Finnigan LCQ Mass spectrometer Part 2

A look at the physics stuff, and quick play with vacuum bits.

[VGScreens]

The craftsmanship on that thing is incredible. I could look at it all day.

[shogoonn]

The black stuff inside the detector is indeed a resistive layer. It provides voltage gradient along the length of the electron multiplier horn's wall. It's basically a standard electron/photomultiplier-like construction, except there are no discrete dynodes (each having a slightly higher potential than the previous one), the dynode is distributed in the form of a continuous voltage divider. The horn shape and field gradient makes the electrons travel to the centre of the detector, knocking off more and more electrons as they collide with the walls on their way in. The detector is mounted at an angle relative to the ion stream, probably because there is a conversion dynode, from which the electrons are emitted when it's hit by a positive ion. This prolongs the life of the detector, since there are no ions reaching it (and eventually depositing on the surface).

[Eric-ssip]

Hi, i have experience in such high vacuum systems. In your setup are many things that are not quite right. But first yes your rotary pump has reasonable size for your system. One source of error could be the oil in the forevacuum pump which is outgasing or the grease in the prcision bearings of the turbopump is not warm and the pump needs longer to reach its operating speed (some computerbased controler have a special mode for this scenario). And you should use vacuum grease (e.g. PTFE) to get a better seal ob the o rings.
It is very complicated to take a close look at all facetts in a such short time because there are far to many. If you want i could try to answer your questions and give you tips.

[KristoffDoe]

This thing shown around 10:35 is *_ion trap_* - arguably the most important part of this machine, and everything else is there just to make this thing do its job. :)

[illiteratebeef]

I really love these industrial component teardowns. I've been watching some of your older videos and I wish you could do these more often. Keep up the good work!

[nexaentertainment]

Man this thing is insanely interesting. This sort of stuff is way above my head. I can follow most of the EE/CE stuff (I would hope so at least, as that's what I'm studying), but man, this sort of engineering is just on another level.

Thanks for taking this sort of stuff to bits and sharing it with us all (and testing it out and all that)!

[jabelsjabels]

Jeez, that thing is beautiful inside!

[NoName-btoy]

Two vids out in two days!
Two great too.
Cheers Mike ya legend!

[chuckvanderbildt]

I would venture to say with at least a semi-straight face that for most of your previous videos I had a decent understanding of what it is you're showing us, but in this case I am just hopelessly lost. Looks nice, though!

[DantalionNl]

16:00 I spot a bigclive safe box as the main switch

[witeshade]

I always find it fascinating to see how huge and macro-scale the machining and shaping of devices have to be in order to operate properly on the microscopic scale. The majority of modern state-of-the-art electronics is unbelievably tiny, so it's really interesting to see something that's so big and physical in order to get super precise measurements.

[NanoCottage]

When did you last change the oil in the vacuum pump? To get the best performance the oil needs to be fresh as it provides the seal on the rotary vanes. Having new oil makes a huge difference, refrigeration guys change their oil often, like once a week. Some pump manufacturers recommend new oil every job for peak performance. If it's still not good enough after an oil change then you can get a rebuild kit with new seals and vanes for not much money.

[vsnail]

1:25 aren't those three grub screws in the periphery for active locking?

[schweinhundert]

With a big enough leak (which you may very well have), squirting solvents like isopropyl alcohol on points you think might be leaking will normally cause a spike in the pressure that you can see with the gauge. If the leak is really huge you may see the pressure go down with isopropyl alcohol, as the solvent freezes into the gap, and then you'll see it rise. Good way to detect leaks because it doesn't depend on absolute accuracy of the gauge.

[TobyAsE]

Okay, I know how a mass spectrometer works, it's quite easy in principle. But that you need something like THIS to actually perform the experiment is impressive!

[DoRC]

you might want to get with the guy from applied science. he has experience with rigging turbo pumps to things they weren't designed for.

[ITTFami]

9:51 reminds me of that General Electric turboencabulator design.

[davidgustafik]

Holy crap, this is the non-RF black magic! Thanks for the peek inside of such an unusual instrument!

[mikeissweet]

Some incredible engineering and machining in this thing. Now i feel compelled to research turbo pumps

[yiyou]

The thing @5:40 is the electron multiplier, not the metal part.
@7:50, the rpm of turbopump is way higher than 6k rpm, it should be around 50k rpm.
You will need a roughing pump which is more powerful that what you have there. I believe you need a flow rate at around 300 lpm.