Response to the letter to the editor

Excerpt

We thank the letter to the editors by Fujii et al. and appreciate their excellent work in investigating the permeability of radioisotopes, including ²¹¹At, with various protective materials. As they have pointed out, volatility was reported for ²¹¹At, similar to iodine as a halogen isotope. We assume that permeability depends on the gap of the materials at the micro level. Since all films, which are collectively called plastics, have small pores, it is inevitable that gases, including oxygen and nitrogen, will pass through them. When the plastic films are arranged in descending order of gas permeability, they are as follows: polyethylene > polyvinyl chloride > polyvinylidene chloride [1]. This exactly matches the astatine transmittance data published by Ohnuki et al. [2]. …