Grimm-type cathode 

https://doi.org/10.1351/goldbook.08484
Cathode for a glow electric discharge consisting of a flat sample, which is cooled during the discharge process so that thermal volatilization is suppressed and the sample material is removed by sputtering only.
Source:
PAC, 2021, 93, 647. (Glossary of methods and terms used in analytical spectroscopy (IUPAC Recommendations 2019)) on page 720 [Terms] [Paper]