The vapor is heated by more than 100 K through the virtually adiabatic compression, however
it re-cools on the way to the condenser. So the assumption that Tm = 60 K is quite conservative.
The thermal transmission coefficient k [17] declines significantly as the concentration of
inert gas increases, which results in a larger condensation surface area. Inversely, with a lower
concentration of inert gas, it is possible to work with a larger backing pump and a smaller
condensation surface area. Particular attention should be paid to small leakage rates, as they,
too, increase the concentration of inert gas