Beetle in a Geißler tube

[Physikfan]

The two pictures show a beetle in a Geißler tube:
(DC source, 9 kV, cathode top, anode bottom)



Exposure normal, with room lighting, fluorescence on the glass wall


Exposure 2 f-stops underexposed, room dark, fluorescence on the glass wall


Exposure 2 f-stops underexposed, room dark

[Mads Barnkob]

Interesting colours on the beetle, I know that some insects have patterns and markings that only show under UV, but the big differences between colours on the beetle here surely suggest that it was doped/contaminated with different materials to make it glow in different colours?

It is a sealed tube right? That glass blower actually put that beetle in-there when making the tube or can you open it up and put samples in, evacuate and fill with gas?

[Physikfan]

Beetle in daylight without discharge:

[Physikfan]

Hi Mads Barnkob

"Interesting colours on the beetle, I know that some insects have patterns and markings that only show under UV, but the big differences between colours on the beetle here surely suggest that it was doped/contaminated with different materials to make it glow in different colours?"

The beetle is an artefact, you see the colours of different fluorescent materials.

"It is a sealed tube right?"

Yes, the tube is more than 100 years old.

"can you open it up and put samples in, evacuate and fill with gas?"

No, but I will try to get a tube which can be evacuated and filled with a gas.

Regards

Physikfan

[Physikfan]

Bottom of the beetle in daylight without discharge:

[futurist]

I thought it's a real beetle, now it makes much more sense

[shrad]

I have a couple Y2K commemorative lamps with the same kind of fluorescing material with E27 sockets... sad they are not the other form ones like this beetle, but they are nice too

I'll try to make a picture when I have the opportunity to put one out of their box...