Today Robert did some ISI injections to test the new R0 tracking of the ETM reaction chains.  To turn the tracking on/off, Robert ramped the gains for the ETMX and ETMY R0 Length damping between 0 and -20 over 15 seconds.  See alog 54506 for implementation yesterday during maintenance.  Robert will post more detailed plots showing the reduction in scattering when the tracking is on. 

I looked back at a couple of ndscope traces from Robert's injections and it's clear that the tracking is doing useful things, even with just a quick glance.  In the attached plot, the bottom 2 rows are DARM BLRMS that are representative of the scattering we see.  'RLP2' in purple is about 20-30 Hz, and 'RLP3' in brown is about 34-60 Hz.  The top two traces in the plot are EX, and the middle two are EY.  The blue and green traces (1st and 3rd rows) show displacement between the main and actuation chains, while the orange and red traces (2nd and 4th) show how much actuation is happening on the R0 stage.  When these go to zero, Robert has turned off the tracking.  Robert's injections stop just after the -2000 second mark, and times after that are with our currently increasing microseism.  It is quite clear from this plot that during the times that Robert is making injections and we don't have the R0 tracking on, we see many glitches represented in the BLRMS traces.  When the R0 tracking is on, the BLRMS indicate much less glitching is going on.

Robert will post more detailed plots from today's work, and then tomorrow (when we're expecting the microseism to be pretty high) he'll do some more on/off testing.