Brightness of Radioluminescense?

[Alumen]

How bright could you possibly get a radioluminescent material to glow? Let's use tritium as the radionuclide. How would you mathematically calculate the brightness? What is the best radionuclide and phosphor to use? Obviously it has to be a β-emitter. Would it depend mainly on the β energy?

Thanks for any help in advance.

 

[daveb]

Best is a subjective term. Best could be the chaepest, the most efficient, the lest toxic to people or the environment, the easiest to produce, the most abundant naturally - any of these could qualify as "best".

 

[etudiant]

The glow is from the phosphorus that lines the bulb containing the tritium. The tritium does not glow, it just radiates beta particles.
So your question is what is the maximum beta emission that a suitable phosphorus can handle. One hint might be given by the old CRTs, which could easily second as a roomlight even though the electron beam only illuminated a speck of the screen at anyone time. So my guess is a shorter half life material than tritium could support a much brighter beta light.
There are ogoing efforts to use such beta lights to power long life solar cells that are essentially impervious to outside conditions. Presumably the developers of these devices are trying to answer your question also.

 

[Alumen]

Right, I know that it's not actually the tritium glowing. And strangely enough that is the same experiment that I am doing in the lab. I did some tests today with some glow in the dark paints that have a similar color and output power of a low end tritium bulb. I managed to get about 2 centivolts from a solar panel NOT geared for the correct wavelength. I am having serious issues obtaining real tritium paint(or something similar). Our lab does not have the necessary equipment or chemicals to do this. And since it is more of a personal project I haven't had much help.
Any idea where to buy it? I am sure regulation is pretty tight on tritium as it's used in thermonuclear weapons.

 

[daveb]

The exempt quantity for tritium is 1 millicurie, so (aside from cost) there is no regulatory reason you couldn't get some quantity less than that. Of course, tritium is difficult to handle since it is usually in tritiated water, which is tough to control.