ID: 
270
Maker's Name: 
Philips
Where made: 
Holland
Dimensions: 
1.6 × 1.6 × 4.8 cm

A voltage of around 1000 Volts is applied between a coaxial rod and the case.

The passage of a beta or gamma ray through the end Mica window causes the gas to conduct and produce an electrical pulse. The discharge is self-quenching.

Geiger tubes count emissions only. They do not measure the energy of the source.