Why is this level of vacuum stability so important although not mentioned by Jed? The Mizuno protocol requires maintaining 300-1000 Pa of D2 in the reactor for days or weeks, without any contamination of oxygen (air) getting in. I know from my past Glowstick work that this is the real challenge of the experimental protocol and must be correct. I'm not shy about buying good equipment, and have invested around $3k so far in building the apparatus. The turbo pump system will be around $10k new or $5k used for a known good system with low hours. Definitely not interested in junk parts for this important piece of the system!
I completely agree. I am happy with the Roughing pump/turbo/ion gauge set-up - and with the QMS (though it is an antique) but maintaining a long-term vacuum (days) is very hard. I am just doing a rebuild of my system -swapping oit everything with a mechanical connector for silver-brazed fittings. For those who haven't considered this problem what leaks in is air...and so you lose your deuterium by turning it into heavy water.