Richard, Filiberto, Ed, Betsy
Following on from Andy's probing alog 27841 regarding funny looking OSEM spectra, today we looked into a few fishy signals. Based on spectra he took from before and after the early June power outage which show signal changes, he and Jenne identified the following set of problematic OSEM signals. I've annotated the list with status as to what we found or fixed today:
ITMY L2 LR - Fixed after power cycling the Satallite Amp box (see alog below)
ITMY R0 RT - Signal looks funny before power outage, old problem, TBC...
MC1 M3 UL - Signal looks funny before power outage, old problem, TBC...
PRM M2 UR - Fixed after power cycling the Satallite Amp box (see alog below)
PR2 M1 T2 - TBC...
PR2 M3 UL - Giant nominal YAW Bias which has been on this SUS for over a year - very little signal on OSEM - mechanical fix when vent
PR2 M3 LL - Giant nominal YAW Bias which has been on this SUS for over a year - very little signal on OSEM - mechanical fix when vent
SR2 M1 LF - Funny comb feature, TBC...
SR2 M1 T1 - Funny comb feature, TBC...
SR2 M1 T3 - Funny comb feature, TBC...
ETMX L2 LL - 50Hz turn up noise, TBC... Turn up is due to LOCK ACQ PUSHING, turn up not present during nominal SUS damping, no LOCK ACQ, see below plot
ETMX L2 LR - 50Hz turn up noise, TBC... Turn up is due to LOCK ACQ PUSHING, turn up not present during nominal SUS damping, no LOCK ACQ, see below plot
ETMX L2 UR - 50Hz turn up noise, TBC... Turn up is due to LOCK ACQ PUSHING, turn up not present during nominal SUS damping, no LOCK ACQ, see below plot
ETMY L2 UR - 50Hz turn up noise, TBC... Turn up is due to LOCK ACQ PUSHING, turn up not present during nominal SUS damping, no LOCK ACQ, see below plot
IM3 M1 LL - TBC...
We plan to pursue ITMy R0 and SR2 this week at next opportunity.
Before doing the sat amp power cycle, we first tried a coil driver power cycle on a few of our funny OSEM sets. This did not appear to clear the errant noise in any of the 4 cases. We then embarked on the sat amp power cycle which cured the 2 shown in the above list. Tomorrow we hope to revisit ITMY R0 RT and SR2 M1 which we have left off troubleshooting today with only coil driver OFF spectra. (Betsy, tomorrow you should use the attached spectra as a jump off point.)
TBC... Note the wildly different looking symptoms both of which were seen by Lundgren in 20675 AUG 2015.
Attached is the ITMY L2 OSEM signal spectra shown from before and after today's fix. The PRM M2 OSEM before and after-fix spectra are very similar to this.
ETMX High freq turn up during LOCK ACQ, not a stand alone OSEM signal feature.
ITMy R0 RT investigation - this morning Richard and Fil performed another round of tests on the ITMy R0 RT (shared cable and electronics with R0 LF, M0 RT, M0 LF). After power cycling the SAT box, other SAT box cable reseating, and reseating of the main cable to the chamber, the noise on this channel still exists.
SR2 M1 bouncy noise on 3 of 4 TOP investigation - Richard and Fil powert cycled the Sat AMp box for this set of 4 OSEMs, but the noise is still there.
TBC...