In this paper, the authors reported on a design method of a directional gamma~ray measuring instrument suitable for field measurement consisting of a disk" shaped shield and a survey meter. The authors newly defined indices regarding viewing angle, which is required to determine appropriate shield size and distance between the shield and survey meter, and the configuration of the instrument was examined quantitatively with the indices using radiation analysis code PHLTS. An example of viewing: Angle ±45° with various size shield and a 3 "inch Xal∗ scintillation survey meter was discussed and confirmed that a 150mm shield 35mm from the scintillator gave appropriate results.
- Nuclear disaster
- Radioactive contamination. directional radiation dose. measuring instrument