This is a reminder that whenever the PMC is unlocked, especially for an extended period of time, the FSS and ISS should also be disengaged; otherwise, the respective autolockers will continue to try to engage these systems despite not having the means to do so (because they have no light, since the PMC is unlocked).  If there are ever any questions as to how to properly and safely disengage the PSL stabilization systems, CONTACT ME.  It does not matter if I'm offsite for any reason (RDO, vacation, sick, etc.).

From the 10-day trends Ryan posted this morning, neither the ISS nor the FSS were properly disengaged, so were left trying to lock all weekend.  For the FSS see the plot H1:PSL-FSS_NPRO_XTALTEMP in this set of plots.  It's clear from this plot that the FSS autolocker was doing a temperature search while trying to lock the RefCav, which means the NPRO PZT was also ramping.  Since there was no light in the FSS path the RefCav could not lock, so the search continued all weekend.

For the ISS, see the plot H1:PSL-ISS_DIFFRACTION_AVG in this set of plots.  The ISS diffraction should be completely flat if it is off, but the series of downward spikes indicate the ISS was trying to lock and failing to do so, since there was no light on the ISS PDs (my guess is it kept lowering the diffraction percentage to try to increase light on the ISS PDs, and unlocking when the diffraction hit 0% to start the process again).  This can also be seen in the behavior of the PMC reflected power (1st attached picture), which was moving around substantially all weekend as the ISS was trying and failing to lock; can also see the ISS diffracted power moving between 0% and 40%.  A zoomed in portion is also attached, in which it's seen that the ISS diffraction was moving from zero to ~20% (but as high as 50%) in a roughly 15 second period; note the changes in PMC Refl during this time (the small spikes in PMC Trans are not the PMC trying to lock, it's small flashes of resonance as the temperature of the PMC changes combined with the FSS actuating on the laser frequency).

While not strictly necessary, it's good practice to also close the PSL external shutter if the stabilization systems are going to be disabled for an extended period.

I don't think that this will compromise the performance of the ISS or FSS, but this does represent unnecessary wear on the mechanical components that are the actuators for both of these stabilization subsystems.  I should have caught that the PSL was left in this state, but did not pay attention to the alog during my RDO weekend and therefore did not catch this.  For this I apologize.

Just adding a note:

As of the end of the day, Sheila and I have left the sidebands OFF, and the HAM6 high voltage ON (per WP #12545).

See Elenna's comment on her previous measurement where this saturation happened.

Turn off the sidebands - instructions in this alog.

Sheila and I ran one more OMC scan with sidebands off after OM2 heated up. Attached is the screenshot with scans off both ITMX and ITMY, data is saved in [userapp]/omc/h1/templates/OMC_scan_single_bounce_sidebands_off.xml

I also ran two OMC scans, single bounce off ITMY, 10 W input, with the sidebands ON. One measurement I ran with the sidebands set to 23 dBm and 27 dBm (9 and 45 MHz) and another set to 20 dBm and 21 dBm (9 and 45 MHz). I will use these measurements to calibrate the modulation depth. Data saved in /opt/rtcds/userapps/release/omc/h1/templates/OMC_scan_single_bounce_RF_cal.xml

SR3 heater was on for this measurement but it should have little effect on my results.

Looked closer at these HWS signals during SR3 heater heat up and cool down. In all these plots, the two t-cursors are used as the reference and shown HWS live image.

• Heat up plot attached
• Cool down plot attached (ITMX was misaligned so there's no HWS data)

Some strange things:

• ITMX heat up ndscope spherical power looks the opposite direction of ITMY, this isn't physical. Looking at the HWS Live plot, this isn't really want's happening, it appears that the SR3 signal just appears if the edge of ITMX is heating up so the center that the calculations are made from isn't correct, making the calculated spherical power wrong.
• In both the heat up and cool down of the ITMY signal, there appears to be two steps with a flat region in the middle. Looking at the the flat region only, attached, it appears that the spherical power is continuing to change in the expected direction, unsure why this change isn't shown in the calculated spherical power.

[Shoshana, Michael]

We've managed to get all of the hardware/parts installed in and we've closed up the BRS chamber. We had to add an inch of shims beneath to motor mount in order to get it to fit/align properly, but otherwise there were only minor complications during installation. We've tested the pico-motor and the mass adjuster using the pico-motor driver that we brought from UW and both seem to work fine. 
For in air balancing, we left the new mass adjuster centered to increase range for future adjustments for when the BRS is pumped down and running, and tried to just stick to moving masses that are inaccessible when the BRS chamber is pumped down. We unfortunately reached the maximum range with the internal masses and had to slightly move the manual mass adjustment system (what is currently used to adjust the center of mass) from center, but that might be returned to center after we re-balance it when it's pumped down. Right now the resonance frequency looks to be around ~7mHz (around 130 second period) which is about the same as it was before Mass Adjuster installation, but we'll check again after the chamber has been pumped down.
Tomorrow we'll finish all of the wiring and electronics to hook up the pico-motor to the LIGO system. The plan is to pump down the BRS chamber tomorrow and re-balance and test the pico-motor some more.

The reference pattern has a higher intensity than expected and we aren't sure why. Right now our best guess is that the light source drifted slightly, and we'll look into it more tomorrow.

EPO tag for BRS pics

[Shoshana, Michael]

Pumped down the BRS chamber overnight and started the ion pump this morning and got it down to 1.9e-6 Torr before we left end End-X. We also wired up the picomotor to the LIGO picomotor controller system. It is hooked up to the 7th channel X-direction and we tested it out and were able to hear it spinning for both directions. The BRS's thermal insulation was reapplied the box closed and the temperature sensors and heating plate were all re-attached and plugged back in. The reference beam's intensity has gone down to be closer to normal somehow, so it doesn't seem to be anything to worry about
We might go back to End-Y one more time tomorrow to clean up the wiring and do a final check of the vacuum pressure.
We waited for the temperature to equilibrate a bit before balancing  because we were hoping that as the temperature rises it would drift back to center, but we ended up using the mass adjuster to try and balance it.
It looks like the + - wires for the damping were switched, meaning when the damping was on it would ring up the BRS. Fixed by changing a line in the BRS code[IF H1_ISI_GND_BRS_ETMY_CAPDRIVE>=0] by switching the [>=0] to [<=0] and switching [H1_ISI_GND_BRS_ETMY_CAPOUTL] and [H1_ISI_GND_BRS_ETMY_CAPOUTR], and [H1_ISI_GND_BRS_ETMY_RELAYL] and [H1_ISI_GND_BRS_ETMY_RELAYR]


FROM THE END-X INSTALL:
Coupling/decoupling move: 1.25k steps
Maximum: +-140k steps
Be careful: +-100k steps

NOTE: MOVING PICOMOTOR +(POSITIVE) DIRECTION TRANSLATES TO MOVING THE BRS UP

TOTAL MOVEMENT TODAY:+21k steps

Centered both ETMY and ETMX BRSs.
For ETMX net movement was +2200 steps, for ETMY net movement was -3200 steps.
For ETMX we saw that the DRIFTMON was moved by about ~3.27 counts per step, and ~2.3 counts per step for ETMY

Cleaned everything up for the ETMY BRS and relabeled all the wires. The final reading that we saw for the ion pump was 9.9e-7 Torr (186uA, 6950V) which seems about right. We left some extra mass adjuster parts with Jim just in case. 

Shoshana, Michael

We took tilt subtraction spectra as a final life check of the BRSs. Both BRSs appear to be in good working order and doing their jobs well.