oli.patane@LIGO.ORG - posted 14:49, Thursday 27 June 2024 - last comment - 16:06, Thursday 27 June 2024(78709)
Lockloss
Erik, EJ, Dave:
Following the discovery that h1sush2a's DACs had been in FIFO-HIGH-QUARTER error since 9th April 2024, I have done a rewrite of cds_status_ioc.py to catch these errors and report them on the CDS overview. Future RCG releases will raise these errors to the DAC bit in the STATE_WORD.
I found that cds_status_ioc was quite out of date, and needed a rewrite rather than addition of a DAC status monitor.
The new code's features are:
Get the number of frontends from the IOP INI files in the current DAQ running configuration
Parse the IOP INI files for all of its input data; num FECs, DCU_IDs, Number of ADC per frontend, Number of DAC per frontend.
On each processing run, the ADC_STAT and DAC_STAT PVs are read. None critical bits are masked out, and if any critical bit is bad an error is displayed.
For ADC, critical bits are: ONLINE, CHAN_HOP
for DAC, critical bits are: ONLINE, FIFO_STAT, FIFO_EMPTY, FIFO_HIGHQUARTER, FIFO_FULL
The IOC updates its clock every second, and process the CDS system every 5 minutes (GPS modulo 300). I've added PVs to show processing time, total num of ADCs and total num of DACs in CDS.
Oli, Sheila, Jim, Camilla
We've been having trouble keeping the ALS X arm locked, so Oli put the request for the X arm guardian to "UNLOCKED" which means that it asks the PLL to lock and nothing else. We've been sitting here for 15 minutes and see that the PLL can't stay locked in this configuration where the ground motion doesn't matter and the laser should easily stay locked.
The second two attachments show how much the fiber beatnote depends on outdoor temperature, it is now varying by more than 20dBm, while last summer with similar temperature swings it would only vary by 4dBm. This year the problem seems to be coming and going, for about a week at a time the temperature dependence seems to go away.
We won't be able to lock the IFO while the PLL is not staying locked like this, this problem seems to be coming and going recently, so it may explain a lot of IFO downtime.
At 20:03 I noticed that the PLL hadn't unlocked in 25 minutes, so I tried relocking the ifo and was able to get through to where we stop using ALS
20:45 UTC NOMINAL_LOW_NOISE
20:48 UTC Observing
TJ, Sheila
We looked at the PLL logic. When we are in observing, the PLL is requested to be locked. We see times when the logic stops trying to lock it, with H1:ALS-X_FIBR_LOCK_ERROR_CODE = 262144 = 2^18.
Looking at the attached medm screen, counting the error codes starting with 0, the 18th one is beatnote strength. This checks out because the beatnote momentarily dipped below -10dBm at this time, and the limit is -10dBm. TJ looked and the Y arm limit is -20dBm, so TJ changed the X arm limit to match and accepted that in SDF.
There is still an issue with the fiber beatnote having this strong temperature dependence that needs investigation, but this will stop it from preventing locking when it is on the edge for now.
Thu Jun 27 10:10:45 2024 INFO: Fill completed in 10min 42secs
Jordan confirmed a good fill curbside.
Jennie W, Sheila
We want to do an OMC scan after unlocked today so we can estimate the mode-matching into the OMC with a hot OM2.
Set SRM, ITMX and ETMs to mis-aligned, IMC locked in guardian.
Ran DC centering loops 3 and 4 to centre on AS_A and AS_B QPDs, then ran OMC ASC to align into OMC_A and OMC_B QPDs. Waited for this to converge spots in centre of QPDs with current nominal QPD offsets.
Made sure that OMC guardian was paused then moved PZT2 slider to bottom of its range on ther OMC_Control screen and ran scan with template:
Did scan but sidebands are still on so can't do visibility measurement easily.
Ref 12-14 are today's scan measurements saved in /ligo/home/jennifer.wright/Documents/OMC_scan/2024_06_27_OMC_scan.xml.
Analysis ongoing.
See attached the spectra with identified peaks, corrected for the non-linearity of the PZT.
See also the fit to the double peak of the carrier 02 mode (can't distinguish the two peaks with the current OMC but a double peak fit still seems to work better than a single peak).
From the fitted height of the C02 and C20 we can estimate the mode-matching.
(0.11086 + 0.11086)/(0.11086 + 0.11086 + 3.13)
gives us 6.62 % mode-mismatch.
The fitted background light level when no modes are on the PDs was 9.13 e-3 mA (not quite the dark offset as labelled in the pdf) as light could still be scattering onto the DCPDs when the OMC is off-resonance.
The fitted halfwidth at half-maximum power is 0.330 MHz and the transverse mode spacing between horizontal and vertical is at most 0.195 MHz.
According to the design document (see table 20 of LIGO-T1500060-v1), this current OMC (001) has a half-width of 0.327 MHz and a transverse mode spacing between horizontal and vertical modes of 0.109 MHz.
This is consistent with the attached fit.
Analysis code is in OMCscan_nosidebands14.py and fit_two_peaks_no_sidebands14.py in /gitcommon/labutils/omc_scan/figures/2024-06-06 on the /dev branch (ie. it will not be on the workstation branch as this is the master branch).
06/27 16:03 Lockloss after calibration sweep was done and right as commissioning was started. Unknown cause
20:48 Observing
Calibration was run between 06/27 15:33 and 16:01 UTC
Calibration monitor screenshot
Broadband (2024/06/27 15:33 - 15:39 UTC)
File: /ligo/groups/cal/H1/measurements/PCALY2DARM_BB/PCALY2DARM_BB_20240627T153409Z.xml
Simulines (2024/06/27 15:39 - 16:01 UTC)
Files:
/ligo/groups/cal/H1/measurements/DARMOLG_SS/DARMOLG_SS_20240627T153950Z.hdf5
/ligo/groups/cal/H1/measurements/PCALY2DARM_SS/PCALY2DARM_SS_20240627T153950Z.hdf5
/ligo/groups/cal/H1/measurements/SUSETMX_L1_SS/SUSETMX_L1_SS/SUSETMX_L1_SS_20240627T153950Z.hdf5
/ligo/groups/cal/H1/measurements/SUSETMX_L2_SS/SUSETMX_L2_SS_20240627T153950Z.hdf5
/ligo/groups/cal/H1/measurements/SUSETMX_L3_SS/SUSETMX_L3_SS_20240627T153950Z.hdf5
15:32 UTC I took us out of Observing to run a calibration sweep and then we will be doing some commissioning.
TITLE: 06/27 Day Shift: 1430-2330 UTC (0730-1630 PST), all times posted in UTC
STATE of H1: Observing at 152Mpc
OUTGOING OPERATOR: Ryan C
CURRENT ENVIRONMENT:
SEI_ENV state: CALM
Wind: 4mph Gusts, 3mph 5min avg
Primary useism: 0.01 μm/s
Secondary useism: 0.08 μm/s
QUICK SUMMARY:
Observing at 155Mpc and have been Locked for almost 5 hours. We have commissioning today starting at 15:30UTC
TITLE: 06/27 Eve Shift: 2300-0800 UTC (1600-0100 PST), all times posted in UTC
STATE of H1: Lock Acquisition
INCOMING OPERATOR: Ryan C
CURRENT ENVIRONMENT:
SEI_ENV state: CALM
Wind: 7mph Gusts, 5mph 5min avg
Primary useism: 0.01 μm/s
Secondary useism: 0.06 μm/s
QUICK SUMMARY:
Another Lockloss
This Lockloss has some really interesting motion on the ETMS and ITMS for atleast about 2 minutes before the lockloss.
My heade was burried in my laptop at the time, but I don't know what I would have done had I looked up and seen DARM acting that strange.
And once again SUS-ETMY PI ESD Driver had sustained elevated activity up above 2000 - 3000. there were no verbal alarms about elevated PI's
I readjusted the H1:SQZ-SHG_FIBR_REJECTED_DC_POWER back down again.
Sitemap -> SQZ overview -> SQZT0 -> click half wave plate. seen here:
then opened the controller screen via the button.
then clicked on the correct Pico motor, then enabled it.
This allowed me to move the pico motors in the Up down and left right directions which move 2 differerent wave plates while watching the NDSCOPE to minimize the signal.
be sure to move the pico motor slowly, and dont request a move while it's yellow. I was told to click it & let it finish.
TITLE: 06/27 Eve Shift: 2300-0800 UTC (1600-0100 PST), all times posted in UTC
STATE of H1: Observing at 150Mpc
CURRENT ENVIRONMENT:
SEI_ENV state: CALM
Wind: 11mph Gusts, 8mph 5min avg
Primary useism: 0.02 μm/s
Secondary useism: 0.06 μm/s
QUICK SUMMARY:
Lockloss 4:42 UTC
I checked for a spike in the wind at the time and didn't see anything abnormal, low seismic activity at the time too. There was some PI ESD DRIVER motion that seemed mildly elevated, but earlier during that lock it had been higher.
Relocking was simple after an Initial_Alignment.
Observing reached by 6:13 UTC
TITLE: 06/26 Day Shift: 1430-2330 UTC (0730-1630 PST), all times posted in UTC
STATE of H1: Lock Acquisition
INCOMING OPERATOR: Tony
SHIFT SUMMARY: Currently relocking and at ENGAGE_SOFT_LOOPS. Two locklosses during my shift, and we had a good amount of trouble messing with ALSX during relocking this second time.
After thislast lockloss, I went to Initial alignment, and while trying to lock green arms I had the same issues with the beatnote frequency and so Sheila and I went to adjust the fiber polarization to get it back to the values that it seems are ideal for ALS-X_FIBR_LOCK_FIBER_POLARIZATIONPERCENT and ALS-X_FIBR_LOCK_FIBER_TRANSRIGHTPOL, the closer we got to the correct values for those two channels, the worse the beatnote would get. It seems like the ideal max splot for the ALSX beatnote is 8.8dB and we started with it around -20dB, but as we adjusted the fiber polarization, the beatnote went down to -30dB. Trying to then adjust the fiber polarization to maximize the beat note sent the two fiber polarizatoin channels the complete opposite direction that we wanted, so we went back and based our movements on those two channels to slightly improve those values, and changed the minimum beatnote value to be -20dB (tagging ops, needs to be accepted in sdf) instead of -10dB as a temporary fix for now to make sure that we don't get stuck in fault again like last night.
LOG:
14:30 Detector unlocked and at FIND_IR
- Initial alignment had been done by H1 Manager, but it had become stuck at the end at 10:46UTC and hadn't tried relocking again until 13:54UTC, and by that time it seems like the alignment had drifted because it couldn't lock
14:37 We started going through CHECK_MICH_FRINGES so I took us to DOWN and ran another initial alignment
14:52 Initial alignment done, relocking
15:41 NOMINAL_LOW_NOISE
15:47 Observing
16:04 Lockloss
16:29 Initial alignment complete, relocking
17:11 NOMINAL_LOW_NOISE
17:14 Observing
22:04 Lockloss
- Went to Initial alignment, had the same issues with the beatnote frequency and so Sheila and I went to adjust the fiber polarization to get it back to the values that it seems are ideal for ALS-X_FIBR_LOCK_FIBER_POLARIZATIONPERCENT and ALS-X_FIBR_LOCK_FIBER_TRANSRIGHTPOL, the closer we got to the correct values for those two channels, the worse the beatnote would get. It seems like the ideal max spot for the beatnote is 8.8dB and we started with it around -20dB, but as we adjusted the fiber polarization, the beatnote went down to -30dB. Trying to then adjust the fiber polarization to maximize the beat note sent the two fiber polarizatoin channels the complete opposite direction that we wanted, so we went back and based our movements on those two channels to slightly improve those values, and changed the minimum beatnote value to be -20dB instead of -10dB as a temporary fix for now to make sure that we don't get stuck in fault again like last night.
We are not directly measuring the amount of power in the correct polarization. Instead, we measure the power in the wrong polarization as well as the power exiting the fiber using a beam sampler. Unfortuately, the reflection of this beam sampler is stronlgy polarization dependent, so that the calculated percentage and power in the correct polarization is only valid when the polarization is adjusted correctly!
Instead of looking at these values, one should just maximize the beat note, or minimize the power in the wrong polarization.
TITLE: 06/26 Eve Shift: 2300-0800 UTC (1600-0100 PST), all times posted in UTC
STATE of H1: Lock Acquisition
OUTGOING OPERATOR: Oli
CURRENT ENVIRONMENT:
SEI_ENV state: CALM
Wind: 20mph Gusts, 16mph 5min avg
Primary useism: 0.03 μm/s
Secondary useism: 0.06 μm/s
QUICK SUMMARY:
Current SQZ issue is Pump Fiber rej port in HAM7 High, nominal 35E-3, align fiber pol in sqzt0
H1:SQZ-SHG_FIBR_REJECTED_DC_POWER = 0.312
I understand I should move the Pico motors before Inject Squeezing.
In the seiproc model we have some code that produces IFO basis ground motion channels i.e.: XARM_GND=ETMX_X_GND - ITMX_X_GND. There's X/Y arm and CARM and DARM channels. They've in for years, but I'm not sure that much has been done with them. While talking to Neil about some earthquake stuff, I realized we don't have blrms calculated for these IFO dof ground channels, something that might be really useful for earthquake or microseism studies.So, I've filed ECR E2400233, channels went in at LHO yesterday. I'll let Huyen know, but the seiproc model parts aren't common between the sites.
Built a second SHG with the PPKTP crystal from MIT, did a measurement on the conversion efficiency and fit for the single pass nonlinear conversion efficiency Enl = 0.0055W-1. The single pass measurement of the PPKTP crystal give a nonlinearity deff = 5.41 pm/V. Generally deff of PPKTP is quoted around 9.3pm/V (Table 5.1 of Georgia's thesis)
Measurement of the phase matching curve with input power of 60 mW shows a dip around 35 celcius. The temperature controller reads in kOhm and is converted into celcius via the Steinhart-Hart equation:
A1 = 0.003354016
B1 = 0.0002569850
C1 = 2.620131e-6
D1 = 6.383091e-8
R25 = 10000
R = R_meas / R25
T = ( 1 / (A1 + (B1 * np.log(R)) + (C1 * np.log(R)**2) + (D1 * np.log(R)**3) ) ) - 273.15
Phase matching curve is plotted by using Equation 3.14, 3.20 and Table 3.2 from Sheila's thesis. I have fitted the sinc curve with T0 = 34.9 and i_max = 11.79 , 18.00 and 32.00.
Mount Saint Helens for our currently used SHG: 76239
I found a single/double pass SHG study that was done for the Virgo squeezer by Leonardi et al. here https://iopscience.iop.org/article/10.1088/1555-6611/aad84d
Daniel pointed out that Eq.2 from this paper shows an "additional phase from the red/green dispersion in the rear mirror turn around path" in the double pass scheme. I've attached a couple plots as a function of arbituary x (this variable is related to delta T) at various phase mismatch delta phi. I think the phase mismatch between the red and the green in the double pass alone might explain most of the mountains we are seeing here (?). this might not be the answer to all the problems but it's a good place to start (Figure 7 also looks very interesting).
Maybe the mountains can be patched up if we have a capability of translating one of the mirrors.
Ryan C, M Robinson, R Kumar
Given below is the summary of work done in the triples lab in the last two months regarding assembly of A+ HRTS suspension for O5 (refer to alog 76635 which gives the details about the first assembly in March 2024- assembly s/n 02). We have assembled four new suspensions (assembly s/n 03, 08, 01, 11), which brings the total number of assembled (with BOSEMs) and characterized suspension in the lab to five. All five assembly till now has been for the FREESTANDING version (only the base differs- which is as per D1900287).
In this round of assembly and testing procedure of HRTS we have made two new improvements as listed below,
1. Class B PEEK wire install tool (top mass to PUM - as shown in the picture attached) - This new PEEK part has been designed by the RAL team after we had wire breaking issues in the first round of assembly. Using this new tool we can safely and quickly install the wires between top mass and PUM outside the cage on the optical bench.
2. Vibration Isolation set up as shown in view01 and view02 - While running transfer function measurements, the HRTS suspension was strongly coupling-in with the lab/building environment (ground vibrations, doors, HVAC etc). To partially isolate the SUS, we now have an optical bench (12in by 18in, Thorlabs Nexus Breadboard) sitting on a 1inch thick viton pads (placed at the four corners of the bench). Also, Chris fabricated a hard top transparent cover for us to protect against the turbulent air flow in the lab.
Cage S/N 03 (April 2024)
Suspended masses (as per specifications):-
Top Mass = 749gm, Penultimate mass = 803gm, Dummy optic = 300gm
| BOSEM S/N | OLC | offsets (-OLC/2) | Gain (30,000/OLC) |
| S1900810 | 30629 | 15314.5 | 0.979464 |
| S1900795 | 31353 | 15676.5 | 0.956846 |
| S1900754 | 29884 | 14942 | 1.003882 |
| S1900809 | 24739 | 12369.5 | 1.21266 |
| S1900782 | 23231 | 11615.5 | 1.291378 |
| S1900626 | 30032 | 15016 | 0.998934 |
Transfer function measurements for HRTS assembly S/N 03 is attached here.
Cage S/N 08 (April 2024)
Suspended masses (as per specifications):-
Top Mass = 755gm, Penultimate mass = 803gm, Dummy optic = 301gm
| BOSEM S/N | OLC | offsets (-OLC/2) | Gain (30,000/OLC) |
| S1900701 | 30772 | 15386 | 0.974912 |
| S1900716 | 31514 | 15757 | 0.951958 |
| S1900713 | 31407 | 15703.5 | 0.955201 |
| S1900705 | 23915 | 11957.5 | 1.254443 |
| S1900700 | 26432 | 13216 | 1.134988 |
| S1900712 | 31165 | 15582.5 | 0.962618 |
Transfer function measurements for HRTS assembly S/N 08 is attached here.
Cage S/N 01 (May 2024)
Suspended masses (as per specifications):-
Top Mass = 752gm, Penultimate mass = 804gm, Dummy optic = 300gm
| BOSEM S/N | OLC | offsets (-OLC/2) | Gain (30,000/OLC) |
| S1900646 | 28515 | 14257.5 | 1.052078 |
| S1900705 | 30408 | 15204 | 0.986582 |
| S1900612 | 32048 | 16024 | 0.936096 |
| S1900653 | 24963 | 12481.5 | 1.201779 |
| S1900669 | 23010 | 11505 | 1.303781 |
| S1900655 | 32286 | 16143 | 0.929195 |
Transfer function measurements for HRTS assembly S/N 01 is attached here.
Cage S/N 11 (May 2024)
Suspended masses (as per specifications):-
Top Mass = 750gm, Penultimate mass = 803gm, Dummy optic = 301gm
| BOSEM S/N | OLC | offsets (-OLC/2) | Gain (30,000/OLC) |
| S1900645 | 25810 | 12905 | 1.16234 |
| S1900649 | 29934 | 14967 | 1.002205 |
| S1900683 | 31808 | 15904 | 0.943159 |
| S1900629 | 27963 | 13981.5 | 1.072846 |
| S1900689 | 23763 | 11881.5 | 1.262467 |
| S1900634 | 28063 | 14031.5 | 1.069023 |
Transfer function measurements for HRTS assembly S/N 11 is currently under processing and the latest plots will be attached soon.
Conclusions: - The transfer function measurements ties-up nicely to the model, however we do see some low frequency coupling and unwanted peaks. The cross coupling and unwanted peaks are due to environmental noise which is difficult to fully isolate in the lab.
I will also post a plot comparing the transfer function measurement results for all five suspension that we have tested.
Attached below are the transfer function measurement results for Freestanding suspension SN_11. I see some strong cross coupling in Vertical dof, possible combing from R dof.
Some sort of sudden ground motion
23:04 Observing