Kyle R., Rakesh K. 

Last week Rakesh K. and I bolted together the NEG pump assemblies that get mounted atop the OMC tube prior to pumping down the Verex+YBM+XBM.  "Others" have shown (confidential study) that these NEG pumps can be a significant source of particulates in the size range that is of concern us if not first subjected to a few cycles of 1) heat soak at 250C (condition step), 2) heat soak at 550C (activation step), 3)cool down, 4) vent using UHP N2 followed by 5) a sustained viscous cross-flow of UHP N2 (60 psi source).  After a few of these cycles, the measured particulate falls off to acceptable levels (near zero counts per cf).  

We were able to complete the assembly of (3) ea. of these pump assemblies.  I had hoped to complete (3) of these conditioning cycles in the lab for each pump assembly prior to installation but have had to succumb to the schedule.  As such, each NEG pump will need to complete the remaining cycle(s) after installation on to the OMC tube.  This will be done before exposing the Vertex vacuum to these pumps.  Note that the blank flange, opposite that used to introduce the viscous UHP N2 flow, gets removed for this process so as to allow liberated particulate to exhaust from the pump housing.