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Reports until 16:01, Tuesday 07 January 2014
H1 General
andres.ramirez@LIGO.ORG - posted 16:01, Tuesday 07 January 2014 (9141)
Ops Shift Summary
Fire Department on site doing maintenance
Installation and alignment of the GigE cameras at the HAM2 and HAM3 spools – Kiwamu
Centering SR2 BOSEMs at LVEA – Jeff B.
Baffle work at LVEA West bay – Mitchell
Electrician working at H1 electronics room
Work at End X – Sheila/Koji/Alexas
Turning Off aLOG, SVN, and awiki services due to hardware problems – Jonathan
Work on H1 PSL diode room – R. Savage
Cable pulling from Electronics room to HAM2 – Luis
aLOG, SVN, and awiki services have been turned ON – Jonathan
Remove the HAM1 viewport covers and/or camera cans – Keita/Kiwamu/Sheila/Koji/Alexa
Soft-close GV20  at End X- Kyle
Removing yellow cover from viewports on HAM1, HAM2 and HAM3 – Stefan
Fix to the ETMX, ETMXY, TMSX and TMSY models – Jeff K.
Hardware cabling at End X - Richard
H1 ISC
stefan.ballmer@LIGO.ORG - posted 15:50, Tuesday 07 January 2014 - last comment - 19:40, Tuesday 07 January 2014(9140)
h1asc updated and recompiled with LLO ASC_MASTER changes
In anticipation of some new changes to the ASC_MASTER library part, I updated it to the latest version from LLO. This includes pitch and yaw outputs for RM1,RM2,OM1,OM2. I updated our h1asc.mdl accordingly, recompiled and restarted it. SVN version number 6759.
Comments related to this report
stefan.ballmer@LIGO.ORG - 18:09, Tuesday 07 January 2014 (9148)
I modified ASC_MASTER library part to route initial green arm alignment signals in and out. This added six new inputs (green arm signals) and twelve new output signals (controls for TMS, PZT1, PZT2, both pitch and yaw).

ASC_MASTER.mdl was checked in to SVN: revision 6761

I also updated h1asc.mdl to deal with the additional in and outputs. For now I connected the twelve RFM IPCs to ISCEX/Y and SUSTMSX/Y. The inputs are still grounded, because the sending models have to be updated first.

h1asc.mdl was checked into SVN: revision 6762

The model was compiled, installed and restarted.

stefan.ballmer@LIGO.ORG - 19:40, Tuesday 07 January 2014 (9149)
I am in the process of updating the ISCEX and ISCEY models to receive the newly sent alignment dither signals for the PZTs.

ALS_END.mdl was updated, and checked into SVN: revision 6763

I am in the process of editing h1iscex.mdl and h1iscey.mdl

More tomorrow.
H1 SEI
hugh.radkins@LIGO.ORG - posted 15:19, Tuesday 07 January 2014 - last comment - 17:35, Tuesday 07 January 2014(9139)
H1 ETMX ISI T240s w/ HEPI Tilt

Back on 23 December, Keita found the need to tilt the HEPI to pitch the TMS.  Attached is a plot showing the T240 signal going back 30 days from now.  The time keita tilted the HEPI is pretty obvious in the middle of the trends when tilted axes of the T240s are affected.  Much of the period since 23 Dec has the ISI off (tripped from T240 saturations) and so not the source of the increase in these T240 signals.

As I've logged before, the ETMX ISI has not managed to stay engaged for more than a few hours since this time.  Notice too on these trends, the signals with the largest amplification has a regular hit of the rail.  The second plot I've attached is a single channel of 15 days.  Notice the rail hit every 24 hours; this is to the minute as best I can tell from a 15 day dv trend.  I am suspicious that this is real given the periodicity.

Finally, the last plot zooms in to 8 days of this channel and I've added a channel indicating the HEPI tilt.  Notice in the middle of the plot where on 2 & 3 Jan I'm mucking about with tilts and ISI.  The noise of the T240 is reduced when there is no tilt applied.

Images attached to this report
Comments related to this report
hugh.radkins@LIGO.ORG - 17:35, Tuesday 07 January 2014 (9144)

Duplicated this situation at ITMY.  We removed the HEPI position loops and took the ISI to damping only and then tilted the HEPI -12000 counts in the same method as the ETMX.  Attached is the nominally affected channels.  Upper right trace is the offset.  There is no large difference between the periods of offset and no offset; certainly not to the extent it is seen on the ETM.  Fabrice is currently repeating this measurement at ETMX while ISC has relenquished control.

Images attached to this comment
H1 SUS (AOS, CDS, INS, SEI)
jeffrey.kissel@LIGO.ORG - posted 15:02, Tuesday 07 January 2014 (9138)
ETM and TMS Models Re-routed to Latest Version of Match System Wiring Diagram
J. Kissel, T. Vo, R. McCarthy

Both sites have simultaneously discovered that the optical lever signal wiring has changed between version 5 and version 6 of the ETM System Wiring Diagram, D1002741, specifically page 4. However, since we're just now turning on the EM optical levers (whose signal installation required the change), we discovered that the front-end Simulink model is still wired according version 5 as cables were plugged in according to version 6. Note that the drawing changes were made back in July of 2013, as a part of resolving Integration Issue 78, but this week is the first time the changes have been exposed to installation reality at either site. 

As such, I have re-wired the following models:
${userapps}/sus/h1/models/
h1susetmx.mdl
h1susetmy.mdl
h1sustmsx.mdl
h1sustmsy.mdl
such that, in the ETM models:
(1) Remove ADC1 from the top-level, since it no longer used in the ETM control models.
(2) Change the From tag for the optical lever signals from "ADC1_2_QUAD" to "ADC0_2_QUAD," such that it receives signals from ADC0.
(3) Re-selected ADC0 channels 0_24, 0_25, 0_26, 0_27, which are Quadrants A, B, C, D on D1002741, and Segments 1, 2, 3, and 4 in the QUAD simulink Library part, respectively.
and in the TMS models:
(1) From the ADC0_2_TMTS From tag, re-selected ADC0 channels 0_28 and 0_29 for M1 RT and M1 SD, respectively.

Richard has now swapped the analog cabling accordingly, such that now both analog and digital match version 6.

Note, the naively annoying signal shuffling that affects and separates the TMTS OSEM signals was done to preserve the last two channels on the ADC0 as open/spare required for the standard DAC and ADC duotone signals of every IO chassis.

All top-level models (which is all that was affected by these changes) have been committed to the userapps repo as of this entry.

H1 SUS ETMX AND H1 SUS TMSX have had their damping restored, and their alignment offsets restored to what they were just before the reboot. 

As the SEI/SUS watchdog system still stands, taking down the suspension models trips the HEPI and ISI, so I've restored the ISI to damping, and left HEPI untripped but requesting no actuation, since I don't know the state of these chamber's commissioning. I have not restored the 12000 nrad offset that Keita has installed to fix the differential alignment between ETMX and TMSX (see LHO aLOG 9064) that's need to lock the arm cavity on green (see LHO aLOG 9127) because he's put it in the hidden offset of the RY IPS blend filter bank, and I'm not sure whether position loops are functional. This should be moved to the DC BIAS location, and position loops should be run. I'll speak with Keita and the SEI team.
Logbook Admin General
jonathan.hanks@LIGO.ORG - posted 10:52, Tuesday 07 January 2014 - last comment - 11:26, Tuesday 07 January 2014(9136)
aLOG going down to examine possible hardware issues
The aLOG is being turned off to examine possible hardware issues.
Comments related to this report
jonathan.hanks@LIGO.ORG - 11:26, Tuesday 07 January 2014 (9137)
Our testing is done.  We were unable to reproduce the problems seen yesterday during the power cycle of the MSR UPS.  The hardware appropriately handled having UPS power removed and having facility power removed.
H1 ISC
keita.kawabe@LIGO.ORG - posted 10:47, Tuesday 07 January 2014 (9135)
initial assessment of Xarm ALS green beam mode matching using ITM baffle PD

When aligning the X arm I thought that the green beam is too small on ITMX and ETMX, but when I actually looked at the data, the beam size on ITMX is not bad.

  Beam radius at ITMX [mm]
Theoretical (using nominal ROC of ETM and ITM) 37.8
Measured (using straight shot beam on baffle PD) 33

I adjusted the TMSX sliders to maximize one of the baffle PDs, moved TMSX in yaw such that the power on the PD drops, and assessed the beam size assuming that the beam is sufficiently smaller than the beam radius.

Attached plot shows that 4.4urad TMSX slider change in YAW makes one of the baffle PDs to drop from the peak by about half (.125/.240 = 0.521 to be more precise). From alog 9126 we know that the slider calibration for YAW is 1.07 [urad/urad], so the beam displacement is x=1.07E-6*4.4urad*4E3m=18.8mm.

exp(-2x^2/w^2) = 0.125/0.240= 0.521, x=18.8mm, therefore:

w=sqrt(-2/ln(0.521))*x=32.9mm.

I don't claim that the measurement has a mm accuracy, though, because I don't know the baffle PD size.

Images attached to this report
H1 CDS
cyrus.reed@LIGO.ORG - posted 10:34, Tuesday 07 January 2014 (9134)
Restarted h1slow-cds EPICS gateway process

Sheila and Alexa reported issues seeing Beckhoff channels from the control room workstations, so I restarted the h1slow-cds EPICS gateway process.  This appears to have corrected the problem.

H1 CDS
sheila.dwyer@LIGO.ORG - posted 09:25, Tuesday 07 January 2014 (9131)
heatx1 restarted

Alexa and I restarted h1ecatx1 after we got a run time sytem not found error (from PLC2 or run time 2)  

H1 IOO
kiwamu.izumi@LIGO.ORG - posted 07:56, Tuesday 07 January 2014 (9128)
IMC WFS A recentered, and whitening gains set back to 36dB

I recentered the beam on WFS_A of IMC because the beam was found to be off from the diode by a couple of mm horizontally. Probably I accidentally bumped a steering mirror when I was working on the GigE cameras on IOT2L. And indeed, no other photodiodes showed such a big off-centering. Due to this WFS_A without the beam on its diode, IMC ASC kept unlocking IMC. After the centering, IMC ASC came back to normal. IMC seems stable.

Also, I noticed that the whitening gain for both WFS_A and B was set at 45 dB which should be 36 dB according to this alog (alog 9094). So I set them back to 36 dB.

H1 ISC
sheila.dwyer@LIGO.ORG - posted 23:38, Monday 06 January 2014 (9127)
locked x arm with green

Kiwamu, Sheila

We locked the X arm.  We started with Keita's alingment, adjusted the ITM a little bit until we saw some fringing.  At the end station we adjusted the demod phase watching Imon (photo of switch positions on phase shifter is attached), then tweaked the ITM alignment again.  We tried moving the ETM around but found that Keita's alignment was pretty much the best we could find.  This means in the end we had 

  ITM ETM
PIT 86.0 342
YAW -64.0 -37.0

Once we had the PLL locked we locked the PDH easily (In 1 pol negative, -4dB in1 gain, common comp and the first boost on, and the slow option on (meaning no slow feedback).  REFL PD B dropped from 18000 counts unlocked to around 16000 counts when we were locked on the carrier.   We measured a transfer function (last attachment), the ugf was roughly 8kHz.  

Last we checked ISCT1 for a beam, but didn't find anything there.  

Images attached to this report
H1 ISC
sheila.dwyer@LIGO.ORG - posted 19:43, Monday 06 January 2014 (9125)
X end refl PDs aligned

There is currrently 5.8mW on the refl PD A this signal is not showing up in the fast digital system, neiher the beckhoff readback nor the fast system readbacks are working for this channel right now.  

Refl B has 1.4mW of green aligned onto it REFL_B_LF_OUTPUT is 15500 right now and beckhoff is reading 4.6V.  The hardware switch on this is currently set to 20dB. 

I also aligned the QPD and plugged X (which is vertical the way the qpd is mounted) into ISC extra Analog input 1, Y (horizontal) into analog input 2, and the sum into analog input 3.  right now there is 6.2mW on the QPD, resulting in 4.7 V on sum, and roughly zeroed in X and Y.  

H1 SUS
keita.kawabe@LIGO.ORG - posted 19:30, Monday 06 January 2014 - last comment - 17:59, Monday 13 January 2014(9126)
X arm alignment and slider calibration, part 2

References:

This is an update of the above alog entries. After turning off the isolation loop for EX ISI, I started the initial alignment of the TMS, ITMX and ETMX again.

This was done by pointing TMS to ITM arm cavity baffle diodes PD1 and PD4 (note that for ITM baffle PD4 is connected to PD3, so the actual channel I looked at was H1:AOS-ETMX_BAFFLEPD_3_POWER), take note of the TMSX alignment slider values, set the TMS slider to the mean of PD1 and PD4, then align ITMX to point the beam to ETMX baffle diodes etc.

The bias sliders are calibrated using 4000m arm length and the vertical/horizontal distance between the PDs.

In the table below, (P, Y) refers to the alignment slider values for each optic,  "Aligned" is the mean of PD1 and PD4

optic TMSX ITMX ETMX
PD1 (P, Y) (109, -203) (67, -80) (322, -1)
PD4 (P, Y) (178, -266) (99, -47) (362, -71)
Aligned (P, Y) (143.5, -234.5) (83, -63.5) (342, -36)
Slider calibration (P, Y) [urad/urad] (1.04, 1.07) (1.17, 1.14) (0.90, 0.51)

Note that HEPI still has 12000 counts RY offset to relieve TMSX PIT which is due to 300urad systematic in ETMX.

Comments related to this report
keita.kawabe@LIGO.ORG - 17:59, Monday 13 January 2014 (9246)

An error in the table,  TMSX YAW = 1.14 urad/urad instead of 1.07.

H1 SEI
keita.kawabe@LIGO.ORG - posted 19:02, Monday 06 January 2014 (9124)
EX ISI isolation is shaking things too much

Turning End X ISI isolation loop on (which was declared to be the default state of ETMX ISI) makes ALS beam move too much. It's so bad that, by the time the beam comes from TMS to ITMX to ETMX to ITM baffle diode, the beam motion is larger than the beam radius.

After fighting with it for a few hours I concluded that we cannot do anything useful with it, so I turned it off and left it as damping only.

Don't turn on the isolation. If you think you have a better isolation filter, you need to coordinate with integration team to find a good time slot for testing.

LHO VE
kyle.ryan@LIGO.ORG - posted 16:37, Monday 06 January 2014 - last comment - 09:18, Tuesday 07 January 2014(9123)
Changed VE configuration for HIFO-X
Valved-in IP1,2,5, and 6*Dumped GV7's unpumped gate annulus volume into pump cart*Valved-out YBM turbo*Opened GV7*Valved-in IP12*Dumped GV20's unpumped gate annulus volume into pump cart*Valved-out X-end turbo*opened GV20*Dumped GV5's unpumped gate annulus volume into pump cart*Opened GV5
Comments related to this report
kyle.ryan@LIGO.ORG - 09:18, Tuesday 07 January 2014 (9130)
IP1,2,5 and 6 @ 5000V as of 1630hrs 1/6/2014 (optimal for 1x10-8torr < pressure < 1x10-7torr) 
H1 SUS
jeffrey.bartlett@LIGO.ORG - posted 16:35, Monday 06 January 2014 (9122)
Install Glass M3 Mass in H10SR2
Andres R. & Jeff B. 

   After replacing the metal EQ Stops with the silica tip in chamber EQ stops, we installed the glass mass in H1-SR2. The mass is now suspended on a new wire loop. The measured pitch and roll of the M1, M2, and M3 masses are almost zero, (as close to zero as we can measure with an optical level). 

Per the XYZ Local CS document for H1-SR2 (D0901128) the center of the optics, including the spacer (D1100180), should be at 220.9mm above the ISI table. The measured height of the center of the M3 optics in H1-SR2 is 221.28mm above the ISI. As it is hanging, the center of the optic is 0.38mm high, which is within the +- 1mm tolerance for the center of the mass. 

Tomorrow we will center the OSEMs and start running transfer functions. 

M3 measurement data: 
Measured height of top of M3 mass = 215.7mm
Measured height of bottom of M3 mass = 64.79mm     
Center of M3 mass -->(215.7 – 64.79)/ 2 = 75.46mm 
Height of center of mass --> 64.79 + 75.46 = 140.25mm
Adjustment for spacer --> 140.25 + 81.03 = 221.28mm 
Height of beam path with spacer = 220.9mm
Mass height to beam path differential --> 221.28 – 220.9 = 0.38mm 
H1 AOS
kiwamu.izumi@LIGO.ORG - posted 19:28, Thursday 02 January 2014 - last comment - 08:17, Tuesday 07 January 2014(9100)
I/Q phase adjustment done with all REFL and POP demodulators

[Stefan, Kiwamu]

We adjusted the phase difference (e.g. LSC-REFL_A_RF9_PHASE_D) of all the REFL and POP demodulators except for a WFS channel which showed suspiciously small signals.

 

Observations on the I/Q relations:

We discovered that the amplitude imbalance between any pair of I and Q were good and were typically less than 0.5%.  Also, the extra imbalance that can be introduced by changing the whitening settings are almost comparable to 0.5% and we concluded that it was pointless to correct the amplitude imbalance at this point unless the whitening settings are fixed. Therefore we didn't attempt to correct them this time. On the other hand, the phase difference was not as sensitive as the amplitude imbalance to the whitening settings. They were found to be typically off by a couple of degrees from 90 in the first place, while changing the whitening settings didn't rorate them more than 1 degree. This is the background story of why we ended up adjusting only the phase differences.

 

One demod board doesn't look healthy:

In the process of the adjustment, we found that channel 4 of the WFS REFL_B_RF9 demod board (SN:S1000994) displayed too small signals in both I and Q by a factor of 2-ish in their amplitudes compared with the rest of three channels. We must pull this board out of the rack and take a close look in the EE shop.

 

Adjustment of the phase difference:

We used the same technique as Anamaria did at LLO (see LLO 6829). The RF frequency was set apart by 40-50 Hz from the LO frequency in each demodulator by using an IFR RF source. The RF level was at -40 dBm for the LSC demods and -41 dBm for the WFS demods. None of the whitening stages were engaged. The whitening gains were simply set to be their maximum (i.e. 45 dB) during the measurement. The belows are the results:

* * * in-vac 1f

H1:LSC-POP_A_RF9_PHASE_D       87.30
H1:LSC-POP_A_RF45_PHASE_D      92.93
H1:LSC-REFL_A_RF9_PHASE_D      88.63
H1:LSC-REFL_A_RF45_PHASE_D     92.98

* * * in-air 1f

H1:LSC-POPAIR_A_RF9_PHASE_D    87.78
H1:LSC-POPAIR_A_RF45_PHASE_D   92.95
H1:LSC-REFLAIR_A_RF9_PHASE_D   88.27
H1:LSC-REFLAIR_A_RF45_PHASE_D  92.98

* * * 2f and 3f

H1:LSC-POPAIR_B_RF18_PHASE_D   89.17
H1:LSC-POPAIR_B_RF90_PHASE_D   91.05
H1:LSC-REFLAIR_B_RF27_PHASE_D  91.39
H1:LSC-REFLAIR_B_RF135_PHASE_D 84.49
 

* * * WFS REFL 9

H1:ASC-REFL_A_RF9_SEG1_PHASE_D 88.28
H1:ASC-REFL_A_RF9_SEG2_PHASE_D 88.34
H1:ASC-REFL_A_RF9_SEG3_PHASE_D 88.55
H1:ASC-REFL_A_RF9_SEG4_PHASE_D 88.55
H1:ASC-REFL_B_RF9_SEG1_PHASE_D 89.17
H1:ASC-REFL_B_RF9_SEG2_PHASE_D 88.32
H1:ASC-REFL_B_RF9_SEG3_PHASE_D 88.64
H1:ASC-REFL_B_RF9_SEG4_PHASE_D 0
 

* * * WFS REFL 45

H1:ASC-REFL_A_RF45_SEG1_PHASE_D 91.96
H1:ASC-REFL_A_RF45_SEG2_PHASE_D 93.15
H1:ASC-REFL_A_RF45_SEG3_PHASE_D 92.37
H1:ASC-REFL_A_RF45_SEG4_PHASE_D 93.18
H1:ASC-REFL_B_RF45_SEG1_PHASE_D 92.80
H1:ASC-REFL_B_RF45_SEG2_PHASE_D 91.65
H1:ASC-REFL_B_RF45_SEG3_PHASE_D 92.88
H1:ASC-REFL_B_RF45_SEG4_PHASE_D 93.00
 

Comments related to this report
kiwamu.izumi@LIGO.ORG - 20:23, Thursday 02 January 2014 (9102)

One correction to my previous alog:

We corrected the amplitude imbalance of REFLAIR_B_RF135 because this showed a big imbalance unlike the rest.

H1:LSC-REFLAIR_B_RF135_I_GAIN  0.993

H1:LSC-REFLAIR_B_RF135_Q_GAIN  1.007

daniel.sigg@LIGO.ORG - 08:58, Friday 03 January 2014 (9103)

The demod for H1:LSC-POPAIR_B/H1:LSC-REFLAIR_B is the unit in the shop and not the one on the floor. It gets retrofitted with LP/HP filters for the 18/90MHz signals.

kiwamu.izumi@LIGO.ORG - 08:17, Tuesday 07 January 2014 (9129)

Filiberto and Aaron swapped the demod board (i.e. WFS_REFL_B_RF9) with a spare. The spare is now in.

H1 SUS
keita.kawabe@LIGO.ORG - posted 16:31, Tuesday 24 December 2013 - last comment - 18:00, Monday 13 January 2014(9087)
OSEM calibration of TMSX, ETMX and ITMX

References: D1201036 (BSC9 ACB assy) and D1200314 (BSC3)

Gerardo read the distances between the baffle diodes off of CAD drawings for me (see the attached cartoon). 

ITM baffle PD1-PD4 separation is 11.3" over 4km (72 urad) both horizontally and vertically. For ETM the number is 11.8", so it's 75 urad.

Don't know why the patterns are different for ETM and ITM, but using these we can calibrate TMSX, ITMX and ETMX bias sliders. Note the factor of 2 between TMS and mirrors, this is because TMS moves with the beam but mirrors don't.

  TMSX P TMSX Y ITMX P ITMX Y ETMX P ETMX Y
PD4-PD1 [urad in slider offset]

187-118

= 69

-253+190

= -63

99-66.6

= 32.4

-38+72.9

= 34.9

355-310

= 45

-34-26.5

= -60.5

Slider Calibration

[urad/urad]

72/69

= 1.04

72/63

=1.07

75/32.4/2

= 1.2

75/34.9/2

= 1.1

72/45/2

=0.8

72/60.5/2

= 0.6

Slider sign positive=down positive=out of L positive=down positive= inside of L positive=down positive=out of L

 

Calibration of ETMX is somewhat suspect (at 10urad level) because of the fact that the position loop of EX ISI got accidentally off before I did ETMX adjustment.

Images attached to this report
Comments related to this report
keita.kawabe@LIGO.ORG - 09:50, Tuesday 07 January 2014 (9133)

There's an update on this. Nothing changed significantly, but anyway see the alog below:

https://alog.ligo-wa.caltech.edu/aLOG/index.php?callRep=9126

keita.kawabe@LIGO.ORG - 18:00, Monday 13 January 2014 (9247)

One error in the table, TMSX Y calibration = 1.14 urad/urad instead of 1.07.

H1 ISC
keita.kawabe@LIGO.ORG - posted 13:58, Monday 23 December 2013 - last comment - 09:49, Tuesday 07 January 2014(9064)
Green beam finding in X arm (Daniel, Keita)

Summary: Green injection hits the center of ITMX, comes back to the center of ETMX, and then back again to the center of ITMX. The alignment is good, with one caveat that HEPI should be tilted significantly in  PIT to help TMS. Since EX PIT is unaffected by the HEPI, we're using EX sus bias to point it down by 330 urad.

1. Green beam from TMSX to ITMY

After Kyle opened the GVs we started scanning TMS to find the green beam on ITMX baffle diodes. Somehow PD4 amplifier was busted so we reconnected PD4 to PD3  amplifier.

At first TMSX was pointing up too much, and I had to give HEPI a PIT (RY) offset of -12000 counts to H1:HPI-ETMX_BLND_IPS_RY_OFFSET with a gain of 1. HEPI loops were all open, so that just gave a DC offset to the HEPI angle. After that treatment, we were able to maximize the output of three baffle diodes using the following offsets for TMS bias:

  Center =(PD1+PD4)/2 PD1 PD2 PD4
H1:SUS-TMSX_M1_OPTICALIGN_P_OFFSET 152.5 118 53 187
H1:SUS-TMSX_M1_OPTICALIGN_Y_OFFSET -221.5 -190 -256 -253

See E1300634, figures 12 and 13, for the diode layout. PD1 and PD4 are two diagonal ones around the baffle hole, PD2 and PD3 are far from the mirror. "Center" is the mean of PD1 and PD4 and should be close to the real center of the optic.

Baffle diode channel names are H1:AOS-ITMX_BAFFLEPD_1_POWER etc., but they are not trended as of now. Also note that H1:AOS-ITMX_BAFFLEPD_3_POWER is actually reading PD4.

Transimpedance for the PDs were set to 20 kOhm, and when maximized the outputs were about 2.5V for PD2 and PD3, and about 2.3V for PD1.

Comments related to this report
keita.kawabe@LIGO.ORG - 16:34, Monday 23 December 2013 (9071)

2: ITMX reflection on ETMX

Got the beam reflected off of ITMX on ETMX baffle diodes. We used a factor of 10 larger trans impedance (200kOhm). All diodes worked and the channel numbering made sense.  H1:AOS-ETMX_BAFFLEPD_1_POWER= ETMX baffle PD1 etc.

  Center PD1 PD2 PD3 PD4
H1:SUS-ITMX_M0_OPTICALIGN_P_OFFSET 82.8 66.6 36 65.6 99
H1:SUS-ITMX_M0_OPTICALIGN_Y_OFFSET -55.5 -72.9 -41 -8.9 -38

Despite 10x higher trans impedance the maximum we got was something like 6V (VS 2.5V), so it's like a factor of 4 reduction. Probably the mode matching into the arm is not good.

keita.kawabe@LIGO.ORG - 16:53, Monday 23 December 2013 (9072)

3: ETMX reflection back to ITMX

I had to tilt the ETMX significantly in PIT, but anyway.

  Center PD1 PD2 PD4
H1:SUS-ETMX_M0_OPTICALIGN_P_OFFSET 332.5

310

290 355
H1:SUS-ETMX_M0_OPTICALIGN_Y_OFFSET

-3.75

26.5 -10 -34

Transimpedance is again 20kOhm and the maximum was about 0.3V, so it's a factor of 2 reduction in power (VS 6V 200kOhm ETM diodes).

At this point I had a power back in REFL B diode, and saw a fringing, but after 5 minutes the fringing was gone. Either the alignment is drifting (turns out that the ISI was undamped), or the frequency noise is too large (couldn't lock PLL).

During this operation I tripped ETMX watchdog, HEPI was restored after that but I forgot about ISI. That is OK, it's just that ISI was undamped.

keita.kawabe@LIGO.ORG - 17:11, Monday 23 December 2013 (9073)

4. ETMX initial alignment implication

The above shows clearly that, without any suspension slider bias, ETMX is pointing up 330 urad.

This should be either the initial alignment (we dead reckoned 300 urad caused by the weight of first contact) or the optic drifted after pumping down, but the former is more likely.

keita.kawabe@LIGO.ORG - 09:49, Tuesday 07 January 2014 (9132)
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