Tag Archives: radon

Cesium 137 Detected in my Rain! (Radioactive Rain Detected)

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As you all know, I have always maintained that there is Fukushima fallout in the rain… but that the levels (even if they are unsafe) are too low for a Geiger counter to detect.

My sensitive Gamma Spectrometer has now (I believe) detected Cs137 in a rain water collection bucket which concentrates, or so it seems, the Cs137.

Most of the radiation detected by Geiger counters from rain is from Radon Washout, a processes whereby radon in the air (decays from natural uranium around the world) is “washed” out and falls to the ground in the rain. The decay chain is sudden and very quick, providing a few hours of potent readings before falling to background.

Inspector (regular or EXP) Sensitivity to Iodine 125:

0.02 µCi = 740Bq = 44,400Bq/60seconds
(At contact for I-125)

http://seintl.com/products/inspectorplusEXP.html

Iodine -125 Electron Capture
Gamma – 35.49 keV 6.60 %
X-Ray – 27.47 keV 75.7 %

http://ie.lbl.gov/toi/nuclide.asp?iZA=530125

Best energy range for detection by LND7317 probe:
10 keV = 100 keV (max)

The range where detector efficency falls rapidly (Cs137 is also in this range):
100 keV = 1000 keV (declining)

http://seintl.com/images/InspEnResponseC137_large.jpg

A great place to find data on isotopes:
http://ie.lbl.gov/toi/

*** Update! ****

I have calculated the activity:

My original calibrated Cs137 source (cal. vs. NIST tracible source, source ID SRS:80899-854, at 95% accuracy) was 3737 Bq.

I accounted for decay of the source:
3737*e^-((ln(2)/10979)*173) = 3696.4059560683608390980241545539265887454856828520474 Bq
=3696 Bq

For an ROI of the same size for both calibrated sample and rain water sample, I ran tests and determined counts per second:

Calibrated Source 91.2633 c/s
Rain Water Sample: 0.01439814814814814814814814814815 c/s

Now, I divided the detected calibrated sample c/s into the expected c/s to determine ratio of emission vs detection for the energies around 661.66 keV. (3696Bq * 0.851 [intensity for gamma from Ba137m])/2 = 1572.648. The division by two is because I entirely detected one side of the thin sample disk. so… 91.2633 / 1572.648 = 0.05803161292291727074335769987944

My detector is only about 5.8% efficient for such energies. (lower than my 12% “ball park by half”)

Now, merely divide the counted detection from rain by the efficiency and you have about the correct result.
(311counts/21600) /0.05803142216185694446564011781403 =

=0.01439814814814814814814814814815 / 0.05803142216185694446564011781403 = 0.24810951742643665986093914169915

Or 0.248 Bq/liter

(that is zero point two four eight Becquerels per liter)

Thoughts?

Nuclear Isotope Identification – Why Is something Radioactive?

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Radioactive materials are easy to detect with a Geiger counter, but cannot be identified with a Geiger counter. You need an isotope detector.

One of the most widely used isotope detectors is a Gamma Scintillation Spectrometer. In this video I explain how Gamma Spectrometers work. I also show you actual real-time capture of gamma spectra from several sources:
Cs-137
Cs-134
Eu-152
Am-241
Np-237
And Natural Uranium & progeny.

Please visit my website for a short explanation of the basics of radiation!

What is Radiation?

Spectrum Techniques (Where I get my sources and Spectrometry equipment)
http://SpectrumTechniques.com/ucs30_system.htm

GeigerCounters.com (Where I get my Geiger counters)
http://GeigerCounters.com

Radioactive Rain – April 21, 2012, Virginia

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I tested my rain again and found radon progeny once more.

It should be somewhat obvious by now, given the occurring, what the source of all of this.

Radioactive Rain – Radon Washout Found!

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Here is the short 3 minute version of the same video with only the results. =)

Radioactive Rain, 3rd July, 2011

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I live on the east coast of the United States in a cozy little state known as Virginia. I am extremely far from Fukashima, and yet, I have logged incidences of radioactive rain several times. Though I have read of many on the internet who seemingly record readings of 600+ counts per minute (10-40 times normal background) I normally find only slight elevations, no more than twice background, which are only decipherable to me via statistical analysis.

July 3rd, 2011 I detected a slight increase in radiation during a rain storm. From past experience with rain, I have found that monitoring at ground level, or in the rain, yields much higher results. Most of the time my Geiger Counter records data from my office, next to my window, about 30 feet above the ground. As a result, changes in radiation readings are more slight, but never-the-less, detectable.

There is most likely little reason for concern, given the slight readings and their very possible non-Fukashima origin, perhaps being the result of pollution (often beta and alpha emitter containing). Without an scintillator, it is nearly impossible to accurately determine the cause.

The radiation seems to dip rapidly upon the onset of rain, rising to normal levels during the rain and slowly building after the rain. When next I am confronted with a storm I can easily track, I will test my rain levels, wind, and other data in conjunction with my radiation monitoring.

Data on my unit:
International Medcom, Model CRM-100 (eff. RadAlert 100)
Detector: LND 712 Thin Mica Window Ne+Hal

Raw change from norm


Sorry for the low quality of the graph. My graphing software is very good with numbers, but very poor with presentation.

I tested the data from 05:10 PM, EST, 030711 until 03:44 AM, EST, 040711. The average reading was 15.23 CPM. From this I calculated a simple standard deviation and arrived at σ=3.98. This would mean that readings of 11.25< = and readings of =>19.21 would be indicative of an abnormal event. I like to treat multiple sustained readings, or a segment of greater amplitude, as a true indicator of an event.

Rain brings about upwards curve in radiation

Rain brings about upwards curve in radiation


Above is the raw data from Geiger Graph software. Note the rise in the average readings follows the rain. If you are skeptical of the rain, please look up historical data for rain fall for Fredericksburg, VA for late 030711.

Here is a link to the actual raw data.
Here is a link to my past month’s data showing my normal average of 14 CPM
June 1 – 15
June 16 – 30