Unlocking the Invisible: An Introduction to Scintillators, Semiconductors, and Gamma Spectroscopy
Last edited Sat Sep 14, 2024, 03:54 AM - Edit history (3)
When I was a kid, I worked on the preparation of radioimmunoassay sets, which were at the time, the most sensitive means of measuring biomolecules in human and animal subjects. (These assays were, special - and now rarely used - forms of ligand binding assays which are still in use today, albeit with different detection modalities.) They worked back then by labeling an analyte, most often proteinaceous, with radioactive 125I (iodine 125), prepared by proton bombardment (in an accelerator) of 124Te, and then adding a sample containing the analyte to a tube coated with an antibody. From the amount of the radiolabeled that bound to the antibody after exposure to the sample and washing, and then to the radioactive molecule labeled with 125I, one could calculate, using a calibration curve, the concentration of the analyte, within the limits of detection, in the sample, most often human blood or urine, but sometimes other matrices.
It was, back in those days, nearly 40 years ago, one of the most sensitive tests for biomarkers of disease and health, known. The use of these tools saved lives. In modern times radioimmunoassay has been largely supplanted by mass spectroscopy, which does not involve radioactivity but does involve small scale particle accelerators. I have worked in mass spectroscopy for much of my career.
When I was doing that work, preparing radioimmunoassays, I, and the others in the lab, unavoidably absorbed some radioactive 125I which, predictably, concentrated in our thyroid glands measurably. We were required therefore to check our thyroids regularly, which I did, more often than was required, pretty much every day using Geiger counters. We were all above background levels of radioactivity; I was for about three years, not dramatically so; I was roughly double background. It was a fun item of conversation at parties, "I'm radioactive!."
All human beings, like all living things, are, in fact, radioactive, largely because of the naturally occurring radioactive isotope of the essential element potassium, 40K, and all will give a signal with a sensitive enough Geiger counter. We all contain, as well, other radioactive isotopes (background radiation), some of which are generated in the upper atmosphere from collisions with particles from the sun, the most famous being 14C generated by a 14N[p,n]14C reactions of protons in the solar flux with atmospheric nitrogen, some residuals from open atmosphere nuclear weapons testing, and some, far less than other sources, from reactors generating clean and sustainable nuclear energy, some from reprocessing of used nuclear fuel, some from rare industrial releases in accident events such as the Bogeymen at Fukushima and Chernobyl.
I am very clear in stating that nuclear energy is the last best hope of the human race, in my view, and the planet as a whole, but I understand radiation where as most people trained by our "but her emails" media fear radiation, most often to the limit of absurdity. I understand radiation very well, in fact far better than when I worked with it.
Anyway, if you are interested in learning how radiation detection works, you may wish to sign up for an instructional video to learn about the detection of radioactivity. It is provided by the American Nuclear Society, an organization working to save the world from dangerous fossil fuel waste, aka "air pollution," aka "extreme global heating." Both of these, unlike so called "nuclear waste," kill people in vast numbers, the former on a scale of millions per year, and the latter rising in that direction.
The instructional webinar, apparently designed for school teachers, is here and you can sign up:
Unlocking the Invisible: An Introduction to Scintillators, Semiconductors, and Gamma Spectroscopy
There's nothing like knowledge to confront mysticism.
Enjoy.