continuum source 

in atomic spectroscopy
https://doi.org/10.1351/goldbook.08463
Source that emits electromagnetic radiation with relatively constant intensity over a broad spectral region.
Note:
The use of such a source allows for correction of spectral interferences.
Source:
PAC, 2021, 93, 647. (Glossary of methods and terms used in analytical spectroscopy (IUPAC Recommendations 2019)) on page 715 [Terms] [Paper]