Jeff and Betsy will swap the glass optic into the SR3 suspension when Jeff gets back from end Y.

Swapping cable on dust monitor.

about 20 min ago

H1 ISI ETMX trips again on actuators.

Got up to:
Level 2 isolation on both stages,
TCrappy blends on both stages,
ST1-ST2 sensor correction on

Went back to what I was doing, then ~5 minutes later, both ST1 and ST2 actuators trip.

What is the difference between when visiting commissioners design all of these improvements vs. when they trip? Day time vs. night time? Weekends vs. During the week? There's something systematically wrong with our commissioning process.

For the records. GPS time 1078083583. Tripped on Actuators. 

Level 2 isolation on both stages, no ST1-ST2 sensor correction on. Had been running on "Start" blends on both stages for quite some time, T240s were pleasantly green. Tried moving ST1 from "Start" to "TCrappy", tripped halfway through on actuators. First glitch in captured screen show is start of switching third spike killed it.

Since glitch appears much larger in horizontal, we'll try switching vertical first (Z, RX, RY), then horizontal (X, Y, RZ).

• Longitudinal: +0.5 mm
  • Tolerance: ±3.0 mm
• Lateral: +0.2 mm
  • Tolerance: ±1.0 mm
• Vertical: -0.1 mm
  • Tolerance: ±1.0 mm
• Yaw: 20 µrad CW
  • Target: 0 µrad
  • Tolerance: ±50 µrad

All is within spec, we are ready to move forward with HEPI actuator attachment; IAS will take another look afterwards to ensure we are still within spec.

Has been for about 20 min.

Sometime between leaving the cartridge test stand and yesterday inside of BSC10, the optics in the suspension got really dirty.  The barrels of the ETM test mass, ERM optic, and PUM have accumulated alot of particulate.  I wiped these clean just prior to welding in Jan and recall them looking much better than they do in the pictures below when they were hanging on the test stand.  So, between the last bit of cartridge work, the cartridge flight and the in-chamber work over the last week lots of particulate has swirled around the in-vac hardware (about a 2 week duration).  Here's the sequence of cleaning in case Calum wants to know:

On test stand, just prior to flight:

- I wiped and vacuumed SUS, bagged both SUS and TMS

- Hugh wiped all of the ISI above, then bagged ISI

Cartridge flight Feb 24th

~2 days after in-chamber I wiped entire floor and viewport surfaces of BSC10 chamber, I did NOT inspect optics

- cabling, TMS payloading, SEI float/balance

- yesterday, I see this gross particulate accumulation, some on the suspension structure too, harder to see since it's metal surfaces though

- I wipe the entire floor of chamber again

More cleaning to follow, obviously.

We had a lot of trouble early in the evening isolating ETMX, we kept tripping the watchdog on stage 2.  We tried reseting the CPS offsets, and eventually were able to get it to isolate with Tcrappy and level 2 controllers, but the motion was rather large (~ten fringes per second).  We left stage 2 with damping only. 

Alexa, Daniel, Sheila

We normalized the refl PDH error signal, and saw that we can stay in the linear range of this signal with only ALS COMM locked. 

We first normalized LSC-X_TR_A_LF by adding a gain of 0.000154 so that the tranmission peak is at roughly 1.  We set LSC-REFLBIAS to  REFL_A_RF9_I over the transmitted power (LSC-X_TR_A_LF).  The first screen shot is the PDH, the transmitted power, and the normalized error signal as we move the COMM VCO set frequency.  In the red trace we moved the frequency by 2kHz; meanwhile, in the blue trace we moved half as fast over 1kHz.  We used Alexa's equation from alog 7054  to roughly calibrate the signal: 80Hz cavity pole/150 counts pp of the PDH signal=0.533Hz/count.

We put this gain into the REFL_BIAS filter, we will do a more carefull calculation in the morning. With this calibrated error signal we were able to measure an out of loop spectrum of the noise between the arm cavity and the PSL.  Attached are some of the spectra that we took. In the top panel the green trace is a reference with the cleanroom over HAM1 on, in the red trace we turned the cleanroom off and Alexa tried to tune up the arm cavity alignment by maximizing the green transmitted power.  This realingment clearly helped at low frequecies, and reduced the coherence with the ETMX PIT oplev. 

The RMS we measured is completely dominated by low frequency noise that changed, probably because the alignment was drifting.  The RMS down to 0.1 Hz varied from 30Hz-70Hz, we also measured an RMS of 58Hz down to 0.01 Hz.

We saw coherence with the end station PDH reflected signal above 1kHz,  coherence with the PIT oplevs (mostly ETMX, which currently has level 2 controlers on Stage 1 and damping only on stage 2) around the PIT resonances (0.4-0.5 Hz), and coherence with YAW OpLevs from 0.04-0.5 Hz.  We also looked for coherence with some of Robert's PEM sensors, we have coherence from the periscope on ISCT1 from about 50-100Hz, as we kind of expected.

Tonight the noise is much worse than it was on saturday, the transmitted power was not stable at all over time.  This might be because we don't have as good of an alignment, or be because the arm cavity motion is larger because of the problems with ETMX ISI.  We also measured the spectrum with higher and lower gains in the COMM board, higher gain did not seem to help, which is different from the situation on saturday alog 10439 . 

Started ETMY TF at gps 1077929299 on opsws0 for M0 and R0 in undamped and damped config. The measurement will be running for ~15 hours. This is to assess for rubbing after installation in chamber, and before tomorrow's alignment check.