Geissler tube with a contact problem

[Physikfan]

To all friends of antique Geissler tubes

The picture shows a complex shaped Geissler tube.


Unfortunately, the corresponding metal cap with eyelet is missing during a contact.
Please, does anyone know how to fix this problem?

Best regards

Physikfan

[Mads Barnkob]

Sure is a beautiful and complex tube you got there, would be a shame if it can not be repaired.

Is there still a lead/wire in the socket/weld of glass around the conductor?

I have repaired a missing cap on a regular electron tube with a similar cement as those described in these threads: http://www.antiqueradios.com/forums/viewtopic.php?t=101584 and http://www.antiqueradios.com/forums/viewtopic.php?t=151137

[Physikfan]

I hope to have found a usable electrically conductive adhesive now
to solve the problem with the one contact (missing metal cap with eyelet).

[Physikfan]

Unfortunately there are more problems:

Contact with cap:



Contact without cap:

[Mads Barnkob]

Looks like a bust

Both terminals are damaged in each their way.

The one missing cap will be hard to repair, maybe try to grind away some of the glass to get access to a tiny bit of the wire, but not breaking vacuum.

The one with cap seems to have lost its discharge terminal on the inside and its rattling around in the end of the tube.

[Physikfan]

Hi Mads Barnkob

I have followed your suggestions and have provisionally treated the electrode without cap with conductive silver.
The tube works, the operating voltage is about 13 kV.



One question remains:
Which gas makes this white discharge?

Best regards

Physikfan

[Physikfan]

In a catalog for physical demonstration devices from 1909 I found one
similar Geissler tube:

[Physikfan]

These are the first, just with reflection grating and camera primitively recorded grating spectra of the Geissler tube:





The second green line of the first spectrum is also in the second spectrum as the middle line and in the third spectrum
included as the leftmost line.

The question is now:
Which gas coresponds to these spectra.

Best regards

Physikfan

[Physikfan]

This is the composite grating spectrum of Spectrum 1 and Spectrum 3.
However, the colors are strongly distorted by the camera's automatic white balance.



The question is still:
Which gas corresponds to this spectrum?

regards

Physikfan

[Physikfan]

I will use such a transmission grating spectrum of a fluorescent lamp (mercury lines) to calibrate the lines of the Geissler tube,
green line 546 nm.