Proposed to Betsy and Keita the option of leaving the QDP80 roughing pump valved in overnight to gain headway on pump down (pressure currently at 30 Torr at BSC2 and 20 Torr at pump station). We typically don't pump overnight because of potential risk of backstreaming into main volume if a pump + interlocked valve fails. After some thoughtful discussion we decided it is not worth the risk and will resume per standard procedure and rough during "business hours" when a vacuum person is onsite to monitor and react in case of emergency. HAM6 in-chamber activities will be pushed back as a result, but schedule allows for this. QDP80 is valved out for the night.

The good news is when the new roughing pumps are operational, we will have a second interlocked valve for redundant protection in order to pump overnight.