Paschen, Friedrich Louis Carl Heinrich

Born Jan. 22, 1865, in Schwerin, Mecklenburg; died Feb. 25, 1947, in Potsdam. German physicist.

Paschen graduated from the University of Strasbourg in 1888. From 1901 to 1924 he was a professor at the University of Tübingen. Between 1924 and 1933 he was director of the State Physics and Technical Institute in Berlin. In 1889, Paschen formulated an expression for the sparking potential between a pair of electrodes in a gas, which became known as Paschen’s law. In 1908 he discovered the first two lines of the hydrogen spectral series that later acquired the name of the Paschen series. Together with E. Back, he discovered the Paschen-Back effect in 1912. Paschen also constructed a highly sensitive needle galvanometer, a hollow-cathode gas-discharge tube, and a concave diffraction grating.