This is likely a very odd set of questions, so I'll start from the beginning in hope of making them a little less odd. About two and a half hours ago I was going through some old devices I had and I came across a bug zapper and as I plugged it into test it and I set it on my workbench which happened to have a few Nixie tubes and a CRT spread around it and when I plugged in the bugs zapper it worked (thankfully) but the Nixie tubes started to Glow and so did the CRT, now the Nixie tubes, I would imagine was the roughly 4,000 volts that the things kicking around, I'd imagine the field probably piped them up a little bit, but after some fiddling, I figured out that the CRT was UV which some of you probably knew, but the CRT has clear sides and a white face I think it might be a black and white, it's in a case and it's intended to test CRT television drivers I guess, I think the idea is that you unplug the original tube and plug in this thing and if your tube is bad this will show a picture and I'd imagine you can also tell by what it's doing some other things that might be wrong, it's around 8in, looks really cool. And I've been trying for a while to figure out a good way to display it while showing off the tube, which shows as a white disc on one end of the box, so my idea was to put in a few UV LEDs in it, and my questions are, do you think a few LEDs would be enough to light the phosphor to a noticeably? I was thinking maybe 4 to 8 placed radially. I'd imagine it would, but does anybody know if it would cause burn in? I would really like to avoid it, and if anybody knows of a way that wouldn't cause burn in, while still using the original phosphor please let me know.
thanks

 

The in that makes up the faceplates of CRTs made about about 1950 relatively low optical transmission because this enhances contrast. Figure your faceplates will probably pass 60% to 75% of the light generated by the phosphors provided the phosphors have the typical reflective aluminum film backing.

The there is the problem that the glass used for the faceplate is even less efficient at transmitting UV.

Taking that into account, you probably will not get enough parameters to calculate the light output, so the best way to answer your question is to set up an experiment. You need to find the wavelengths that offer the best conversion from UV to visible, do some initial tests with UV LEDs with peak emission at a chosen wavelength, and get started on a design.

One other thing, there will be reflections of the UV from the faceplate. Taking the chosen wavelength into account, it would be a good idea to place a UV blocking filter between the faceplate and the viewer.