Comment raith SNF 2009-11-18 15:05:49: excessive vibration evident at High Mag -- readjusted isostats

jwc at jwc at
Wed Nov 18 15:05:50 PST 2009

It was noted that excessive vibration was evident in RAITH SEM imaging during focusing operations.  Check the gimbal vibration isolation isostats and found one gimbal not floating.
Checked N2 lines for leaks -- none
Checked for clogs -- none
equal pressure -- but only 30 psi delivered to gimbals -- which is under float specification.
Checked supply pressure and found reduced to only 30 psi!!!  Not good.
Adjusted upwards to 50 psi float level and increased by additional 5 psi for a total pressure to float platform properly of 55 - 57 psi.
Vibration much reduced albeit we are impacted by crane operations across the street about 100 m from this location.  RF splash on motor operations evident on every crane lift.  temporary installation while they place equipt. at nanocenter

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