The green banana test with a 265 nm UVC LED

[Stefano]

I forgot to eat the banana until today. It was very ripe, and it was really time to eat it. So I took the final images and ate it this afternoon. This was 8 days after the initial irradiations.

 

I apologise if my (smartphone) camera didn't autofocus properly, I tried my best.

 

First burn:

 

The skin felt dry in the burn above.

 

Second burn:

 

Then I wanted to know how deep the discoloration was, and it was very shallow. It almost didn't penetrate at all into the skin:

 

First burn:

 

Second burn:

[Gamma]

I assembled a CU-20STR-UVC-280 from Cutter Electronics on a Heatsink with the hopes of killing fungus in lenses. I don't know how much exposure they would need, with the problem of glass absorbing lots of the the UVC radiation.

I tried UVC radiation on a banana after seeing this topic.

 

This is the setup for one side of the banana. I used PVA glue to hold the items on.

 

On the other side of the banana I used the piece of aluminium to hold up the decoration.

 

This was the result after running the LED on one side of the banana for hours.

I operated the LED on the other side for less time.

 

The next photos were made almost three days a later

[Stefano]

Wow, poor banana! I just don't want to imagine something like that on human skin. That's a nasty burn. You can be sure your LED is working well.

 

If you want to kill fungus inside the lens, you will not be able to do that. The best accidental UV lenses reach down to 300-310 nm, so any light with a shorter wavelength is blocked. UVC LEDs are also relatively weak compared to mercury lamps, so you will need a much longer exposure time (about 30/40 times longer at the same input power) to have the same effect, as UVC LEDs (at 265 nm) are about 30/40 times less efficient than mercury lamps. Longer wavelength LEDs, like 280 nm are more efficient, but the effectiveness of their light is lower. The peak germicidal capability of UVC light is at about 260-265 nm.