Position Dependence for Count Rates in a Polyethylene Naphthalate Survey Meter

Abstract

A thin polyethylene naphthalate (PEN) sheet (72 × 140 × 0.5 mm) with one face enhanced with prism treatment was used for a survey meter. PEN has a relatively high effective refractive index of 1.70, which directly affects light propagation generated in the sheet. We show its radiation counting response at a 9 × 23 array of different locations on the detection window of the PEN survey meter, when irradiated with beta particles from a 90 Sr radioactive source. The variability in radiation counts on the detection window, obtained by dividing the maximum value by the minimum value, was 1.23 along the Y-axis and 1.05 along the X-axis. This knowledge can be useful in the design of radiation detectors mounting PEN sheets.