Today, during our contamination control discussions, Gerardo discovered that the X-beam tube manifold purge valve was still closed.  He opened it and the BSC3 soft cover showed sights of life billowing outward a bit.  So, it seems that since the vent ~10 days ago, we have only had the MC purge enabled which was not enough to supply positive pressure to all of the vented volume.  Darn.

To improve hampered HEPA flow at the BSC3 entrance (the walking plates almost completely occult the line-of-sight to the cleanroom ceiling HEPAs), I have set the draw fan previously used in chamber cleaning near the front of the chamber door through the soft wall curtains.  I have not turned it on because I am waiting for a particle counter to magically appear near the door to monitor the dust level (ehem, also ~10 days late).