~1000 hrs. local time 

A measured pressure of 14 microns was observed 5 minutes after having isolated the pump.  So, an improvement from 230 microns to 14 microns in ~45 hours of pumping with a two-stage scroll pump.  

I vented the pump connection and added an O-ring valve in series with the existing O-ring valve (see attached image) then evacuated the space between them.  This was done in the hopes that the existing O-ring valve has been the source of this dewar's consistently poor vacuum retention (leaky valve?).   

This completes WP #7037