With the ever-growing risk of nuclear disasters and threat of radioactive material being released into the environment, detecting its presence is vital for any intervention or research activity. The Geiger counter is a device developed for this exact purpose and the scientists Hans Geiger and Earnest Rutherford invented it as early as in the year 1908. However, over the years, the Geiger counter has seen many improvements although the principle behind its functioning remains the same. Therefore, this article will look at the evolution of the Geiger counter from its early developments placing especial emphasize on the functional improvements made in the counter by different scientists.
How did the early Geiger counters function?
Although the basic structure did not change much from its earliest invention, the earliest Geiger counters were made of a metal tube with a thin metal wire running along its middle. The space between the tube and the wire remains sealed off and the space created within this enclosure is filled with an inert gas such as helium or argon. The wire is supplied with a high voltage while the tube remains voltage negative to that of the wire. When the Geiger counter is taken to an area with radioactivity, an ion or electron penetrating the tube can tear the electrons of atoms in the gas and because of the positive voltage in the wire, the separated electrons are attracted to the wire. Through this mechanism, the attracted electrons gain energy and collide with more atoms, which make them release more and more electrons. This would ultimately create an avalanche of electrons, which can be detected as an electrical current.
Thus, the earlier Geiger counters, although were sensitive to the ionizing radiation of even the smallest intensity, could not differentiate between the types of radiation or its varying intensities. Therefore, these devices are only known as ‘counters’ as against the different names used to name the newer and more specific Geiger counters and related devices.
What is the difference between modern day Geiger counters and the one invented by Geiger?
In the beginning, the Geiger counters were only able to detect alpha particles of ionizing radiation. However, the research done by Geiger and Walther Müller, who was a doctoral student working with Geiger, made way for a newer version of the Geiger counter in 1928, which can measure other ionizing radiations. However, Sidney H. Liebson in the year 1947 developed the modern version of the Geiger counter, which is known as the ‘halogen counter’. The difference between the ‘halogen counter’ and the earlier Geiger counters was its ability to last long and function with a lower operating voltage.
What are the alternates for Geiger counters at present?
Among the alternative detection methods for Geiger counters, some are able to detect alpha and beta particles of the ionizing radiation more effectively. These are known as alpha and beta scintillation counters while specific detectors for gamma particles are also available. However, these devices are much more costly than the traditional Geiger counters, which makes them impractical to be used in the field for everyday research.