high-pressure mercury lamp (arc)

https://doi.org/10.1351/goldbook.H02825
Radiation source containing mercury at a pressure of ca. 8 MPa (ca. 80 bar) or higher which emits lines over a background continuum between about 200 and 1400 nm.
See:
lamp
Source:
PAC, 1996, 68, 2223. (Glossary of terms used in photochemistry (IUPAC Recommendations 1996)) on page 2246 [Terms] [Paper]