Blogger's Note: I used radiation sources for 33 years while at the Naval Research Laboratory in Washington DC and for several years before my retirement I was curator of NRL's very hot Cobalt-60 gamma ray source. So I know a lot more about nuclear radiations than the guy in the street, but much, much less than those who actually specialize in radiation.
However, by joining the Ionizing Radiation Detection Group on LinkIn, I've gained access to some of the real experts. In particular, I learned from F. Patrick Doty, Distinguished Member of Technical Staff, Sandia National Laboratories, that the highest reported activity as of the end of March due to Fukushima-fallout measured by the University of Washington was only 32 mBq/m3, meaning that "about 2 atoms of iodine decay per minute per cubic meter of air." Trivially small!
The other part of the good news is the extremely high sensitivity of the measurements and the fact that they are being published. Although the data below end at the end of March, I presume measurements continue to be taken and that any new spikes in activity will be published shortly at the UW Physics site.
Otherwise, for those wanting a better understanding of the means of analyzing radionuclides in the air, Dr. Doty recommended downloading this EPA guide book.
The Japanese earthquake and tsunami caused a severe event at the Fukushima Nuclear Plant. At the University of Washington Physics Department we rapidly adapted one of our basic research labs to monitor for the arrival of trace amounts of fission products produced at Fukushima. On Friday, March 18, we detected the first trace amounts of radioactive isotopes from Fukushima in Seattle. We stress that the overall amount of the radioactivity is extremely low, at least thousands of times below EPA limits. For all of the details, see our recent article on the arXiv!
Here are the most recent data
Click here to view more peaks visible in our data.
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