May 18, May 25, 2021 We held IER Special Seminars online.＜by Dr. Thomas Johnson＞
Venue
Online (Zoom)
Guest Lecturer
Dr. Thomas Johnson, Professor of Colorado State University
In some of the classes of the Master’s Program of Major in Environmental Radioactivity, distinguished external researchers are invited as guest lecturers, and their classes are open to other faculty members on campus as “Special Seminars”.
◆Lecture 1◆ D&T:Tue. May 18, 2021, 10:20am‒11:50am JST
Lecture Title: Overview of external radiation dose measurement
On May 18, the online lecture on the subject “Radioecology” by Prof. Thomas Johnson was attended by three IER graduate school master students and several IER members. In this lecture, Prof. Johnson presented the basic approaches used for calculations of the doses from external gamma- and beta- radiation. The lecture greatly benefited from the example calculations of the specific gamma ray constant and doses from the point, linear and planar sources of gamma-radiation, as well as it provided useful online links to dose calculation tools such as Biota DC and VARSKIN as well as the JAEA nuclear database. In the Q&A session, the lecture participants discussed the environmental factors that can impact the air dose rates, such as variations in soil moisture content etc., and compared the magnitudes and sources of the ambient dose rates in Japan and in Colorado.
◆Lecture 2◆ D&T:Tue. May 25, 2021, 10:20am‒11:50am JST
Lecture Title: Biological Effects of Radiation on Animals
On May 25, the lecture on the subject “Effects of Radiation Exposure” by Prof. Thomas Johnson was attended by three IER graduate school master students, two CSU students and several IER members. Prof. Johnson reviewed the available data on the effects of radiation on animals including those acquired in Chernobyl, and discussed the basic concepts applied in the Radiation Protection of the Environment, such as Reference Animals and Plants (RAPs) and Derived Consideration Reference Levels (DCRL) introduced by the ICRP. In the concluding part of the lecture, Prof Johnson emphasized the needs for the further improvement of the biota dosimetry and identification of ecologically-relevant endpoints. In the Q&A session, the lecture participants discussed about radiation as a possible factor of natural selection, about the decrease and recovery of populations of some animal species in Chernobyl, and about the perspectives of introduction of the tissue weighting factors for improving of the biota dosimetry.