Are there higher output UV-C lamps?

Are there higher output UV-C lamps?

Medium pressure mercury (Hg) lamps are also used, particularly in water purification. Such lamps resemble high pressure mercury lamps—i.e., are much more compact—and use a clear or doped quartz envelope, depending on application. While the efficiency of the 253.7-nm emission is significantly reduced and broadened due to reabsorption of the radiant energy, it is nevertheless an important source, as it can be operated at much higher power per unit length than low pressure mercury lamps.

Other sources, such as rare gas-halogen (e.g., krypton-chlorine, Kr-Cl) discharge, have been shown to produce significant emission in the far UV-C region (205 to 230 nm). The advantage of sources such as those emitting 207 nm or 222 nm, is that the deactivation rate of some bacteria and viruses appears to be relatively high, and the effect of the emission on human skin and eyes is much reduced compared to the 253.7-nm mercury emission.[22] However, depending on the glass envelope, small but significant levels of longer wavelengths may be of concern.[23] At this time, such sources have been developed in the research laboratory, but their presence in the marketplace is still very limited in comparison to that of mercury lamps, and there is little experience yet with any widespread use.

[22] Buonanno M, Ponnaiya B, Welch D, Stanislauskas M, Randers-Pehrson G, Smilenov L, Lowy FD, Owens DM, Brenner DJ. Radiation Res. Germicidal efficacy and mammalian skin safety of 222 nm light. 2017;187:493-501.

[23] Woods JA, Evans A, Forbes PD, Coates PJ, Gardner J, Valentine RM, Ibbotson SH, Ferguson J, Fricker C, Moseley H. The effect of 222-nm phototesting on healthy volunteer skin: A pilot study. Photodermatol Photoimmunol Photomed. 2015;31:159-66.

in water purification. Such lamps resemble high pressure mercury lamps—i.e., are much more compact—and use a clear or doped quartz envelope, depending on application. While the efficiency of the 253.7-nm emission is significantly reduced and broadened due to reabsorption of the radiant energy, it is nevertheless an important source, as it can be operated at much higher power per unit length than low pressure mercury lamps.

Other sources, such as rare gas-halogen (e.g., krypton-chlorine, Kr-Cl) discharge, have been shown to produce significant emission in the far UV-C region (205 to 230 nm). The advantage of sources such as those emitting 207 nm or 222 nm, is that the deactivation rate of some bacteria and viruses appears to be relatively high, and the effect of the emission on human skin and eyes is much reduced compared to the 253.7-nm mercury emission.[22] However, depending on the glass envelope, small but significant levels of longer wavelengths may be of concern.[23] At this time, such sources have been developed in the research laboratory, but their presence in the marketplace is still very limited in comparison to that of mercury lamps, and there is little experience yet with any widespread use.

[22] Buonanno M, Ponnaiya B, Welch D, Stanislauskas M, Randers-Pehrson G, Smilenov L, Lowy FD, Owens DM, Brenner DJ. Radiation Res. Germicidal efficacy and mammalian skin safety of 222 nm light. 2017;187:493-501.

[23] Woods JA, Evans A, Forbes PD, Coates PJ, Gardner J, Valentine RM, Ibbotson SH, Ferguson J, Fricker C, Moseley H. The effect of 222-nm phototesting on healthy volunteer skin: A pilot study. Photodermatol Photoimmunol Photomed. 2015;31:159-66.