Tolansky, Samuel (1907-1973)

English physicist who analysed spectra to investigate nuclear spin and magnetic and quadrupole moments. He used multiple-beam interferometry to explore the fine details of surface structure.

Tolansky was born in Newcastle-upon-Tyne and studied mainly at Durham. From 1947 he was professor at London University.

Tolansky made a particular study of the spectrum of mercury. He also studied the hyperfine structure of the spectra of halogen gases such as chlorine and bromine, and of arsenic, iron, copper, and platinum.

During World War II, Tolansky was asked to ascertain the spin of uranium-235, which is the isotope capable of fission in a nuclear chain reaction. Although he had to use samples in which the proportion was only 0.7%, he was fairly successful.

Multiple-beam interferometry can be used to resolve a structure as small as 15 Å (15 × 10−10 m) in height. Tolansky examined the vibration patterns in oscillating quartz crystals and the microtopography of many different crystals, particularly diamonds.