Displaying reports 71001-71020 of 84443.Go to page Start 3547 3548 3549 3550 3551 3552 3553 3554 3555 End
Reports until 08:34, Tuesday 09 September 2014
H1 PSL (PSL)
peter.king@LIGO.ORG - posted 08:34, Tuesday 09 September 2014 (13826)
PSL Diagnostic Breadboard Scan
During the relative power noise measurement, the output of the photodiode was 9.715 V - 9.725 V, or a photocurrent of 49 mA.  The measurement is close to the reference measurement.  A little better above 3 kHz and below 10 Hz.  A little worse in most places elsewhere.  In all places much better than the laser requirement.

The frequency noise measurement was done with the common gain set at 30 dB and the fast gain at 15 dB.  The error signal displays a step function behaviour from 2 Hz to about 20 Hz.  This was evident in the previous two scans performed.  We know that the frequency servo needs some maintenance, as the unity gain frequency was previously measured to be around 200 kHz.  The reference cavity transmission was about 1.84 V when this measurement was performed.

Nothing out of the ordinary for the beam pointing measurement.

During the mode scan measurement the following messages were displayed.
[========================                          ]  48%  5m12s / 10m00sNo significant mode found! The roundtrip gouy phase might be wrong.
[========================                          ]  48%  5m10s / 10m00sNo significant mode found! The roundtrip gouy phase might be wrong.
[========================                          ]  49%  5m08s / 10m00sNo significant mode found! The roundtrip gouy phase might be wrong.
[=========================                         ]  49%  5m06s / 10m00sNo significant mode found! The roundtrip gouy phase might be wrong.
[=========================                         ]  49%  5m04s / 10m00sNo significant mode found! The roundtrip gouy phase might be wrong.
[=========================                         ]  50%  5m02s / 10m00sNo significant mode found! The roundtrip gouy phase might be wrong.
[=========================                         ]  50%  5m00s / 10m00sNo significant mode found! The roundtrip gouy phase might be wrong.
[=========================                         ]  50%  4m58s / 10m00sNo significant mode found! The roundtrip gouy phase might be wrong.
[=========================                         ]  51%  4m56s / 10m00sNo significant mode found! The roundtrip gouy phase might be wrong.
[==========================                        ]  51%  4m54s / 10m00sNo significant mode found! The roundtrip gouy phase might be wrong.
[==========================                        ]  51%  4m52s / 10m00sNo significant mode found! The roundtrip gouy phase might be wrong.
[==========================                        ]  52%  4m48s / 10m00sNo significant mode found! The roundtrip gouy phase might be wrong.
[==========================                        ]  52%  4m46s / 10m00sNo significant mode found! The roundtrip gouy phase might be wrong.
on during data acquisition.
Traceback (most recent call last):
  File "/opt/rtcds/userapps/trunk/psl/common/scripts/noisereport_v0_7/framebuilder.py", line 245, in get_online_data
    raise FramebuilderError()
FramebuilderError

Received 408 secs data, 214.7 MB.
Generated raw data pack "../../../../../../../../ligo/lho/data/psl/psl_noisereports/2014-09-09/dbb_msc-001.zip".
Generated report "../../../../../../../../ligo/lho/data/psl/psl_noisereports/2014-09-09/dbb_msc-001.pdf".

This is the first time I've seen such messages.  Doing a visual comparison between the modescan from today and last week's scan, there are no noticeably different peaks present in the normalized power vs. frequency plot.  The reported higher mode power is nominally the same at 4.5%, although the number of higher order modes counted is lower in this week's scan (53 vs. 58).  The relative misalignment reported for this week's scan is lower.

A repeat of the modescan measurement did not encounter the same problem(s).  The problem must have been related to something in the data acquisition system.  The second report generated didn't look all that different from the first report.

The ISS relative power noise measurement was done with the gain slider set to 10 dB and REFSIGNAL to -2.03 V.  The diffracted power is reported as ~9.5%.  The output AC levels of both photodiodes A and B is 2.03 V and 2.07 V respectively.  The offset slider is set to 4%.  The out of the loop measurement looks good.  Almost flat from ~1 kHz to 30 Hz.  The low frequency part of the spectrum is better than the reference measurement from about 40 Hz down.  The position plot at the end of the report looks like something is clipping.  We might want to look at this when we have an appropriate time.
Non-image files attached to this report
H1 ISC
kiwamu.izumi@LIGO.ORG - posted 02:49, Tuesday 09 September 2014 (13824)
Michelson contrast = 99.1 %

I measured the Michelson contrast in the daytime today. It was 99.1 %. No ring heater or CO2 lasers were engaged during the measurement.

I used ASAIR_A_LF to observe the DC light at the dark port.

H1 ISC
kiwamu.izumi@LIGO.ORG - posted 02:32, Tuesday 09 September 2014 - last comment - 13:41, Tuesday 09 September 2014(13822)
PRMI locked on sidebands

Lisa, Sheila, Alexa, Nic, Jamie, Kiwamu

We managed to lock the PRMI on the sidebands tonight. We estimated the servo gain settings from the gains in the carrier-locked condition. The lock was stable and lasted for more than 40 min.

Also, we saw an angular drift in pitch of PR3 when the carrier was locked. This behavior was consistently observed.

 

(Carrier lock)

We intensively worked on the carrier-locked PRMI in the daytime and we could repeatedly lock the PRMI on the carrier. The script which Alexa wrote is now interpreted in a guardian code by Sheila. It uses the variable finesse technique. The code is available but it is still a working progress. 

At about 3 pm local, we noticed that the motion in the Michelson was too large for us to keep locking the PRMI. At that time, Fil and Aaron were working around the beer garden, but this may not be a direct cause of the Michelson fluctuation because we did not see a significant improvement after they left. At this particular point, we could not keep closing the Michelson locking loop because of too large angular motion in the Michelson. This large motion gradually disappeared some time later and we could get back to the locking activity in the evening.

(PR3 tends to drfit in pitch)

When we locked the carrier-PRMI, we noticed that the power build-up degraded on a time scale of approximately 10 minutes or so. After some investigation, we identified it to be PR3 which drifted only in pitch by about 0.5 urad. We repeated the same observation a couple of times. PR3 always tends to drift to the negative side in the oplev counts. After a unlock event, it tends to go back to the original angle on a similar time scale. This indicates some kind of thermal issue. In fact, I did not observe a similar effect when the PRMI was locked on the sidebands. Sheila implemented an oplev servo on PR3 to mitigate the issue. In parallel, we should start working on some ASC loops.

Also, the BS oplev showed an approximately 0.5 urad drift once, but this did not seem to correlate with the power degradation. Perhaps this was simply some readout noise or something.

(Carrier lock without the variable finesse technique is difficult)

I still don't understand why this is so difficult, but locking the carrier-PRMI without the variable finesse turned out to be difficult. Since we already knew the right gain settings based on the variable finesse condition, we tried locking the PRMI directly. However, I succeeded in locking it only once. Plus, the lock did not last more than 20 seconds or so. Probably this was because I did not have the power normalizations which make the servo loops less sensitive to the angular fluctuation in the PRMI. This needs further investigations.

According to the variable finesse technique, we estimated the right MICH gain with ASAIR_RF45_Q to be -7, and the PRCL gain to be -0.2 with REFL_A_RF45_I. When I obtained the short lock, the gain settings were -9 and -1 for MICH and PRCL respectively. I used a trigger and triggered filters for both loops. It was around 4:23:56 in UTC.

(Sideband lock)

We then moved onto locking of the sideband-resonant PRMI. I simply flipped the sign of the PRCL loop to do this. But, this did not work -- I did not get a short lock. So I suspected some kind of cross-coupling in the sensing matrix and started trying to the other REFL sensor, REFL_A_RF9, which should be less sensitive to the Michelson motion. I measured the difference in the readout gain of the RF9_I and RF45_I by locking the carrier. The RF9 was smaller by 13 dB than the RF45. Taking this into account I tried some gain settings in MICH and PRCL while keep using ASAIR_A_RF45_Q for the MICH control. I attach a trend of some signals below to show the PRMI had been locked for a while, more than 40 min. Note that I did not have to re-align an optic to maintain the lock. I did not see drift in PR3 in this configuration.

The first acquisition was made with a MICH gain of -10 and PRCL gain of 0.7. These numbers are not far from the expected. Once it started locking, I tuned up the alignment, demodulation phases, UGFs and locking thresholds. I attach a screenshot of the whole settings, MICH  and PRCL open loop transfer functions.

It seems that lock acquisition is smoother with a slightly lower gain in MICH. For example, I kept using a MICH gain of about -7 for locking and increased it to the nominal gain of -17 once it was locked.

Images attached to this report
Comments related to this report
kiwamu.izumi@LIGO.ORG - 02:36, Tuesday 09 September 2014 (13823)

P.S.

I was asked by Keita to take some video of the PR2 and PR3 baffle cameras when the carrier-PRMI is locked.

Here are the recorded videos from tonight. It looks like the frame rate was screwed up for some reason -- it looks as if they are fast forwarded ... both vidoes were originally taken for roughtly 10 seconds.

Non-image files attached to this comment
kiwamu.izumi@LIGO.ORG - 02:56, Tuesday 09 September 2014 (13825)

I am leaving the sideband-resonant PRMI locked.

kiwamu.izumi@LIGO.ORG - 13:41, Tuesday 09 September 2014 (13834)

(Some lock stretches were observed)

There are three major lock stretches last night. They lasted 2 hours, 3 hours and 1.5 hours in chronological order. The attached below is trend of the intracavity sideband power.

 

(A lock loss analysis)

I looked at two lock loss events from the last night at around 10:33:46 and 13:59:00 in UTC to see if there is a clue to improve the stability of the PRMI.

Both lock losses seemed have been triggered by some misalignment. The attached below is a number of time series for the first event:

Note that the second event looked similar to the first one. Here are my observatoinal notes:

  • It seems that the PRCL loop turned in unstable presumably because of the bad alignment. An oscillation is visible in the PRCL error signal a few second before the lock broke.
  • Also, the ITMX oplev yaw resembles the intra cavity power curves -- indicating that ITMX may have been leading the power fluctuation through its misalignment at that time.  Also it resembles the MICH feedback signal. Probably ITMX was lound at this point for some reason.
  • In parallel to the ITMX yaw motion, the BS pitch oplev showed some fluctuation before the lock loss. I guess this is because of the large longitudinal feedback on BS which tried to keep up with a large motion of ITMX, resulted in a large L2P coupling in BS.
  • Note that I did not install a power normalization for the length signals last night.
Images attached to this comment
H1 SEI
jeffrey.kissel@LIGO.ORG - posted 16:30, Monday 08 September 2014 - last comment - 11:58, Tuesday 09 September 2014(13817)
BRS Tuneup
J. Kissel, S. Sachdev, K. Venkateswara

Krishna discovered that the Beam Rotation Sensor software had stopped outputting data around Sep 4, Thursday, night ~11:30 PM (~1093890000). Unclear why the software had failed, but it meant we had take a trip to the X-end to restart the software.

Instructions to restart the software:
(1) Head into computer users room, and wake the windows laptop sitting on the shelf ~1m up in the last rack on the left.
(2) Note the "rate" number in the upper left corner -- this is actually the DC value to which the BRS has drifted.
(3) Close the running analysis screen, by exiting out of the window (the red x in the upper right corner). This stops the software.
(4) Find (ctrl+F) the line in the code with the comment "DC subtract here," and change the value that's subtracted from "refLP[2]" to the "rate." Subtracting off the DC component of the signal helps reduce the impulse sent to the 1 [mHz] high-pass filter, therefore reducing the ring-down time upon start-up.
(5) Save the updated code (ctrl+S).
(6) Restart the software by hitting the "|> Start" button in the top-middle.
(7) Check that you now see reasonable rotation sensor signals in the raw ADC channel, H1:ISI_GND_BRS_ETMX_RY_INMON.

The DC value we subtracted was 1227 [ct]. The second attachment is pictures of the screen for steps 4&5 then 2&3.

In addition, I was showing Surabhi around the PCal components, so we rung up the BRS. So we spent ~30 minutes damping the suspension with our mass. This was only my second shot at this flying solo, so it took a little while to remember how massive I am. Instructions supplementing the notes from LHO aLOG 13538,
To damp:
- Open up a StripTool watching H1:ISI_GND_BRS_ETMX_RY_INMON close enough to the BRS that you can see it, but still an appreciable distance away (I plug the workstation into the wall socket on the West side of the BSC9, and push it as far North as I can).
- When the tilt signal is just after the maximum on the upper-half of its sign wave, stand close to the North (+X) side.
- The tilt signal is influenced artificially by the 1 [mHz] high-pass filter, which causes the signal to turn up deceivingly fast as one stands near the BRS -- don't wait until the trough to step away from the BRS.  
- As the resonance gets damped, you need to stand near for less and less time
- +/- 500 [ct] amplitude = need to stand on one side for a full half cycle (~30-50 seconds), +/-50 [ct] amplitude = only a few seconds at a time
- +/- 25 counts is good enough. 
- Once the tilt signal is at +/- 50 [ct], I (at ~180 [lbs], or ~80 [kg]) need only stand as close as the Southwest HEPI pier for 5-10 seconds to create the right amount of damping force.

First attachment is a time series of our trial and error attempts at figuring out the above procedure.
Images attached to this report
Non-image files attached to this report
Comments related to this report
krishna.venkateswara@LIGO.ORG - 11:58, Tuesday 09 September 2014 (13831)CDS, DetChar
Jeff said that there were no error messages on the laptop screen, which indicates that it was a failure of the CCD camera. This mostly happens because of grounding issues in my experience. The CCD is grounded through the USB hub powered by an extension cord in the VEA and the laptop is powered off the rack power supply in the computer room. If there was a small voltage spike between these two different grounds - which can happen when high power devices are turned on/off, that might have caused the CCD camera to fail.
The system worked for ~13 days without failing, so hopefully this problem will not be very frequent.
H1 ISC (ISC)
lisa.barsotti@LIGO.ORG - posted 16:23, Monday 08 September 2014 - last comment - 16:27, Monday 08 September 2014(13815)
Mode matching to the OMC - Revision
I was skeptical about my  previous mode matching model , which indeed was not right. 
I didn't have the correct SR2-SR3 and SR2-SRM3 distances ( E1200616 ) calculated according to the H1 SR3 and SR2 ROCs. 

Based on lessons learned from L1, we expect the matching to the OMC X/Y in single bounce to be determined by the different ITMs ROC, while the overall scale is set by the combination of PR3(SR3) ROC + PR2-PR3(SR2-SR3) distance. 

The "theoretical numbers" for the PR2-PR3(SR2-SR3) distance calculated on the base of the measured PR3(SR3) ROCs should give us a mode matching close to optimal.

Indeed, the theoretical numbers for the mode matching are closer to perfect mode matching, as it should be: 

single bounce X = 96%
single bounce Y = 99.5%

Because of the uncertainty in the PR3 and SR3 ROCs, and in the PR2-PR3(SR2-SR3) distance, the overall matching can be somewhat worse, and the X/Y asymmetry should be amplified by the SR3 ROC/ SR3-SR2 length mismatch. 

For example, a mismatch SR3 ROC / SR2-SR3 length equivalent to 1 cm error in SR2-SR3 length would give us:

single bounce X = 90%
single bounce Y = 96%

A mismatch SR3 ROC / SR2-SR3 length equivalent to 2 cm error in SR2-SR3 length would give us:

single bounce X = 82%
single bounce Y = 90%

And so on. 

However, based on  Koji's calculations, we see pretty much the same mode mismatch X/Y (12%-13%). 

So, the message is that we can't really predict the overall matching to the OMC, given the uncertainty in the recycling cavity parameters. However, we should be able to see an asymmetry X/Y due to the different ITMs ROCs. The measured OMC matching numbers are not unreasonable (12%-13%), but they don't show the X/Y asymmetry that we expected. I am not sure why, but probably we don't care now. We might at some point want to repeat an OMC X/Y scan with dither on to have more precise measurements.

Comments related to this report
lisa.barsotti@LIGO.ORG - 16:27, Monday 08 September 2014 (13820)
These are the updated alamode files.
Non-image files attached to this comment
H1 General
jeffrey.bartlett@LIGO.ORG - posted 16:16, Monday 08 September 2014 (13819)
Add Water to Diode Chiller
Added 200ml water to diode chiller to silence intermittent alarms.   
H1 General
jeffrey.bartlett@LIGO.ORG - posted 16:14, Monday 08 September 2014 (13818)
Ops Day Shiff Summary

LVEA is Laser Hazard

08:50 Hanford Fire Department on site for annual fire extinguisher inspection
10:24 Jason – Alignment of ITMX OpLev
11:08 Bubba & HFD – Fire extinguisher inspection in LVEA
11:05 Mike – In LVEA working on charging experiment
13:00 Filiberto – Pulling cable between HAM2 and HAM3
14:03 Jeff K. – Taking students to End-X
14:40 Add 200ml water to diode chiller
14:42 Jason – Realign PR3 OpLev

LHO VE
kyle.ryan@LIGO.ORG - posted 15:47, Monday 08 September 2014 (13816)
IP4 back online
After ~3 hours of pumping with an aux. cart, I started IP4 -> I isolated and decoupled the aux. pump cart once the HV and current were at normal values

Note - all IPs are valved-out at this time, Corner Station still being pumped only by YBM and XBM turbos
H1 PSL
jeffrey.bartlett@LIGO.ORG - posted 14:26, Monday 08 September 2014 (13813)
PSL Status
PSL Status: 
SysStat: Green 
Output power: 33.7w  
Frontend Watch: Good
HPO Watch: Red  

PMC:
Locked: 5 days, 1 hours, 31 minutes
Reflected power:    2.1w
Power Transmitted: 23.2w 
Total Power:       25.4w 

FSS:
Locked: 0 days, 0 hours, 25 minutes
Trans PD: 1.802v

ISS:
Diffracted power: 8.779%
Last saturation event: 4 days, 18 hours, 43 minutes  

H1 CDS (DAQ, SYS)
david.barker@LIGO.ORG - posted 13:14, Monday 08 September 2014 (13812)
summary of recent beckhoff windows machines problems

here is a summary of the recent windows issues we had with the Beckhoff IOCs. At today's slow controls meeting we found that the alog record was incomplete.

Thursday 28th August, 03:15PDT. h1ecatx1 rebooted after auto update. h1ecatx1plc2 came back up with bogus EPICS values. System was rebooted. Details in alog.

Tuesday 2nd September, 07:05PDT. h1ecatx1 stopped running, all EPICS data frozen. A restart was made late morning which only ran for a few minutes. System was restarted again later in the afternoon and made statble.

H1 SEI
hugh.radkins@LIGO.ORG - posted 12:02, Monday 08 September 2014 (13810)
WHAM5 ISI TFs w/ HEPI Locked/At Air -vs- HEPI Isolating/Under Vacuum; and, compared to HAM4

Attached is a plot with the HAM5 CPS magnitudes from July 18 (at air HEPI locked) and from 6 Sept when we are under vacumm and the HEPI has closed position loops.  The things we believe are SUS resonances are cleaner now and the HEPI structure modes are lowered in frequency and Q. 

The feature just below 6hz is decidedly softer than the one seen on WHAM4--see comparison in the second attached plot.  All these 'HEPI' features are positioned/shaped differently between HAMs 4 & 5.  Maybe this is external mechanical and I should give everything a good hand-on look-see.

Images attached to this report
LHO VE
kyle.ryan@LIGO.ORG - posted 11:49, Monday 08 September 2014 (13811)
HAM6 turbo crash
~0915 - 0930 hrs. local 

The HAM6 turbo and its scroll backing pump were accidentally de-energized this morning resulting in the maglev turbo "crashing" onto its emergency bearings -> Chris M. was cleaning the floor near where the pumps were plugged in and accidentally tugged/shifted the shared power cord causing it to lose electrical connection -> I was in the LVEA at the time and heard the "characteristic" sound of the non-levitated turbo spinning down from 48,000 rpm on its unlubricated bearings (not unlike a steel garbage can full of rocks rolling down a steep hill) -> I was able to isolate HAM6 while the rotor was still spinning -> Both of the in-series foreline safety valves worked as intended and the scroll pump was isolated upon the loss of AC -> I was able to restart the pumps without difficulty and was able to resume pumping after ~15 total down time -> HAM6's pressure was perturbed with the loss of pumping and saw a pressure rise from 1 x 10-6 torr to 6.5 x 10-6 torr while the pump was isolated  

This is the second "crash" of this turbo due to loss of power.  This first happened years ago and was also the result of a "wiggled" power cord.  Back then the power cord to the pump cart was removable via an unreliable 1/4-turn twist lock connector.  As a result of this first crash the twist lock connector was abandoned in favor of permanently terminating the cord internal to the cart's control box.  

Note to others:  

Are energized PZTs in HAM6 vulnerable to rough vacuum?  If so, are there protection systems?
H1 SEI
hugh.radkins@LIGO.ORG - posted 11:21, Monday 08 September 2014 (13809)
WHAM5 ISI TF w/ & w/o SUS Damping

There are a few features in the ISI TFs around the resonances of HAM5 but not seen on HAM4.  Jeff suggested TFs with the SUS off.  Attached is the result.  The only thing that stands out without deeper study is a small feature at ~1.5hz on V1.

I reran the TFs completed Saturday but with only 1/4 the averages and just between 0.5 & 5hz.  And, Kiwamu turned the SUS damping back on for the last 15 minutes or so.  This should only affect the V3 results.

Images attached to this report
H1 ISC
nicolas.smith@LIGO.ORG - posted 11:20, Monday 08 September 2014 (13808)
Near term OMC plans

Nic, Dan

Here is a short checklist outlining the short term plan for the OMC. Many of these times require interferometer time so will need to be coordinated with other activities.

  • Due to the new TT actuation matrix, we must recommission the dither alignment servos.
  • Do the tests/characterization described in Zach’s OMC manifesto elog.
    • Compile OLGs of all servos in their desired state.
    • OMC transmitted noise should be characterized, a good reference for the RIN incident on the OMC will be IFO-REFL (the ISS isn’t working right now).
    • OMC length noise has not been measured yet, this one seems like a high priority.
H1 AOS (ISC, SUS)
kiwamu.izumi@LIGO.ORG - posted 09:43, Monday 08 September 2014 (13807)
BS oplev not great again

Sheila, Alexa, Kiwamu

Even though we swapped the oplev laser for BS recently. The BS optical level laser power started showing another power modulation, which resulted in kicks on BS through the damping loops.

For now, we recentered the beam on the QPD to reduce the intensity coupling.

The power modulation looks more like a step which randomly shows up as a function time as shown in the attached screenshot. The modulation depth is roughly 1%. This was actually big enough to cause BS angle agitation which was visible at the dark port digital camera. The coupling seemed bigger in the horizontal direction presumably due to a bigger off-centering in the horizontal direction on the QPD. After the re-center, the coupling seemed to have become lesser, but it is still kicking BS in its angle. This needs to be fixed.

Images attached to this report
H1 ISC (ISC)
lisa.barsotti@LIGO.ORG - posted 14:27, Saturday 06 September 2014 - last comment - 14:42, Monday 08 September 2014(13797)
OMC scan - single bounce ITMY
Nic, Jamie, Lisa

With the QPD alignment engaged, we did a scan of the OMC in ITMY single bounce configuration. Data are being sent to Koji right now for a careful analysis, but our rough estimate is that indeed the matching to the OMC is around 90%, so slightly better than for ITMX, as expected. 

Scan data: Sep 9, 2014 21:10:08 - 21:12:00 UTC
Comments related to this report
nicolas.smith@LIGO.ORG - 14:34, Saturday 06 September 2014 (13798)

Screenshot of the scan data. Koji will post a more complete analysis (a la 13767)

Images attached to this comment
koji.arai@LIGO.ORG - 00:01, Sunday 07 September 2014 (13801)

I don't know if Lisa, Nic, and Jamie believe this or not, the mode matching was 0.82 for this scan, which was indeed worse than the result with ITMY.
Note that this mismatch still includes the effect of the misalignment. This scan involved more 1st order mode.

Should we just incorporate the 1st order into the 0th order, qualitatively to saying? In this assumption, both arms are not so different.

Carrier Mode X arm (mA) Yarm (mA)
0th 13.13 9.15
1st 0.088 0.28
2nd 1.65 1.25



1 - 2nd/(0th+1st) 0.88 0.87

Here are the result of the mode decomposition for the Y arm

Carrier  
Order mA
0 9.153
1 0.28
2 1.251
3 0.102
4 0.264
5 0.0192
6 0.04144
7 0.02544
8 0.0108
   
Upper sidebands (45MHz)
Order mA
0 0.319
1 0.005
2 0.0294
3 0.004
4 0.0065
   
Lower sidebands (45MHz)
Order mA
0 0.318
1 0.005
2 0.0297
3 0.004
4 0.0065
   
2nd order Upper sidebands (90MHz)
Order mA
0 0.0021
1 0.00002
2 0.00075
   
2nd order Lower sidebands (90MHz)
Order mA
0 0.0021
1 0.00002
2 0.00075
   
Upper sidebands (9MHz)
Order mA
0 0.13
1 0.0026
2 0.012
3 0.0012
4 0.0035
   
Lower sidebands (9MHz)
Order mA
0 0.13
1 0.0026
2 0.012
3 0.0012
4 0.0035
   
Sidebands of sidebands
(+/-9MHz+/-45MHz) mA
-54 0.002
-36 0.002
36 0.002
54 0.002
Carrier TEM00 9.15 mA
Carrier TEMnm 1.99 mA
Sideband   1.04 mA
       
Mode matching  0.821  

Here "mode matching" is defined by 1-(CR_TEMnm / CR_TEM00)

Non-image files attached to this comment
lisa.barsotti@LIGO.ORG - 14:42, Monday 08 September 2014 (13814)ISC
Yes, that makes sense to me. Once the dither is working we can make more precise measurements. But I guess the point is that the mismatch is around 10%, and we don't see a significant asymmetry between X and Y as in L1. 
H1 ISC (ISC)
lisa.barsotti@LIGO.ORG - posted 14:32, Tuesday 02 September 2014 - last comment - 16:29, Monday 08 September 2014(13708)
Expected matching to the OMC
The new H1 ITMs ROC (ITM03 and ITM11) are similar to the ones in L1, but they are swapped (the wavefront error is larger from X than from Y). 

Based on  T1300954 (table 3) and Hiro's wisdom, the effective ROCs of the H1 optics, as measured in reflection, going through the bulk, are:

R_ITMX (ITM03) = 1939.3 + (-10.92*2*1.457); 
R_ITMY (ITM11)= 1939.2 + (1.56*2*1.457);

By looking at the L1 data in single bounce without TCS (below), one should expect something like ~20% mode mismatch for X and something somehow better for Y.

L1 Mode mis-match:
NO TCS:
ITMX    14.5%
ITMY    22%

Even with an input beam perfectly matched to the PRM, I would expect something like:

modematching asX with OMC = 0.8408
modematching asY with OMC = 0.91229


Comments related to this report
lisa.barsotti@LIGO.ORG - 18:51, Friday 05 September 2014 (13792)ISC
To improve the contrast while maximize the matching to the OMC, CO2 central heating should be applied to ITMX to match ITMY. Since we don't have central heating right now, one could use the ring heater to match ITMY to ITMX. This would make the matching to the OMC worse, but a better contrast. 
lisa.barsotti@LIGO.ORG - 16:29, Monday 08 September 2014 (13821)
See 13815  entry  instead.
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