[2D19-23] Environmental Radioacitivty and Radiation Measurement 2

[2D19] Simultaneous estimation of surface concentrations and soil-depth profiles of radiocaesium with NaI(Tl) pulse height distributions measured over the ground surface.

*Jun Moriizumi¹, Hisashi Ichikawa¹, Shigekazu Hirao², Hiromi Yamazawa¹ (1. Nagoya Univ., 2. Fukushima Univ.)

Keywords:radiocaesium, surface concentration, soil-depth profile, pulse height distribution measurement, EGS5

A method with pulse height distribution measurement with NaI(Tl) detector for simultaneous estimation of both surface concentrations and soil-depth profiles of radiocaesium isotopes has been developed, and its precision and feasibility were discussed. An assumption of uniform horizontal distribution of radiocaesium within 300 m square around the measurement point reproduced well depth profiles denoted with two parameters (relaxation mass depthβ₀, peak depthζ₀). Realistic sets of the parameter values can be estimated, although they were not unique.