“A Chip Is Born: Inside a State-of-the-Art Clean Room” from Wired is just good clean nerd fun: bunny suits, sexy stainless steel vessels, yellow lighting so as to “avoid interference with the UV”.  The cool stuff even includes a cool lack of stuff,

On the right is one of the large silver pumps used to create extreme vacuums inside the machine — as low as 10-12 atmospheres. (By comparison, the air pressure at 200 kilometers [about 124 miles] above the Earth, where the Space Shuttle orbits, is about a hundred times thicker, at about 10-10 atmospheres.)

Congratulations to them. But, have you heard that the LHC has 27 freakin’ kilometers of beam pipe at 10-10 torr, that’s 10-13 atmospheres, as well as many thousands of cubic meters of insulating vacuum at 10-6 torr (~10-9 atmospheres). Their nothing is a trifle of our nothing.

Of course the reason we need such a pure vacuum is because the proton beams will be circulating in this 27 km tube for hours at a time. Even tiny amounts of gas will lead to unwanted collisions. In small amounts this scattering contributes annoying background and in large amounts it could degrade the beam or contribute heat leading to a quench.

Just the process of creating these extreme vacuums can be pretty interesting. At right you can see a TurboMolecular Pump (diagram & combo), clearly bad-ass. Let me wikipedia that for you. You can get only so far with spinny things, though. The final stage of sweeping up troublesome molecules is accomplished by non-evaporable getter, you can call it NEG to impress your friends. It is just a chemical coating. The NEG is activated in a process called “bake-out.” Heaters temporarily raise the temperature of the vacuum vessel to 350 or 220 C.  In bare metal sections the heat releases gas trapped on the surface of the metal.  In other sections the heat actives the NEG and stray gas molecules are trapped.  You can read a little more in an ATLAS e-News from 2008.