Slashdot Mirror
JAXA Creates Camera That Can See Radiation
New submitter Ben_R_R writes "The Japan Aerospace Exploration Agency has created a camera that can 'see' radioactive contamination by detecting gamma rays emitted by radioactive cesium and other substances. The camera has been tested in the disaster evacuation zone around Fukushima. The image captures levels of radiation in six different colors and overlays the result over an image captured with a wide angle lens."
Usually, you just put a scintillating crystal, e.g. thallium-doped sodium iodide, in front of your detector. Gamma photon hits crystal, crystal emits photon in the visual range, photomultiplier detects visual photon. TFA is somewhat silent on how this differs from your run of the mill gamma camera which has been known for half a century by now.
Ubi solitudinem faciunt, pacem appellant.
Oh great, now we're going to be overwhelmed with Japanese tourists taking pictures of radioactive things!
Shot 1: Dad and the kids smiling at camera and glowing in dark.
Shot 2: Look! Our Toyota doesn't need headlights!
Shot 3. Mr. Fujimoto and his radioactive shoes!
Shot 4. Godzilla. No, really, Godzilla. Run!
I was wondering the same.
Detecting gamma rays is pretty easy. Detecting within a few degrees which direction they came from is much harder. Lenses and mirrors won't work (at least, at any reasonable scale) to form an image. You could have two layers of detector, and measure the location of the gamma ray as it passes through both. You could look for Compton scattered electrons from the gamma ray, which would be easier to determine the direction of, but I don't think that would fit in something camera sized.
I'm also curious to know what exposure time the gamma ray camera needs - I'm guessing it will be pretty long - minutes, at least, maybe hours.
Quattuor res in hoc mundo sanctae sunt: libri, liberi, libertas et liberalitas.
I saw the camera on NHK World and it is not what you may think is camera sized. It is a big cube with about 1 m sides. It also includes a small optical camera, so that you get a composite of the visual picture and the gamma radiation distribution. It is supposed to be used to check the buildings in contaminated areas and see where the radioaktive material is located.
***Quis custodiet ipsos custodes***
Geiger counters tell you if there's radiation at the counters sensor. This lets you measure/see where the radiation is coming from.
This gamma ray camera from the same institute may be something related? It seems to use Scintilation from a dislocated electron (which gives away path and energy) combined with the point of impact of the gamma ray on a detector plate.
=~ s,(.*),<sarcasm>$1</sarcasm>,g if any_point_you_wish();