Investigation on distribution of radioactive substances in Fukushima, 4; Study on the ecological half-lives of ambient dose rates using car-borne survey data with fused LASSO

Liu, X.; Machida, Masahiko  ; Saito, Kimiaki  ; Tanimura, Naoki*

Ecological half-life has been widely used to describe the long-term decrease of ambient dose rates in addition to radioactive decay. In the present work, we introduce a new, robust, and efficient numerical method to extract space dependent ecological half-lives from car-borne survey data. Numerical results indicate complexed ecological half-life profiles, which are originated from their spatial patterns.