Andres R. and Jeff B. installed the Quad-4 Upper Structure on the BSC-6 ISI at End-Y. No issues or difficulties were encountered, although the fit under the test stand is very tight. The Lower Structure is at the end station and is ready for conversion to glass.
Noticed CP6's dewar was exhausting through the "Full Trycock" circuit and that the nominal pressure regulated exhaust circuit was warm and that the tank vapor pressure was 0 psi indicated (~15 psi is nominal). This was likely in this state by the driver following the most recent delivery -> I closed the Full Trycock valve. Tank vapor pressure should build up to normal in the next day or so.
MichaelR, JanP, RickS Yesterday, we continued the work on the FSS path alignment. We found that the EOM mounting base did not allow it to get to the 10 cm beam height so we replaced it with a modified iLIGO base. Here are the powers we measured: power at input to the FSS power adjust PBSC 400 mW power downstream of PBSC 20 mW power at base of FSS periscope 8.5 mW visibility (measured with drive to EOM disconnected) (160-60)/160 = 63%
Attached is a DTT whitenoise measurement of the ITMY R0 Pitch DoF with a reference from 11/23/2011. Today's measurement is in red and with a 0.01Hz resolution. Measurements were performed after today's mechanical adjustments.
Note that this data was taken the in the interim because mechanical adjustments to the reaction chain. Newer over night data (full aLOG coming shortly) shows much less badness. However, the lessons learned from this transfer function: - Because only the higher resonant frequencies have changed, whatever mechanical problem that is causing the badness is likely *internal* to the suspended chain. - The most likely culprit: either cabling jumps between the stages are extra stiff for some reason (temporarily having it moved, cocked to one side, etc etc), or there was rubbing between chains of the the newly aligned lower stage flags. - It's not shown here, but the main chain was taken at the same time, and didn't show any particular badness, so all fingers point to the cabling. Moral of the story -- things (on the reaction chain) look better in future measurement, with very little mechanically changed.
Travis S., Betsy B., Jeff G. Today,more mechanical adjustments on the H2 ITMY QUAD were made today. The diagonalization measurements were run on the M0 and R0 top masses for the Vertical and Yaw degrees of freedom. Results attached. M0 Vertical isolation = ~18dB M0 Yaw isolation = ~17dB R0 Vertical isolation = ~7dB R0 Yaw isolation = ~11dB
Dave B., Richard M., Filiberto C., Jeff G. The SUS H2 ITMY Simulink modelh2susitmy.mdlwas modified today to accommodate the L2 (UIM) AOSEM signals. On theh2susb478machine, the first ADC card's "cardNum" is designated 0 (zero) in the Simulink model; the second ADC "cardNum" is 1 (one). The previous version of theh2susitmymodel routed the ITMY PUM signals to the first ADC card on theh2susb478machine. According to the latest BS, ITM, and FM Suspensions Controls Wiring (D1001725-v9), the PUM controls wiring should be routed to the second ADC card ("cardNum" = 1) on theh2susb478machine. The appropriate changes were made toh2susitmy.mdlto reroute the PUM signals to "cardNum=2". The new version was compiled and make installed ontoh2susb478. The signals were confirmed on the H2 ITMY PUM by medm readout. The AOSEMs now can to be normalized and centered to the flags.
Attached are plots of dust counts > .5 microns.
Today, Travis moved 62g from the AR side of the UIM to the HR (which was already the heavy side of the mass) in order to free up more range on the pitch roll bar adjusters. This did the trick and brought the pitch in to ~100uRAD. We then moved on to aligning the UIM and PUM OSEM/flag pairs. This was immediately problematic in that the signals of these 8 OSEMs looked strange. Richard help us diagnose that the L1 (UIM) signals were connected to the L2 (PUM) MEDM and vice versa. This was remedied via switching the 25pin 225 cable connections at the feedthru panel. Unfortunately, there were more troubles with L2. Dave discovered a DUO tone channel in the wrong place, and Garcia had some residual code changes to make. This recovered 3 of the 4 L2 channels, but there was still one that looked fishy. Garcia is investigating it more tonight. I am crossing my fingers that it is not the quadra-puss cable on the QUAD. I was able to align and set the 2 lower BOSEMs of the UIM to 50% OLV, but was running out of range on the uppers when the LVEA went laser safe and I quit for the night. More alignment ...to be continued.
Yesterday, seismic restarted testing HAM-ISI in the staging building. It seems that one of the horizontal GS13 is malfunctioning. The symptoms are similar to those we see when the proof mass is stuck (no low frequency response but high frequency response looks OK). After hitting the GS13 with a wrench and handling it, the mass is still stuck. I have attached Powerspectra of the 3 horizontal geophones when the ISI is locked (H3 geophone is the bad one).
The horizontal GS-13 POD SN 68 was opened and inspected. The flexure rods were not broken and the proof mass was moving freely when the geophone was leveled. One kinematic foot or the crossbar was probably not tightened down allowing the geophone to tilt inside the leveled can. Consequently the mass proof was touching the stops.
Kinematic feet of the horizontal GS13POD SN 68 were readjusted and the crossbar tightened up. After adding the can and reinstalling the GS13 in the HAM-ISI, a powerspectrum (attachment) confirmed that the geophone is functioning properly.
Today we moved the ETM Quad-04 to the Y end station. The Lower Structure weighed 539lbs and the Upper Structure weighed 255lbs. Total weight for the metal build of Quad-4 is 794lbs, which should be close to its’ final weight. The next step is to mount the Upper Structure to BSC-6 and prep the Lower Structure for the monolithic build.
Diagonalization measurements were run last night and today on the M0 and R0 top masses on H2 ITMY. For the M0 Yaw DoF, the non-Yaw OSEMs are about ~15dB isolated from M0 Yaw. The drive was a 1.3Hz sine wave with a 250ct amplitude. The measurement resolution was 0.02Hz. For the M0 Vert DoF, the non-Vert OSEMs are about ~19dB isolated from M0 Vert. The drive was a 2.25Hz sine wave with a 1000ct amplitude. The measurement resolution was 0.02Hz. For the R0 Yaw DoF, the non-Yaw OSEMs are about ~21dB isolated from R0 Yaw. The drive was a 1.3Hz sine wave with a 250ct amplitude. The measurement resolution was 0.02Hz. For the R0 Vert DoF, the non-Vert OSEMs are ONLY ~6-7dB isolated from R0 Vert. The drive was a 2.25Hz sine wave with a 1000ct amplitude. The measurement resolution was 0.02Hz.
I had to tighten a connector in the front panel of the HV module for the injection locking. Therefore I switched off the injection locking for a few minutes to do that work. After finishing the laser is now running injection locked again.
MichaelR and RickS Today we leveled the FSS path beam at the 10 cm optical height (centered on lenses and irises). The mount for the AOM does not allow it to go low enough with the beam level, so we replaced it temporarily with the eLIGO AOM mount sitting on 1" spacers. We will modify the aLIGO mount and replace it ASAP. We set up the FSS path to use the frequency upshifted beam and adjusted the alignment to get the following powers with the VCO mod level set at Max (32767): 47 mW incident on the AOM 33 mW in single pass (upstream of curved mirror M25) 20.5 mW double pass (downstream of PBSC and first turning mirror M26) 42% double pass efficiency. Not great. We did not check the beam size at the AOM or the RF power delivered to the AOM. We installed irises in both the single-pass and double-pass paths to block the unwanted diffraction orders.
Attached are plots of dust counts > .5 microns. The dust monitor at end X appears to have alarmed with a sensor failure over the weekend.
Installed awgstream-2.15.4a to temporarily fix a problem of not recognizing all the excitation channels as valid.
All stabilization loops (PMC, FSS, ISS) were locked this week for the first time all together for more than an hour with 154W downstream of the PMC. The frequency stabilization is not optimized yet, because the temperature control of the tank is not installed and the beam downstream of the AOM needs to be realigned. I will post some diagnostic breadboard measurements later this week. During installation I misaligned the camera in reflection of the PMC. So no worry, when one beam image is missing on the TV screen.
[Patrick, Jan] We traced the 12kHz oscillation that we were struggling with down to the problem that there is no impedance in the output of the AI filters. This caused a oscillation at high frequencies which apparently coupled into the PZT ramp signal (ramp is generated digitally). We build an adapter with 100 Ohm resistors between input and output of the 24 channels and this solved the problem. Since this problem is also present in all other channels (PMC, ISS, FSS) we will look for some board redesign or adapters for those channels too (currently in discussion with Peter King)
X1 QUAD 04 BUILD 03 Brett S., Jeff B., Andres R., Jeff G. Cabling adjustments were made on the QUAD 04 BUILD 03 to reduce the effect of the cable routing on the Pitch DoF for the R0 chain. Evidence of cabling affecting Pitch on R0 is detailed in an earlier post. DTT whitenoise transfer function measurements were taken between adjustments to cable arrangements to assess the cabling effect on Pitch. The attached pdf is of the M0 and R0 top mass transfer functions taken via Matlab for the six Euler-basis DoFs. The previous measurements on the attached plots are the same as in the previous post: ORANGE - H2SUSITMY, "Before Lacing" BLACK - H2SUSITMY, "After Lacing 1" MAGENTA - H2SUSITMY, "After Lacing 2" CYAN - X1SUSQUAD04, "Before Lacing" GREEN - X1SUSQUAD04, "After Lacing 1" RED - X1SUSQUAD04, "After Lacing 2" - (Latest Measurement) For the M0 chain, the latest measurement is identical. This is to be expected since M0's cabling was not changed. For the R0 chain, the L, T, V, R, and Y DoFs are identical between the latest X1 QUAD 04 measurements on 11/19/2011 and 11/22/2011. The concern was that the cabling stiffened the Pitch DoF such that the lowest resonant modes shifted to higher frequencies after cabling (see page 11 - CYAN vs. GREEN). However, it is evident the latest cabling adjustments helped reduce QUAD 04 R0 Pitch's stiffness such that it's lowest resonant modes closely match the H2 ITMY Pitch DoF after it's lacing was completed (page 11). Parameters for the 11/19/2011 and 11/22/2011 measurements were identical drive and response.
QUAD 04 BUILD 03 Diagonalization The diagonalization measurements on the QUAD 04 BUILD 03 M0 and R0 masses were performed again after recent cabling work from the previous week. The attached plots are of both the M0 and R0 top masses for the Vertical and Yaw degrees of freedom. For the M0 mass, both the Vertical and Yaw degrees of freedom are ideally isolated at near ~30dB from the other OSEMs. The Vertical drive was a sine wave at 2.25Hz with 100cts of amplitude. The Yaw drive was a sine wave at 1.3Hz with 100cts of amplitude. For the R0 mass, both the Vertical and Yaw degrees of freedom are isolated at roughly ~24dB from the other OSEMs. The Vertical drive was a sine wave at 2.25Hz with 100cts of amplitude. The Yaw drive was a sine wave at 1.3Hz with 100cts of amplitude. These results indicate the QUAD 04 M0 and R0 top mass OSEMs are diagonalized ideally.
Attached are plots of dust counts > .5 microns.
