FAMIS 28229

pH of PSL chiller water was measured to be between 10.0 and 10.5 according to the color of the test strip.

From the previous alog post, Sheila measured a power drop across BL2 lens.

Here I modeled the loss of the 700um beam waist across the 2.5mm BL2 lens aperture.

The expression for the transmitted power obtained by modifying the Gaussian beam equation to include a displacement d² = d_x² + d_y² is shown here.

And here's the contour plot for the loss (1-T) across the lens aperture for a beam transversing across various spots on the lens.

Following on from this log (alog #89046), we have already checked that the MC mirrors are restored to their previous positions from before the power cut in December. We know the seismic state now should be as close as we can manage to this time 2025-12-03 11:28:44 UTC when the mode cleaner was locked at 2W input power and before any HEPIs were locked for the vent.:

Summary of seismic state now:

HAM ISI locked. HAM 2, 3, 4, 5, 6 ISI isolated.

HAM1,2 and  BSC2 HEPI locked. HAM 3,4,5,6 HEPI isolated - ie. as per nominal operation.

I trended the IM osems and the MC2 and IM4 QPDs in HAM2 while the mode cleaner was locked for mode scans yesterday (reference time is 2026-02-05 18:44:36 UTC).

It seem as though the MC2 and IM4 trans powers we have are lower now, but also the IM mirrors have changed.

As Sheila did yesterday I will try and summarise these changes in a table and compare whether this makes sense with the greater HAM1 loss we have because of the JAC (~40 %).

Just posting an updated version of Sheila's table to compare this new time (3rd December).

So after this Sheila and I are going to try turning on the IMC ASC and working out if we can tune the alignment onto IM4-TRANS using the IMs.

WP13007

The rawminute trend copy to permanent archive completed 04feb2026. Today I reconfigured NDS1 to serve these data from their permanent archival location and started the deletion of the files from TW1.

NDS1 was restarted at 12:51 for the new configuration.

FAMIS 38837

CO2 lasers have been off for the past month for vent activities and HWS SLEDs were just turned on a few days ago, so this month's trends don't show much activity.

Fri Feb 06 10:08:33 2026 INFO: Fill completed in 8min 30secs

This is for FAMIS #39750.

Laser Status:
    NPRO output power is 1.841W
    AMP1 output power is 70.43W
    AMP2 output power is 139.4W
    NPRO watchdog is GREEN
    AMP1 watchdog is GREEN
    AMP2 watchdog is GREEN
    PDWD watchdog is GREEN

PMC:
    It has been locked 0 days, 21 hr 23 minutes
    Reflected power = 27.19W
    Transmitted power = 103.9W
    PowerSum = 131.1W

FSS:
    It has been locked for 0 days 18 hr and 54 min
    TPD[V] = 0.4791V

ISS:
    The diffracted power is around 4.0%
    Last saturation event was 0 days 0 hours and 0 minutes ago

Possible Issues:
    PMC reflected power is high

TITLE: 02/06 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: 0mph Gusts, 0mph 3min avg
    Primary useism: 0.02 μm/s
    Secondary useism: 0.31 μm/s 
QUICK SUMMARY:

HAM1 JAC work will continue.  HAM7 is closed but pumpdown has not started yet.  LVEA continues in the Bifurcated Laser Safe state.

While Keita will report the detail about the heater wiring trouble shooting, here is the quick report for the JAC heater functionality.
The attatched plot shows the two thermistor signals (top/bottom) and the heater input (middle). The temperature is reasonably changing with the heater driver input.

[Jason, Masayuki]

• The laser power was increased to 1 W, and a beam dump campaign for ghost beams was carried out. First, a mirror-mount beam dump plate was installed on the JM2 mirror mount.
• Next, a beam dump to catch the AR reflection from the EOM was installed next to JAC_L1.
• Then, the s-polarized beam separated by the EOM was dumped between JAC_L2 and JAC_L3. Since a balance mass was present in this area, the beam dump height had to be adjusted. A dog clamp was inserted between the post and the beam dump to raise the height.
• When observing the beam between JAC_L2 and JAC_L3, multiple vertically separated beams were seen. At first, this was suspected to be a reflection returning from the HAM2 septum viewport; however, the beams did not disappear even after blocking the downstream path, indicating that this was not the cause. The most likely origin is multiple reflections from JAC_L1, although this has not been confirmed.

We still need to find the back reflection beam from the septum viewport, and discuss what we will do for the vertically separated beams.

I never made updated plots for the lock duration and prevelance of the DARM glitch locklosses for the last couple months of O4c (up to Sept 1st, 2025, up to Oct 1, 2025), so here they are. The performance during October and November mostly line up with what we had been seeing in August and September following the bias change (86027).

Through October and November, the frequency of DARM glitch locklosses, and locklosses in general, was still lower than they had been before the ESD bias change. October went realy well. November wasn't the best month for ETM glitch locklosses - we had 8 locklosses due to ETM glitch during the month. That's only slightly worse than the amount we saw in August right after the bias was doubled, but during November we were locked for less time overall due to O4c ending on November 18th and PEM week not requiring us to keep the IFO locked overnight or on weekends, so that's not the best. However, we still had longer locks on average during November vs before the bias change.

O4 DARM Glitch vs All Locklosses
O4c Lock Length Distribution
O4c Lock Stats

TITLE: 02/06 Day Shift: 1530-0030 UTC (0730-1630 PST), all times posted in UTC
STATE of H1: Planned Engineering
INCOMING OPERATOR: None
SHIFT SUMMARY: Work continued in HAM1 on/around the JAC, including ghost beam hunting and fixing a shorting cable. OMC scans were also taken today at points when the IMC could be locked (manually, since the IMC_LOCK Guardian is struggling to lock the IMC itself). HAM7 sits with its doors on, but pumpdown timing is still being discussed.
LOG:

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

Today we ran some more OMC scans with the ITM ring heaters on. At first we ran the OMC scan with the 9/45 sidebands on, single bounce off ITMX. Then we turned sidebands off and did both ITMX and ITMY.

[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.

Pictures:
JM3 beam position, JM3 position, and L2 position

(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.

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/