Mercury plasma lamps

The mercury-free fluorescent lamps and plasma display panels require alternative luminescent materials for efficient conversion of ultraviolet radiation to visible light. The quantum cutting (two photon luminescence or photon-cascade emission) was demonstrated in famous "Eu -Gd " pair" containing system employing the concept of down-conversion, which means that two visible photons are emitted after... 

The photosensitivity of PMMA is significantly enhanced by the incorporation of 10 to 40 mole% 3-oximino-2-butanone methacrylate. Terpolymerization with methacrylonitrile increases that sensitivity still further, P(M-OM-CN) (69 16 15) being 85 times more sensitive than PMMA on exposure to the full output of a 1000 watt mercury lamp. Upon addition of external sensitizers, this sensitivity may be increased by an additional factor of 2 to 3. The high resolution characteristics of PMMA have been retained and the polymers in question show good plasma resistance. 

In the FIR region, the mercury arc lamp is most frequently u.sed. Its spectrum is emitted from the plasma as well as from the red glowing silica wall (Bohdansky, 1957). 

New xenon plasma fiashlamps, which generate significant light intensity in the deep UV region (<250 nm) are better suited for direct photolysis than conventional mercury-based UV lamps. Spectra of xenon flash lamps are different than those of the mercury arc lamps and in the range of IR to the UV-C region (300-200 nm) (23). The spectral emission of the xenon flash lamps depends on the current density and the plasma temperature. 

Whereas atomic fills usually furnish line emission spectra, molecular fills give continuous emission bands [61], The total emission output of the most common lamp - the mercury EDL (Hg EDL) - in the region 200-600 nm is approximately the same as that of the electrode lamp with the same power input [62], The distribution of the radiation is, however, markedly different, as a result of much higher Hg pressure and the greater number of atoms present in the plasma. EDL emit over three times as much UV and over a half as much IR as a conventional lamp [63]. It has been noted that EDL and electrode lamps provide different spectra when the fill contains a rare-earth material but similar spectra when a non-rare-earth fills are used [64]. Addition of material had very substantial effects on the spectral distributions of EDL [62]. 

I 1.6.14. Mercury-Containing and Mercury-Free Plasma Lamps... 

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