a few parameters to be considered for pumping:
1x10^-8 mbar vacuum.
the load of the rare gas clusters is 0.1mbar x l/s, requiring a 1000l/s turbomolecular pump.
the inner area of the chamber is 2m^2.
the volume of the chamber is 0.16m^3.
the area of the llnl experiment is 3m^2.
for the previous experiment we had a 1000l/s pfeiffer corrosiveturbo vacuum pump, which needs a backing pressure of 10^-2 mbar. a scroll pump is good for that.
comments from christoph bostedt, berlin:
S=R*A/p
and R=8*10exp-9 mbar/(sec*cm^2) (outgassing stainless steel after one hour pumping), A ca 2*10exp4 cm^2, p=10exp-8mbar
i.e. 16000 l/sec needed sucking capability. which would be gigantic!
to save the day: R can be reduced by electropolishing, and we can work at worse vacuum than 1e-8mbar, so we can reduce S by an order of magnitude.
so we would need app. 2 1000l/s pumps for the chamber, and 1 1000l/s pump for the clusters.
