Hans Geiger

Hans Geiger (1882–1945) was a German physicist who developed methods for detecting ionizing radiation and collaborated with Ernest Rutherford on experiments that revealed atomic structure.

Ernest Rutherford: A New Zealand-born physicist who established the nuclear model of the atom and pioneered experimental nuclear physics. Geiger worked in Rutherford’s Manchester laboratory on experiments measuring alpha-particle scattering.
Geiger–Müller tube: A gas-filled detector that produces an electrical pulse when ionizing radiation triggers an avalanche of charge. Geiger and Walther Müller developed this detector to register individual radiation events.
Geiger–Marsden experiment: A series of experiments in which alpha particles were scattered by thin metal foils, including gold. Geiger and Marsden measured the rare large-angle deflections that prompted Rutherford’s nuclear interpretation.
Radiation detector: An instrument that detects or measures ionizing radiation by converting its interactions into observable signals. Geiger’s designs became influential examples of particle-detection instruments.
Ernest Marsden: A physicist who, with Hans Geiger, conducted the gold-foil scattering experiment under Ernest Rutherford’s direction. Marsden shared the experimental work with Geiger that produced evidence for a concentrated atomic nucleus.
Ionizing radiation: Radiation energetic enough to remove electrons from atoms or molecules, producing charged particles. Detecting this radiation was the central problem behind Geiger’s instrument designs.
Rutherford model: A model of the atom with a small, dense, positively charged nucleus surrounded by electrons. The model explained the large-angle alpha-particle deflections recorded by Geiger and Marsden.
Radiation protection: Practices and standards that limit harmful exposure to ionizing radiation. Portable Geiger–Müller counters made radiation levels easier to monitor in laboratories and workplaces.
Walther Müller: A German physicist who collaborated with Hans Geiger to develop a practical tube for detecting ionizing radiation. Their detector, introduced in 1928, became the best-known instrument associated with Geiger’s name.
Gas ionization: The creation of positive ions and free electrons when energetic particles or photons interact with a gas. Geiger’s counters exploit gas ionization to turn a particle’s passage into an electrical signal.

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