Tag Archives: contamination

Basic Isotope Identification (Gamma Spectroscopy)

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Please read below (Resource links, etc)

Copyright:
All materials in this video are copyright of me. I created them all. The screen captures of the software are from Spectrum Techniques.

My Equipment:

Spectrometer: UCS30 – http://www.spectrumtechniques.com/spec_systems.htm
Sources: Cs137 – http://www.spectrumtechniques.com/disc&laminated_sources.htm
Lead: rotometals.com

Gamma Energy Resources:

http://ie.lbl.gov/decay.html
http://ie.lbl.gov/toi/radSearch.asp
http://simplynuclear.com/index.php?title=Common_Gamma_Energy

Thorium Hypothesis
Isotope Energy Branching Ratio
Actinium 228 13 keV 0.38
Thorium 232 *63.81 keV 0.00267
Lead 212 *77.11 keV 0.175
Thorium 228 84.37 keV 0.01266
Thorium 228 131.61 keV 0.001355
Thorium 228 166.41 keV 0.001075
Thorium 228 215.99 keV 0.00263
Lead 212 238.63 keV 0.433
Actinium 228 *338.32 keV 0.113
Thallium 208 510.77 keV 0.226
Thallium 208 *583.19 keV 0.845
Bismuth 212 727.33 keV 0.0658
Actinium 228 911.21 keV 0.266
Actinium 228 968.97 keV 0.162

Uranium Hypothesis
Isotope Energy Branching Ratio
Uranium 238 13 keV 0.08
Uranium 235 19.59 keV 0.61
Lead 210 46.54 keV 0.0425
Lead 214 77.11 keV 0.099
Thorium 234 92.38 keV 0.028
Thorium 234 92.8 keV 0.028
Uranium 235 143.76 keV 0.1096
Uranium 235 185.71 keV 0.572
Radium 226 *186.1 keV 0.35
Thorium 227 235.97 keV 0.123
Lead 214 *241.98 keV 0.075
Lead 214 *295.21 keV 0.185
Lead 214 *351.92 keV 0.358
Bismuth 211 404.85 keV 0.0378
Bismuth 214 *609.31 keV 0.448
Bismuth 214 768.36 keV 0.048
Protactinium 234m 1001.03 keV 0.00370

Potassium 40 Hypothesis
Isotope Energy Branching Ratio
Potassium 40 *1461 keV 0.1067

Depleted Uranium Hypothesis
Isotope Energy Branching Ratio
Thorium 234 13.3 keV 0.045
Thorium 234 *63.29 keV 0.048
Thorium 234 *92.38 keV 0.028
Thorium 234 *92.8 keV 0.028
Uranium 235 19.59 keV 0.61
Uranium 235 *143.76 keV 0.1096
Uranium 235 185.71 keV 0.572
Protactinium 234m 1001.03 keV 0.00370

Spectrum Techniques Universal Computer Spectrometer UCS30 – A Review and Overview

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A nice little unit, the UCS30 comes with 512, 1024, 2048, or 4096 channels. The unit has a built-in high voltage source and a pre-amplifier.

There are many great and wonderful scientific devices which we can obtain and use to understand our world. The most important things we can do in our lives are to learn all that we can and teach as much as possible to all who will listen.

The unit can be seen at http://spectrumtechniques.com/

Oh… and no, they didn’t ask or pay me to show off their unit. Unfortunately, I had to buy the unit myself 🙂

A Demonstration of Nuclear Radiation

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A quick demonstration of nuclear radiation. Just for fun and maybe even a little education. =)

Basic Isotope Identification!!! – Gamma Spectroscopy 101 – Full Lesson

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Where to buy isotopes:

http://spectrumtechniques.com/

Where to find lists of gamma energies:
http://simplynuclear.com/index.php?title=Common_Gamma_Energy
http://ie.lbl.gov/toipdf/eandi.pdf
http://ie.lbl.gov/decay.html
http://www.gammaspectrometry.co.uk/appendices/appendixd.pdf

Where to get a detector
http://www.gammaspectacular.com/products/scintillation_detectors
http://spectrumtechniques.com/detectors&stands.htm
http://www.ludlums.com/component/virtuemart/gamma-detector-171-detail?activetab=options

Where to get an MCA
http://www.gammaspectacular.com/products/sound_card_spectrometry_drivers
http://spectrumtechniques.com/spec_systems.htm

Where to get uranium!!! (how could you live without it?)
http://unitednuclear.com/
http://minresco.com/radioactive/radioactive01.htm

Equations (simplified for quick and dirty use!!!)

  2 * (E keV)^2
___________________ = Compton Edge
  511 keV + 2(E keV)

                  2 * (E keV)^2
E keV – ________________ = Back Scatter peak
                  511 keV + 2(E keV)

(Tom’s opinion)
Best source for calibration: Cs137
Best detecttor type: NaI(Tl) 1″ or greater!
Best free MCA software: PRA 8

Tom’s Isotope Tables!!!

http://simplynuclear.com/index.php?title=Common_Gamma_Energy

Polonium 210 Gamma – Found?

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Hello,

A week or two ago I set out to detect the infamous Polonium 210 gamma ray at 803.1 keV using a NaI(Tl) scintillation detector and a mere 3.7 kBq of Po210. This isn’t too hard, or so I have been told, to do with a HPGe or using my equipment and a significantly larger activity of Polonium. The problem is that only a few gammas will be emitted, only some will actually reach the detector, and of those only a tiny fraction will be detected! But… Who am I to listen? Lol I think that I found the gamma and it stands out in the spectrum, but I thought I would go a little further. This is not a formal paper (note my informal tone). I just thought that I would post a little more than a simple message.

Polonium 210 Gammas

Polonium 210 Gammas

My Environment

I have a temperature stabilized environment with a average temperature fluctuation of 0.8 c. from the mean over a period of six hours. The detector was allowed a full day to warm up and become stable. Calibration was performed several times and with several sources, including Co60 and Cs137. Redundant calibrations were performed and tested against each other to detect any changes.

The Test

A new (less than seven days old) small circular plastic disk containing approximately (+/- 20%) 3.7 kBq of Po210 was placed directly in front of the detection crystal at a distance of 1 cm. Between the source and the crystal, a thin Pyrex glass layer was placed. The test was allowed to run for six hours and then repeated without the Po 210 source to account for background. The background was removed from the sample spectrum to produce the results.

My Findings

A scientific result which can credibly called “true”, insomuch as any result is true”, requires at least five standard deviations from the mean of a set of data to rule out likely error. Given the very low amount of data logged and the generally entropic nature of the testing setup, such an outcome is unlikely. As a result, a positive declaration of the detection of Po210 gammas using the experiment as performed is unlikely.

A set of 60 data points was taken before and after background removal. These data sets were treated as a population set from which a simple population standard deviation was calculated, for both before and after background removal. Based upon calibration of the unit, the channel numberd 832 was the most likely channel to detect the gamma in. For both the origional data and the data with background removed, the channel, 832, displayed a clearly greater than other channels near it and for the set. For the raw data, channel 832 was 3.3636861676 deviations from the mean and with the background removed, the same channel was 3.2797495046 deviations from the mean. The variance between the data with and without background was 2.56%.

Sample Gross counts
________________________________
Channel     Count          Sigmas
828          17          -0.6757272749
829          16          -0.1812926775
830          21          -0.6757272749
831          28          0.8075765174
832          39          3.2797495046
833          19          -0.1812926775
834          25          0.0659246212
835          19          -0.6757272749
836          27          1.7964457123
.
Sample – Background
________________________________
Channel          Count          Sigmas
828          0          -0.7820334787
829          2          -0.9704752808
830          0          -0.0282662703
831          6          1.2908263444
832          16          3.3636861676
833          2          -0.4051498745
834          3          0.7255009381
835          0          -0.4051498745
836          10          1.1023845423