Your machines
kept in this browser, never sent anywhereNothing here yet. Open an archetype, change one thing, and save it here.
read read from the base typed entered by hand, not read from the base
Commission, step 7 of 8
How long until it reaches the number I specified?
The pumpdown curve is the first honest measurement a chamber makes. This step compares the predicted curve against the specification set in step one.
The machine you laid
Back to the builderReading the machine you laid.
What already answers this
Nothing below is a copy. Each line is the surface of this site that carries the answer, and what it carries.
- /tools/outgassing/#calculate runs the pumpdown from the sourced gas load, and names the key it read
- /academy/surface-science/ carries the desorption that makes the tail of the curve
- /scale/ places the reached pressure back on the ruler the specification used
The curve this machine will follow
The machine you laid at step four carries its walls, their material and their state, and the speed the network delivers at the chamber. The outgassing base carries what those walls give off at the times somebody measured them. This is the two put together, and nothing else.
typed The target this machine has to meet. Entered by hand, not read from the base, and carried in the address with the machine.
| Pumping time | Pressure | Gas load | What dominates |
|---|
What this curve assumes, and what it refuses
What these figures rest on
Surfaces are counted by one rule: Every wall the gas sees counts, from the chamber inclusive to the pumps exclusive.
The pressure formula is F-CHIGGIATO-IONSOURCES, P. Chiggiato, Vacuum Technology for Ion Sources, CERN, Geneva, arXiv:1404.0960.
Not in the base yet
What this step cannot answer, and why. Every count below is read from the corpus at build, so this block shrinks on its own the day the data grows.
- unsourced The pumpdown model reads 258 entries of sourced outgassing and no pump curve at all. A pump that loses speed near its base pressure is not modelled, so a predicted time near the ultimate is optimistic and the calculator says so.
- unsourced No commissioning record from a real machine is carried. Nothing here is validated against a chamber that was actually pumped down.