6.2.3 Jet Theory and Design Equations - Jet Theory and Design Equations Summary - Background Pressure

The background pressure P_b in the region between the nozzle and the skimmer can be found by using the following relation between the throughput and the source conditions:

(4) 

where T_c is the vacuum chamber temperature, usually assumed to be at room temperature. Expressing T_c and T_o in degrees Kelvin, P_od in torr cm and d in cm the numerical value C (l/cm^2 s) given for several gases in Miller's article (Ref. 21) and shown in Table 3 can be used.

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