My university has a sputtering machine which is this crazy expensive piece of equipment that has to have a really strong vacuum pump and wacky copper seals and if it loses power for even a minute it has to spend 16 hours pumping it’s vacuum back down.
I know people talk about how a perfect vacuum is like near impossible, but why? We can pressurize things really easily, like air soft co2 canisters or compressed air, which is way above 1 atmosphere in pressure, so why is going below 1 atmosphere so hard? I feel dumb asking this as a senior mechanical engineering student but like I have no clue lol.
In: 3143
Below one atmosphere is also pretty easy. We can get ‘close’ to vacuum, no trouble.
But imagine trying to pressurize a CO2 canister, not to *roughly* two atmospheres, but *exactly* two atmospheres. Accurate down to ten molecules in the whole space. Suddenly you have to keep very close track of every possible place even single molecules can come from.
Things like microscopic cracks in your components, sticking to the surface of your components, or even downright being absorbed. Even metals will sublimate a very tiny little bit, and some even do it so much that they’ll easily ruin your vacuum.
If anything, this precision gets *easier* under high vacuum. You know that every molecule in the tank is one molecule too many, as opposed to trying to somehow measure 2 atm accurate down to the parts per quintillion.
Latest Answers