González Fernández, VerónicaGrützmacher, KlausSteiger, AndreasPérez, Conchade la Rosa, Mª Inmaculada2024-02-052024-02-052017Gonzalez-Fernandez et al 2017 Plasma Sources Sci. Technol. 26 1050040963-025210.1088/1361-6595/aa88e5https://hdl.handle.net/20.500.14352/99210Received 5 April 2017, revised 20 August 2017; Accepted for publication 29 August 2017; Published 19 September 2017.In this work, Doppler-free two photon optogalvanic spectroscopy is used to measure the electric field strength in the cathode fall region of a hollow cathode discharge, operated in pure hydrogen, via the Stark splitting of the 2S level of atomic hydrogen. The cathode fall characteristics are analysed for various pressures and in a wide range of discharge currents. Tungsten is used as the cathode material, because it allows for reliable measurements in a fairly wide range of discharge conditions and because of its minimal sputtering. Two cathode diameters (10 mm and 15 mm) are used to study the dependence of the cathode fall on discharge geometry. The measurements reveal that the cathode fall characteristics are quite independent on the cathode diameter for equal cathode current density; hence the measurements can be used to test one dimensional modelling of the cathode fall region for low pressure hydrogen discharges using e.g. plane parallel electrodes.enghttps://creativecommons.org/licenses/by/4.0/nc-nd/journal article1361-6595https://doi.org/10.1088/1361-6595/aa88e5https://iopscience.iop.org/article/10.1088/1361-6595/aa88e5/metaopen access533.9543.422Hollow cathode dischargeLaser spectroscopyOptogalvanic detectionElectric fieldCathode fall regionÓptica (Física)Electrónica (Física)2204.10 Física de Plasmas2209.01 Espectroscopia de Absorción