Dear colleagues,

I'm at the design and specification stage for a noble gas preparation line,
equipped with Ti-sponge getter, SAES-NP10 getters and cryogenic heads for
separation of Ar, Ne and He. I plan to build the line out of stainless
steel tubing and NUPRO bellows valves. I have two main questions:

1) Does electro-polished tubing give a significant advantage over standard
finish ss tubing.

2) Does anyone have any specific recommendations over the valve
specification, particularly with respect to valve stem tips. I want to use
pneumatically actuated valves. I understand that some labs use copper valve
stems whilst others use ss stem inserts. As far as I can make out, with
copper the baking limit is 200 C, whilst ss stems can be baked to 300 plus
C.

Any advice that colleagues may have will be very gratefully received.

Best wishes,

Paul Dennis