and
)
radiation produced by an electrical discharge in a lamp with the inner side covered by an amalgam of mercury with another element such as indium or gallium to control the vapour pressure of the mercury. These lamps have 2-3 times the UV output for the same wavelength as the standard low-pressure mercury lamp.
Source:
PAC, 2007, 79, 293
(Glossary of terms used in photochemistry, 3rd edition (IUPAC Recommendations 2006))
on page 302