Jordan, Travis

After yesterday's preparation works (see aLog 84475) the pumpdown procedure was started on HAM1.
2 purge chamber-air measurement was done, one was during purging; the purge air dew point was -40.3 deg C; the blowdown air dew point was -40.1 deg C. This is very dry, so a very good start for the pumpdown.
The pumpdown was started with the Supersucker cart's 500 l/min Anest Iwata scroll pump, then at <500 mTorr, the recently installed 500 l/s Leybold turbo was switched on. As the pressure dropped down to the E-5 Torr region, the purging all metal valve on the top of the chamber (valve for the new gauge) was closed.

In the meantime, the HAM1 gauge was wired (see aLog 84494). The channel was also added to DAQ for trending, and can be seen on the MEDM screen. Thanks for all of this to Fil, Dave, and Patrick!

At the moment, the pressure in HAM1 is 6.5E-5 Torr, tomorrow the chamber must be ready for leak check. In preparation for leak checking, all the double O-ring flanges were wrapped with Kapton-tape, to avoid flooding the annulus volume with He during leak checking - here note that because the feedthrus are all populated with cables, bagging of flanges will be hardly possible, so the area will be flooded with He anyways.