The development and use of a tissue equivalent proportional counter analysis system to measure the dose delivered to the gut of an anthropomorphic phantom from a fission source

An electronic system has been developed which allows simultaneous pulse height data acquisition for a dynamic range of four orders of magnitude. The system was used to examine lineal energy spectra from a tissue-equivalent proportional counter exposed to monoenergetic neutrons and gamma rays, as well as mixed radiation fields. These spectra were quantified in terms of the microdosimetric parameters and in order to compare with the work of other experimenters, and the predictions of the computer codes NESLES. The results here served to enable development of an automated method of separating neutron and gamma ray dose components in a mixed field. The detector was then placed in a mid-abdominal position in a realisitic anthropomorphic phantom, which was positioned at both 10m and 170m from a bare, unmoderated critical assembly. Free-field measurements were also conducted at these two distances. Hence neutron and gamma ray doses, and dose transmission factors to the gut were obtained as a function of phantom orientation with respect to a fission source