Current Gamma and Beta spikes
On the EPA website, numerous midwest states are experiencing Gamm and Beta spikes on 5/25/11. Can someone please explain these spikes and why the EPA is not increasing monitoring based upon their own data? These spikes have ocurred at a time of devestating tornadoes in the Kansas/Missouri/Oklahoma area.
The spikes in gamma and beta
The spikes in gamma and beta count rates can be caused by natural radioactivities in the air (radon decay chain) or instrumental effects (gain drift from temperature changes or electrical interference).
As for the first cause (radon daughters): the concentration of radon gas and its decay products depends greatly on temperature and weather patterns. When the air is cooler, or when there is an inversion layer "holding down" air near the ground, there can be a higher concentration of radon gas and its decay products -- especially Lead-214 and Bismuth-214, which are strong gamma and beta emitters and are quite radioactive. Other weather conditions can cause large variations as well, especially rain. Rain washes the radon progeny out of the air. So when it rains, there should generally be a short spike in the gamma and beta counts followed by a period of lower counts.
Weather and temperature cycles generally repeat over the course of 24 hours. If you look at any of the EPA RadNet air data, there are always up and down patterns that have a frequency of 1 day. Any other spikes above and below would be due primarily to rain or other conditions, and electrical interference (which the EPA notes on its RadNet website).
These spikes happen all the time, and that is why the EPA is not increasing their monitoring. If this weren't natural, then they would know, and we here in BRAWM certainly would know, too.
Mark [BRAWM Team Member]
tornadic storm fallout , apparenly
talk about disturbing! http://pissinontheroses.blogspot.com/2011/05/alert-62-times-background-r...
Fear not -- it is just natural
Thanks for posting that video, Ana. I think that person should do the same test that our forum contributor James did and take careful data with the detector in exactly the same place for 4 hours. The activity will have a half-life of about 40 minutes, and the sample will return to background levels in about 3 to 5 hours, depending on the initial activity of the sample and the variation in the background.
Actually, it appears that that blogger has already done similar tests -- they measure that the activity is back to background in about 3 hours. That is a great sign! This cannot be fallout from Japan. It takes about 6 days for fallout to reach the U.S. from Japan. By that time, the quantity of whatever isotope would have decayed away by at least a factor of 2^(-(6 days)*(24 hours/day) / (3 hours)) = 2^(-48) = 3.6 * 10^(-15), which is practically zero. By contrast, Iodine-131 (8 day half-life) would decrease by 2^(-(6 days)/(8 days)) = 2^(-0.75) = 0.59, which is why we were able to measure it here.
The simplest explanation for those measurements is that Lead-214 and Bismuth-214 are present in our environment and in the air from the decay of Radon-222, and those isotopes have 27 minute and 20 minute half-lives, respectively. Since Lead-214 decays into Bismuth-214, the total activity from their sum is not exactly an exponential, but it is approximately an exponential with a half-life of about 40 minutes. This exactly explains the air filter data that James took:
http://www.nuc.berkeley.edu/node/4109#comment-8146
http://www.nuc.berkeley.edu/node/4109#comment-8149
Mark [BRAWM Team Member]
Spikes in San Diego as well !
Hhhhmmm we are spiking here in San Diego too and there are no high winds or tornados.
San Diego has been "spiking" for a while now
There's nothing happening now that hasn't happened for over a month.
And has happened in years prior as well.
Spikes here on the West Coast....
Just resulted in the EPA removing some of the beta counts from their online graphs and data sets....
Spikes
You probably hit the nail on the head... the tornadoes probably kicked up all sorts of junk including local radon. This probably happens every time there are tornadoes.