West Coast background monitoring

[Carl Willis]

Cs-137 and I-131 are fission products, and as such represent only a tiny and undetectable fraction of the natural decay products of uranium (U-238 mostly). The alpha decay branch is far more probable than the spontaneous fission branch.

The fission-product isotopes are formed in reactors in large quantities by neutron-induced fission.

-Carl

[Chris Bradley]

Uranium and Thorium can *either* decay (alpha emitters) *or* fission naturally.

The 'fissioning' may be accelerated by neutrons. U-235 fissions into a distribution of isotopes you can find on; viewtopic.php?f=14&t=6898#p47930 The fission releases more neutrons that then induce more fissions.

[Edward Miller]

I've been thinking about the same thing.

Heres the Berkeley Nuclear Engineering Air Monitoring Page
http://www.nuc.berkeley.edu/UCBAirSampling

Then there's these guys.
http://radiationnetwork.com/

I think it'd be an awesome addition to a personal weather station to log and graph background counts similar to how individuals contribute to http://wundergound.com

So what would be a good geiger that I could run non-stop and log the data to a computer?

[Steven Sesselmann]

Check out Rad software from BlackCat systems with this software you can log the counts and publish the chart to an FTP to a server at regular intervals.

http://www.blackcatsystems.com/RadMap/map.html

Steven

[Jon Rosenstiel]

Ok, my GM setup recorded a sharp increase in the background count rate during the afternoon of the 20th (Sunday)… but I’m kind of suspicious as there were lots of other weather related things going on at the same time. (Re: Gusty winds, sporadic rain, heavy rain). Unfortunately, I had to terminate the count at 5:00 pm because the cardboard sunshield protecting my detector was not faring well in the rain.

The patio table wipes turned up nothing but the usual background peaks. (Pb-214, Bi-214, K-40). I plan to re-run the wipes in a day or two using my HPGe detector, I’ll post results (or lack of same) in a couple of days.

Before I plotted it I was certain the rise in count-rate was related to the drop in pressure, but that doesn't appear to be the case. Hopefully someone here can shed some light on the sharp increase in count-rate.

Note: I did manage to capture close to 2-inches of rain water in a plastic tub… with a bit of luck that may shed some light on this.

Edit 3-22-11: This morning I discovered that the sharp increase in count-rate was due to operator error.

Jon Rosenstiel

[Steven Sesselmann]

James,

To record and count background radiation with a GM counter, I think the RAD software from Blackcatsystems is excellent. It's a free download here;

http://www.blackcatsystems.com/GM/page3.html

If you have your own gamma scintillator the simplest way to do Gamma Spectrometry is with Intune, PRA and a suitable Bias supply.

http://www.beeresearch.com.au/

I have a new improved model coming out in a few days, with inbuilt preamp.

Steven

[I have an association with this product ]

[Frank Sanns]

Jon,

Have you ever seen a rise of background counts in such weather conditions before? From your curves it does not look barometric pressure is the culprit. I assume the wind was out of the west or north west which would exclude any significant radioactive mineral deposits being carried your way.

Based on the small quantities that may have been present it is not totally surprising that the NaI detector did not see anything. There are some possible causes so it is not conclusive until the HPGe results are in. You may get another shot at this in the coming days, depending on the winds, as the reactors are still acting poorly.

It is very interesting that you stopped the test just as you reached the magic 65 cpm number that I had predicted.

Thanks for sharing and we look forward to your results.

Frank Sanns

[Richard Hull]

Remember, The uptick in background could be radioactive xenon or another radioactive inert gas which would not show in a wipe test. It would be ephemeral and not likely to stick around. Only a GM would see this, unless you captured gases. Just a thought.

I have personally held out that reactor Xenon might be the only thing that makes it to the west coast.

Ricahrd Hull

[Jon Rosenstiel]

The sharp increase in count-rate was due to operator error. (An electronics SNAFU I discovered this morning).

Sorry for the misinformation.

Jon Rosenstiel

[John Futter]

Jon
We have seen this at work
As rain starts it washes radon daughters out of the atmosphere giving quite a sharp rise in counts as the rain starts. It does drop back again even if the rain continues

Took quite abit to prove and then of course doing more reading it was well documented by others.

[Jon Rosenstiel]

HPGe gamma spec of patio table wipe turns up iodine-131... cool!

Jon Rosenstiel

[Richard Hull]

Just chatted with Jon and he has another wipe test going on now and just two hours in, he says he is getting a Cs137 peak forming! (more specifics later, I am sure)

Wow!

It must be understood that this is still nothing with a micro amount of something. Zero reason to worry. Jon's instrument is ultra sensistive well beyond even our best people's NaI detectors and spectro materials

At last we know for sure that southern Cal has 131 Iodine in the air. Thanks again Jon!
I assume the GM background remains un-impacted at a statistical level?

Richard Hull

[Carl Willis]

Wow. That's impressive.

I have been running some air-sample tests (since Sunday) here in Albuquerque that have so far failed to turn up anything other than radon/thoron daughters. The apparatus for doing this is a box fan on my roof to which I have been taping paper towels. Albuquerque has had almost no rain (a tiny sprinkle yesterday), but maybe I should wipe a surface and see what shows up.

With regard to Cs-137, it's a little harder to ascribe that to a particular source since so much exists from weapons tests, Chernobyl, etc. on account of the long half life. But the source of I-131 is pretty much unambiguous.

FYI, here's UC Berkeley's latest water sample: http://www.nuc.berkeley.edu/node/1904

They also find Te-132 and its daughter, I-132.

-Carl

[Edward Miller]

Here's another page with individual monitors in Japan.
http://japan.failedrobot.com/

[Frank Sanns]

It is the warmest day of year here by far at 65 F but it is supposed to be snowing by midnight so we have a very strong cold front moving through. I have my beta/gamma probe outside under the eve. My readings are less than 10% different than on any other day. They may not even be higher but without a more rigorous determination, I would say nada here in Pittsburgh but I am collecting a bucket of water. Not much hope in detecting anything with the NaI but I will give it a go in a while when the hail in the bucket melts but before the water freezes tonight.

Frank Sanns

[Steven Sesselmann]

Jon,

That's impressive, it even looks like a needle in a haystack

Steven

[Frank Sanns]

Last night I boiled the 1+liters of collected rain water down to around 80 ml in a glass baking dish. Then I transferred it and a surprising amount of particulate to a 250 ml beaker and evaporated the rest of the water leaving a ring in the bottom 2 cm of the beaker. My 2x2 NaI is a perfect fit into the beaker and the whole works went into my lead castle. After 6 hours of counting, I can not detect any peak around 365 KeV. A pass of the beta gamma scintillation probe also turned up empty. Looks like Jon had all of the fun. This is both a good thing and a bad thing.

Frank Sanns

[Jon Rosenstiel]

The attached gamma-ray spectrum was the result of knowing what to look for (Re: Carl's link to the UC Berkeley spectra) and a bit of luck with the timing of the patio table wipe.

Fission products detected…
8.0-day I-131
2.3-hour I-132
3.2-day Te-132
2.0-year Cs-134
30-year Cs-137

I was rather stunned to see 2.3-hour iodine-132 in the UC Berkeley data and totally blown away to also find it in my data. Is this really possible? Iodine-132 must have hitched a ride on the jet stream.

EDIT 3-25-11: Although 2.3-hour I-132 is a fission product, it's also the decay product of 3.2-day Te-132… the much more likely scenario in this case. Thanks to Richard and Carl for bringing this to my attention.

Jon Rosenstiel

[Richard Hull]

Te132 (78hr) decays to I 132. I imagine that is the source.

Fabulous work Jon!!!!! All this stuff is way down in the mud, but there, nonetheless.

Headlines will read "Radiation from Japan's melting down reactors slams into U.S. West Coast.".........In a series of interviews with noted nuclear measurement specialist, Jon Rosentstiel, KNBC News has learned that...........

Richard Hull

[Jon Rosenstiel]

Te-132 decaying to I-132 makes much more sense Thanks to Richard for pointing this out.

Jon Rosenstiel

[richnormand]

The "other" coast:

Traces of I detected in Iceland and Newfoundland now.

http://news.sympatico.cbc.ca/canada/tra ... l/2bdeb8e3

[taylorw]

Well its here too! I am probably one of the only people excited to see fallout raining down, but who can beat free radionuclides? Sorry about the bit of delay in posting this, I have been way too preoccupied the last few weeks.

There seems to be appreciable quantities of Iodine-131 in melted snow, along with a few other fission products that were reported earlier Isotopes of Tellurium and Cs-134/137. The CTBTO Atmospheric Dispersion Modeling has suggested a concentration due to the effects of atmospheric winds in our general area. This, combined with the process of nucleation on airborne particulate responsible for snow creation and the large quantity of snowfall, has put my collection right in the middle of the plume. I am currently recalibrating the HPGe with a Liquid Radionuclide Standard and will post the results of activity measurements shortly. There seems to be quite a bite of I-131 in un-refined snow melt, but the activity measurement will allow me to see where I fall within other monitoring facilities around the East Coast. It would be interesting to see a.) if a radioecological study can be made if any uptake in the environment is occurring, and b.) to see how much the radioactivity can be concentrated with Physical (i.e. the evaporation concentration at UC Berkeley) or Radiochemical means.

Interestingly enough, volatile Iodine at least, should not be captured in appreciable quantities in conventional Glass Fiber filters, (speciality Activated Carbon ones are used for this application), but it is there! The below spectrums are from 250 mL quantities of melted snow. The large peak, at 384 KeV is the primary Gamma Decay Line of I-131 (81.2%) with another peak at 637 and 284 KeV. (7.3% and 6.1% respectively)

The short lived fission products such as I-131 will slowly drop off, irregardless of the the dynamics of the situation at Fukushima Daiichi, however, the Cs-137/134 measurement should be a good indicator of the situation in both containment and Spent Fuel Pools.

Stay Tuned!,

- Taylor
Reno, NV
Sciradioactive@gmail.com
Sciradioactive.com

[Richard Hull]

Nice to hear the stuff is makin' it all around.... Shows good circulation in the atmosphere. Of course, at the levels seen and the need for a Ge detector tell immediately there is zero need for concern. Apparently, there was little need for concern even when my bird bath residues read about 10,000 cpm to a common GM counter back in the 50's. I'm still here and those were my pre-teen years when my growing body was lockin' all that stuff down in me and millions of other baby boomers.

Richard Hull

[Jon Rosenstiel]

Good work with the "hot" snow, Taylor. I'm looking forward to your activity measurements.

Jon Rosenstiel

[Carl Willis]

Hi Taylor,

Interesting results, and good work.

The following document is a useful reference on the classical radiochemical methods for isolating iodine isotopes. The iodine in rainwater is probably mostly iodide (I-) at this point. Most of the procedures for concentrating iodine from aqueous solution involve (1) adding a suitable carrier; (2) reduction of any iodate (IO3-) or molecular iodine present to iodide; (3) oxidation of iodide to molecular iodine; (4) extraction into a nonpolar organic phase; (5) extraction back into a reducing aqueous phase as iodide; and (6) precipitation along with the carrier as an insoluble iodide.

http://lib-www.lanl.gov/cgi-bin/getfile?rc000043.pdf

I wish I could snag some of this delicious fallout, but nothing resembling rain has fallen here in Albuquerque. I'm also not privy to the fine detectors you guys have, but I am rushing to put the HPGe on hand into service.

Thanks for the data.

-Carl