Xenon lamp stability

[jedward]

The arc of 4 to 5KW high pressure Xenon lamps originate at the cathode tip.
In operation, the visible arc of our Osram lamps "wanders" with the consequence that the intensity
via our optics fluctuates up to a few percent (we image the arc onto a pinhole and collimate with a parabola).
The lamp is vertical.
The intensity shifts seem to be related to the arc origin on the tip.
Any suggestions on how to stabilize the intensity? ( the power supply is stable)

Is the source of the instability related to the material properties of the cathode tip?
Any experience with other manufacturers lamps?

 

[IRstuff]

You may be too young to remember the ubiquitous Jacob's Ladders in the sci-fi movies of yore. Arcs are essentially partially random processes, and typical arc lamps are "brute force & ignorance" devices. Unless you design your own arc lamp, I would think that you're stuck with the variability.

TTFN
faq731-376

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[jedward]

Not too young to know about ----
This wandering of the arc has been much more pronounced in the past year or two of the thirty years of use under our belts.
My suspicion is a change in the cathode tip processing and the uniformity of the materials. This was observed in two different, but similar, Osram lamps models- both 4.2K and 5KW.
Almost all of the lamps show "erosion" of the cathode tip near the end of life (1000 Hr), some much earlier than others

 

[MikeHalloran]

A search on {cathode erosion in arc lamps} produced a lot of material. ... not necessarily any solutions, but some explanations.

Mike Halloran
Pembroke Pines, FL, USA