Tag Archives: dose

Geiger Counter vs. Scintillator

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Geiger counters are an indispensable tool for any scientist, professional or amateur (like me). The Geiger counter can detect radiation quickly and effectively. They are also relatively cheap, ranging from a few hundred to a few thousand dollars (most are under $1,000). Geiger counters have varying abilities and detect different particles and energy levels of those particles with differing levels of efficiency. By far, beta radiation is detected the best with many tubes detecting 2 to 4 out of ten particles which hit them. Alpha radiation is a bit lower, with many tubes totally blind to them and those which are not only detecting 5 to 10 particles per every 100. Gamma and X-ray radiation is the lowest for Geiger counters, where often between 1 and 3 photons are detected per 100.

Pros — Cheap, easy to use, portable, can detect alpha, beta, gamma, and x-ray.

Cons — Cannot determine isotope (fact), cannot determine energies, very low gamma and x-ray efficiency.

Scintillation counters are the tools of the professional nuclear scientist. Scintillation counters exist for gamma, x-ray, beta, and alpha radiation (a specific unit for each). When used with a multi channel spectrum analyzer, the counter can identify isotopes by their energies. Some Gamma spectrometers can even be used for complex gamma recoil analysis (mossbaur spectroscopy) which aid in determining the molecular bonds of various atoms, such as iron. Crystal sicntillators may cost a few hundred to a few thousand dollars, while a multi channel spectrum analyzer to attach to one is at least a few thousand more. This means an entry level lab-grade unit (like mine) will set you back about $5000. Very powerful soil state units, like those used at universities, can be well beyond $10,000 and even as much as a million dollars. A good High Purity Germanium (HPGe) is at least $10k. These detectors may be used without a multi channel spectrum analyzer, but they only count at that point. Hobbyists have created multi channel spectrum analyzer’s for under 1,000 dollars.

Pros — Can identify isotopes, measures energies, very sensitive to gamma rays (for gamma sicntillators), can probe hyperfine molecular bonds.

Cons — Expensive ($1000 and up), complex, requires extensive skill (physics), portable units are often very expensive.

Links:

Great MCA+Scintillator for entry lab-grade use. This is what I use:
http://www.spectrumtechniques.com/ucs30_system.htm

Small and portable scintillation devices (mega pricy)
http://www.laurussystems.com/IsotopeID.htm

A really great Geiger counter (Inspector EXP+)
http://geigercounters.com/EXP2.htm

Probably the best Scintillation video ever made
www.youtube.com/watch?v=h0dF2FUo5WU

What’s in your rain?

I detect the potassium in a single banana… GM can’t do this. =)
http://www.youtube.com/watch?v=a_SJH7VNAE0

Radio-isotopic Analysis of Post-Fukushima Accident Japanese Soil Samples

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The full document can be read here
All supporting data can be accessed here
Abstract
Radioactive fallout from the triple reactor disaster at the Fukushima Daiichi Nuclear Power Station, following a magnitude 9.0 earthquake and subsequent tsunami, is readily observed in soil samples collected from Japan, well beyond the exclusion zone. Samples from three regions, approximately 210 km, 550 km, and 1060 km from the Fukushima Daiichi Nuclear Power Station, were tested for gross gamma activity and radio-isotopic composition. The primary isotopes of focus were the most commonly detected radio-isotopes of Cesium, 134 Cs and 137 Cs.

Note: Another individual should be listed as a co-contributor, given their important role in providing material from Japan for testing, but their name has been left out for purposes of anonymity. To that person, go my deepest thanks.

Documents and data used in the report. This data will allow anyone to view and come to their own conclusions. Data transparency is important.

Please remember that this document is Open For Comment until March 11.

Radioactive Banana! Peeling Away the Mystery

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Radioactive Banana! Peeling Away the Mystery

All bananas contain potassium (element K). All potassium contains 93+ % Potassium 39, stable potassium, and a little bit of the isotope Potassium 41, perhaps 6+ %. But, all potassium also contains a tiny fraction of the radioactive isotope of potassium, Potassium 40 (K40).

Potassium 40 undergoes three forms of decay, beta -, rarely beta+, and electron capture. The last step emits a gamma ray with an energy of 1461 keV. It is this gamma ray that I detected.

My calculations for the typical radioactivity of a banana:

The number of Potassium (K) atoms per gram of potassium:
(Avogadro’s Number / Atomic Weight of K40) = 6.022 x10^23 / 39 = 1.544 × 10^22 K Atoms/gram

The amount of Potassium in a Banana (approx):
grams of Potassium in a banana = 0.442 grams

Natural abundance of K40 per normal Potassium (A): 0.000117

Half life of Potassium: 3.9357×10^16 seconds (T 1/2).

Calculation:
((Avogadro’s Number) / (Atomic weight)) x (0.442 g) x (A) x (ln 2) / (T1/2)
(((6.022*10^23 / 39)*0.442) x 0.000117) x ln2 / (3.9357×10^16)
=14.0633 decays per second per banana
= 14.0633 Bq Banana^-1
=lol

Practical Gamma Spectroscopy Links

For $350 USD – $500 USD
http://beeresearch.com.au/ – Quality and inexpensive MCA
http://www.physics.usyd.edu.au/~marek/pra/index.html – PRA software for viewing peaks.

You can often find a good scintillation probe on eBay for a few hundred dollars (USD), but you have to shop for it.

$4,000-$5,000 USD
http://spectrumtechniques.com/ucs30_system.htm — Entry lab-grade setup.

Some potassium and banana sites!!!
http://www.orau.org/ptp/collection/consumer%20products/potassiumgeneralinfo.htm
http://en.wikipedia.org/wiki/Banana_equivalent_dose
http://www.chiquitabananas.com/Worlds-Favorite-Fruit/bananas-and-potassium.aspx
http://www.ncbi.nlm.nih.gov/pubmedhealth/PMH0000089/

Gamma Spectroscopy: Americium 241 Smoke Alarm Tested

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0.9 uCi 241 Am Smoke alarm tested using gamma spectroscopy.

Japanese Samples Tested using Gamma Spectroscopy — First Results

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Japanese Samples Tested using Gamma Spectroscopy — First Results

Recently, a friend of mine sent me a series of samples from all across Japan. He, my friend, lives in Japan and obtained these samples at some personal risk. I have started the process of testing each of the many samples using gamma spectroscopy and other techniques. I will be posting my results for each sample as I test them, which may take time given my busy work schedule.

I have tested an air filter from an AC/heater unit in Saga City, Saga Prefecture (1100 Km south of Fukushima), Japan and a sample from just under a water rain spout in residential housing area (back yard), of a person living in Kashiwa City, Chiba Prefecture (26km NE from Tokyo).

I found Cs134 and Cs137 in the soil sample and I believe that I found Kr85 in the air filter. You can read the details and download my full report from my website. Please review my first report, Sample J-F, and my preliminary details of Sample J-A, which I will fully post soon.

www.Anti-Proton.com

Please keep in mind that these sorts of contaminants are quite expected in Japan. Each sample comes from a few hundred to only 1100 km from Fukushima, so the results are expected.