gas-filled phototube

https://doi.org/10.1351/goldbook.G02581
Similar in construction to a @V06586@ except that it is filled with a noble gas (usually Ar) at a pressure of about \(10\ \mathrm{Pa}\). Photoelectrons accelerated by the @A00370@ @E01935@ ionize gas atoms. The additional electrons provide a substantial intrinsic gain.
Source:
PAC, 1995, 67, 1745. (Nomenclature, symbols, units and their usage in spectrochemical analysis-XI. Detection of radiation (IUPAC Recommendations 1995)) on page 1753 [Terms] [Paper]