Composition:   glass envelope (20 x 40 mm) - Pyrex, quartz

                            filling material (1-10 mg) - Hg, Cd, P, I₂, S, Se

                            noble gas (0.1-30 Torr) - Ar

Principle:

            microwave                 UV/VIS radiation

Hg-EDL operation in the block:

Free electrons (e^-) in EDL are accelerated by microwave field.

Accelerated electrons collide with the argon atoms (Ar) and ionize (Ar⁺) or excite (Ar^*) them.

Excited argon atoms (Ar^*) collide with mercury atoms to form exciting states (Hg^*), which emit energii (hn) as UV/VIS radiation at return to ground state (Hg).

Emission spectra for EDL (Pyrex):

1) Line:

2) Continuous:

3) Sun spectrum of visible light:

Pyrex absorbs most of the UV below 290 nm without the necessity of filtering off the undesirable part of radiation.