box, don’t let any of the exposed wiring touch the metal walls.

   Before you install the assembly, cut a large rectangular hole in the wall next to where the Geiger tube will be. The hole will serve as a radiation window. Incidentally, both switches and the headphone pin jacks must be mounted on top of the enclosure.

Procedure for Charging Geiger Counter

1. Needless to say, turn on the power switch (S1).
2. Put on the headphones.
3. Tap the charge switch (S2) firmly in a rapid-fire manner about 60 times, or until you hear random click ing. This is normal background noise caused by cosmic rays.
4. After the unit is charged up, tap the switch occasion-ally to keep it charged. You’ll be able to tell how often this has to be done when you start using the counter. It may range from several seconds to a minute or so

    Assuming you have a gamma source, note that when you bring the source near the Geiger counter, or vice versa, the clicking will increase dramatically.

    If you were fortunate enough to locate more than one source, the counter will indicate their relative strengths by the clicking intensity.    

With the Geiger counter and gamma ray source, you can now do the last part of Experiment 7 (on gamma ray shielding materials).