Geiger counter. Geiger counter operation

German physicist Johannes Hans Geiger (1882-1945) was just assistant to New Zealand chemist Ernest Rutherford (1871-1937), when he invented the Geiger Counter – a device used to detect the level of radiation in the atmosphere.

In the beginning it was just a cylindrical tube with low pressure argon gas, an amplifier and a high voltage source.

The Geiger counter works as follows: when radiation enters the tube containing argon, this gas is ionized, as shown below:

Ionization of argon gas by radiation
Ionization of argon gas by radiation

When ionized, the argon closes the electrical circuit of the device, which is composed of electrodes with opposite electrical charges. With the formation of ions, electricity is conducted between the cathode and the anode, thus triggering a counter or loudspeaker. The signal that indicates the presence of radiation can be sound, a light or the deflection of the meter pointer. Normally, the counter clicks, which allows the counting of radioactive particles.

Nowadays, this device is a great ally for people who work with radioactive material; especially when nuclear accidents occur, as the substances that disintegrate are capable of ionizing the air and thus contaminating other bodies in the environment.


The Geiger counter is used to measure radiation levels.
The Geiger counter is used to measure radiation levels.

By Jennifer Fogaça
Graduated in Chemistry
Brazil School Team.

Source: Brazil School - https://brasilescola.uol.com.br/quimica/contador-geiger.htm

The 4 most temperamental signs of the zodiac

Astrology plays an important role in helping us to better understand people's behaviors through t...

read more
The surprising discovery of a bee hive in a British home

The surprising discovery of a bee hive in a British home

The important role of bees in the pollination of several plant species is widely recognized. Howe...

read more

The 5 laziest zodiac signs; Is yours on the list?

Astrology is an ancient science that has been used for centuries to understand human personalitie...

read more