose-mean lineal energy values were qualitatively compared with literature data. The silicon microdosimeter was also covered with a tissue-equivalent plastic (A150) and with a nylon converter. The results showed a contribution of heavy recoils (mainly carbon and nitrogen nuclei) generated in the tissue-equivalent plastic lower than that measured by the TEPC, owing to their stopping in the titanium-based dead layer of the silicon device.