Scintillation Detector

A scintillator is an organic plastic sheet (there are also liquid scintillators), which fluoresces photons when hit by a particle such as a muon, alpha particles etc. Usually extremely sensitive photomultiplier tubes (PMT) are connected to the scintillators to measure the photons (which knock off photo-electrons in the tube).

The principle of the scintillation detector is basically the same as with Geiger-Müller tubes or ionization chambers - two scintillators with two photomultiplier tubes are connected to a coincidence detector.

See: The Berkeley Lab Cosmic Ray Telescope Project

UPDATE 2-JAN-2005:
Actually it is also possible to detect muons with only one scintillation paddle and one photomultiplier tube:

"Most cosmic ray muons are easily to discriminate from terrestrial backgound. [...] If you watch your PMT [photomultiplier] output on an oscilloscope you will see a series of pulses and an occasional *LARGE* pulse. Those large pulses are [the muons]. They happen less frequently than the events of terrestrial origin. So if you set your detection threshold (using a comparator, etc) you can filter out most of the local background radiation simply by pulse height discrimination." -Charlie, W5CDT @ CDV700CLUB


This sort of detection requires a gamma scintillator (NaI - sodium iodide scintillator; plastic scintillators are not suitable for energy determination) of large area, but small volume.

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