Radiation Detection Goes Digital

RedEaredSlider writes "In science fiction, explorers wave around a single device and pick up many kinds of radiation — think of the tricorders on Star Trek or Dr. Who's sonic screwdriver. A professor at Oregon State University is bringing that a bit closer to reality, though in this case it's for finding radioactive material. It's a radiation spectrometer, and it works on a very old principle: particles and photons that hit certain materials will make them emit flashes of light. But for decades, radiation spectrometers had been limited to detecting only one kind of radiation at a time. David Hamby, an OSU professor of health physics, felt that there was a need for a device that could see at least two kinds of radiation, as well as be smaller than the models currently available."

Comments

Bad bad article and summary

[tastiles]

As a physicist that works with radionuclides, I'm appalled at this article. It is horribly written. "The crystal vibrates in a certain way" made me laugh.

A better summary is provided by OSU public relations dept at
http://oregonstate.edu/ua/ncs/archives/2010/dec/new-technology-speed-cleanup-nuclear-contaminated-sites-reduce-costs-and-create-jo

Radiation detectors have been digital for a long long time. Some of the electronics has been analog because analog electronics are faster and always will be for filtering and integration.

Re:Not news.

[__aagctu1952]

Mod Parent Up.

Beta particles (electrons ejected from the nucleus, basically) have a mean free path of about a foot in air. Place anything else in between, like a thin sheet of aluminum or a little bit of plastic, and it sucks up the betas real quick.

The other big problem is that gammas are quantized, beta particles are not. When something radioactively decays, it gives off gamma rays of distinct, unique energies -- very useful for determining the radioactive isotope you're looking at. Not so for betas; they're emitted over a wide range of energies, and it can be very difficult (but not impossible) to tell what you're looking at by betas alone. I don't mean to downplay what this accomplishes, in a nice, small form factor. But this doesn't revolutionize the world of radiation detection. To date, no one has really been crying for a combined, digital, gamma and beta detector. Maybe if you build it, they will come, but I don't see a large market for this.

The (now grand)parent should be modded up, but one thing in your post is just plain wrong: the range of beta radiation is not "about a foot"; the range of beta radiation depends on its energy. Betas from a low energy nuclide like 35S, for example, do have a range of almost exactly a foot (32 cm) in air, but the high energy beta radiation emitted by 90Sr/90Yr OTOH has a range of slightly above 10 meters in air. And as for the quantization, beta emitters too have very distinct energy distributions (which you can look up in any good data sheet).
But you're right about portable beta spectrometry being pretty "meh". If it's high enough energy to worry about, it's easier to just look at the bremsstrahlung, really.

BTW, this was a really horrible article. There were no technical details whatsoever (well, just enough to realize that someone had been trying to explain scintillation to the very obviously non-techie journalist), and they seem to mix up radiation spectrometry with plain radiation detection...