Monthly Archives: May 2012

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

Waterford Crystal – Radioactive!

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Waterford Crystal – A beautiful addition to any home! It shines, looks lovely, and it is radioactive!


I recently tested a piece of Waterford crystal to see why it was radioactive. For a long time I have wondered by my Geiger counter went crazy when near it. The truth was quickly revealed by Gamma Spectroscopy! The little Angel statue contained potassium 40, (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.

Amazing!

Waterford Crystal Angel

Waterford Crystal Angel

Waterford Crystal - Gamma spectrum

Waterford Crystal - Gamma spectrum

Radioactive Fiesta® Ware – Happy Cinco de Mayo!!!

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Fiesta® Ware – Cinco de Mayo!!!

It’s the fifth of may and everyone is celebrating the French receiving some sort of “beat down” by the Mexicans. Sounds like a party, but why not make it a Fiesta!?

I thought it a good time to find and buy a Fiesta® Ware plate of my very own.

Fredericksburg Virginia, close to me, has dozens of antique shops. Most antique shops I have visited in the United States are literally full of hundreds of pieces of uranium glassware and uranium ceramics.

How much uranium is in one of my local stores? Let’s do some “ball park” guess work. =)
I have read that glazes for (this is a touch anecdotal) ceramics, like Fiesta® Ware contained about 10-12% uranium by mass, while depression glassware contains about 2%. If I suppose that a normal antique shop has about five pieces of Fiesta® Ware at 50g’s of glaze each and 50 pieces of depression glassware at about 150grams each… we would get:

5pieces (50g)0.12 + 50 pieces(150g)0.02 = 180g of uranium =) That’s 6.3 ounces…

Of course, this is merely a guess.

Anyhow, the piece I purchased (for a mere $20) is quit lovely, behind lead, and old too. The gamma spectrum I detected showed a much greater U-235 peak at 185.71 keV and 143.76 keV than I would have expected for natural uranium. Also, the equilibrium of Pa-234m is low but growing faster than my DU marbles… I would have to call this processed natural uranium oxide. I would guess that my does is somewhere between 2-8 mR/hr at contact, which is why I keep the plate far away and behind lead. =)

Data from: http://pbadupws.nrc.gov/docs/ML0829/ML082910862.pdf
and http://www.orau.org/ptp/collection/consumer%20products/fiesta.htm

Nuclear Alchemy: The Transmutation of one Element into Another

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Nuclear Alchemy: The Transmutation of one Element into Another

I bombard aluminum 27 (13 protons and 14 neutrons), the stable type we have all come to know and love, with energetic alpha particles (two protons and two neutrons) at an energy of 5.3042 MeV! (MeV means Millions of Electron Volts). Most of the alpha particles would have bounced off of the aluminum without joining… but some would. Those lucky alpha particles bonded with the nucleus of the aluminum 27 to produce a new element: phosphorus 30! (15 protons and 15 neutrons). The reaction emits one spare neutron with way too much energy! =(

The phosphorus 30 has a short half-life of a mere 2.49 minutes, decaying into stable silicon 30 (14 protons and 16 neutrons) via beta+ decay (a positron). The position emitted is an Anti-Electon! That’s right, anti-matter. The quick little positron has an average energy of about 1438 keV (a max of 3203.3!!!). The position lasts only a short time before slamming into a normal electron and annihilating with an energy of 1022 keV, expressed as two gamma rays, each with 511 keV of energy. It is these emissions which I detect, using gamma spectroscopy. A Geiger counter would never be able to give me these results.

Al-27 + He-4 → P-30 + N
(e+) + e → y

I had calculated the energy of the reaction many times, but each calculation was a little wrong. I asked a very smart physicist for some help and he gave me a formula for figuring it out, but my math and his still didn’t add up…

Here is what I used for my determination:
I took the mass of an atom of P-30
(4.97802×10^-26 kg), call it M, and the mass of a single Neutron (1.67493×10^-27 kg), call it N, and the energy of the alpha particle which slammed into the aluminum (which was not at rest, but probably not doing too much whilst in its lattice, 5304.2 keV = 8.498×10^-13 joules, call it E. Also, let Em = momentum of P-30 atom after ejection of neutron, En momentum of neutron after being ejected: Em = (N/(M+N))E =(1.67493×10^-27 kg / (4.97802×10^-26 kg+1.67493×10^-27 kg)) 8.498×10^-13 j = 2.76620721*10^-14 joules = 172.6531 keV En = (M/(M+N))E = (4.97802×10^-26 kg /(4.97802×10^-26 kg+1.67493×10^-27 kg)^-1) 8.498×10^-13 j =8.22137928×10^-13 joules = 5.131382 meV

But… his numbers didn’t match (he thought the neutron would be 2.574 MeV and the phosphorus 30 would be 0.086 Mev.

Either way… OMG! That’s too much neutron flux for me in my tiny home lab. =)