Brian Lowery July 11, 2011

 Primary  From space ▪ Lower energy cosmic rays come from sun ▪ Higher energy cosmic rays come from other places in the universe (example – supernova)  Mostly light elements (75% H, 25% He), but a few high mass elements, electrons, or gamma rays  High energy collision with molecules of upper atmosphere – can be 10x10 6 times more energetic than collisions with man-made accelerators.

 Secondary  Products of the high-energy collision  Many of the secondary cosmic rays have very small half lives ▪ Collide with more particles ▪ Products decay ▪ Those products decay ▪ Etc. ▪ Create a shower of cosmic rays ▪ Animation Animation  Muon ▪ One of the decay products of particles made in the upper atmosphere

Lepton – light weight Charged – interacts via EM Force Generation II of matter -- heavier than Generation I -- Less stable (1/2 life = 2.2 μs)

#1. Counter --scintillating material lights up when interacts with charged particle -- covered so no light can escape #2. PMT -- Photomultiplier Tube -- Converts light signal into electrical signal

 Plateau multiple counters  Are we getting good data?  Performance study – noise?  Coincidence level – can we see what others set at?  Plateau Process – where do we set voltage?  How can we make it better for our classroom?

 SPARC/CosmicExtremes.pdf SPARC/CosmicExtremes.pdf  tonshoweroverchicago.mpeg tonshoweroverchicago.mpeg  000CRMDUserManual.pdf 000CRMDUserManual.pdf