Monthly Reports of Background Levels and Rain Water Tests for 2015
This short animation of Northern, and Southern Hemisphere air circulation, shows why we can get detections so far south.
Roof down pipe filter design for rainwater testing, http://sccc.org.au/down-pipe-filter-design
Southern Hemisphere Background Radiation Report For November 2015
At the beginning of November and again on the 14th November, a 40%+ increase in day average backgrounds levels were detected at my location on the East Coast Of Australia, near Brisbane. Tests were conducted to try an establish the source of the elevated background.
There were evening storms on the 14th, during one of these elevated background events, so a car rain swab was collected on the morning of the 15th November. The rain had been sitting on the car overnight. A scintillator test of it was started on the afternoon of the15th. It was tested for ~24 hours.
Radon is formed in the normal radioactive decay of Thorium which produces Radon-220, and Uranium which produces Radon-222. Both of these different Radon isotopes decay slowly into lead.
In the test chart you will see isotope maker peaks for Lead Pb-212 and an X-ray at 77 keV. These are decay daughters of Radon-220. This suggests that Thorium-232 was the source. There are also traces of Lead Pb-210, and Potassium-40. Lead Pb-210 is the decay daughter of Radon-222. This means there was also some Radon-222 in the air at the time.
The test detected trace amounts of Th-232 decay daughters, so the rain swab test chart only shows the tops of the main Th-232 decay daughter and X-ray peaks. A Thorium gas mantle test shows the main Thorium Th-232 decay daughter peaks. I have provided it as a reference. As you can see from the gas mantel test, the equipment here can separate the combined X-ray daughter peak around 89/90 keV, from the main 77 KeV peak.
November 15th Rain Swab Chart.
Thorium Mantel Chart for Comparison
Where is the Thorium-232 coming from?
Sources of atmospheric releases of Thorium-232 could be the recent Indonesian, New Zealand or South American volcanic eruptions, or a mining operation somewhere? There is a lot of volcanic activity in the Southern Hemisphere at present. Because the elevated detections where detected along the entire Eastern Coast of Australia, by numerous private monitoring stations, I am leaning towards volcanic activity, rather than a mining operation.
My opinion is that the November 2015 elevated detections are a combination of,
1. The increased background we get every year in the warmer months, as a result of Fukushima equatorial breakthrough.
2. An increase from recent Southern Hemisphere volcanic activity.
The local November month average background radiation for November 2014, 2013, and 2012, works out to 0.130 uSv. The volcanic activity, or whatever source created the recent increase, appears to have increased the November 2015 month average local background to 0.137 uSv.
These measurements are recorded by a GammaScout Alert Geiger counter, logging every 60 seconds. The data is downloaded and turned into a day average chart, and eventually a month average chart.
Here are month day average charts for November 2015, 2014, 2013, and 2012, local background radiation levels.
Day Average Chart November 2015
Day Average Chart November 2014
Day Average Chart November 2013
Day Average Chart November 2012
Southern Hemisphere Background Radiation Report For October 2015
Caloundra and Cairns October day average background comparison chart - Here is the Cairns station operator's Caloundra and Cairns background comparison chart. Cairns is on the east coast of Australia, and it is much closer to the equator than Caloundra, see location map. Background levels at both locations saw an increase in background levels towards the end of October. Caloundra had more dynamic swings in background levels from mid October, than Cairns.
October 2015 monthly average background radiation level was 12% above the pre-Fukushima average.
October day average chart:
October average for 2014 was 14% above the pre-Fukushima average.
October average for 2013 was 25% above the pre-Fukushima average.
October average for 2012 was 19% above the pre-Fukushima average.
In the chart, Cairns is red and Caloundra yellow.
On this page you will find all the month and year average charts, for local background radiation levels from November 2007 to 2015.