GEIGER COUNTER

                                          When a material is suspected of bieng radioacring, a Geiger Counter is used to detect the radiation, The device was invented by the German Physicist hans Geiger (1882-1945) as part of his investigations with Rutherford into beta-ray radiactivity in 1913. Futher developed with the help of Miller, the Counter across which a hight  voltage is applied, contains a gas help at low pressure, which surrounds metal cathode cylinder. This has a thin wire anode running down the centry. If any particles of lonizing radiation enter, the gas is ionized and a momentary current runs through the tube. The charge in voltage is amplified electronically to give a reading.
          

                          Radioisotopes are widely used in medicine and radiation can also be a dangerous hazard in much scientific and industrial work. Instruments measuring radioactivity are vital to health and safety.