TITLE: 02/05 Day Shift: 1530-0030 UTC (0730-1630 PST), all times posted in UTC
STATE of H1: Observing at 156Mpc
OUTGOING OPERATOR: Oli
CURRENT ENVIRONMENT:
    SEI_ENV state: CALM
    Wind: 10mph Gusts, 7mph 3min avg
    Primary useism: 0.01 μm/s
    Secondary useism: 0.36 μm/s
QUICK SUMMARY:

• 14:02 UTC Observing
• We've been locked for 1.5 hours
• Wind is low, 2ndary microseism is rising slightly
• Light dusting of snow around site and town

TITLE: 02/05 Eve Shift: 0030-0600 UTC (1630-2200 PST), all times posted in UTC
STATE of H1: Preventive Maintenance
INCOMING OPERATOR: Oli
SHIFT SUMMARY:

H1 made it back to Observing about an hour into the shift---mainly held up by rung up violin modes which took almost an hour to damp down.  The violins are still high, but slowly coming down. 

Range does look about 4-6Mpc lower for this lock.  Ran the Range Comparison Check measurement between current lock and about 24hrs ago during the long 20hr lock.  See attached plots run via ( python3 range_compare.py 1422710713 1422768313 ).  
LOG:

• H1 was powering up during the ops handoff
• 0138 NLN & Observing (after 50min of violin damping while waiting for OMC Whitening).
• 0337--0339 SQZ bumped H1 out of Observing due to SQZ_FC, but it came back purely on its own.

Attached are ASC SDF Diffs which were ACCEPTED to get H1 to OBSERVING.

As per WP 12314 we did work towards installing new digital video controller computers.

In the morning Jonathan Hanks and Austin Farias installed a new switch (sw-msr-video1) in the video rack.  This switch is a 10g fiber switch and will be used to carry the camera lan traffic to the new h1digivideo computers.

In the afternoon Dave removed some of the old conlog computers to make room for h1digivideo4.

In the afternoon Dave/Jonathan/Patrick installed h1digivideo4, ran fiber from it to sw-msr-video1.  Then we installed the OS via a PXE boot and preseed.  H1digivideo has been added to puppet to get the config in place.  Jonathan and Patrick installed a test camera in the MSR (cam-msr-test) on the camera vlan in order to do testing of h1digivideo4 prior to moving it fully into production.

We are leaving the work permit open as Dave will be removing more of the old conlog machines tomorrow.

At this point we have not removed analog video equipment.  Dave has been making sure we have good drawings of the current setup before we dismantle anything on the analog side.

Today Francisco Llamas and I took PS4 down the EndY to do a run of the mill End station measurement following the instructions outlined on the T1500062 PCAL End Station Power Sensor Responsivity Ratio Measuremets: Procedures and Log .

Running the following command from a cds directory /ligo/gitcommon/Calibration/pcal/O4/ES/scripts/pcalEndstationPy

python generate_measurement_data.py --WS "PS4" --date '2024-12-10'
Reading in config file from python file in scripts
../../../Common/O4PSparams.yaml
PS4 rho, kappa, u_rel on 2024-12-10 corrected to ES temperature 298.5 K :
-4.7042776679256315 -0.0002694340454223 4.3277259408925024e-05
Copying the scripts into tD directory...
Connected to nds.ligo-wa.caltech.edu
martel run
reading data at start_time:  1422728370
reading data at start_time:  1422728815
reading data at start_time:  1422729150
reading data at start_time:  1422729720
reading data at start_time:  1422730125
reading data at start_time:  1422730470
reading data at start_time:  1422730600
reading data at start_time:  1422731280
reading data at start_time:  1422731630
Ratios: -0.5336711312890802 -0.5439438081494363
writing nds2 data to files
finishing writing
Background Values:
bg1 =        18.798280; Background of TX when WS is at TX
bg2 =        5.347941; Background of WS when WS is at TX
bg3 =        18.777599; Background of TX when WS is at RX
bg4 =        5.320714; Background of WS when WS is at RX
bg5 =        18.859360; Background of TX
bg6 =        0.059221; Background of RX

The uncertainty reported below are Relative Standard Deviation in percent

Intermediate Ratios
RatioWS_TX_it      = -0.533671;
RatioWS_TX_ot      = -0.543944;
RatioWS_TX_ir      = -0.526984;
RatioWS_TX_or      = -0.536057;
RatioWS_TX_it_unc  = 0.052568;
RatioWS_TX_ot_unc  = 0.055834;
RatioWS_TX_ir_unc  = 0.056378;
RatioWS_TX_or_unc  = 0.059744;
Optical Efficiency
OE_Inner_beam                      = 0.987336;
OE_Outer_beam                      = 0.985232;
Weighted_Optical_Efficiency        = 0.986284;

OE_Inner_beam_unc                  = 0.041823;
OE_Outer_beam_unc                  = 0.044559;
Weighted_Optical_Efficiency_unc    = 0.061112;

Martel Voltage fit:
Gradient      = 1637.895833;
Intercept     = 0.036157;

 Power Imbalance = 0.981114;

Endstation Power sensors to WS ratios::
Ratio_WS_TX                        = -0.927975;
Ratio_WS_RX                        = -1.384608;

Ratio_WS_TX_unc                    = 0.044554;
Ratio_WS_RX_unc                    = 0.037548;

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

Key Pcal Values :
GS           =      -5.135100; Gold Standard Value in (V/W)             
WS           =      -4.704278; Working Standard Value             

costheta     =      0.988362; Angle of incidence
c            =      299792458.000000; Speed of Light
             
End Station Values :
TXWS         =        -0.927975; Tx to WS Rel responsivity (V/V)
sigma_TXWS   =        0.000413; Uncertainity of Tx to WS Rel responsivity (V/V)
RXWS         =        -1.384608; Rx to WS Rel responsivity (V/V)
sigma_RXWS   =        0.000520; Uncertainity of Rx to WS Rel responsivity (V/V)

e            =        0.986284; Optical Efficiency
sigma_e      =        0.000603; Uncertainity in Optical Efficiency

Martel Voltage fit :
Martel_gradient         =        1637.895833; Martel to output channel (C/V)
Martel_intercept   =        0.036157; Intercept of fit of     Martel to output (C/V)

Power Loss Apportion :
beta          =        0.998844; Ratio between input and output (Beta)  
E_T          =        0.992544; TX Optical efficiency
sigma_E_T          =        0.000303; Uncertainity in TX Optical efficiency
E_R          =        0.993693; RX Optical Efficiency
sigma_E_R          =        0.000304; Uncertainity in RX Optical efficiency

Force Coefficients :
FC_TxPD          =        9.152911e-13; TxPD Force Coefficient
FC_RxPD          =        6.219661e-13; RxPD Force Coefficient
sigma_FC_TxPD          =        4.976837e-16; TxPD Force Coefficient
sigma_FC_RxPD          =        3.035146e-16; RxPD Force Coefficient
data written to /ligo/gitcommon/Calibration/pcal/O4/ES/measurements/LHO_EndY/tD20250204

Beam spot picture
Martel_Voltage_test.png
WS_at_TX.png
WS_at_RX.png
WS_at_RX_BOTH_BEAMS.png
LHO_EndY_PD_ReportV5.pdf

Sheila, Camilla

SQZ_MANAGER had go overcrowded so we removed some of the unused states to make the graph simpler to understand and remove the number of states that could be accidently mis-clicked and cause issues. Original graph and new graph attached.

Changes:

• We only ever indent to use FIS while data taking or in a push if there was something wrong with the FC, so we removed all unneeded FIS states: SCAN_SQZANG_FIS, SCAN_SQZANG_FIS, RESET_SQZ_ASC_FIS, RESET_SQZ_ANG_FIS, and edge  ('FIS_READY_IFO', 'NO_SQUEEZING')
• Also removed the set and save alignment states for the ZMs, these were only useful when the HD was aligned to a different alignment that the IFO, which isn't an issue any more. Removed:  ALIGN_HD, SET_ZM_SLIDERS_HD, SET_ZM_SLIDERS_IFO, SAVE_ZM_SLIDERS_IFO, SAVE_ZM_SLIDERS_HD,
• Removed state RESET_SQZ_ANG_FDS  as if the SQZ ang has ran away, ASC will probably be bad too, so just use RESET_SQZ_ASC_FIS.
• Removed edge between:  ('SQZ_READY_HD', 'NO_SQUEEZING').

Still want to do a larger deep dive into what SQZ_MANGER and each of it's subordinates are doing so that the log is easier for the operators to read and troubleshoot from. Also we expect we can change "OFFLOAD_SQZ_ASC" to be a "manual to" state that can be completed independently of if we're in SQZ or no sqz. Anyone with SQZ_MANGER open should close and reopen.

[M. Todd, C. Compton, G. Vajente, S. Dwyer]

Summary

To understand the effect of the Relative Intensity Noise (RIN) of the CO2 laser (Access 5W L5L) proposed for CHETA on the DARM loop, we've done a brief study to check whether the addition of the RIN as displacement noise in deltaL will cause saturation at several key points in the DARM loop such as the ESD driver and DCPDs. The estimates we've made on the RIN at these points are calibrated with the DARM model in pydarm, which models the DARM loop during Nominal Low Noise; however, appropriate checks have been made that these estimates are accurate or at least over-estimating of the effects during lower power stages (when the CHETA laser will be on).

CHETA RIN to ESD drive

This estimate is done by propagating displacement noise in deltaL (how CHETA RIN is modeled, m/rtHz) to counts RMS of the ESD DAC. The RMS value of this should stay below 25% or so of the saturation level of the DAC, which is 2**19. To do this, we multiply the loop suppressed CHETA RIN (calibrated into DARM) by the transfer functions mapping deltaL to ESD counts (all are calculated at NLN using pydarm).

The CHETA RIN in ESD cts RMS is 0.161% of the saturation level, and in L2 coil cts RMS is 1.098%, and in L3 coil cts RMS is 0.015%. It is worth noting that the CHETA RIN RMS at these points is around 10x higher than that which we expect with just DARM during NLN.

We also checked to make sure that the ESD cts RMS during power-up states is not higher than that during NLN, meaning the calibration using NLN values gives us a worst case scenario of the CHETA RIN impact on ESD cts RMS.

List of Figures:

    1) Loop Model Diagram with labeled nodes
    2) CHETA RIN in ESD cts RMS
    3) CHETA RIN in L2coil cts RMS
    4) CHETA RIN in L1coil cts RMS
    5) DARM Open Loop Gain - pydarm
    6) DARM Sensing Function - pydarm
    7) DARM Control Function (Digitals) - pydarm
    8) Transfer Function: L3DAC / DARM_CTRL - pydarm
    9) Transfer Function: L2DAC / DARM_CTRL - pydarm
    10) Transfer Function: L1DAC / DARM_CTRL - pydarm
    11) ASD/RMS ESD cts during power-up states - diaggui H1:SUS-ETMX-L3_MASTER_OUT_UL_DQ
    12) CHETA RIN ASD (raw)

CHETA RIN to DCPD ADC

This estimate is done by propagating displacement noise in deltaL (how CHETA RIN is modeled, m/rtHz) to counts RMS of the DCPD ADC. The RMS value of this should stay below 25% or so of the saturation level of the DAC, which is 2**15. To do this, we multiply the loop suppressed CHETA RIN (calibrated into DARM) by the transfer functions mapping deltaL to DCPD ADC counts, using the filters in Foton files. This gives us the whitened ADC counts, so by multiplying by the anti-whitening filter we get the unwhitened DCPD ADC cts RMS, which is what is at risk of saturation.

The CHETA RIN in DCPD cts RMS is 3.651% of the saturation level. Again, it is worth noting that the CHETA RIN RMS at this point is around 10x higher than that which we expect with just DARM during NLN.

We also checked to make sure that the DCPD-A ADC channel is coherent with DARM_ERR. In short, it is up to 300Hz, where controls noise dominates our signal -- after 300Hz shot noise becomes the dominant noise source and reduces our coherence.

List of Figures:

    1) Loop Model Diagram with labeled nodes
    2) CHETA RIN in DCPD ADC cts RMS
    3) Transfer Function: DCPD-ADC / DELTAL_CTRL
    4) Coherence: DCPD-A / DARM_ERR

Codes used:

Calibrating CHETA RIN to ESD cts RMS

Calibrating CHETA RIN to DCPD ADC cts RMS

Previous related alogs:
    1)  alog 82456

J. Oberling, R. Short

After our work in the PSL enclosure this morning (see Jason's alog82636 for details), Jason and I made our way back to the control room for our last few tasks. From there, we first calibrated the PDs after each amplifier using the measurements made on-table. Since it had been enough time where we felt that the environment had settled down enough in the enclosure with the fans off, I attempted some more PMC alignment using the picomotors and was able to get PMC transmitted power up to just above 105W. With the PMC looking good, I enabled the ISS and adjusted the RefSignal to bring the diffracted power back down to around 4% (and accepted the RefSignal in SDF). We then were able to lock the RefCav and touched up the alignment here also, but there wasn't much to gain; the signal on the FSS TPD currently hovers around 800mV.

With the PSL recovered, I ran a rotation stage calibration since the output power of the PMC had changed as a result of our work today. Appropriate screenshots of SDF and the fit are attached.

TITLE: 02/04 Day Shift: 1530-0030 UTC (0730-1630 PST), all times posted in UTC
STATE of H1: Preventive Maintenance / Lock Aquisition
INCOMING OPERATOR: Corey
SHIFT SUMMARY: Busy maintenance day, PR2 spot move took a little while but we had trouble getting started. The violins look elevated as we're getting to ENGAGE_ASC, I envision us spending time in DAMP_VIOLINS or OMC_WHITENING to damp them down during this aquisition.
LOG:                                                                                                                                                                                      

• 17:36 Norco on site
• 18:03 HAM7 CPS glitch, ISI wd tripped
• 20:50 UTC Manual_IA, we had some trouble starting up the IA as there was some issue with SDF revert setting gains, we were seeing large L3_ISCINF_OUTPUT signals on the ETMs and ITMs. alog82637
• 22:22 UTC Oli swept the LVEA

Some of the maintenance tasks completed today include:

• OMC duotone freq changed to match LLO alog82626
• PR2 spot move
• PSL PMC/amplifier investigation alog82636
• SUS_PI guardian updated alog82628
• PCAL end station measurements, a beam movement at EX, and a standard measurement at EY
• VAC turbo pump checks/tests alog82629, air compressor valve fix
• Computer rack checks for cameras, new digivideo computer hardware, removing old analog camera hardware
• TCS CO2X laser testing alog82624
• Xarm tumbleweed control
• Acme pest contractor site checks

TITLE: 02/05 Eve Shift: 0030-0600 UTC (1630-2200 PST), all times posted in UTC
STATE of H1: Preventive Maintenance
OUTGOING OPERATOR: Ryan C
CURRENT ENVIRONMENT:
    SEI_ENV state: CALM
    Wind: 17mph Gusts, 11mph 3min avg
    Primary useism: 0.04 μm/s
    Secondary useism: 0.28 μm/s
QUICK SUMMARY:

H1 is currently on its way back up (currently holding at PREP DC READOUT Transition for Sheila).

Ryan-C mentioned a few items I need to keep an eye on post-Maintenance (i.e. new PI Mode guardian change and rung up violins). 

Microseism looks decent and it's breezy (but below 20mph).

R. Short, J. Oberling

In an effort to understand our ever-increasing PMC reflected power (and associated loss of PMC transmitted power), today we measured the slopes (output power vs injection current) of the pump laser diodes for the 4S-HP amplifiers.  We have power monitors on the pump diodes (calibrated in %, with 100% being our pump diode power at install), but we don't exactly trust them; the monitors for Amp1 show the Amp1 pump diodes are outputting less power than upon install (as we expect after 3 years of almost 24/7 operation), but the monitors for the Amp2 pump diodes indicate we are outputting more power than upon install.

We measure the diode slopes using our water-cooled, 300W-capable roving power meter.  Since the pump diodes are ganged together in groups of 2 to their power supplies (1 power supply powers 2 pump diodes, so 8 total pump diodes are powered by 4 power supplies) we have to make sure the diode from the group of 2 that we are not measuring is being dumped; we use an 80W-capable air-cooled beam dump for this.  The steps for measuring the slopes are:

• Unplug the fiber for the 1st diode in the group of 2 and install it into a fiber holder that is directed into the power meter
• Unplug the fiber for the 2nd diode in the group of 2 and install it into a fiber holder directed at the beam dump
• Step up the injection current for the relevant power supply in 1A steps (make sure the other 3 supplies are set to 0.0 A), measuring the output power at each step
• Switch the fibers so the one directed at the dump is now directed at the power meter and vice versa
• Step up the injection current in 1A steps, measuring the output power at each step
• Reinstall the fibers into their original ports on the amplifier
• Repeat the above for the remaining groups of fibers

The results are given the 1st attached spreadsheet, with a comparison between today's measurement and the measurement done during install shown in the 2nd attached spreadsheet.  Immediately one sees that, despite what the pump diode monitors imply, all 8 pump diodes are outputting more power than they were at install back in 2021.  I have no explantion for this right now, we were expecting the output power to be lower (since they've been running almost 24/7 since January 2022, and were up an down mulitple times during install starting with Amp1 first light in October 2021).  So we are currently pumping both amplifiers with more pump light than we were at the end of install in January 2022.

To give you an idea of the degree of overpumping, at install for Amp1 we were running all 4 pump diodes at 9A of injection current; this in turn gave us between 46 W and 47 W of output power from the pump diodes for Amp1.  We are now running at 9 A for pump diodes 1 and 2 and 8.8 A for pump diodes 3 and 4, which is giving us between 48 W and 50 W of output power for the Amp1 pump diodes (with the exception of diode 4, which is around 46.5 W).  This can and does change the size and location of the output beam waist from the amplifiers, as the thermal lenses in the amplifier crystals change with changes in pump power, which then impacts the mode matching to the PMC.  What this doesn't exactly explain is why we've been seeing a slow increase in PMC reflected power (maybe beter mode matching would make it more stable? Maybe by over-pumping the amps we're oversaturating the gain profile to the point where small changes in injection current cause large changes in output beam size/shape?).

In recovering the amplifiers we optimized the pump diode fiber alignment; this was necessary since we deinstalled the fibers from the amplifiers to measure the slopes.  This is done by very slightly loosening the fiber connector, enough that you can turn the fiber in its port on the amplifier.  With the amplifier on and a power meter measuring the output power, loosen one fiber connector and slowly rotate the fiber while watching the power meter (which will change by several thenths of a W).  When the power peaks, tighten the fiber connector.  Repeat for the remaining fibers.  In doing so we brought the output power of Amp1 to 71.4 W from 69.6 W, and the output power of Amp2 to 141.5 W from ~140.0 W.  Interestingly, and not really surprising when you stop to think about it, optimizing the fiber alignment also resulted in a very slight shift in output beam alignment.  We didn't immediately notice this until we recovered the PMC and had to do some alignment tweaks to max the transmitted power (we had ~50W reflected at first, but this dropped very quickly with a few Small step size angle tweaks from one of our picomotor-controlled mirrors, indicating the alignment shift was very small).  As a result of this we realigned the beam onto the amplifier power monitor PDs.  We also had to recalibrate our Amp2 Out monitor PD; I can't readily explain why right now.  Another thing we noticed is that the optimum pump fiber alignment for the amplifier is not necessarily the optimum alignment for the pump diode monitors; we saw the monitor percentages change while rotating the pump fibers, and most of them peaked when the amplifier output was not maxed (for example, pump diode 2 for Amp1 peaked at 99%, but the best output for the amplifier was achieved at a monitor reading of ~89%).

Speaking of the PMC, by making no other changes to the system besides optimizing the pump diode fiber alignment, we saw an immediate improvement to our reflected power.  Ryan did a quick tweak while in the enclosure which brought the reflected power down to ~24 W, and a more detailed alignment in the Control Room brought the reflected power down to ~23.6W.  At the time we completed this work (~12:30pm PST) and with the ISS ON and diffracting ~4.1%, we had 104.9 W transmitted from the PMC and 23.6 W reflected (at the start of the day there was ~101.7 W transmitted and ~27.2 W reflected).  As a check to see how the PMC would react to changes in injection current, we lowered the Amp1 currents from 9.0 A and 8.8 A to 8.8 A and 8.8 A (bringing the injection current more in-line with where we were at install).  This brought PMC Refl down by ~0.5 W.  We then brought the Amp2 injection currents down to 8.6 A from their current 9.1 A; this skyrocketed the PMC reflected power to ~30 W.  So bringing Amp1 more in-line with its install configuration makes PMC Refl better, but then bringing Amp2 more in-line with its install configuration makes PMC Refl much worse.  Huh.  We returned the injection currents back to where we've had them (9.0 A and 8.8 A for Amp1, 9.1 A and 9.1 A for Amp2).

There is still mode matching work to do, as can be seen by the shape of the PMC Refl spot.  We will have to do that at a later date since that is time consuming work (we would have to do it all in one go, Amp1 -> Amp2 then Amp2 -> PMC, which will likely take longer than a 4-hour maintenance window).

NOTE: We did not recalibrate the pump diode monitors, as we left the injection currents where we have been running the system.  However, the percentage readings of the monitors did not come back to where they were before we started today's work.  We will recalibrate these monitors once we decide if we want to change the injection currents.  So for now the pump diode monitor percentages are not truly representative of where we are running the pump diodes (and as I think today's work has shown, they never really have).

This closes LHO WP 12315.

Sheila, Dave, Ryan Crouch, Tony

This afternoon after the maintence window when we first started using guardian, once the ASC safe.snap was loaded by SDF revert we started sending large signals to the quads.  We found that this was due to the camera servos having their gains set to large numbers.  This was set this was in the safe.snap file. 

After I set these two zero in safe.snap (which is really down.snap), Ryan again went through the guardian down, and this time we started to saturate the quads because of the arm asc loops (which we probably didn't notice the first time because we tried running down when we saw that there was a problem, and down would turn these off but not the camera servos).

Dave looked in the svn for this file, which he had committed this morning with this set of: diffs from this mornings svn commit  .  Looking through these, it kind of seems like somehow the safe.snap may have been overwritten with the observe.snap file. 

Dave reverted that to the file from 7 days ago, which has Elenna's changes to the POP QPD offsets. Then I reverted all the diffs, so that we set all settings back to 7 days ago except those that are not monitored.

After this, Mayank and I were using various initial alignment states to make some clipping checks, which Mayank will alog.  We noticed that the INP1Y loop (to IM4) was oscillating, so we reduced the gain in that from 10 to 40, on line 917 of ALIGN_IFO.py  We also saw that there is an oscillation in the PRC ASC if we sit in PRX, but we haven't fixed that.  These should not be due to whatever our safe.snap problem is, we hope.

Edit to add: We looked at the last lockloss, when the guardian went through SVN revert at 7 am yesterday Feb 3rd.  It looks like the camera gains were 0 in the safe.snap at that time, but it was 100 by the time we did SDF revert at 20:51 UTC (1pacific time) today.

FAMIS 23731

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

Summary: anti-aliasing improvements (82440) seem to have removed quite a few spectral artifacts -- but not the ones that originally motivated the anti-aliasing investigations, i.e. the narrow line contamination around violin modes.

Background / timeline

Anti-aliasing improvements were made Jan 23-24th. There was a failed attempt on Jan 23 (82412), a temporary reversion, and then a successful attempt on Jan 24 (82440). Reports by Evan (82455) and Jeff (82512) provided a first look at improvements to the spectrum. Earlier observations indicated that at least some of the aliasing artifacts displayed "amplitude variations on the order of factors of a few and frequency shifts on the order of 0.1 Hz, at least for the artifacts observed near 758 Hz." (82329) 

A closer look at the mitigated peaks

In order to look more closely at the improvements flagged in 82512, I compared daily Fscan spectra from Jan 22 (before) to Jan 26 (after). As an example, let's look at the two peaks in the region of 760 Hz.

These peaks have disappeared after the change, which is good news. However, these are pretty "broad" peaks by the standards of CW detchar. Figures 1 and 2 show zooms of the spectral comparison. This seems consistent with the frequency variation reported earlier, but notably unlike the mysterious narrow peaks that have been appearing around the violin modes. I've reviewed the rest of the 10-2000 Hz band in Fscan data, and so far all of the improvements I've spotted are similarly "broad."

Going back to the example case near 760 Hz: in O4a spectra, a pair of corresponding peaks can be seen (figure 3)-- but not identical. Their locations are slightly off of January 2025 locations. To understand this better, I tracked the peaks in weekly spectra across O4 (figures 4 and 5). Both shift over time, in similar ways. I also double-checked that they've disappeared and stayed gone since Jan 24, see figures 6 and 7. Note that these plots are not all on the same colorbar; they were adjusted for visibility in each case.

I've also not made similar tracks for any of the other peaks, nor looked above 2000 Hz. I have attached the frequencies of all the peaks I've noted as a text file for future investigations; there are way more decimal places than are actually meaningful because I was just picking these off a high-resolution plot and not doing any kind of careful width estimation.

Evidence of violin mode region narrow line contamination persists after the changes

While doing the comparison, I ended up spotting an example of more violin mode region contamination in the January 26 spectrum, just a couple of days after the anti-aliasing improvements. This hadn't been picked up by initial visual inspections of the production Fscan plots, but putting the spectra side-by-side made it much easier to see what was happening. It turns out that a number of the lines are readily identifiable as intermodulations of the elevated violin mode peak +/- calibration line frequencies (a situation which has been seen before, for instance in 79825). Figure 8 highlights these lines (marked with small gray circles), plus the relevant violin mode peak.

[M. Todd, C. Compton]

Camilla had data she took from the CO2Y ISS PDs, (both AC and DC), and we wanted to calibrate those measurements into the laser RIN. Today, we took data for CO2X following the same procedure.

DC values were taken from alog 82262 and DC/AC gains from the pre-amplifier are taken from the dcc diagram. All measurements were taken up to 20kHz.

We had time to do more measurements with various Pulse-Width-Modulation frequencies to see their effect. Interestingly, while the ASD (cts/rtHz) seems to go up with higher PWM frequency, the overall RMS goes down...I think we care more about the RMS RIN, so it may be advantageous to have our PWM at higher frequencies.

List of Figures:

    1) RIN of CO2Y laser comparing continuous wave versus PWM at 5kHz
    2) RIN of CO2X laser comapring continuous wave (locked vs unlocked) and the PWM at 5, 10, 25 kHz
    3) The DC values for the CO2X data are taken from the ndscope trend

Codes:

    1) Calibrating the CO2Y data
    2) Calibrating the CO2X data

Functionality test for the corner station turbo pumps, see notes below:

Output mode cleaner tube turbo station;
Scroll pump hours: 6276.1
Turbo pump hours: 6321
Crash bearing life is at 100%

X beam manifold turbo station;**
Scroll pump hours: 2347.9
Turbo pump hours: 2349
Crash bearing life is at 100%

Y beam manifold turbo station;
Scroll pump hours: 3119.6
Turbo pump hours: 1793
Crash bearing life is at 100%

**Note for the output mode cleaner tube system, the scroll pump is making a little of extra noise when starting, the scroll pump was flagged for such noise during last FAMIS task.

FAMIS tasks 31344, 31328 and 31336.

I've updated the SUS_PI guardian code to make it a bit neater - before the code would go over and do all the checks for each PI one at a time and there were four copy+pasted versions of almost the same thing being done. I made a dictionary for each PI we currently check and put those in a new file piparams.py, then imported that into SUS_PI.py and created one big loop in the gen_PI_DAMPING class. I also make it so in the IFO_DOWN state, the dictionary values that change during monitoring are reset when the IFO loses lock. I've tested this out (although while the IFO was down so I couldn't check every configuration) and it worked. I've committed both SUS_PI and piparams to svn.

Please let me know if any issues are encountered with it Tagging Ops

Maintenance activities have wrapped up, following the Front End restart, and the PSL rotation stage calibration. We are relocking and doing some measurements during an IA (PRC clipping checks).

h1omc0 duotone frequency was changed to 1920/1921 Hz.  LLO changed l1lsc0 duotone frequency to the same value at the same time.

This invovled a restart of all h1omc0 models.

[Matthew Camilla Louis Sheila]

There is concern that the CO2 laser proposed for the CHETA design has enough intensity noise to saturate the ESD preventing lock.

By calibrating the displacement noise projected from CHETA RIN data into counts at the L3_ADC, using the DARM loop OLG and transfer function between DeltaL_ctrl and L3_ADC, we can get a rough estimate of whether we expect the CHETA noise to saturate the ESDs. This is done by looking at the RMS of the cts/rtHz of CHETA noise at the ESD and comparing it to the 25% of saturation level (2^19 counts).

Figure 1 is the loop model for mapping the displament noise (CHETA RIN) to ESD counts, Figure 2 is a plot of the darm olg, Figure 3 is plot of the tf from deltaL_ctrl to L3_adc.
Figure 4 is the projection of CHETA RIN to the ADC counts, showing that we do not estimate CHETA is likely to saturate the ESDs.

Next steps are to see if we estimate CHETA nosie to saturate the DCPDs at different power up stages.