TITLE: 02/05 Day Shift: 1530-0030 UTC (0730-1630 PST), all times posted in UTC
STATE of H1: Planned Engineering
OUTGOING OPERATOR: None
CURRENT ENVIRONMENT:
    SEI_ENV state: MAINTENANCE
    Wind: 11mph Gusts, 7mph 3min avg
    Primary useism: 0.03 μm/s
    Secondary useism: 0.39 μm/s 
QUICK SUMMARY: JAC output alignment continues in HAM1 today, and the HAM7 door is on and will start pumping down soon.

The PSL FSS had been searching for resonance with the autolocker on all night with no success, so I turned it off for now. I imagine the PZT ramp frequency was manually changed yesterday for JAC work and just was not reverted, so the autolocker wouldn't work.

(Randy, Jordan, Travis, Gerardo)

After lunch we installed HAM7 -Y door.  Note regarding this door to keep it on our memory, there are nicks and a few scratches on the door's flange surface, between 10 to 2 O'clock, but the scratches and nicks are away from the O-ring sealing area.

BTW, all the bolts are on the door, and they were torqued.

We also installed the two 12" OD blanks on the +Y door access ports.  Both blanks will need to be tested for leaks once the chamber is pumped down.

[Keita, Jennie, Masayuki]

Summary

After completing the EOM alignment, we realigned the beam to the IMC using JM2 and JM3. During this process, a large shift of JM3 was observed and corrected. By iteratively moving JM3 toward the PSL side, the mode mismatch was improved to below 1%. We also confirmed the presence of a diffracted s-polarization beam from the EOM with an angle consistent with expectations. Finally, we measured the power throughput and completed the alignment of the TRANS PD path.

Details

After finishing the EOM alignment, we attempted to align the beam to the IMC using JM2 and JM3. At this point, we noticed that JM3 had moved significantly. We re-tightened the dog clamp and the mirror mount, after which the alignment recovered. The mode mismatch (ratio of 2nd-order mode height to TEM00) after this realignment was 0.93/48 = 1.94%. This is actually worse than we measured yesterday, would be because the EOM crystal clipping was solved and it changed the beam shape.

To further improve the mode matching, we decided to move JM3. First, JM3 was shifted by 0.5 inch toward the PSL side, which improved the mode mismatch to 0.57/41.8 = 1.36%. We then moved JM3 by an additional 0.5 inch, resulting in 0.32/39 = 0.821 %. A further 0.5 inch shift improved the mismatch to 0.25/38.8 = 0.644%. Since this level was sufficient, we stopped the adjustment at this point.

We observed an additional beam separated by approximately 1 cm from the main beam at a distance of about 1 m from the EOM. This is likely the s-polarization beam diffracted by the EOM. The relative angle between the two beams was approximately 0.5 degrees, which is consistent with expectations.

We then measured the power throughput using a power meter. The measured powers were 94 ± 2 mW at the EOM output, 95 ± 3 mW at the EOM input, 7 ± 1 mW at JAC REFL, and 100 ± 1 mW at JAC input which indicates no significant loss.

We also checked the beam position at JM3 and confirmed that it was shifted by approximately 1/4 inch in the +y direction. The iris after JM3 and the iris after the periscope were then centered.

Finally, we aligned the TRANS PD path. Using JACT_BS1, we temporarily installed an HR mirror in place of the laser window to obtain sufficient light to the TRANS PD. With this configuration, we aligned the photodiode such that the reflected beam from the PD was properly dumped into the beam dump. Also, we make sure the transmission beam from the laser window will be cought by the same beam dump by removing the mirror and make sure that the beam coming from the JAC is directly hitting the beam dump.

M. Todd, S. Muusse, C. Compton, S. Dwyer

I wanted to get another measurement of what the HWS think the coupling factor is for thermal lens from ring heater power.

The HWS were not on, so after filling out a work permit Camilla and I went out and turned on the HWS SLEDs. Then we restarted the HWS codes in the individual computers. We also asked Jim to take ITMY ISI to fully isolated.

After waiting about 25 minutes for the HWS to get a baseline reading we turned up both ITMY and ITMX ring heaters by 4W (2W/segment). The HWS will track the defocus and I will compare with my models tomorrow morning. I wanted to do both ITM ring heaters to get a self-consistent measurement.

We also plan on doing single bounce OMC scans tomorrow morning with the ITMs being sufficiently thermalized after the RH turn on. This should give us another lens (punny pun here) to look at the thermalization business.

J. Oberling, J. Wright, R. Short

The new IOT1 in-air optics table, a.k.a. the "JAC table," now has all of its optics, wavefront sensors, and photodiodes mounted, cables run, and is ready to be rolled up chamberside. This table is slated to be on the -Y side of HAM1 and contain PDs and WFS for the JAC reflected beam path.

We placed the components on the table according to the layout as close as possible, but some adjustments had to be made to account for things like cable routing or base sizes (for example, the singular GigE camera is not currently in its proposed position due to the network cable being hit by the table enclosure door; this will need to find a different spot). Routing of the RF cables for the WFS and picomotor cables may also need to be adjusted after final positions are decided. Many of the optics needed to be cleaned before being placed in their mounts. Two of the SMA connectors on the REFL PD were damaged to the point where cables could not be screwed in well enough, but Marc was able to fix these by (carefully) bending the connectors back with pliers. Once the door is back on HAM1 and the JAC reflected beam is exiting the viewport, we can move IOT1 into place and proceed with fine alignment of components on the table, after which the table layout should be updated with an "as-built" version.

Dripta and I went to EY yesterday (Feb 3rd) to do both an ES and a TX module maintanence. We followed T1500062-v21 with out much deviation until the end when we started the TX module maint.

Obligitory Before and After beam spots on the apature of RX sphere.

Data Analysis: 
python3 generate_measurement_data.py --WS PS4 --date 2025-11-03 
Reading in config file from python file in scripts
../../../Common/O4PSparams.yaml
PS4 rho, kappa, u_rel on 2025-11-03 corrected to ES temperature 299.4 K :
-4.701912257515925 -0.0002694340454223 2.686163396659873e-05
Copying the scripts into tD directory...
Connected to h1daqnds1
martel run
reading data at start_time:  1454177475
reading data at start_time:  1454177902
reading data at start_time:  1454178300
reading data at start_time:  1454179000
reading data at start_time:  1454179400
reading data at start_time:  1454179750
reading data at start_time:  1454179900
reading data at start_time:  1454180530
reading data at start_time:  1454180888
Ratios: -0.5341330662181019 -0.5436335114505099
writing nds2 data to files
finishing writing
Background Values:
bg1 =        18.796205; Background of TX when WS is at TX
bg2 =        5.033949; Background of WS when WS is at TX
bg3 =        18.801656; Background of TX when WS is at RX
bg4 =        5.198797; Background of WS when WS is at RX
bg5 =        18.803508; Background of TX
bg6 =        -0.514446; Background of RX

The uncertainty reported below are Relative Standard Deviation in percent 

Intermediate Ratios
RatioWS_TX_it      = -0.534133;
RatioWS_TX_ot      = -0.543634;
RatioWS_TX_ir      = -0.526715;
RatioWS_TX_or      = -0.535124;
RatioWS_TX_it_unc  = 0.054072;
RatioWS_TX_ot_unc  = 0.053357;
RatioWS_TX_ir_unc  = 0.053158;
RatioWS_TX_or_unc  = 0.054774;
Optical Efficiency
OE_Inner_beam                      = 0.986243;
OE_Outer_beam                      = 0.984385;
Weighted_Optical_Efficiency        = 0.985314;

OE_Inner_beam_unc                  = 0.041515;
OE_Outer_beam_unc                  = 0.041813;
Weighted_Optical_Efficiency_unc    = 0.058922;

Martel Voltage fit:
Gradient      = 1637.852893;
Intercept     = 0.265584;

 Power Imbalance = 0.982524;

Endstation Power sensors to WS ratios::
Ratio_WS_TX                        = -0.927845;
Ratio_WS_RX                        = -1.384820;

Ratio_WS_TX_unc                    = 0.044117;
Ratio_WS_RX_unc                    = 0.038945;

=============================================================
============= Values for Force Coefficients =================
=============================================================

Key Pcal Values :
GS           =      -5.135100; Gold Standard Value in (V/W)             
WS           =      -4.701912; Working Standard Value             

costheta     =      0.988362; Angle of incidence
c            =      299792458.000000; Speed of Light
             
End Station Values : 
TXWS         =        -0.927845; Tx to WS Rel responsivity (V/V)
sigma_TXWS   =        0.000409; Uncertainity of Tx to WS Rel responsivity (V/V)
RXWS         =        -1.384820; Rx to WS Rel responsivity (V/V)
sigma_RXWS   =        0.000539; Uncertainity of Rx to WS Rel responsivity (V/V)

e            =        0.985314; Optical Efficiency
sigma_e      =        0.000581; Uncertainity in Optical Efficiency

Martel Voltage fit : 
Martel_gradient         =        1637.852893; Martel to output channel (C/V)
Martel_intercept   =        0.265584; Intercept of fit of     Martel to output (C/V)

Power Loss Apportion : 
beta          =        0.998844; Ratio between input and output (Beta)  
E_T          =        0.992056; TX Optical efficiency 
sigma_E_T          =        0.000292; Uncertainity in TX Optical efficiency 
E_R          =        0.993204; RX Optical Efficiency 
sigma_E_R          =        0.000293; Uncertainity in RX Optical efficiency 

Force Coefficients : 
FC_TxPD          =        9.154540e-13; TxPD Force Coefficient 
FC_RxPD          =        6.225064e-13; RxPD Force Coefficient 
sigma_FC_TxPD          =        4.888564e-16; TxPD Force Coefficient 
sigma_FC_RxPD          =        3.063586e-16; RxPD Force Coefficient 
data written to ../../measurements/LHO_EndY/tD20260203/

TITLE: 02/05 Day Shift: 1530-0030 UTC (0730-1630 PST), all times posted in UTC
STATE of H1: Planned Engineering
INCOMING OPERATOR: None
SHIFT SUMMARY: HAM7 door is on! 
LOG:                                                                                                                                                                                                                                                                                                                                                                                                                                                        

Squeezed in a quick photoshoot of HAM7 (right after ISI-unlocking/measurements by Jim + purge air being turned up and before Door Team sealed it up).  HAM7 was open roughly from 11:16am-11:48amPDT for photos.  Since there was only one door off, lighting wasn't great and limited to shots from the -X side of HAM7.  Used Canon DSLR camera followed by iPhone shots; snapped a handful of macro lens shots for fun.  

Photo Album (109photos) uploaded to Google folder HERE.

The HAM7 suspensions are good to go. I am only presenting the results for the OPO (in 89015), ZM1, ZM3, and ZM4 since those are the four suspensions that were adjusted/in the way of the HAM7 work.

I accidentally remeasured ZM4 (RyanC had already measured it after it was moved 88827), so I processed my measurement along with the others I did.
I had remeasured ZM4 instead of ZM3 when the ISI was stil locked, so I had to measure ZM3 with the ISI unlocked and DAMPED, but it didn't seem to affect the measurements. 

A before vs after comparison for these three ZMs(regular, zoomed) shows that they all look the same today as they did back in 2022.

ZM1 TF measurements
Settings
- ISI LOCKED
- SUS DAMP OFF
Data
/ligo/svncommon/SusSVN/sus/trunk/HXDS/H1/ZM1/SAGM1/Data/2026-02-04_1700_H1SUSZM1_M1_WhiteNoise_{L,P,Y}_0p02to50Hz.xml
r12881
Results
/ligo/svncommon/SusSVN/sus/trunk/HXDS/H1/ZM1/SAGM1/Results/2026-02-04_1700_H1SUSZM1_M1_ALL_TFs.pdf
r12881

ZM3 TF measurements
Settings
- ISI DAMPED
- SUS DAMP OFF
Data
/ligo/svncommon/SusSVN/sus/trunk/HXDS/H1/ZM3/SAGM1/Data/2026-02-04_2000_H1SUSZM3_M1_WhiteNoise_{L,P,Y}_0p03to50Hz.xml
12883
Results
/ligo/svncommon/SusSVN/sus/trunk/HXDS/H1/ZM3/SAGM1/Results/2026-02-04_2000_H1SUSZM3_M1_ALL_TFs.pdf
r12885

ZM4 TF measurements
Settings
- ISI LOCKED
- SUS DAMP OFF
Data
/ligo/svncommon/SusSVN/sus/trunk/HXDS/H1/ZM4/SAGM1/Data/2026-02-04_1730_H1SUSZM4_M1_WhiteNoise_{L,P,Y}_0p02to50Hz.xml
r12880
Results
/ligo/svncommon/SusSVN/sus/trunk/HXDS/H1/ZM4/SAGM1/Results/2026-02-04_1730_H1SUSZM4_M1_ALL_TFs.pdf
r12880

Comparison with last measurements
/ligo/svncommon/SusSVN/sus/trunk/HXDS/Common/Data/allhxdss_2026-02-04_ZM1ZM3ZM4CloseoutComparison_ALL_TFs.pdf
/ligo/svncommon/SusSVN/sus/trunk/HXDS/Common/Data/allhxdss_2026-02-04_ZM1ZM3ZM4CloseoutComparison_ALL_ZOOMED_TFs.pdf
r12886

Jeff, Oli

We were a bit unsure yesterday about the OPO but after some more measurements today I've confirmed that it is looking good. It still doesn't look like it did in 2022, but it works for us.

After some cable redressing last week the OPO was looking a lot better (88921), and then some further redressing was done (88957), which didn't seem to help, but at least didn't make Yaw worse. Those measurements were all taken with the ISI Locked. Yesterday I took what were supposed to be closeout measurements with the ISI now unlocked and DAMPED, but those measurements looked different from last week's, and not in a good way. There were two sets of measurements taken yesterday, one with the OPO damping all off (2026-02-03 1815UTC), and one where the DOF being measured was turned off, but the other DOFs were left damping (aka semi-off) (2026-02-03 1730UTC). Both measurement sets looked about the same besides a small increase in the highest frequency peak, but nowhere near the height it had been at last week(regular, zoomed).

In both sets of measurements, the lowest- and highest-frequency peaks (cross-coupling from T and V, respectively) were much smaller than they had been last week (last week we had thought the lowest peak had been split off from the main Yaw peak, but it was actually a shifted T cross-coupling). This was unexpected. The only (known) difference between last week's measurements and these two sets is the difference in the ISI, Locked vs Unlocked and DAMPED.

We decided to look at previous OPO measurements(regular, zoomed, txt explaining timeline from Jeff) taken with the ISI Locked, DAMPED, and ISOLATED, and found that the OPO resonances go down in Q when going from Locked to DAMPED. It also looks like once the ISI is ISOLATED, the resonances will rise back up(better zoom in). This could make sense as to why we're only seeing changes in the T and V resonances since the ISI moving side to side or up and down while in DAMPING would couple more directly into the OPO than when the ISI rotates.

The only way to confirm this idea was to take more measurements while the ISI was either Locked again or ISOLATED. Since yesterday afternoon the ISI had to be Locked again, I was able to take some measurements this morning(2026-02-04 1545UTC(all damping off), 2026-02-04 1630UTC(damping semi-off)), and they confirmed that the OPO looks like it did last week(regular, zoomed). So we're pretty sure once the ISI is back to ISOLATED it'll look like it did when the ISI was Locked earlier today and last week.

Yesterday's Measurements
- ISI Unlocked and DAMPED
2026-02-03 1730UTC
- OPO M1 DAMP all ON EXCEPT for DOF we are measuring (Semi-Off)
Data
/ligo/svncommon/SusSVN/sus/trunk/OPOS/H1/OPO/SAGM1/Data/2026-02-03_1730_H1SUSOPO_M1_WhiteNoise_{L,T,V,R,P,Y}_0p02to50Hz.xml
r12868
Results
/ligo/svncommon/SusSVN/sus/trunk/OPOS/H1/OPO/SAGM1/Results/2026-02-03_1730_H1SUSOPO_M1_ALL_TFs.pdf
r12869

2026-02-03 1815UTC
- OPO M1 DAMP all OFF
Data
/ligo/svncommon/SusSVN/sus/trunk/OPOS/H1/OPO/SAGM1/Data/2026-02-03_1815_H1SUSOPO_M1_WhiteNoise_{L,T,V,R,P,Y}_0p02to50Hz.xml
r12868
Results
/ligo/svncommon/SusSVN/sus/trunk/OPOS/H1/OPO/SAGM1/Results/2026-02-03_1815_H1SUSOPO_M1_ALL_TFs.pdf
r12869

Today's Measurements
- ISI Locked
2026-02-04 1545UTC
- OPO M1 DAMP all OFF
Data
/ligo/svncommon/SusSVN/sus/trunk/OPOS/H1/OPO/SAGM1/Data/2026-02-04_1545_H1SUSOPO_M1_WhiteNoise_{L,T,V,R,P,Y}_0p02to50Hz.xml
r12874
Results
/ligo/svncommon/SusSVN/sus/trunk/OPOS/H1/OPO/SAGM1/Results/2026-02-04_1545_H1SUSOPO_M1_ALL_TFs.pdf
r12876

2026-02-04 1630UTC
- OPO M1 DAMP all ON EXCEPT for DOF we are measuring (Semi-Off)
Data
/ligo/svncommon/SusSVN/sus/trunk/OPOS/H1/OPO/SAGM1/Data/2026-02-04_1630_H1SUSOPO_M1_WhiteNoise_{L,T,V,R,P,Y}_0p02to50Hz.xml
r12878
Results
/ligo/svncommon/SusSVN/sus/trunk/OPOS/H1/OPO/SAGM1/Results/2026-02-04_1630_H1SUSOPO_M1_ALL_TFs.pdf
r12877

Comparison plots
2022 vs last week vs yesterday
/ligo/svncommon/SusSVN/sus/trunk/OPOS/Common/Data/alloposs_2026-02-03_H1SUSOPO_StillPossibleIssue_ALL_TFs.pdf
/ligo/svncommon/SusSVN/sus/trunk/OPOS/Common/Data/alloposs_2026-02-03_H1SUSOPO_StillPossibleIssue_ALL_ZOOMED_TFs.pdf
r12872

ISI Locked v Damped v Isolated
/ligo/svncommon/SusSVN/sus/trunk/OPOS/Common/Data/alloposs_2026-02-03_H1SUSOPO_MaybeMysterySolved_ALL_TFs.pdf
/ligo/svncommon/SusSVN/sus/trunk/OPOS/Common/Data/alloposs_2026-02-03_H1SUSOPO_MaybeMysterySolved_ALL_ZOOMED_TFs.pdf
r12871

Everything looking good today
/ligo/svncommon/SusSVN/sus/trunk/OPOS/Common/Data/alloposs_2026-02-03_H1SUSOPO_LookingGood_ALL_TFs.pdf
/ligo/svncommon/SusSVN/sus/trunk/OPOS/Common/Data/alloposs_2026-02-03_H1SUSOPO_LookingGood_ALL_ZOOMED_TFs.pdf
r12887

The front fan bearing in Fan 1 inside AHU-1 was replaced this morning. Fan is currently off since Fan 2 is running in the lead position. 

All the whitening gain and filter are off.

at JAC-PZT_DRV_IN**/JAC-PZT_DRIVER_VOLTS: 532nm/179V = 2.97nm/V
at JAC-PZT_DRV_OUT_DQ = 532nm/8601cnts = 0.062nm/cnts

J. Kissel
- D2500175 :: S3228003
   . D2100573
   . E2300345
- D2400281

I'm finally back in the optics lab, taking the next steps towards assembling the SPI. 

Specific to this entry -- I'm assembling the Class A clean components of the fiber-coupled seed laser light. In other words, I'm integrating 
    (1) S3228003*** -- One of the 4.5" (inch) 1064nm V-FT Optical Fiber Feedthrough (Feedthru) Conflat Flange (DIAMOND) (D2500175) -- which includes the "off the shelf" (OTS) feedthru and integrated 3 [m] patch cord (the industry jargon for fiber optic cable), and its MIT-designed strain relief assembly D2100573 -- all delivered to LHO after class-A cleaning and assembly at Caltech per E2400159.
    (2) the ANU-designed Fiber Storage Spool assembly, D2400281, of which we have two.

Sina characterized the power transmission of all three of the feedthrus at Stanford before the clean-n-bake process, and identified that S3228003 had 100% transmission, so I've chosen that to be assigned to the MEAS path, where we need the most input power (as it's distributed through the most number of beam splitters). I plan to further integrate the patch cord into the SuK fiber collimator S0272503 for no better reason that to "pair the S[...]03 feedthru with the S[...]03 fiber collimator." 

***The serial numbers for the OTS feedthrus (D2500175) are of the alpha-numeric form 2153228V00n, where n = 1, 2, 3. That full version of the serial number is indicated in their ICS record, but in order to conform to the mold of the DCC S-numbers, I truncated the format to be numeric, S322800n, i.e. removing the identical leading 215 and misleading/unnecessary V character in the middle. 

Pictured here is 
    - The pre-assembly components of the fiber storage spool (First) 
    - The completed assembly of the spool with S3228003's patch cord wound up within it (Second and Third)

The feedthru's patch cord still has a Thor Lab Narrow-Key Mating sleeve (but NOT polarization maintaining) ADAFCB3 that is not intended to be a part of the final assembly, just there for fiber storage during shipment. I'd yet to detach it in these pictures.

Commentary:
     - Coiling the fiber within the spool was nerve racking. It feels like you're trying to coerce dry spaghetti into a curve without it snapping. If you let it go, it "sproings" into a wild relatively straight mess. In the end, holding it all mid-air with both hands, I used the weight of the mating sleeve to slowly pull the coil tighter as I rotated the coil nudging the rest of the coil into the newer smaller circle, until I met the radius of the storage spool. I had the goal of coiling it with one end "on top" and the other "on the bottom" of the stack, but I gave up on that. Once to the desired radius and no smaller, I used the securing cross, resting loosely across only 1/4 of the spool to hold the bulk of the coil of fiber in place while I tucked the rest of the length into the guiding channel. This is doable with a chair and patience in the open space of the optics lab, but I'm not looking forward to ding this in chamber.
     - Thinking through the install, my current plan is as follows :: WHAM3 D5 is currently a 12 inch blank with no 4.5 inch flange adapters. So it *needs* to be replaced by a 12 inch to 3x 4.5 inch flange adapter. So let's create the full 12 inch flange assembly with the 2x, MEAS and REF, fiber feedthroughs and 1x 4.5 blank -- and spool the fibers -- in the optics lab. Then we bring and install the whole 12 inch assembly on to HAM3 as a whole. 

Took HAM7 close out measurements this morning. They look ok, like the measurements taken in 2024. I believe there are known OPO plant interactions with the ISI plant that make it difficult to get clean tfs like other chambers. We should be ok to close.

As noted on Friday, RLF QPD A segment 3 railed Nov 29th, and has been railed since then.  

Filiberto, Kar Meng, Marc and I went to the rack and swapped the two cables for WFS1 + WFS2 on D2000552.  The saturaed segment moved with the cable which could indicate the problem is the in vacuum QPD.  

The 105kHz segment went quiet at the same time as the problem on the DC segment.  This happened on a Saturday, before the chamber was vented.  It had been two days of not locking the squeezer or the IFO before this happened.  

Edited to add:  This is the QPD used for filter cavity length control.  We did lock the filter cavity after the segment broke, December 4th.  

Today Rahul and I worked on reducing the last bit of clipping in HAM7.  The power budget shows a couple of percent more loss than we've expected previously, but I don't think we can improve it much right now so this is good enough. QPDA segment 3 is railed. 

This morning we found that we had some loss on B:L2, see Rahul's power budget alog as of lunchtime: 88971.  In hindsight, this was also possible in the power budget that Kar Meng reported before the suspension work this week, 88847. We translated the beam in the -Y direction in the SFI2 aperture, so it would make sense that we might need to translate the lens in the -Y direction.  However, there is no space to move it because the mount is already as close as it can be to SFI2 (photo).  So, we translated the beam using B:M3, using the power meter to judge when we were improving the alignment.  We found that this aperture is very small, there isn't much of a plateau where we aren't clipping.  

After doing what we could to reduce the yaw clipping here we did a careful power budget with the thorlabs power meter, we seem to have  8% loss to SQZT7, 11-14% loss from output of the OPO to the homodyne, which is a bit worse than past measurements ( 65066): 

• Opo 0.97-1mw
• Input to sfi1 0.97 mW
• Output sfi1 0.95 to 0.97 mW
• Hitting zm1 0.95 to 0.97 mW
• Return from filter cavity after sfi1 0.92 to 0.97 mW
• After BL1 0.93 mW
• Input to sfi2 0.92-0.94 mW
• Output from sfi2 0.91-0.92 mW
• After B:L2 0.86-0.91mW 
• After bm4 0.86-0.90 mW
• On the table bottom of the periscope 0.87-0.89 mW
• Before the homodyne 0.86 mW
• Refl power 24mW

We attempted to move B:M3 in pitch to see if we could reduce clipping on B:L2 that way, but that did not improve the transmission.  In pitch we also saw that we increased the clipping with small moves in either direction.  I will try to look up the beam size and aperture size next week to see if this makes sense.  

We adjusted B:B4 and ZM4 a bit to align onto the two irises on SQZT7. 

We also walked the two picomirrors used to center the FC QPDs, with the seed beam which saturates the diode.  From the control room I reduced the power and was able to mostly center, but it seems that QPDA segment three has been railed at 33.9 since November 29th.  

After we finished up, I went back to check the FCGS alignment onto SQZT7, which was not good, so I went back in for a few minutes to get that beam onto the filter cavity reflection diode.  I also had a look at the red + green co-alignment, which looks similar to what Kar Meng posted in 88859.  

We also checked that the new cable routing doesn't block the beam onto H:PD1, we couldn't see the beam but we think it looks like a clear path.  Rahul also took a photo of where the beam exits SFI2.