Because finding the statistical uncertainty in a transfer function data point, as a function of its coherence and how many averages were taken, comes up just about every few years (e.g. the last time I saw it was in the LLO eLOG), here it is quoted in the aLOG for the next generation: Relative uncertainty in transfer function magnitude: d|TF| 1 - C ----- = sqrt ( ------- ) |TF| 2 C N where C is the coherence, and N is the number of averages. Absolute uncertainty in transfer function phase: 1 - C d <(TF) = sqrt ( ------- ) [rad] 2 C N where C is the coherence, and N is the number of averages, and is in units of radians. Ref: Bendat and Piersol, "Random Data" 2nd Ed, p317.
I exited the LVEA about 1635 pst. I've got the two Actuators on Corner3 (SE) connected. Three corners to go. HEPI is unlocked.
Results of todays look at the suspended optic: Longitudinal using the same corner cube to optic offset as measured on the test stand (454.3mm) added to the EDM shot = 5629.3mm, desired distance 5629.8, error o.50mm. Tolereance of +/- 3mm Latitude desired tolerance (beamline) +/- 1.0mm, measurement 1.4051mm Error correction .4051mm minimum. Needs to move south direction. Vertical desired tolerance beamline +/- 1.0 mm, measurement -1.1054mm. Error .1054 mm minimum. Needs to move up. Pitch: desired 639 urad up +/- 100urads. Error 275urads (angle set at 89deg, 57', 48" = 0urads) optic needs to pitch down.I used an iris to prevent AR side clipping Yaw: desired 270deg +/- 100urads. Error 1.0 mrads urads. ISI/SUS needs to rotate ccw Looks like some HEPI tweaks are next and another round of measurements
7:30-12:25 Heading to Mid Y - Jodi 8:05 --> PSL Check List (OK) 8:25 --> Ace portable toilets on site for maintenance 8:52-9:20 Working at End X – Aaron 9:20-12:00 Heading to End Y (chassis installation) – Aaron 9:31-12:30 Going to End Y (Cleaning/Organizing) - Karen 9:48-10:29 Performing work on GV-6(PT-124) in LVEA - Kyle 10:12-11:00 Going to End X to do HEPI work – Hugh 10:00-10:15 CDs work(reverted h1 susitmy model back to original/h1 iscey model rebuilt and restarted) - Dave 10:15-12:06 Running cables by BSC2/BSC3 (LVEA) - Filiberto 11:04-11:39 Doing measurements at End X - Keita 11:10-12:30 ITMs work (LVEA)- Betsy/Travis 11:31--> LN2 delivery to CP6 (Mid X) – Praxiar 11:36--> Vendor delivery on site (Water) 13:01- HEPI work on HAM4 – Hugh 13:19- Back to Mid Y – Jodi 13:26- Going to End Y to work on illuminator – Filiberto 13:47-16:00 Heading to End Y (electronics testing) - Jax 14:59- LVEA transitioned to Laser Hazard
Dave B., Patrick T. 122,128 channels are now monitored. The list is in /ligo/lho/data/conlog/h1/output_pv_list/monitored_pv_list_2014mar04-14_44.txt.
Fil, Thomas Since it was Tuesday maintenance day, I thought it would be a good time to try to improve/fix the ITM optical levers: - The sign conventions for positive and negative directions now fully match suspension bias sliders. This solves the negative sign difference in Keita's ALOG-10331 between the OpLev and his coordinate system. I will plan on doing this for the ETMs as well, but with the new damping loops that are initiated on the lower stage, I'm going to talk to Stefan before making a change. - Arnaud's ALOG-10426 pointed out that the noise floor at high frequency (above 100Hz) for ITMY was different from ITMX and ETMX by two orders of magnitude. I let him know that the main difference in electronics is the whitening/anti-whitening chain not being activated for ITMY because we don't have enough binary daughter boards for all the optical levers on site (they are being ordered by Mohana). Since we are in need of this optical lever to be in its final configuration, Fil created a jumper plug to recreate the daughter boards to activate two levels of whitening to make all test mass OptLevs match. Figure 1 shows that improvement of the noise floor of ITMY so that it's even better than ITMX now. Figure 2 shows that we did activate 2 levels of 1:10 whitening.
Today's restarts tested my new model restart logger. Here are the contents of the file /opt/rtcds/lho/h1/data/startlog/2014/03/04/2014_03_04_model_start.log
2014_03_04 09:53 h1susitmy
2014_03_04 09:58 h1iscey
2014_03_04 11:46 h1isibs
2014_03_04 12:24 h1isiitmy
2014_03_04 12:25 h1isietmy
2014_03_04 12:44 h1lsc
2014_03_04 12:47 h1pemmx
2014_03_04 12:54 h1isiitmx
2014_03_04 13:10 h1isietmx
13:11PST performed DAQ restart. Was not a clean restart, the following frontends required a restart of their mx data stream: susauxex, susex, pemmx, susauxey, iscey, sush2b, sush56, susauxb123, susauxh34, susauxh56. As normal, h1psl DAQ flags went red/green during these resyncs.
DAQ restart was needed due to new models on: h1susitmy, h1iscey, h1isibs, h1isiitmy, hisietmx, h1lsc, h1isiitmx, h1isietmx.
DMT broadcaster was reconfigured to add one new channel: H1:PSL-PERISCOPE_A_DC_POWERMON
h1broadcaster was very slow to come back from the DAQ restart. We manually restarted it and it eventually started. No errors were seen to explain this.
The models (master and local models), scripts and MEDM screens have been updated to support new changes made by the Stanford crew (see update list DCC T1400012).
Everything went well and has been committed.
J. Kissel, A. Pele Following the same procedure outlined in LHO aLOGs 9453 and 9079, Arnaud and I balanced the coils on the PUM stage of H1 SUS ETMX. The final balanced gains in the L2_COILOUTF bank are H1 SUS ETMX Channel Balanced COILOUTF Gain L2 UL +1.034 L2 LL -1.014 L2 UR -0.986 L2 LR +0.966 The precision to which we could balance the coils was limited by the day-time ground motion (we saw an almost instantaneous loss in SNR once the day-time 1-10 [Hz] noise increased around 8:30a PT), but we believe the obtained values are good to within +/- 0.5%. This balancing has reduced the L3 P and Y caused by a L2 pringle excitation at 4 [Hz] by DOF Reduction Factor @ 4.0 [Hz] P > 6.0 (peak below the noise, and totally incoherent) Y > 7.3 (peak below the noise, and only ~60% coherent) The first attachment shows the result from which these values were obtained, comparing the optical lever ASD at 4 [Hz] driven from L2 at the same amplitude for both balanced and unbalanced configurations.
Measurement Details ------------------- Coil Driver Configuration: State = -2, with all COILOUTF compensation filters turned off This is the configuration which gets the most drive to the coils, given that the analog driver in this "acquire" configuration has [z:p] = [1.35:80.5], see LLO aLOG 4495). Demodulator filters used: SIG band pass: BP4.0Hz = butter("BandPass",2,3.5,4.0) DEMOD I & Q low-pass: CLP50mHz = cheby1("LowPass",2,3,0.05) Demodulator Drive Parameters Freq [Hz] Amp [ct] Sin [ct] Cos [ct] 4.0 125000 10000 10000 4.0 125000 10000 10000 Note -- we started off at 6 [Hz], but was not able to get enough SNR with a half-hour's worth of effort, so we moved down to 4 [Hz]. Again, we want to stay away from any suspension resonances that might complicate the signal, but get the frequency high-enough that we get lots of cycles inside the 50 [mHz] band pass. SEI Configuration: HPI: Level 1 Isolation, "Pos" position sensor only blend filters ST1: Level 3 Isolation, "TCrappy" blend filters (in all DOFs) ST2: Level 3 Isolation, "TStart" blend filters (in all DOFs) Note -- we had started around 7:30a PT this morning, but the day-time ~1-10 [Hz] noise quickly started to create a lot of excess noise at our drive frequency. We played around with the ST2 blend configuration until we found something we'd liked. I'm not sure that it makes sense -- the TCrappy filters have a factor of 2e-4 displacement sensor isolation at 1 [Hz], where the TStart only has a factor of 0.3 -- but the SNR was clearly better with TStart on ST2. (see LHO aLOG 10408 for blend filter details). Resulting Demod Phases: Measured using a 300 second average of the demodulated signals, i.e. tdsavg 300 H1:SUS-ETMX_LKIN_P_DEMOD_I_OUT H1:SUS-ETMX_LKIN_P_DEMOD_Q_OUT H1:SUS-ETMX_LKIN_Y_DEMOD_I_OUT H1:SUS-ETMX_LKIN_Y_DEMOD_Q_OUT H1 ETMX L2 Demod Phase [deg] Unbalanced Value [ct] Balanced Value [ct] P 145 I +1.385 pm ~0.5 -0.12 pm ~0.75 Q -0.064 pm ~0.5 -0.08 pm ~0.75 Y 153 I +1.027 pm ~0.2 -0.09 pm ~0.25 Q 0.054 pm ~0.2 0.08 pm ~0.25 To perturb the PIT or YAW balancing by 1%: /ligo/svncommon/SusSVN/sus/trunk/Common/PythonTools/perturbcoilbalance_fourosem.py H1 ETMX L2 [PIT/YAW] 0.01 Exact balanced values: Measured using a simple command line caget, i.e. caget H1:SUS-ETMX_L2_COILOUTF_UL_GAIN H1:SUS-ETMX_L2_COILOUTF_LL_GAIN H1:SUS-ETMX_L2_COILOUTF_UR_GAIN H1:SUS-ETMX_L2_COILOUTF_LR_GAIN H1 ETMX L2 Coil COILOUTF Gain UL 1.03422 LL -1.01374 UR -0.98575 LR 0.96623 Of course, these values are set at arbitrary precession, they're rounded to the above quoted precession (a) because the measurement uncertainty is no better than 0.5%, and (b) the MEDM screen does not display out to higher precession, so further precision would not be visible.
I checked the amount of fluid that has oozed from the H1 ETMX H2 Parker valve since 25 Feb. It is maybe a couple teaspoons so we are safe for a few weeks before I need to clean it up again.
As part of WP4476 I rebuilt, installed and restarted h1iscey. Its safe.snap showed no "cannot connect" errors, but it is out of date and has only about 50% of the channels defined.
The new autoBurt.req has 15,666 entries. The safe.snap has 7,095 and the latest hourly autoburt has 8,520. So I'll keep it with the safe.snap restoration for now.
WP closeout waiting for DAQ restart and safe.snap update.
h1susitmy has been running a special HWWD test version built against RCG trunk since Jan 9th and did not get upgraded to RCG2.8.3 last Tuesday. Today I reverted the h1susitmy.mdl file back to the original code, compiled against 2.8.3 and restarted the model. The safe.snap is out of date, 673 PVs are not connecting. I burt restored the system to 9am today (local time).
Waiting on a DAC restart to close out WP 4475
Since the h1fw1 system has been stable for several days, the default NDS server has been changed back to h1nds1. This should only affect new logins or new processes started from new shells or by opening desktop icons.
The HAM-ISI BLEND_SWITCH_ALL screen wasn't working properly at LHO: it was impossible to switch all the blends at once (white screen).
This issue has been fixed by the Stanford crew (see Hugo's SEI log: https://alog.ligo-la.caltech.edu/SEI/index.php?callRep=391)
I've 'svn up' and everything works fine now.
Attached is the 18 hours trend of the X arm WFS from last night. Seems like it's doing something sensible. Happy periods are indicated by pink arrows at the bottom left.
I calibrated PRM actuation transfer function measured in alog #10450.
Measured PRY error signal is smaller by factor of 2 from the calculation and suspension model. This means that demodulation phase is off by 60 deg, or PRY modematch(including misalignment) is 50%, or suspension model is off by factor of 2 (or combination of all of them).
[Motivation]
We wanted to check the PRCL loop signal chain (We have done this for MICH loop already; see alog #10213).
Also, we need calibrated actuation TF for designing the compensation filter which does not saturate DAC.
[Method]
1. Made PRY simulink model (It lives in /ligo/svncommon/NbSVN/aligonoisebudget/trunk/PRMI/H1
).
2. Change optical gain from PRM motion to REFLAIR_A_RF45_I to match the measured OLTF (which was measured in alog #10450).
3. Use this optical gain to calibrate PRM actuation transfer function.
[Result]
1. OLTF_PRCL_1077847156.png: OLTF compared with model and measured. Flat gain is fitted in the model and this gives the optical gain. The measured optical gain was 1.3e3 W/m.
2. From the REFLAIR signal chain in alog #10213, calibration factor for REFLAIR_A_RF45_I_ERR in PRY is 3.4e11 counts/m.
3. ActTF_PRM_1077847156.png: Calibrated PRM actuation transfer function. Red curve is plotted using zpk from LISO fitting of the measured TF (alog #10450) and divided by 3.4e11 counts/m for calibration. Blue/Cyan curve is from the suspension model using /ligo/svncommon/SusSVN/sus/trunk/Common/MatlabTools/TripleModel_Production/generate_Triple_Model_Production.m
and calibrated using the numbers from ./MatlabTools/make_OSEM_filter_model.m
(or LIGO-T1000061). M3 and M2 crossover and measurement look healthy. Note that the overall gain of the measurement agrees with model just because we don't have independent measurement of the optical gain. Even so, crossover frequency doesn't change.
[Discussion on optical gain]
Theoretical expression for PDH signal is
dPmod/dL = 2*8*pi/lambda*Peff*J0(beta)*J1(beta)*(t1**2*r2)/(1-r1*r2)
With
Effective input power: Peff = 7.3 uW * 4 /Tprm**2 = 0.032 W (alog #10213; incident power on REFLAIR_A was 7.4uW when PRM and ITMY is misaligned)
Modulation depth beta=0.07 (alog #9395)
Amplitude reflectivity/transmissivity of PRM: t1 = sqrt(0.03)
Amplitude reflectivity of BS/ITMY compound: r2 = rBS*rBS*rITMY = 0.50
This gives dPmod/dL = 3.1e3 W/m (+/- ~10%). Here, Pmod is RF modulation amplitude of laser power, and dL is one-way length change of PRC, which equals to PRM motion. (Optickle gives 1.5e3 W/m since Optickle assumes demodulation gain of 1/2).
Even if I include the loss of the cable we measured(alog #10213), theoretical value is 2.5e3 W/m (= 3.1e3 W/m * 0.81), or 6.5e11 counts/m at I_ERR. This is factor of 2 larger than the measured.
Since theoretical value assumes perfect modematching and demodulation phase, actual value might be smaller. Also, note that measured optical gain is derived from the model which assumes that suspension model is acurate enough.
[How to solve this challenge]
- Calibrate BS actuation transfer function using simple Michelson, and compare it using the measurement done in PRY. This will be an independent measurement of PRY optical gain.
- Measure PRY modematching
From OLTF measurement in simple Michelson, we know that the BS suspension model is quite accurate (within ~10%; see alog #10127).
So, by comparing the actuation transfer function model and measurements done in PRY (alog #10450), we can estimate PRY optical gain independent of PRM suspension model.
Attached is the comparison of the measurement and model. This gives calibration factor for REFLAIR_A_RF45_I_ERR in PRY to be 4.3e11 counts/m.
This is different by factor of 1.3 from estimation using PRM.
This means that PRM suspension model is off by ~30% or calibration factor changed during BS measurement and PRM measurement. Still, 4.3e11 counts/m is significantly smaller than the theoretical value calculated above.
Note that BS changes PRY length by sqrt(2) * (BS longitudinal motion). Attached plot is counts (at H1:SUS-BS_M3_ISCINF_L_IN1) to PRY length change, not counts to BS longitudinal motion.