(1882 – 1945)
Image: Wikimedia User GFHund
On September 30, 1882, German physicist Johannes Wilhelm Geiger was born. He is best known as the co-inventor of the Geiger counter and for the Geiger–Marsden experiment which discovered the atomic nucleus.
Hans Geiger started his physical and mathematical studies at the University of Erlangen, where he finished his final examinations and his doctorate on measurement of radiation. He moved to Manchester, where he became assistant to Arthur Schuster and later on Ernest Rutherford. In this period, Rutherford published his model of the atom and Geiger is known to have made significant contributions to his experiments and theories. Geiger remained in Manchester until about 1912 and came back to Germany as one of the leading experts working on the measurement of radiation. Famous James Chadwick followed Geiger to Berlin and they both started a fruitful working relationship until Geiger became professor at the University of Kiel.
In the mid 1920s, Geiger also worked together with Walther Bothe on various measurements. Bothe received the Nobel Prize of Physics for these achievements after the death of Hans Geiger. The period in Kiel was also quite important for Geiger. Along with his assistant Walther Müller, he was able to develop the particle detector measuring ionizing radiation, which became famous as the Geiger-Müller-counter. It was released in 1929 and increased Geiger’s reputation dramatically. He moved back to Berlin and became director of the Institute of Physics as the successor of Gustav Hertz. In 1945, Geiger’s house in Potsdam, Germany was confiscated and he passed away only later in the same year.
|Geiger-Müller counter from 1932
(1882 – 1945)
Image: Wikimedia User Science Museum London
Hans Geiger’s masterpiece is known to be the Geiger-Müller counter, which is also known simply as the Geiger counter. It belongs to the best known instruments of its kind since it was operated as a hand-held device. Even though his invention does have its limits, especially when it comes to very high radiation rates, it became popular for the use in various scientific fields, such as geology, health physics, experimental physics, and the nuclear industry.
The counter itself is basically made of two major elements. The most important Geiger-Müller tube as well as the display component. The tube is able to sense radiation due to its filling of helium, neon, argon and a little pressure, which conducts a small electrical charge when particles or photons of radiation make the gas conductive by ionization. Through the Townsend avalanche effect, the ionization is amplified and the radiation can be measured easily.
At yovisto,you may enjoy a video talk by Sean Bonner on his design of an affordable mobile radiation sensor system for independent citizen monitoring and cartography of radioactive contamination as part of an answer to the Fukushima disaster.
References and Further Reading:
- Hans Geiger at MIT
- History of Portable Radiation Detection Instrumentation from the period 1920–60
- Klaus Wiesemann zu Geiger anlässlich der Benennung eines Hörsaals an der Universität Kiel nach Geiger, 2008 [PDF]
- Annotated bibliography for Hans Geiger from the Alsos Digital Library for Nuclear Issues
Related Articles in the Blog:
- Wilhelm Conrad Röntgen – The Father of Diagnostical Radiology
- Lise Meitner – The Misjudged Genius
- James Chadwick and the Discovery of the Neutron
- Ernest Rutherford and the Discovery of the Nucleus