Discharge lamps that contain XE not as a buffer gas but for creating light (spectrum completion) need to have at least 60 bar/870 psi when at operating temperature.

Traditionally, tungsten HID electrodes are activated with thorium oxide alloyed into the wire. This thoria doping reduces work function for lower cathode drop. This was also done for TIG welding electrodes for the same reason. Thoriated tungsten TIG electrodes are falling out of favor for other formulations, most notable lanthanated tungsten electrodes. Looking this up, it seems an identical change has been observed with HID lamps. Instead of thoria, you just use lanthanum oxide (lanthana?)

I have never heard of lanthanated tungsten outside of a welding context. Lanthanated tungsten has a higher work function than thoriated tungsten, so performs slightly worse in terms of voltage drop. Is this performance loss also observed in newer lamps that (presumably) use lanthanated electrodes?

Did this thorium to lanthanum transition ever really happen for mainstream HID lamps, or was it just for some niche lamps where lanthanum was used?

I also discovered that pieces of TIG tungsten can be used as HID electrodes because they are doped for the same purpose at pretty much the same percentages. I highly doubt I will ever find myself making my own HID lamp, but I will keep that in mind in case I ever get rich enough to have the equipment necessary to do that.

Pyrex-style borosilicate glass has a CTE of 3.3e-6/C (referred to as 3.3 from now on). To make a feed through wire seal, you need a CTE that is more or less matching. Tungsten is usually used for this (CTE of ~4.5). Why didn't they make a nickel-iron alloy with 3.3 CTE to seal to boro? No idea. Why didn't they use a glass formulation with a ~4.5 CTE that they could easily use with tungsten? No idea. But neither of these things are what I am talking about.

Sealing thin tungsten wire directly into 3.3 CTE borosilicate usually works. But when you get to thicker wire or full-on rods, that isn't the case as much. So they make a graded seal. 3.3 CTE boro to ~4 CTE uranium-boro to ~4.5 CTE tungsten. It is a graded seal. That makes sense, that is just what you gotta do when there is a CTE mismatch. But why uranium glass? Adding uranium isn't the only way to raise glass CTE slightly. I just looked it up, Schott 8660 has 4.1 CTE, and  1250C working point. This would have worked fine, and without the uranium. I am sure there are many other options as well, this is just a quick example.

I can't imagine it was cheap to use uranium to make glass, why didn't they just use a different normal formulation to make the intermediate glass?

Obviously seeing uranium glass in power tubes and some lamps is a real treat, and I am glad they did that, it is very cool. And I also know it poses no threat to life or health from the miniscule amount of radiation released. But I would just like to know why they chose to use such an exotic solution for a very simple problem. Anyone know?

@Eleco_SR304, is it cold over there? Honestly I'd rather be over there than here as of now. I hate winter with a thriving passion.

Over here just some slow wind and some rain. I know there's worse, but I hope March comes soon 

@dor123, that sounds extreme. What is the wind speed?

Over here we've got somewhat gusty winds as well here in Ohio. Later this weekend, we're suppose to get a possible major snow storm,
as well as very frigid air... -2 degree temperature into next week. My vacation is going to be a longer vacation from work now unexpectedly, because
I know my job will likely close on Saturday, probably until Monday. (6 to 10 inches of snow expected for my area. Off topic: I've already got Monday
and Tuesday off,... then vacation Wednesday and Thursday, off work again next weekend. Due to this snow storm I'll probably be off work for 9 days
in a row, decreasing my paycheck significantly. Not cool man. Not cool. )

We have now a very strong wind storm with strong eastern winds: https://www.youtube.com/watch?v=f9Z3YMxeu2M

Unexpected capture of Suzukir122 out on the road, with his rear bumper flapping in the wind on the highway.
https://www.youtube.com/watch?v=NTAKIDCTuLo

@Medved — True, I just find it odd that they do not fail in batches / pairs of two, and instead one suffers early failure due to poor factory floor quality control? Seems to be the only explanation... probably made overseas in very high volume, and not every unit is perfect...

Quite simple might be the BAG Turgi SM6 SIP ignitors with Starter StE 501. I still have to open up one to see how it is built.
There were also quartz sand filled SIP ignitors from the late 1960s made by BAG TURGI.