J. Kissel

We've gathered our regular Tuesday measurement of the effective bias voltage as a result of charge on the end test masses. After the hiccup of settings loss a few week's ago (LHO aLOG 26793), the last three weeks of results confirm that both test masses are back on there way to zero effective bias voltage. Good! 

Also encouraging, is that the rate of charge accumulation seems to have become consistent between flips of requested bias. This didn't always used to be the case; see LHO aLOGs 22135 or 20387 in which we had evidence that the rate of charge was a crap shoot every time we flipped the requested bias sign. There's no obvious reason why it would be different between now and then, but it's good to see that it may be one less thing we have to worry about.

However, recall, the plan -- to minimize time-dependent calibration error during observing runs: after we've brought the effective bias voltage to zero, regularly flip the requested ETM bias voltage such that it *stays* at zero and never accumulates. Today's results show that we're pretty darn close to zero with ETMY, so we should write that script that automatically flips the requested bias voltage and takes care of all the collateral damage (see LHO aLOG 26826) this week or next, and exercise it. 

Only after we regularly exercise flipping and confirm nothing goes suddenly bonkers, will we say we're comfortable doing it regularly during the run.

I took advantage of today's maintenance period to do some investigation of the PCalX clipping issue.  I dithered the ETM independently in pitch and yaw: leaving yaw in the original 'aligned' position while dithering pitch, and vice versa.  See attached pic if you care about the individual data points. In summary, I found that changing ETM yaw had a much greater effect on the power received by the receiver photodiode (RxPD).  This seems to indicate that we can narrow down our search for clipping to the receiver side of the ETM.

Original 'aligned' values:

Pitch: -16.0 urad

Yaw: 78.8 urad

RxPD: 2.090 Volts

Greatest power for pitch dither:

Pitch: 150.0 urad

Yaw: 78.8 urad

RxPD: 2.315 Volts

Greatest power for yaw dither:

Pitch: -16.0 urad

Yaw: 400.0 urad

RxPD: 3.15 Volts

Combined dither:

Pitch: 100.0 urad

Yaw: 400.0 urad

RxPD: 3.16 Volts

The next chance we have to go to the end station, we'd like to try adjusting the steering mirrors in the transmitter module again (we've tried this once, but with limited success). 

Added 3055 channels. Removed 643 channels. List attached.

ITMY CO2 stopped lasing at 10:00 local and ITMX CO2 stopped lasing at 10:05 local. Both RTD/IR sens. alarms tripped. Only ITMY recovered itself successfully (still required me going to the rack and hit GATE button to restart the laser) while ITMX interlock ramped down and came right back to the tripped value (what the hell happened here?). I'm not aware of any restarts that could have caused them to trip. Both FLOW ALARMs were okay.

Jim, Dave:

Sheila and Jenne made h1asc filter changes over the weekend and we noticed today that the diff file for this system was filled with many copies on a single filter. Investigating further we noted that the problem was with the three filters ASC_CHARD_P, ASC_CHARD_P_A and ASC_CHARD_P_B. Jim noted that these consist of a core name, and filters with additional suffixes, so we suspected a potential string matching issue. In the case of h1asc, the running H1ASC.txt file in the chans/tmp directory had 638 copies of the ASC_CHARD_P filter module, with varying header names.

We were able to reproduce the problem on the DAQ Test Stand. We made changes to the three filters and loaded them individually. When the "core" named filter (ASC_CHARD_P) was loaded many copies of this were created. Further individual loads compound the problem, which is why h1asc ended up with so many copies.

A bug has been opened for this: https://bugzilla.ligo-wa.caltech.edu/bugzilla3/show_bug.cgi?id=1014

We scanned all the H1 filter modules looking for filters which are core names to additional filters. We found 65 cases in the 8900 total number of filters. These filters are distributed over the following systems:

h1alsex
h1alsey
h1asc
h1calex
h1caley
h1iscex
h1iscey
h1lsc
h1oaf
h1odcmaster
h1omc
h1psldbb
h1pslfss
h1psliss
h1pslpmc
h1susetmx
h1susetmy
h1susitmx
h1susitmy
 

Until this issue is resolved, we recommend that users do not individually load filter modules and instead perform full filter file loads from the GDS_TP MEDM screen.

I gathered some new data points from today and fine tuned the calculator. The requested power and measured power now agree within 1%. A 10-day minute trend of PMC transmitted power shows that the PSL power itself fluctuates on the daily basis which will throw off the calibration slightly. The calculator must be re-tuned based on the maximum PSL power going to the IMC, given that the minimum power angle doesn't change.

J. Kissel, B. Weaver
Work Permit: #5880
FRS Ticket: #5489
Integration Issue: #FRS 5506
ECR: E1500045

Betsy and I've installed the individual coil driver switching of HSTS M3 stages as per documentation linked above. The front-end model changes were prepared and described yesterday (see LHO aLOG 27223), though note, we found some bugs and have to recompile again this morning (LHO aLOG 27239), after making the MEDM screen modifications described in the this log.

We've made modifications to the following MEDM screens:
/opt/rtcds/userapps/release/sus/common/medm/hxts/
M       SUS_CUST_HSTS_OVERVIEW.adl         <--- made CD STATE and TEST/COIL ENABLE settings and readbacks for each quadrant independent, 
                                                and linked to new non-generic HSTS screens mentioned below
and created new screens:
/opt/rtcds/userapps/release/sus/common/medm/hxts/
?       SUS_CUST_HSTS_M3_EUL2OSEM.adl      <--- used to be generic with all HXTSs, but now specific to HSTSs
?       SUS_CUST_HSTS_BIO.adl              <--- used to be generic with all HXTSs, but now specific to HSTSs
and screen shots of each are attached. 

Unfortuanely, because the BIO settings and EUL2OSEM matrix elements are new channels for the M3 stage, one has to, by-hand, re-enter every suspension's
    - Requested coil driver state
    - The TEST/COIL ENABLE switch
    - The M3 EUL2OSEM matrix elements.
and then hit "LOAD MATRIX" on all of the M3 EUL2OSEM matrices. We used Betsy's screenshot from last night to do this (from LHO aLOG 27225).


We've also made our best attempt at updating the safe and down.snap files which had to have the former, ganged BIO channels replaced with the individual coil BIO channels. This required quite an SDF dance:
1) On SDF SAVE SCREEN for each SUS, 
    - change SAVE TABLE to "EPICS DB TO FILE" in order to update the snap file with the new epics database channel list currently running with the new model
    - change FILE OPTIONS SELECTION to "OVERWRITE" in order do this with the currently loaded snap file
    - Hit SAVE FILE
    (We did this with every safe, down, or observe snap file for a given suspension)
2) On SDF RESTORE SCREEN for each SUS,
    - SELECT REQUEST FILE that you want to load in with the new updates
    - LOAD TABLE
    This should cleared out any of the channels with have disappeared from the model and create a bunch of new channels which are NOT INITitallized.
Since keeping track of all of these channels and snap files was a bear, I don't promise that we've gotten everything right. We'll just have to keep an eye on them over the next few weeks to check if we've missed anything.

Jenne's working on updating all Guardians that controlled the M3 stages of the HSTSs, and coding up the 3-coil-motion necessary for switching the coil state one at a time like is done on the beam splitter. 

Below are RPN and Modescan scans for both LO and HI power.

David.M, Jenne.D, Richard.M

We tested some of the electronics for the L4C geophones which are soon to be installed as an array. These were three L4C Concentrator Chassis (D1600144, labelled '1', '2', and '3' on front) and two L4C Interface Chassis (D1600148, labelled '1' and D1600152, labelled '2').

These are all working correctly. The only alteration made was to swap the 9 pin plugs for 'L4C 6' and 'L4C 7' on the board of Interface Chassis D1600148 (currently labelled as Interface Chassis '1' on front), since they were the wrong way around.

I've attached a pdf with the pin layout for each chassis for reference:

Here are the trends from the past 12 days. The past couple of weeks have been agitated by a number of chiller trips and ongoing work.

Jenne, Sheila, Evan, Kiwamu

Today we aimed to have a long stable lock at 30 Watts. We did have one lock of more than half an hour at 30 Watts, which we lost due to commisioner error.

• We measured the coupling of test mass pitch to arm power fluctuations.  More information will be coming later. 
• We noticed that we can loose lock because of the CSOFT instability driven by power fluctuations when we power up too quickly for our soft loops to keep up.  We rewrote the INCREASE POWER state to pause and wait for soft loops at 10 Watts intervals.
• In 3 out of our last 4 locking attempts, we have lost lock in DARM offset.  The one time we made it Jenne did the steps in the guardian by hand.  There don't seem to be any changes in the code for this state....
• We had a few locklosses engaging the ISS 2nd loop.  The thresholds needed to be adjusted, now it is working.
• We did some A2L tuning today.
• We had a couple of sudden locklosses, where our recycling gain was slowly decaying, and it looks like the PR2 (REFL WFS) loop and SRC2 (AS_C to SR2 and SRM) loops ran away in the last fractions of a second.  This seems like the lockloss we had because of the sign flip in the REFL WFS, because we increased the bandwidth of the PR2 loop it is now a fast lockloss.  We measured the open loop gain of PRC2 both at 30 Watts (where the recycling gain is decaying) and at 2 Watts, the optical gain is lower at the 30 Watts measurement which was taken right before one of these locklosses. 
• We decided based on this to try moving soft loop offsets, but we want to picomotor the TMSY QPDs before moving the offsets...  we are leaving this for tomorow...  We turned off the CHARD blends so that we can move picomotors, and are leaving them off for now, but should turn them back on when we are done with picomotors.

Also, the ISS 1st loop is oscillating pretty much every time we loose lock and needs to be fixed by hand. we are leaving IFO undisturbed at 23 Watts 7:50 UTC

Sheila, Jenne, Evan

We have suspected for some time that the POPAIR B diode (which we use to extract POPAIR18 and POPAIR90 signals) is saturated in full lock, because these signals do not scale appropriately when increasing the PSL power. Now that we are seriously trying to use POPAIR90 to diagnose DRMI angular behavior during power up, we would instead like to use a signal that we can trust.

We tried a few different things today:

• Take the rf monitor for POP45 (in-vac) and feed it into the POPAIR90 demodulator. This seems to give a signal that scales appropriately with the PSL power (good), but the SNR is worse (bad).
• Take the rf monitor for POPAIR45 and feed it into the POPAIR90 demodulator. Same performance as above.
• Insert a 12 dB coupler directly into the POPAIR45 line. Feed the coupled output into the POPAIR90 demodulator. This gives a signal that scales appropriately with the PSL power and has comparable SNR to POPAIR90.

The last of these is the configuration that we have now. Whitening and dark offsets were set to give appropriate signal levels.

Careful examination will actually show that there appears to be a bit of saturation with this POPAIR45 signal as the power is increased. According to the POPAIR_A_LF channel, there is 83 mW (!) of dc power on this PD at 25 W. Probably we should be closing the POP beam diverter at this power, or else we need to swap some optics on the table.

Ideas for how to improve:

• Put the coupler on POP45 instead, since the POP PD has four times less light than POPAIR A. Requires rechecking the phasing of POP45 for MICH and SRCL in full lock. Has the advantage of giving us POP90 information even when the POP beam diverter is closed.
• Investigate whether POPAIR B can be made to give sensible signals. Perhaps we should modify it, just as we did in order to make REFLAIR B give sensible signals.

J. Kissel, B. Weaver
Work Permit: #5880
FRS Ticket: #5489
Integration Issue: #FRS 5506
ECR: E1500045

As a band-aid solution to the ganged-coil-driver-state-switching-lock-losses-during-acquisition, recently identified to be PRM (see LHO aLOG 27158), we're going to modify the M3 stage of the HSTS's library part to have individual control over coil switching similar to what was done with the M2 stage of the Beam Splitter some time ago (see E1500045).

Because of the breakdown of suspension-type library parts, we must changes to
/opt/rtcds/userapps/release/sus/common/models/
HSTS_MASTER.mdl
MC_MASTER.mdl
and instead of copying the un-library-parted BSFM_MASTER M2 COILOUTF bank, we created a new library part to be copied into the HSTS_ and MC_MASTER_M3 stages, called
/opt/rtcds/userapps/release/sus/common/models/FOUROSEM_COILOUTF_MASTER_INDIVIDUAL_CTRL.mdl
We've confirmed that these updated models compile, and they've been committed to the userapps repo.

We'll work on MEDM screens tomorrow morning, once we've compiled the updated models and we have new channels. There will be some settings (namely the coil driver state settings) that will be lost from the channel name switch, so we'll make sure to replace those in the SDF system accordingly. We'll also make our best attempt EVER at preserving the alignment of these SUS after the restart.

Kiwamu, Darkhan,

We updated the ETMY L1 stage (UIM) compensation filters FM2, FM3, FM4, FM7, FM8, FM9 of ETMY_L1_ESDOUTF_{UL,LL,UR,LR} with zeros and poles more accurately fitted to the most recent measurements by Jeff K. from ER8 (LHO alogs 20846, 21283). We have not updated the acquisition circuit zero-pole pair, because the measurements do not include the response of this circuit (for details see LHO alog 21142).

We've also updated the ETMY L2 stage (PUM) compenstation filters FM1, FM2, FM3, FM6, FM7, FM8 of ETMY_L2_ESDOUTF_{UL,LL,UR,LR} to their fitted values (LHO alogs 20846, 21232).

Python scritps were used to load new vailes into the Foton file, the scripts are based on Kiwamu's script for updating filter in the L3 stage (ESD) (LHO alog 27150). The scripts are committed to CalSVN at

Runs/PreER9/H1/Scripts/SUS/setH1SUSETMY_UIMDriver_compensations.py
Runs/PreER9/H1/Scripts/SUS/setH1SUSETMY_PUMDriver_compensations.py

Notes for CAL FOLKS:

• UIM and PUM filter replicas in CAL-CS model have not been updated accordingly at the moment;
• The extra compensations (for imperfect front-end filters) in the Matlab DARM calibration model are not necessary anymore, must be removed from the model.