1. Geiger counter NTHU General Physics Laboratory
A Geiger–Müller counter, also called a Geiger counter, is a type of particle detector that measures ionizing radiation, Fig1. It detects the emission of nuclear radiation: alpha particles, beta particles or gamma rays by the ionization produced in a low-pressure gas in a Geiger–Müller tube, which gives its name to the instrument.
NTHU General Physics Laboratory
Fig1.

2. Checking before the experiment:
Checking the detector connects with the instrument.
Putting the radiation material Co-60 on the sample holder, Fig2.。
Putting the holder into the top position, Fig3.。
Fig2.
Fig3.

3. Users Guide
Turn power on. Move the interval timer switch to the “0.5 minute" position.
Checking if ”STOP” light on? If not, press “STOP” .
Checking High Voltage setting：COARSE=600, and FINE=0。
Press “RESET”.
Press “COUNT”, when the “STOP” light on, record the data.
Repeat step5&6, take data 50 times .