(Jeff, Kiwamu, Stefan) With the H1:LSC-REFLAIR_A_RF9_I calibrated in Hz, and the open loop transfer function measured, here is the noise it sees: Input Mode Cleaner transmitted frequency noise. Also plotted is dark noise (shutter closed). We do not know yet what the ugly noise ~1/f^3 noise is.
The loop transfer functions are attached: Open loop gains: CARM_OLG_RED.txt CARM_OLG_GREEN.txt Closed loop gains: CARM_CLG_RED.txt CARM_CLG_GREEN.txt Inverse closed loop gains CARM_iCLG_RED.txt CARM_iCLG_GREEN.txt Inverse closed loop gain with a factor of 1/2 gor Green Hz to Red Hz conversion: CARM_iCLG_RED_g2r_special.txt
S. Ballmer, J. Kissel We had made an estimate for the coil driver noise in low-noise mode (State 3, ACQ off, LP ON), and ruled it out. However, I've checked the state of the Binary IO switches, and MC2 is running in State 2, ACQ ON, LP OFF, and and MC1 and MC3 are running in State 1, ACQ OFF, LP OFF. We'll try for this measurement again, with the coil drivers in their lowest-noise mode.
I've plotted the above-attached, red and green, open loop gain transfer functions (see *_full.pdf attachment). Through trial and error, I figured out that the text file columns are (freq [Hz], magnitude [dB], phase [deg]). And remember these are IN1/IN2 measurements, so it's a measurement of - G, not G (which is why the phase margin is between the data and 0 [deg], not -180 [deg]). Also, because the data points around the UGF were so sparse, I interpolated a 50 point fit around the UGF to get a more precise estimate of the unity crossing and phase margin. See _zoom.pdf for a comparison of the two estimates. I get the following numbers (rounded to the nearest integer) for the raw estimate and the fit estimate: The raw CARM UGF is: 136 [Hz], with a phase margin of: 33 [deg] The Fit CARM UGF is: 146 [Hz], with a phase margin of: 30 [deg] The raw CARM UGF is: 169 [Hz], with a phase margin of: 35 [deg] The Fit CARM UGF is: 170 [Hz], with a phase margin of: 34 [deg]
[Stefan and Kiwamu]
We handed the CARM control from the green ALS beatnote sensor over to the REFL infrared demodulated signal. This worked well.
In this configuration, the PSL frequency was locked to the arm cavity and no green light was involved any more. The lock stayed for more than 20 minutes and was long enough to do some further noise investigations.
Update on Noise plot:
We tested two configurations :
In both cases we have three sensors to evaluate the noise performance. We had two channels for the ALS beatnote, which are REFL_SERVO_SLOW and ALS-C_COMM_A_RF_I. The difference is that COMM_A_RF_I is digitized before the common mode board and REFL_SERVO is digitized after the board. Ideally they should be always the same. The last signal is the infrared signal, REFLAIR_A_RF9_I, which is the one derived from the reflected light off of the arm cavity and demodulated at 9 MHz.
Configuration (A)
(Red): The infrared sensor. Therefore this is the in-loop signal for CARM
(Blue): Beat signal at ALS-C_COMM_A_RF_I. Out-of-loop.
(Green) : Beat signal at LSC-REFL_SERVO. Out-of-loop.
Configuration (B)
(Brown): The infrared sensor. Out-of-loop
(Pink): Beatnote at ALS-C_COMM_A_RF_I
(Cyan): Beatnote at LSC-REFL_SERVO. This is the in-loop error signal
Some other noise
(Black): beat-note readout electronics noise at LSC-REFL_SERVO
What we did:
Attached is the attempt to calibrate MC2 using the beat-node signal. The horizontal bar is at 6e-16m/ct. The variability is most likely due to saturation. Without frequency feed-back the beat-node signal tends to run into its range limit. The calibration should be redone with the REFLAIR diode.
Here's the plot I'd made to re-create this transfer function in the model, as requested by Kiwamu and Stefan.
Some additional items: - the REFLAIR_A_RF9_I was calibrated into Red Hz by adding a filter with a gain of 82Hz/(2*1000cts) and a z82:p1e3 cavity pole compensator. - We noticed the the green PDH error sigal at EY (as seen at the analog Imon signal from the demos board) has about 2.5Vpkk signal at ~28kHz. Given that it sometimes bleeds over into the Q sigal, I am pretty sure that we are saturating an RF amplifier before the demos board.
The attached plot shows a measurement of the ETMY from the ISI L witness sensor to the cavity displacement against the quad model from the suspension gnd L input to the test mass L output. Overall there is good agreement except for the factor of about 1.5 between the model and measurement (the model is greater). relevant details: The quad model is the MATLAB struct variable susModel in /ligo/svncommon/SusSVN/sus/trunk/QUAD/Common/FilterDesign/MatFiles/dampingfilters_QUAD_2013-06-14_Level2p1_RealSeismic_model.mat The data was collected starting at GPS time 1058680016 based on Jeff Kissel's log 7194. This time was set to be some arbitrary short time after Jeff's recorded time of when the cavity was set at GPS time 1058670016. The state of the IFO at this time is given by that log, 7194, though the state of the ISI isolation at that time is questionable based on the ASDs and trend data of that time. The measured transfer function comes from the DTT export file: /ligo/svncommon/SusSVN/sus/trunk/QUAD/H1/ETMY/Common/Data/2013-07-23_CavityTFMeasurements_TF There is a corresponding coherence file /ligo/svncommon/SusSVN/sus/trunk/QUAD/H1/ETMY/Common/Data/2013-07-23_CavityTFMeasurements_Coh These files are exported from the DTT file /ligo/svncommon/SusSVN/sus/trunk/QUAD/H1/ETMY/Common/Data/2013-07-23_CavityTFMeasurements.xml This TF and coherence data was exported in the following order: 1. H1:SUS-ETMY_M0_ISIWIT_L_DQ to H1:ALS-Y_REFL_CTRL_OUT_DQ 2. H1:SUS-ETMY_M0_ISIWIT_L_DQ to H1:SUS-ETMY_L3_OPLEV_PIT_OUT_DQ 3. H1:SUS-ETMY_M0_ISIWIT_L_DQ to H1:SUS-ETMY_L3_OPLEV_YAW_OUT_DQ 4. H1:SUS-ETMY_M0_ISIWIT_T_DQ to H1:ALS-Y_REFL_CTRL_OUT_DQ 5. H1:SUS-ETMY_M0_ISIWIT_T_DQ to H1:SUS-ETMY_L3_OPLEV_PIT_OUT_DQ 6. H1:SUS-ETMY_M0_ISIWIT_T_DQ to H1:SUS-ETMY_L3_OPLEV_YAW_OUT_DQ 7. H1:SUS-ETMY_M0_ISIWIT_V_DQ to H1:ALS-Y_REFL_CTRL_OUT_DQ 8. H1:SUS-ETMY_M0_ISIWIT_V_DQ to H1:SUS-ETMY_L3_OPLEV_PIT_OUT_DQ 9. H1:SUS-ETMY_M0_ISIWIT_V_DQ to H1:SUS-ETMY_L3_OPLEV_YAW_OUT_DQ 10. H1:SUS-ETMY_M0_ISIWIT_R_DQ to H1:ALS-Y_REFL_CTRL_OUT_DQ 11. H1:SUS-ETMY_M0_ISIWIT_R_DQ to H1:SUS-ETMY_L3_OPLEV_PIT_OUT_DQ 12. H1:SUS-ETMY_M0_ISIWIT_R_DQ to H1:SUS-ETMY_L3_OPLEV_YAW_OUT_DQ 13. H1:SUS-ETMY_M0_ISIWIT_P_DQ to H1:ALS-Y_REFL_CTRL_OUT_DQ 14. H1:SUS-ETMY_M0_ISIWIT_P_DQ to H1:SUS-ETMY_L3_OPLEV_PIT_OUT_DQ 15. H1:SUS-ETMY_M0_ISIWIT_P_DQ to H1:SUS-ETMY_L3_OPLEV_YAW_OUT_DQ 16. H1:SUS-ETMY_M0_ISIWIT_Y_DQ to H1:ALS-Y_REFL_CTRL_OUT_DQ 17. H1:SUS-ETMY_M0_ISIWIT_Y_DQ to H1:SUS-ETMY_L3_OPLEV_PIT_OUT_DQ 18. H1:SUS-ETMY_M0_ISIWIT_Y_DQ to H1:SUS-ETMY_L3_OPLEV_YAW_OUT_DQ 19. H1:SUS-ITMY_M0_ISIWIT_L_DQ to H1:ALS-Y_REFL_CTRL_OUT_DQ 20. H1:SUS-ITMY_M0_ISIWIT_L_DQ to H1:SUS-ITMY_L3_OPLEV_PIT_OUT_DQ 21. H1:SUS-ITMY_M0_ISIWIT_L_DQ to H1:SUS-ITMY_L3_OPLEV_YAW_OUT_DQ 22. H1:SUS-ITMY_M0_ISIWIT_T_DQ to H1:ALS-Y_REFL_CTRL_OUT_DQ 23. H1:SUS-ITMY_M0_ISIWIT_T_DQ to H1:SUS-ITMY_L3_OPLEV_PIT_OUT_DQ 24. H1:SUS-ITMY_M0_ISIWIT_T_DQ to H1:SUS-ITMY_L3_OPLEV_YAW_OUT_DQ 25. H1:SUS-ITMY_M0_ISIWIT_V_DQ to H1:ALS-Y_REFL_CTRL_OUT_DQ 26. H1:SUS-ITMY_M0_ISIWIT_V_DQ to H1:SUS-ITMY_L3_OPLEV_PIT_OUT_DQ 27. H1:SUS-ITMY_M0_ISIWIT_V_DQ to H1:SUS-ITMY_L3_OPLEV_YAW_OUT_DQ 28. H1:SUS-ITMY_M0_ISIWIT_R_DQ to H1:ALS-Y_REFL_CTRL_OUT_DQ 29. H1:SUS-ITMY_M0_ISIWIT_R_DQ to H1:SUS-ITMY_L3_OPLEV_PIT_OUT_DQ 30. H1:SUS-ITMY_M0_ISIWIT_R_DQ to H1:SUS-ITMY_L3_OPLEV_YAW_OUT_DQ 31. H1:SUS-ITMY_M0_ISIWIT_P_DQ to H1:ALS-Y_REFL_CTRL_OUT_DQ 32. H1:SUS-ITMY_M0_ISIWIT_P_DQ to H1:SUS-ITMY_L3_OPLEV_PIT_OUT_DQ 33. H1:SUS-ITMY_M0_ISIWIT_P_DQ to H1:SUS-ITMY_L3_OPLEV_YAW_OUT_DQ 34. H1:SUS-ITMY_M0_ISIWIT_Y_DQ to H1:ALS-Y_REFL_CTRL_OUT_DQ 35. H1:SUS-ITMY_M0_ISIWIT_Y_DQ to H1:SUS-ITMY_L3_OPLEV_PIT_OUT_DQ 36. H1:SUS-ITMY_M0_ISIWIT_Y_DQ to H1:SUS-ITMY_L3_OPLEV_YAW_OUT_DQ Note, the cavity signal H1:ALS-Y_REFL_CTRL_OUT_DQ is calibrated in Hz. The ISI witness signals are calibrated in nm. The calibration of the optical levers is unknown. The measured transfer function was scaled by multiplying it by 7.0982e-12 [m/Hz] / 1e-9 [nm/m] = 0.0070982 [m^2 / (nm Hz)] The 7.0982e-12 [m/Hz] comes from lambda*L/c where lambda = (1064e-9 / 2) [m], for the green light wavelength L = 4000 [m], for the arm length c = 299792458 [m/s], for the speed of light
Brett and Jeff Summary: I have managed to account for the missing 1.5 factor by adding in the pitch to cavity transfer functions. See the first attached figure. The black curve is the model of the SUS point longitudinal to cavity. The red curve is the same measurement of the SUS point witness sensor (H1:SUS-ETMY_M0_ISIWIT_L_DQ) to cavity (H1:ALS-Y_REFL_CTRL_OUT_DQ) transfer function measured in log 7214. Thus, the same factor of 1.5 exists between these curves. It turns out that the cavity also has a lot of coherence in the same frequency band from the SUS point pitch witness sensor (H1:SUS-ETMY_M0_ISIWIT_P_DQ). So, I followed the assumption that I could account for the missing factor by simply measuring the pitch to cavity transfer function, converting it to length coordinates, and adding it to the longitudinal transfer function. The blue curve is this transfer function converted to length units. The conversion from rotation to length units was done using the measured transfer function from the pitch SUS point witness to the length SUS point witness. The magenta curve is the coherent sum of the two transfer functions. This magenta transfer function agrees much better with the model. Details: What I hadn't taken into account before is that the measured transfer functions between the ISI and cavity are passive. Thus, there are 6 simultaneous excitations influencing the cavity through ETMY which are the 6 DOFs of STG2 of the ETMY ISI. It turns out that 2 of these excitations are coherent to the cavity as well as themselves. The two are the ISI pitch witness and the ISI longitudinal witness. The argument justifying/explaining why one must sum the pitch and long witness to cavity transfer functions in order to agree with the modeled SUS point long to cavity transfer function is intended to be explained in detail in a future document. It will be summarized briefly here. Since the witness long and pitch TFs have good coherence in a band around 1 Hz, (where the measurement needed help matching the model), the long and pitch displacement can be thought of as transformed versions of the same noise. Fundamentally, the noise must be thought of together as a single long-pitch source (analogous to how SUS long and pitch modes are really long-pitch modes), rather than thinking of them separately. The relation projecting the long-pitch seismic motion into long and pitch components is determined by the coherent transfer function between long and pitch. To get the right measurement to match the model, we must find the transfer function between the long-pitch seismic source and the cavity signal. Since none of our measurements directly measure this long-pitch source, we must effectively recreate is with the measured transfer functions from its components. Those transfer function components are then summed coherently as described in the summary above and in the attached plot.
It seems that during these measurements, the ETMY ISI was indeed only damped while the ITMY ISI was isolated. This is evident given the large discrepancy in measured ISI WIT L and P ASDs between the two ISIs. See the attached figure. This data is collected in the DTT file /ligo/svncommon/SusSVN/sus/trunk/QUAD/H1/ETMY/Common/Data/2013-07-23_CavityASDMeasurements.xml and exported in the file /ligo/svncommon/SusSVN/sus/trunk/QUAD/H1/ETMY/Common/Data/2013-07-23_CavityASDMeasurements_Export The exported data is exported in the following order: 1. H1:ALS-Y_REFL_CTRL_OUT_DQ 2. H1:SUS-ETMY_M0_ISIWIT_L_DQ 3. H1:SUS-ETMY_M0_ISIWIT_T_DQ 4. H1:SUS-ETMY_M0_ISIWIT_V_DQ 5. H1:SUS-ETMY_M0_ISIWIT_R_DQ 6. H1:SUS-ETMY_M0_ISIWIT_P_DQ 7. H1:SUS-ETMY_M0_ISIWIT_Y_DQ 8. H1:SUS-ETMY_L3_OPLEV_PIT_OUT_DQ 9. H1:SUS-ETMY_L3_OPLEV_YAW_OUT_DQ 10. H1:SUS-ETMY_MASTER_OUT_F1_DQ 11. H1:SUS-ETMY_MASTER_OUT_F2_DQ 12. H1:SUS-ETMY_MASTER_OUT_F3_DQ 13. H1:SUS-ETMY_MASTER_OUT_LF_DQ 14. H1:SUS-ETMY_MASTER_OUT_RT_DQ 15. H1:SUS-ETMY_MASTER_OUT_SD_DQ 16. H1:SUS-ITMY_M0_ISIWIT_L_DQ 17. H1:SUS-ITMY_M0_ISIWIT_T_DQ 18. H1:SUS-ITMY_M0_ISIWIT_V_DQ 19. H1:SUS-ITMY_M0_ISIWIT_R_DQ 20. H1:SUS-ITMY_M0_ISIWIT_P_DQ 21. H1:SUS-ITMY_M0_ISIWIT_Y_DQ 22. H1:SUS-ITMY_L3_OPLEV_PIT_OUT_DQ 23. H1:SUS-ITMY_L3_OPLEV_YAW_OUT_DQ 24. H1:SUS-ITMY_MASTER_OUT_F1_DQ 25. H1:SUS-ITMY_MASTER_OUT_F2_DQ 26. H1:SUS-ITMY_MASTER_OUT_F3_DQ 27. H1:SUS-ITMY_MASTER_OUT_LF_DQ 28. H1:SUS-ITMY_MASTER_OUT_RT_DQ 29. H1:SUS-ITMY_MASTER_OUT_SD_DQ Note, the cavity signal H1:ALS-Y_REFL_CTRL_OUT_DQ is calibrated in Hz. The ISI witness signals are calibrated in nm. The calibration of the optical levers is unknown. The MASTER_OUTs calibration is also unknown to me. The fist column of the exported data is the frequency vector. Each exported channel then follows in order, occupying the remaining columns. The transfer function export in 7214 above follows a similar pattern, except that each channel occupies two columns. The first is the real part of the transfer function data, the second is the complex part.
After doing some modeling in MATLAB, the analysis in 7236 stating that it is necessary to consider both the pitch and longitudinal seismic noise in the transfer function to the cavity looks to be incorrect. The transfer function between the longitudinal ISI witness sensor and the cavity motion should indeed replicate the quad MATLAB model transfer function between the suspension point and test mass L DOF. Thus, it appears there is a calibration error of 2 in measured transfer function.
Mitchell Robinson, Scott Shankle, Apollo's Randy and Scott - The Baffle assembly has been completed. The Bracket Shim is in place. The Ring has been assembled, installed and aligned in the spool. The Spring Blades are attached to the Top Ring. The baffle is ready to lift and install!
Justin B. covered from ~ 9 - 10:30 08:30 HFD onsite flushing hydrant lines 08:50 Jim B. to end X to swap Dolphin cables on SUS, SEI and ISC 09:27 Mark B./Arnaud P. restarting the BS model 09:31 Terra H. moving clean room @ HAM 4 to facilitate running cables 09:48 Mayflower Metals here to see Ski 09:57 Dave B. power cycling SUSB123 (ETMY & BS) 10:30 Justin B. to H2 PSL enclosure to help PCAL 11:11 HFD done work 12:20 Pablo D. left H2 PSL enclosure 12:22 Richard M. to LVEA to help students with equipment 12:30 Fires spotted off in the distance past end X 12:47 Richard M. out of LVEA 12:55 Filiberto C. climbing on HAM 2 to pull accelerometer cables 14:00 Filiberto C. done 14:43 Pablo D. to H2 PSL enclosure
There is some instability in the ALS system which drives the IFO Y arm out of lock in a matter of just a few hours, causing the ETMY HEPI to saturate before quickly breaking lock. This is a very low frequency PDH noise source, with a period varying from one to four hours. This long term issue has occurred for all locking periods of substantial length (greater than two hours in length) that I have seen over the last month. Both time ranges with HEPI displacement and VCO frequency are shown in the first two plots attached, and the entire locking period is shown; the lock is lost at the right edge of the plots. In the last plot I include instead the calibrated signal for Y-end green laser frequency, and plot the mean. We have checked and ruled out the following as the main source of the unstable displacement noise: - checked the HEPI calibration (Hugh and Vincent measured driven HEPI displacement on ITMY) - tidal strain (the discrepancy between HEPI offset and tidal strain is what caused the instability to be discovered) Possible causes we have not ruled out: - control systems instability - unexpected PSL frequency variation - most likely to reference cavity temperature fluctuation - excess VCO noise Addressing the first hypothesis, I've started to model the PDH slow and fast loop transfer functions to attempt to find their crossover frequency and determine whether this might correspond to the instability. Without a detailed HEPI transfer function, this is not exact, but any crossover frequency looks to be close to 1 Hz, much higher than the instability, so this would appear not to be the most likely cause, as far as crossover instability is concerned, barring an error in the model. Addressing the second hypothesis, I am comparing HEPI offset and green laser frequency with PSL reference cavity frequency to see if the excess noise is introduced by the PLL as opposed to PDH loops, and looking at the third attached plot this seems to be highly likely. I am computing power spectra for each of these signals to comfirm/reject this hypothesis. So far it does look promising, especially considering the fact that reference cavity temperature was used previously to offload tidal displacement, and thus should have a large effect on the ALS arm stabilization. The third hypothesis is not currently being investigated as it seems less likely than the second, but should be accounted for at some point regardless.
Upon Jeff's recommendation I made a new set of blend filters for HAM-ISI that feature:
I installed those filters on HAM3-ISI and compared the isolation performance with what we had before. Plots are attached.
The new set of blend filters help us meeting the requirements below 1Hz, while still keeping motion within requirements above.
Those blend filters are currently installed in the filter bank 9, as "R_eLigo"
The Script I made to create those blend filters is commited under the the SVN (r7461): /svn/seismic/HAM-ISI/Common/Blend_filters/makeHAMISIBlendFilters_Hybrid.m
The resulting set of filters is commited under the SVN (r7462): /svn/seismic/HAM-ISI/Common/Blend_filters/Filters_HAMISI_Blend_Hybrid_24_Jul_2013.mat
What follows are the VxWorks version and boot parameters for all of the vacuum VME crates as of 24Jul2013. This is for posterity/future reference if needed. -- h0vemr: VxWorks (for Motorola MVME162LX) version 5.2. Kernel: WIND version 2.4. Made on Fri Apr 2 10:48:41 PST 1999. Boot line: ei(0,0)hanford1:/opt/CDS/b/vw/5.2/config/mv162-333-8M/vxWorks e=10.1.0.63:ffff0000 h=10.1.0.2 u=barker tn=h0vemr s=/cvs/cds/lho/target/h0vemr/startup.cmd value = 165 = 0xa5 h0vemr > -- h0velx: VxWorks (for Motorola MVME162LX) version 5.2. Kernel: WIND version 2.4. Made on Fri Aug 18 15:16:20 PDT 2000. Boot line: ei(0,0)hanford1:/opt/CDS/b/vw/5.2/config/mv162-262-16M/vxWorks e=10.1.0.62:ffff0000 h=10.1.0.2 u=barker tn=h0velx s=/cvs/cds/lho/target/h0velx/startup.cmd value = 166 = 0xa6 h0velx > --h0vemx: VxWorks (for Motorola MVME162LX) version 5.2. Kernel: WIND version 2.4. Made on Fri Aug 18 15:16:20 PDT 2000. Boot line: ei(0,0)hanford1:/opt/CDS/b/vw/5.2/config/mv162-262-16M/vxWorks e=10.1.0.61:ffff0000 h=10.1.0.2 u=barker tn=h0vemx s=/cvs/cds/lho/target/h0vemx/startup.cmd value = 166 = 0xa6 h0vemx > --h0veex: VxWorks (for Motorola MVME162LX) version 5.2. Kernel: WIND version 2.4. Made on Fri Aug 18 15:16:20 PDT 2000. Boot line: ei(0,0)hanford1:/opt/CDS/b/vw/5.2/config/mv162-262-16M/vxWorks e=10.1.0.60:ffff0000 h=10.1.0.2 u=barker tn=h0veex s=/cvs/cds/lho/target/h0veex/startup.cmd value = 166 = 0xa6 h0veex > --h0vely: VxWorks (for Motorola MVME162LX) version 5.2. Kernel: WIND version 2.4. Made on Fri Aug 18 15:16:20 PDT 2000. Boot line: ei(0,0)hanford1:/opt/CDS/b/vw/5.2/config/mv162-262-16M/vxWorks e=10.1.0.64:ffff0000 h=10.1.0.2 u=barker tn=h0vely s=/cvs/cds/lho/target/h0vely/startup.cmd value = 166 = 0xa6 h0vely > --h0vemy: VxWorks (for Motorola MVME162LX) version 5.2. Kernel: WIND version 2.4. Made on Fri Aug 18 15:16:20 PDT 2000. Boot line: ei(0,0)hanford1:/opt/CDS/b/vw/5.2/config/mv162-262-16M/vxWorks e=10.1.0.65:ffff0000 h=10.1.0.2 u=barker tn=h0vemy s=/cvs/cds/lho/target/h0vemy/startup.cmd value = 166 = 0xa6 h0vemy > --h0veey: VxWorks (for Motorola MVME162LX) version 5.2. Kernel: WIND version 2.4. Made on Fri Aug 18 15:16:20 PDT 2000. Boot line: ei(0,0)hanford1:/opt/CDS/b/vw/5.2/config/mv162-262-16M/vxWorks e=10.1.0.66:ffff0000 h=10.1.0.2 u=barker tn=h0veey s=/cvs/cds/lho/target/h0veey/startup.cmd value = 166 = 0xa6 h0veey >
[Alexa and Kiwamu]
We became unable to lock the reference cavity this morning. The autolocker wasn't capturing a fringe. After some investigation and fiddling some parameters it started locking.
There was an oscillation which seemed preventing the FSS from a stable lock. In the end the oscillation somehow went away.
After the oscillation went away I temporarily increased the common gain to 30 dB which is the maximum. The oscillation didn't happen. I set it back to 27 dB.
Mark, Arnaud, Dave
We power cycled h1susb123 and its IO Chassis as part of the BS noise investigation.
To correct IPC errors at EX, the h1susex, h1iscex, and h1seiex front-ends were powered off, the Dolphin cables were moved to the right side ports, and the computers restarted. Models started OK, IPC errors were cleared with diagnostic reset.
Yesterday, Gerardo bonded on the 1st prism to the LLO destined PUM. He used the new procedure which incorporateed adding borosilicate glass beads to space the glue joint more appropriately. He intends to proceed today with gluing in the magnet/flag discs and then the 2nd prism today/tomorrow.
Late last week, the discs and second prism were glued. The second prism glue joint did not cure with glue across the entire surface. Work continues at CIT/LHO to investigate why and revise procedures. After the optic was airbaked for additional cure as per the existing procedure, and no further change was noticed, it was decided to ship the PUM to LLO. It should arrive at LLO by Wed July 31st. LLO can proceed with using this PUM in the L1-ETMx monolithic assembly.
After much anticipation, we finally receive a pair of bought Ag-coated mirrors from Newport. Within seconds we were able to tell these guys were much better ("order(s) of magnitude better", says Keita) than any other TMS mirrors used for LIGO.
One of them only had a few "spots" which could be seen from the front with light behind it. And this one had no "cloudiness" observed with many other mirrors. The second mirror had minor cloudiness (but they "cleared up"?), and this one had virtually NO holes in it.
Both were cleaned and we took out to EX TMS Lab. We removed the Alignment mirror serving as an F1 Mirror and upon installing the new Newport mirror, Keita noticed that these mirrors are thinner (!). They are probably a couple millimeters thinner than the original mirrors. We were able to accomodate the mirrors by screwing the pitch/yaw actuators out a little more. New mirror was installed and this is where we stopped for the day.
Attached to this entry are a sample of photos.
"Orders of magnitude" is a serious comment.
You can see many tiny spot defects on the new mirror because it's without other terrible things.
As far as the number of coating holes per area is concerned, the new one (Newport) is roughly three orders of magnitude better than the best Edmund mirror (picture) and the alignment mirror (picture).
No systemic scratch (VS something like this bad Edmund).
A very faint bluish color was found in the new mirror but it's much much better than Edmunds.
Mitchell Robinson, Scott Shankle, Thomas Vo - Arm Cavity Baffle Suspension Assembly is complete and ready to suspend. Baffle Box assembly is in process. ----------------------------------------------- Mitchell Robinson, Scott Shankle, Apollo's Randy and Scott - All participants reviewed the Installation Procedure and the Hazard Analysis. The Manifold Cryopump Baffle was brought down from the Balancing Fixture. The Flange Protectors and Baffle Alignment Tooling were attached to the spool. Yet, this baffle continues to be a complete pain in the derriere - the newly fabricated Spacer/Shim's holes are too small. Team will be looking into the feasibility of a clean modification. ----------------------------------
For the DetCharians: as of 1058670016 July 23 2013 20:00 PDT Jul 24 2013 03:00:00 UTC we are leaving the IFO in the following configuration: Input Mode Cleaner: LOCKED (offload to MC2 stages M2 and M2 only, under slow WFS control) Green Arm: LOCKED (no offload to HEPI) HAM2 & HAM3 HEPI: Floating, with offsets, but no control HAM2 & HAM3 ISI: Level 2 isolated All HSTS SUS: Level 1.5 "resg" damping filters filter PR3: Level 1.0 damping filters ITM HEPI: Locked ITM ISI: Level 2 isolated ITM QUAD: Level 2.1 damped BS HEPI: Level 2 isolated BS ISI: Level 2 isolated, but had to diable GS13 watchdogs while isolating to get it up and running BS Triple: Level 2.0 damping filters ETM HEPI: Level 2 isolated ETM ISI: Level 2 isolated ETM QUAD: Level 2.1 damped May it stay locked all night! The calibrated channel for green is H1:ALS-Y_REFL_CTRL_OUT_DQ, in [Hz] (so multiply by lambda*(L/c) to get [m]) The calibrated channels for the IMC are IMC_L = H1:IMC-X_DQ in [m] IMC_F = H1:IMC-F_OUT_DQ in [m]
Note, I missed Vincent's comment about turning on the ST0 to ST1 feed forward in his BSC-ISI and BSC-HPI instruction manual, so none of the BSC-ISIs had their ST0-ST1 FF on for this lock stretch. (This may explain the difficulty behind getting ISI-BS up and running).
The dust monitors in the LVEA are NOT currently being recorded. It appears swapping the dust monitor in the H1 PSL enclosure has broken the communications.
Upon startup the IOC communicates correctly with each dust monitor until it gets to location 16 (the one that was swapped yesterday). After this it starts reporting back errors of the form: Error: ../commands.c: 49: Sent command � not echoed Received ?
I powercycled the Comtrol this morning. It worked after location 16 for a little while, but the error has returned.
Robert says he swapped the dust monitor in the H1 PSL laser enclosure. First one dust monitor was disconnected from the breakout box outside the entire H1 PSL enclosure. If I recall correctly, the dust monitor at location 16 was then still found by the IOC. The communication errors persisted. The first dust monitor was plugged back in and the other one disconnected. The IOC still found the dust monitor at location 16, but the communication errors went away. The dust monitor at location 16 reported calibration errors. It may be that the wrong dust monitor was swapped, leading to two set at the same location number, but this would not explain why the communication errors persisted after the first one was disconnected. As it stands, one of the dust monitors in the H1 PSL enclosure is disconnected. The dust monitor at location 16 is reporting calibration errors. I am not sure where the dust monitor at location 16 is. The dust monitor at location 10 is not found by the IOC. The remainder of the dust monitors in the LVEA are running again.
Sheila swapped the dust monitor in the anteroom with one programmed at location 10. The one she removed from the anteroom is labeled 'H'. It had no charge left in the battery when I got it. There was no change in the status. The dust monitor at location 10 is still unseen, and the dust monitor at location 16 is still giving calibration errors. This leads me to believe that: The dust monitor at location 16 is in the laser room and has calibration errors. The dust monitor at location 10 is in the anteroom and is unplugged at the breakout box outside the enclosure.