Re: headlamp bulbs (devitrifying)

[Huw Powell <human@nh.ultranet.com>]

Smith, Kirby A wrote:
> 
> Phil Payne questioned:
> ---------------------------
> However - with all the received wisdom about not leaving human sweat
> and grease on quartz envelopes - has anyone definitive proof of the
> results?
> --------------------------
> It has been canonical truth in the laser industry for decades that quartz
> pump lamps will be damaged by fingerprints.  Supposedly the oil or acid
> devitrifies the fused quartz envelope in some manner that causes it to fail.
> I am only peripherally associated with this industry so I haven't
> investigated the exact mechanism, but would guess that this is only a
> problem at the operating temperatures of both the repetitively flashed and
> CW tungsten iodide lamps. For us Audiites, this applies to the present
> technology head lamp bulbs.

Gee, the myth I was fed was that the goo caused hot spots. 
Devitrification.  Wow.

Huw (glad I cleaned the spare bulb right away)