Comment by vbelenky

I'm not sure what you mean by clinical unit--the ushio care222 is the longest lasting KrCl emitter I'm aware of, but as all bulbs age, they tend to degrade just by losing output, not by spectral shifting.

Basically everyone in far-UVC is a teeny tiny group selling lamps on basic websites, even those who source care222 emitters from USHIO. It's not a big industry!

We don't source our KrCl bulbs from Shenzen, but not for this reason. Yes, that's true about LEDs, but the physics of LEDs and excimer bulbs are different. Excimer spectra don't smoothly shift the way LED spectra do. Excimer spectra have characteristic peaks based on the energy levels of the possible gas molecule species present in the filler gas. The main change over time is the gradual reduction of the 259nm Cl2* peak, which is the main peak of concern--so it fails gracefully. Another possibility is the degradation of the dichroic filter coating under thermal stress--but I've only ever observed this in diffused units, none where the filtered glass is open to the air, and that will happen even on an Ushio bulb.

Nukit is our competitor but I doubt very much that any concerning spectral shift will take place over the course of the lifetime of their lamp.