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Physics/Film Badge


How does a film badge indicate the type and amount of radiation recieved?

Well, a traditional film badge does not.  It just measures approximate dose.  A more modern thermoluminescent dosimeter badge meant for multiple exposure types will usually have a couple of different types of crystals in them.  The crystals are intentionally made with impurities, which accumulate trapped electrons upon exposure to ionizing radiation.  When heated or exposed to a laser, the trapped electrons go back where they were from, emitting light.  This is why you should never leave a TLD badge in the sunlight, they can lose the trapped electrons and wash out the signal.  See more specifics here: I know mine has both LiF and CaF crystals in it to be sensitive to both neutron and gamma radiation.


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Dr. Stephen O. Nelson


I can answer most basic physics questions, physics questions about science fiction and everyday observations of physics, etc. I'm also usually good for science fair advice (I'm the regional science fair director). I do not answer homework problems. I will occasionally point out where a homework solution went wrong, though. I'm usually good at explaining odd observations that seem counterintuitive, energy science, nuclear physics, nuclear astrophysics, and alternative theories of physics are my specialties.


I was a physics professor at the University of Texas of the Permian Basin, research in nuclear technology and nuclear astrophysics. My travelling science show saw over 20,000 students of all ages. I taught physics, nuclear chemistry, radiation safety, vacuum technology, and answer tons of questions as I tour schools encouraging students to consider careers in science. I moved on to a non-academic job with more research just recently.

Ph. D. from Duke University in physics, research in nuclear astrophysics reactions, gamma-ray astronomy technology, and advanced nuclear reactors.

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