Dosimeter of Fukushima citizen counts 40% lower than actual, Maker admits

On 1/28/2015, “CHIYODA TECHNOL CORPORATION [URL]” announced on their website that their dosimeter shows cumulative exposure dose lower than actual air dose rate by 30 〜 40%.

Fukushima citizens are given the dosimeter of this company, which is the largest “glass badge” maker. The citizens wear these dosimeter to measure the individual cumulative radiation dose in a certain period.

Having a company executive apologize it in the city council of Da-te city in mid January, they officially announced this fact on their website.


The dosimeter counts γ ray only when it comes to the front of the badge. In the circumstance where γ ray comes in all the direction, it shows only 60 〜 70% of the actual radiation dose.

The maker states it is not unrealistic because most of the highly radiosensitive organs are in the front of human body.




Français :

Le fabriquant des dosimètres des habitants de Fukushima reconnaît qu’ils ne mesurent que 60% de la réalité


Le 28 janvier 2015, “CHIYODA TECHNOL CORPORATION [URL]” annonce sur son site web que leur dosimètre affiche une dose d’exposition cumulée inférieure à la dose ambiante de 30 à 40 %.

Les habitants de Fukushima ont reçu des dosimètres de cette société qui est le plus grand fabriquant de “badge en verre”. Les habitants portent ces dosimètres pour relever la dose cumulée d’irradiation pendant un certain temps.
Suite aux excuses publiques d’un dirigeant de l’entreprise mi-janvier lors d’un conseil municipal de la ville de Da-te, ils reconnaissent publiquement le fait sur leur site internet.

Ce dosimètre compte les rayons γ seulement s’ils arrivent face au badge. Lorsque ces rayons γ proviennent de toutes les directions, il n’en prend en compte que 60 à 70 %.
Le fabriquant affirme que ce n’est pas irréaliste parce que la plupart des organes radiosensibles sont sur l’avant du corps humain.

About this site

This website updates the latest news about the Fukushima nuclear plant and also archives the past news from 2011. Because it's always updated and added live, articles, categories and the tags are not necessarily fitted in the latest format.
I am the writer of this website. About page remains in 2014. This is because my memory about 311 was clearer than now, 2023, and I think it can have a historical value. Now I'm living in Romania with 3 cats as an independent data scientist.
Actually, nothing has progressed in the plant since 2011. We still don't even know what is going on inside. They must keep cooling the crippled reactors by water, but additionally groundwater keeps flowing into the reactor buildings from the broken parts. This is why highly contaminated water is always produced more than it can circulate. Tepco is planning to officially discharge this water to the Pacific but Tritium is still remaining in it. They dilute this with seawater so that it is legally safe, but scientifically the same amount of radioactive tritium is contained. They say it is safe to discharge, but none of them have drunk it.


January 2015