Calum, Kate, Betsy

This week, we performed a series of First Contact cleaning tests on the old pilot optic ETM06 as a followup on the ring observed on the ETMy during green-arm resonance last month (alog 15928).

ETM06 has a very similar history to the installed LHO ETMs (ETM08, ETM12).  A FirstContact sheet which had the 2x 3" IAS windows was applied to ETM06 roughly 2 years ago.  After pulling the sheet this week, we observed the ring pattern, as seen on the ETMy.  Via cleaning we were able to remove a section of the ring, which implies the ring discoloration is not from etching.  Our other tests did not indicate there are any age correlations to the protective FirstContact sheets applied to optics.  Reminder - the LHO ETMs (ETMy 125ppm) have recently been measured to be low loss, so there is no current plan to further clean in-situ.

SYS/COC investigations to be continued...

model restarts logged for Thu 22/Jan/2015
2015_01_22 00:06 h1fw0
2015_01_22 00:42 h1fw0
2015_01_22 01:41 h1fw0
2015_01_22 03:05 h1fw1
2015_01_22 03:31 h1fw1
2015_01_22 04:03 h1fw1
2015_01_22 04:29 h1fw1
2015_01_22 05:37 h1fw1
2015_01_22 23:39 h1fw0

X1PLC1 10:30 1/22 2015

X1PLC2 10:31 1/22 2015

X1PLC3 10:30 1/22 2015

Y1PLC2 09:43 1/22 2015

all unexpected frame writer restarts. Recent fw period of instability ended at 5am, could be related to internal RAID diagnostics, investigation proceeding. Conlog frequently changing channels report attached.

In order for people to get some undisturbed DRMI data for glitch hunts or seismic performance evaluation, we've left the DRMI locked with the ETMs misaligned starting at 1:09 AM local time (0909 UTC).

Its been locking fine tonight with only tiny angle tweaks made after locking (but probably unneccesary). Hopefully it will relock by itself overnight. If so, the morning SEI crew ought to be able to be able to switch the seismic filter state and re-eval the control signals with only 0.1-0.2 urad tweaks to PR3, SR3, and BS.

We think that the DRMI CAL channels are out of date, but Kiwamu can probably tell us what they mean in meters units with almost no effort.

Rana, Evan

Tonight, we took some transfer functions from the ETMX/ETMY ESDs to LSC DARM IN1, when controlled by ALS DIFF. Right now we only use ETMX as our DIFF actuator (as we had previously had some trouble using ETMY), but perhaps it is time to revisit this. Using both ESDs will double our range. Additionally, by properly balancing the relative drive strengths between the two ESDs, we can make ourselves more immune to cross-coupling between the ALS-controlled DARM and CARM loops.

For the excitation we drove each L3 TEST L filter bank with 40000 ct from 10 Hz to 40 Hz.

Evidently, ETMX and ETMY have opposite signs and their gains differ by 6 dB or so (at least below 20 Hz, where the coherence is OK). Since we're aiming for a DIFF loop with a UGF of 15 Hz or so, we don't care so much what's going on above 20 Hz, so long as it's not outrageous. So we (hopefully) should be able to implement a balanced ESD drive with little trouble by engaging DIFF with both ESDs (with fiducial output matrix gains), then turning on a line in DARM, and then adjusting the output matrix gains until the line is nulled.

Evan, Alexa, Elli, Sheila, Rana,

• Evan changed the gain on the END Y TR PD to 20dB, while the X end 1 is still at 0dB (alog 16211)
• We realized that with our better recyling gain, the locking offset and gain we used last night were not sensible.  We are not using an offset in sqrt(TRX+TRY) of -1.7, which would put us at 300 pm if the recylcing gain is 30, similiar to the CARM offset that we used before.  We also estimated that the calibration into picometers should be changed from 312 to 180.  (this is the to_pm FM in TR_CARM)
• Alexa realized that the res G filter to supress 1 Hz noise in ALS DIFF was not on, turning this on reduced the RMS of ALS by about a factor of 10, helping us to stay in the linear range of TR CARM.
• We have been stable in the state PREP_TR CARM for 10 minutes or so.  We have been able to turn the gain of the ALS signal down to -11dB on the common mode board, while the TR CARM input was at a gain of 4dB.  
• We changed the low frequency boost in LSC-REFL BIAS, we are no longer engaging FM6 (a true integrator with a zero at 1 Hz).  We also changed FM5 so it is no longer a true integrator, it now has a pole at 1Hz and is turned on in PREP_TR_CARM.  We have also stopped using the lead filter in FM8, we have plenty of phase without it.  
• We measured the cross over in ALS COMM to be at 50 Hz, with 45 degrees of phase margin.

We think that we are loosing lock due to some 12-15 Hz noise in CARM which is non stationary.   We watched the spectrum of CARM locked on ALS with and without DIFF locked, and saw that the non stationary noise is only there when DIFF is locked.  We then looked back at our ALS DIFF design (alog 15025) and decided to reduce the gain by 35%. This has reduced the gain peaking, but we still have nonstationary noise in CARM.  

lock loss times: 1:44:20 UTC, 3:01:27 UTC Jan 23rd UTC lock loss durring swept sine excitation 3:55 UTC

Sudarshan K, Rick S, Darkhan T.

Pcal beam power measurements were taken at EndY.

Measurements inside TX module:
OFS PD outputs 3720 counts, 2.25 V.
TX PD outputs 1592 counts.
Laser power: 2 W.
Servo loop is open.
Heat sink is not installed.

Power measurements before any optics (after the laser shutter) at different voltages:
1.05 W   at 3.0 V
1.35 W      3.5 V
1.60 W      4.0 V
1.86 W      4.5 V
2.07 W      5.0 V

Power measurements, laser power set at 5 V:
OFS PD: 9.06 V    14850 cts.     2.72 mW
TX PD:  4.2  V     6930 cts.    10.1  mW


Power meter is used with OD1.

NE01A-B + NE02A-B attenuators attached to OFS PD.

Power reading inside of TX module between two lenses (combined power of two beams going to ETMY): 1.69 W.


Measurements of two beams at the TX module:
Inner beam: 844 mW
Outer beam: 824 mW


Measurements of two beams at the RX module:
Inner beam: 827 mW
Outer beam: 810 mW
Both beams combined: 1.63 W
RX PD mon (both beams combined) output: 10.3 V


Pictures of Pcal spots on ETMY (f/22, 30 sec):
LHOetm_0250.jpeg - inner beam only on ETMY (outer beam is blocked)
LHOetm_0251.jpeg - outer beam only on ETMY
LHOetm_0252.jpeg - both beams


We left Pcal laser ON, beams on ETMY.

This morning I focused the ETMx GiGe camera (CAM 25) in IR.  I had to zoom in closer to the optic to get the pitcure into focus.  For reference, attached are photos of ETMX before zooming in and after zooming in (which is the current camera configuration).

Using Dave's extract from the Guardian logs since the RCG 2.9 restart to generate an exclude file.  I've loaded SDF Tables for all LHO HPIs (except HAM1.)  Attached is a snap of the donot monitor file; this is Dave's file with filter module core names removed (Guardian uses ezca which doesn't have to use a complete name to manipulate a switch) and the HPI MASTER_SWITCH added (the SEI Manager toggles this switch, not the HPI Guardian.)  Also in the image is the difference table from the SDF before the donot_monitor list was added.  After updating the Table, the diff list went to zero channels.

All HAM HPI currently have no diffs--let's keep it that way.  The BSC HPIs have a few diffs (1-4,) these are a few ISC settings and sensor correction gains that need to be corrected by updating the safe.snap value.  Fab tool!

Thanks to Dave & Jonathan.

J. Warner, A. Pele, J. Kissel

Jim has improved the isolation loop design for the HAM2, HAM3, HAM4, and HAM5 ISIs by increasing the frequency / aggression of the Level 3 isolation filters (along with tweaking the UGF and high frequency rolloff such that the aggressive boost remained stable). As such, we have a great deal more feedback gain in the 0.5 to 5 [Hz] region of all DOFs for these HAMs -- the region where the noise performance is typically loop gain limited -- and therefore the performance improvement has scaled linearly with the gain increase. See "IsoFilterComp" attachments.

We didn't have noise budget yet to prove it, but Jim had recognized that HAM6, the most recently designed chamber had much better performance, and much high boost frequency. 

Arnaud has gathered performance data comparing platform displacement before and after the change, which confirms the goodness locally. See "PerformanceComp" attachements. We didn't grab / compare the rotational degrees of freedom but these have also improved. Now that Arnaud has installed properly-matched, sensor correction, gains (see LHO aLOG 16208), we should expect a little bit better translational performance, so we'll compare again and make sure we capture rotational DOFs. Further, we plan to use calibrated DRMI cavity control signals to ensure that what we've done locally is good for the IFO.

The parameter files for these new current designs can be found here:
HAM2/Scripts/Control_Scripts/Version_3/Hori_ISO_H1_HAM2_Lv3_HR_2014_10_23.m
HAM2/Scripts/Control_Scripts/Version_3/Vert_ISO_H1_HAM2_Lv3_HR_2014_10_22.m
HAM3/Scripts/Control_Scripts/Version_3/Hori_ISO_H1_HAM3_Lv3_IMC_HP_2013_01_16.m
HAM3/Scripts/Control_Scripts/Version_3/Vert_ISO_H1_HAM3_Lv3_IMC_HP_2013_01_16.m
HAM4/Scripts/Control_Scripts/Version_3/Hori_ISO_H1_HAM4_Lv3_HR_2014_09_22.m
HAM4/Scripts/Control_Scripts/Version_3/Vert_ISO_H1_HAM4_Lv3_HR_2014_09_16.m
HAM5/Scripts/Control_Scripts/Version_3/Hori_ISO_H1_HAM5_Lv3_2014_09_25.m
HAM5/Scripts/Control_Scripts/Version_3/Vert_ISO_H1_HAM5_Lv3_2014_09_25.m

8:38 Rick to EX to pick up PCal equipment

9:30 Benton PUD on site

9:32 Fil to LVEA working on PEM mics

9:38 Karen to MY

9:40 Rick done at EX, heading to EY for PCal work

9:57 Jeff and Andres to LVEA for cleanup

10:09 Jeff and Andres out of LVEA

10:45 Benton PUD off site

11:00 Pepsi truck on site

11:10 Karen done at MY

12:23 Fil back to LVEA PEM work

14:00 Fil kicked out of LVEA by mean commissioners :(

I have turned up the preamp gain on the LSC-Y_TR photodiode (a PDA100A on ISCTEY) from 0 dB to 20 dB. The BS immediately before this PD is a BS1-1064-50-2037-45P.

The LSC-TR filter banks have been adjusted as follows:

• LSC-Y_TR_A_LF: gain changed to 0.0185 from 0.185; offset changed from -30 to -40
• LSC-X_TR_A_LF: offset changed from -180 to -171.

Reminder, if you wish to edit the site map, please do so in the /opt/rtcds/userapps/release/cds/h1/medm directory.

Please do not do it in the /opt/rtcds/lho/h1/medm directory as this breaks the symbolic link and the change does not get committed to the SVN version control repository.

I repeated the study I did on the L1 ADC hold times  ( aLOG entry 16455 ) using date from H1.  It is running the tagged RCG 2.9 and has higher thresholds (MAX_ADC_WAIT_CARD_0 of 20, MAX_ADC_WAIT_CARD_S of 3).  

Here, I record values from the IOP model proc file (i.e. cat /proc/h1ioplsc0/status on h1lsc0)

Again, in most cases ADC#0 Max + Max Delta = Max Hold.  It does appear that better limits of 23 and 5 for MAX_ADC_WAIT_CARD_0, MAX_ADC_WAIT_CARD_S (from L1 data) would work here.  The current CDS bugzilla issue is Bug 791

Last week, sts correction gains were measured and calculated on HAM4/5/6 to improve the CPS sensor correction. We measured them today for the remaning chambers.

For the BSC chambers, we locked the platforms to the ground by increasing the blends to 750mHz (cf alog) and turned off the sensor correction. We measured the ratio between the T240 (stage 1) and the STS (ground) signal (should be 1 with the platform moving with the ground). The same measurement was also carried out between STS and L4C for hepi, since IPS sensor correction is used for the Z DOF.

All the measurements using the corner station STS B as input to the sensor correction (ITMX, BS, ITMY) show a factor of two mismatch with the hepi and platform sensors in the X DOF only. There is certainly a calibration error with the STS B seismometer. I checked the calibration filter in the input filter banks and it looks correct (10.17 nm/s /cts). We should investigate more. The other chambers and dofs need a relatively small correction. 

The ISI gains (T240/STS for BSCs and GS13/STS for HAMs) are 

The BSC - HEPI gains (L4C/STS) are

Attached are examples of the transfer functions for ITMY 

To calculate the gains I wrote a script for the bscs in a similar fashion as Sebastien's : it is called BSC_gain_matching_calculation(IFO,Chamber,start_time,duration) located under /ligo/svncommon/SeiSVN/seismic/BSC-ISI/Common/Misc. The results above were obtained using the following parameters : 

start_time=tconvert('01/22/2015 15:35') ;
duration = 45*60 ;

Yesterday I dif the ETMs.  Today I did all the remainder.  All came back under guardian first time.