Assessment of the calibration of gamma spectrometry systems in forest environments

Abstract

A Monte Carlo simulation was used to develop a model of the response of a portable gamma spectrometry system in forest environments. This model was used to evaluate any corrections needed to measurements of Cs activity per unit area calibrated assuming an open field geometry. These were shown to be less than 20% for most forest environments. The model was also used to assess the impact of activity in the canopy on ground level measurements. For similar activity per unit area in the lower parts of the canopy as on the ground, 10-25% of the ground based measurement would be due to activity in the canopy, depending on the depth profile in the soil. The model verifies that an optional collimator cap can assess activity in the canopy by repeat survey.

A Novel Method for Spectrometry Based on Imaging Systems

“…Modern application requirements need the use of brand-new detectors guaranteeing minimum weight and size, a high level of automation, multichannel and wireless connectivity. Nowadays, the most commonly used systems are easy to handle and to be carried by humans [1][2][3], assembled on air vehicles [4], robotic instruments [5], or dive into deep oceans aboard marine submersibles [6][7][8].…”

Gamma-ray attenuation caused by rainforest dispersion compared to Vegetation Index: estimates on the effects in airborne gamma-spectrometry data – example from the State of Rondônia, Amazonia, Brazil

“…Aiming at the calibration of gamma spectrometry systems in forest environments, Cresswell et al (2018) measured gamma rays from the 137 Cs decay, designing a model with a canopy base less than 2 m above the ground and spacing of 2 m between wood trunks, simulating a common Japanese cedar forest. The conclusion was that in the best scenario, one sensor calibrated in open fields would underestimate the radiation measurements up to 35% into a forest with the arrangement stated above.…”