Cesium-134 And Iodine-131 In Australia?

This is in response to a post from Enenews user vital1. A rainstorm with radioactive rain occurred in Caloundra, Australia on January 6, 2014.

vital1
January 9, 2014 at 6:59 pm Log in to Reply
Took a rain swab off a car here on the 6th January 2013.

This swab was tested using a Theremino Geiger counter kit using a Russian SBT-10 pancake probe. Initial peak was around 5 uSv/hr 3,000 cpm. This is the hottest rain washout detected here so far.

location.

http://sccc.org.au/monitoring/Australian-Map.jpg

The decay chart of the rain swab showed classic Radon-222 decay daughter decay.

http://sccc.org.au/wp-content/uploads/2014/01/Rain-swab-Caloundra-060114-AV-TV49.jpg

http://enenews.com/forum-post-radiation-monitoring-data-april-30-2012-present/comment-page-46#comment-445263

vital1
January 10, 2014 at 12:26 am Log in to Reply
Here is the scintillator test chart preliminary assessment, of that rain swab. I used experimental MCA Theremino software for this test. It can get a bit noisy near background. This experimental software is pushing the limits of what can be detected with the equipment here. I have placed peak markers at the top of the chart for reference.

The rain swab Geiger counter and scintillator tests showed that the rain event on the 6th January was mainly Radon-222, and Radon-220 washout.

http://sccc.org.au/wp-content/uploads/2014/01/Rain-swab-Caloundra-060114-TV62-26c-84323+-text.jpg

You can see some of the peaks for Radon-222 and Radon-220 decay daughters still present in the test chart. The main peaks are for Radon-220 daughters at, Pb-212 X-ray (77 kev), Lead Pb-212 (238 keV) and Tl-208 583 keV.

As you can see there is no Cesium present, but traces of Iodine I-129 40 keV?, Lead Pb-210 47keV, U-235 at 185 keV?, and Beryllium Be-7 477 keV. The peak between the Be-7 and 511 peak markers is probably a sum peak of the two.

Any further discussion, or corrections to this assessment are welcome?

Previous rain water tests can be found here.

http://sccc.org.au/pages/The-Food-Lab.html#Soil%20Testing%20Results

This rain sample was measured at 5 μSv/hr. This is 50 times the normal background level for this location.

Since he said further discussion was welcome, I took the liberty of looking at this a little further.

He mentioned that radon-222 (and its daughters) were found. This isotope is part of the uranium-238 decay chain. Nuclear fuel at Fukushima is made up mostly of U-238. It is found naturally underground, though, also. That is what uranium miners dig up from the ground. Uranium-235, the ingredient in enriched uranium, which is present in nuclear fuel, and in small quantities naturally, was also mentioned.

But he also found radon-220 (thorium decay series), and also iodine-129. I-129 is being emitted by Fuku, but it is also being dumped by the La Hague plant, and is probably a small contributor to ordinary nuclear power plant emissions.

But there may be a couple definite Fukushima-related isotopes in this spectrum, cesium-134 and iodine-131. My additions to this graphic are in red. To see this, we need to know the energies (in kEv) of these isotopes, as well as the branching ratios of each peak in the spectrum. From Wikipedia:

In particle physics and nuclear physics, the branching fraction for a decay is the fraction of particles which decay by an individual decay mode with respect to the total number of particles which decay. (link)

Which just means the some energy peaks are larger (in probability) than others, because they decay with different probabilities for the different peaks, and we know how much larger the peaks should be by comparing the branching ratios of the peaks.

isotope   energy (kEv)   branching ratio
-------   ------------   ---------------
Cs-134       569.3            15.4
Cs-134       604.7            97.6
Cs-134       795.8            85.4
Cs-134       801.9             8.7
I-131         80.2             2.6
I-131        284.3             6.1
I-131        364.5            81.7
I-131        637.0             7.2

So the peak of Cs-134 at 604.7 is 14% higher than the 795.8 peak. And the peak of I-131 at 364.5 is over 11 times higher than the peak at 637.

The graphic shows that it is plausible that these isotopes are in the rain sample. And if so, they are certainly from Fukushima. But they fall short of the 95% confidence level (or whatever this level might be) that would indicate “scientific proof” that these isotopes are present, according to whatever definition of what this proof is.

But, the opposite of “scientific proof of the existence of A” is NOT “scientific proof of the non-existence of A”. The opposite is “scientific uncertainty of the existence of A.” Something to keep in mind.