Detection of Radiation Contents: Geiger tubes Photo-Multiplier tubes Cloud Chambers Solid State devices

TOC Geiger Tubes Gas filled tube Voltage is sub-ionization Entering radiation causes chain reaction Electric pulses are counted “Down time” before another detection Gas is not very efficient at detection

TOC Photo-multiplier tubes Scintillation crystal NaI emits light when hit by radiation Low work function photocathode Photo-electric effect electrons cause chain reaction Pulses are counted More efficient than Geiger tubes (NaI is more dense than gas) Better at gamma detection

TOC Cloud Chambers Supersaturated vapors in air Particles nucleate condensation (leave little streaks in air) Air is not very dense

TOC Bubble Chambers Liquid H kept near its boiling point Particles nucleate boiling in their path Usually in a B field - curved tracks

Bubble Chambers B field curves tracks Spiral = losing energy Evidence of pair production

TOC Solid State devices Germanium detector - turns impact of radiation into voltage spike Liquid N 2 to keep it cold Funny joke on Margie