You need to find a diffussion pump. These will get
you down to
Indeed I do (My father spoet most of his working days on high vacuum
systems., I think I'd head ofa 'diff pump' before I even went to school...
OIl, from choice. Mercury vapour, even inside a vacuum system (and some
will, alas, end up in the backing rotary pump) is not something I
particualrly keen on....
There is the minor problem of 'where the heck do I set up a vacuum
system, along with all the other things I am working on' :-)
-tony