HWSY stray beam getting into HWSX sensor - all exterior problem; now fixed

Alastair, Aidan.

We tracked down the source of the cross-coupling between the HWSY probe beam and the HWSX sensor. The offending beam was coming from the HWSY BS (we think). By blocking the Y-beam at various points we were able to figure out where it was coupling across the HWSX and we subsequently placed a dump in front of it before that point (between M8 and M9 in the Y-arm optical layout - see the attached photo).

One more thing, I checked the following configurations to look for any other stray beams:

• Viewed HWSX camera with HWSX probe beam OFF and HWSY probe beam ON: no visible signals on the camera
• Viewed HWSY camera with HWSY probe beam OFF and HWSX probe beam ON: no visible signals on the camera

 

 

optical lever rack/chassis locations and whitening chassis status

Optical Lever Whitening Chassis Rack Locations and Chassis Locations and Current Binary Output Module Status at LHO: D.Cook 10/29/2014
Rack SUS H1-R1: Chassis cabled - Board 1- HAM 2 = No BOM installed
		  Chassis cabled - Board 2- HAM 3 = No BOM installed	
Rack SUS H1-R2: Chassis cabled - Board 1- HAM 2 = No BOM installed
		  Chassis cabled - Board 2- PR3  =  BOM installed
				B1, B2, B4, B9, B10, B12, 17, B18, B20, B25, 26, B28 set HIGH
				(the rest set LOW)
Rack SUS H1-R3: Chassis cabled - Board 1- HAM 5 = No BOM installed
				  Board 2- SR3 = BOM installed
				  B4, B12, B20, B28 set HIGH
 Rack SUS H1-R4: Chassis cabled - Board 1- HAM 4 = No BOM installed
		  Chassis not cabled - Board 2- Empty
Rack SUS H1-R5: Chassis cabled - Board 1- BSC 8 Pier (temp ?) = No BOM installed (jumpered connecter)
		  Chassis cabled - Board 2- BS  =  BOM installed
				B1, B3, B4, B9, B11, B12, 17, B19, B20, B25, 27, B28 set HIGH
				(the rest set LOW)
Rack SUS H1-R6: Chassis cabled - Board 1- ITMx =  BOM installed
				B4, B5, B12, 13, B20, B21, B28, B29 set HIGH
				(the rest set LOW)
   Chassis not cabled - Board 2- Empty
Rack SUS H1-R1 ETMy: Chassis cabled - Board 1- ETMy = BOM installed
				B4, B5, B12, 13, B20, B21, B28, B29 set HIGH
				(the rest set LOW)
		  Chassis not cabled - Board 2- Empty

Rack SUS H1-R1 ETMx: Chassis cabled - Board 1- ETMx = BOM installed
				B2, B3, B5, B10, B11, B13, B18, B19, B21, B26, B27, B29 set HIGH
(the rest set LOW)
Chassis not cabled - Board 2- Empty

This entry has several bugs making the data incorrect. A corrected status chart can be found in LHO aLOG 14749

Ops Summary

08:55 Karen cleaning at mid and end Y
09:03 Ed reinstalling UIM driver for quad test stand
09:05 Hugh bringing HAM2 ISI down to make a safe.snap file
09:24 Gerardo and Alexa transitioning end Y to laser safe (WP 4923)
09:32 Alastair to install FLIR imaging camera on TCS Y table (WP 4924) ... not done, parts need to be made
09:45 Gerardo and Alexa done transitioning end Y to laser safe
10:03 Hugh taking HAM3 down to upgrade matrices and make a safe.snap file
10:12 Truck at gate here to pump septic tank
10:45 Hugh removing malfunctioning HEPI pressure sensor box at BSC2
10:47 Doug cataloguing the status of the switches on the optical lever whitening boards in the LVEA
11:02 Hugh done at BSC2
11:18 Travis moving suspension upper structure into clean room in West bay (heavy)
11:33 Travis done
12:08 Doug done
12:31 Betsy to West bay for 3IFO quad work
12:57 Doug cataloguing the status of the switches on the optical lever whitening boards at the end stations
13:26 Karen done cleaning at mid and end Y
13:48 Hugh to BSC2 to reinstall HEPI pressure sensor box
14:05 Hugh done at BSC2
14:38 Doug in LVEA recording locations of optical lever equipment
14:45 Delivery for Richard
14:45 Doug done

HEPI BSC True Differential Pressures noisier than direct Pump Out Pressure

See the attached for some manipulated data.

There are now pressure signals coming from the End Station VEAs just before the BSCs fluid distribution manifolds.  So the pressure before the actuators and the pressure just after the actuators (before and after the distribution manifolds.)  See the first attachment--you can see that there is some 6psi pressure drop from the last transducer on the Pump Station Manifold to the Transducer just before the supply distribution manifold at the chamber.  This is a distance of some 80 or 90 feet of 1" tube.

The idea is that the Actuators are meant to operate at a consistent pressure drop and having the sensors in the area of operation and where we have tighter temperature regulation would be a better thing.  While these epics channels can be conditioned (smoothed, averaged,...) the second attachment shows how much noisier these raw signals would be to produce the differential pressure signal for the servo.  I've subtracted the Return Pressure from the Supply to get the Differential; the vertical scales are the same for the two EX signals,and the same for the two EY signals.  All plots are in PSI.

Why are they so much noisier?  Let me see, maybe the 80 or 90 feet of cable?  We do have an at chamber active signal amplifier, don't know the DCC off hand but later.

Anyway, I may be a little reluctant to switch HEPI to these signals.  I don't think any one has complained about HEPI because we are running on the direct supply pressure rather than the differential.

WHAM1 HPI Local to Cartesian Matrices Corrected

Yeah, that's right HAM1.  Safe.snap committed to SVN.

Stage 1 Z: high blend versus low blend

With the optical levers now well calibrated, we re-assessed the benefits/drawbacks of blending low on Stage 1 Z.  In the plot attached, ETMX Stage 1 Z was in high blend (T750), while all others were in low blend mode. Data was taken this morning from 3am to 4am PT.

 

- The first plot attached shows that the ETMX optical lever pitch motion is four times higher than the other test masses (second line, third row). This vertical to pitch coupling justify the need for blending low on Stage 1 Z.

- The Yaw motion (second line, third row) shows that the low blends on Stage 1 Z amplify the Yaw motion by a factor of two, through the "Z to RZ coupling" problem that we are trying to solve.

- Just for info, the second attachment shows the Pitch to Pitch transfer functions (second line, second row), from top to bottom mass. ETMX is pretty clean in this configuration as the picth modes are well excited by the Stage 1 vertical motion.

Removed HEPI monitor channels from Conlog

Dave made these read only in the autoBurt.req file and I rescanned the channel list:

H1:HPI-PUMP_EX_BSCRET_PRESS
H1:HPI-PUMP_EX_BSCSUP_PRESS
H1:HPI-PUMP_EY_BSCRET_PRESS
H1:HPI-PUMP_EY_BSCSUP_PRESS

3-30 mHz noise in BRS and T240

K. Venkateswara

I have attached ASD plots from 30k second-data from the BRS and the ground T240 seismometer x channel measured last night, when wind-speeds were fairly low. The first plot is in angle units and the third is in meters. I have also shown the tilt-subtracted ground super_sensor in red.

Both BRS and T240 look similar, but have no coherence. The amplitude of BRS looks lower between 8-20 mHz than the T240X, while it looks higher below that. Note that I have corrected for the transfer function of the T240 (double pole at 4.3 mHz).

The noise level between the two instruments also seems to vary with ground motion. Last Friday, Brian Latnz had suggested that it might be cross-coupling between different axes. This made me wonder if it was due to down-conversion from higher order modes of the beam-balance. I had seen similar issues with it in the lab at UW, which were mitigated when I added some vibration isolation in the form of rubber pads under the platform. So, I tried the same thing under the BRS platform on Monday morning. However, there was no change in the "noise" level as seen in the plots. It may still be cross-coupling in BRS or T240, but it doesn't seem to be the same type of down-conversion that I observed in the lab.

Added 250 mL H2O to the H1 PSL chiller

WHAM3 ISI Conversion Matrices Changed & Snapped

Changed the Local to Cartesian to Actuator matrices on HAM2 ISI  to as per T1000388.  Unlike HAM2, Guardian had no problem reisolating.  Repeated several times, all good.

WHAM2 ISI Taken down to Collect Safe.Snap

Committed to SVN. New Local to Cartesian to Actuator Matrices (Changed Monday but I didn't get snapped) saved.

UIM Coil Driver returned to Quad Test stand electronics rack

The UIM coil driver S0900300 was modified as per E1400164. It was retested for noise and transfer function. The new, raw data will be zipped and posted to it's DCC record. Please inform me of any malfunction due to the removal/replacement of this chassis.

EMTX ISI cart matrices updated, safe.snap committed

While preparing to revisit tilt decoupling at ETMX, I used the opportunity to correct the input and output matrices for the ISI. A new safe dot snap has been made and committed to the SVN. I will also be changing the guardian configuration and changing the blends, it will take a couple minutes to revert if anyone needs it back.

morning meeting notes

Aidan to check coupling between ITMX and ITMY Hartmann sensors
Aidan to check alignment of the X arm CO2 laser on the compensation plate
Richard checking Beckhoff for illuminators at the end stations
Cable work in the LVEA
Jim W. and Krishna to run tilt/decoupling measurements for ETMX SEI
Doug to look at optical levers
Jeff B. to bring in table from staging building on pallet jack
3IFO quad suspension assembly work continuing
Rai W. running purge air and scrollpumps at ETMY for ionizer test
end Y to be transitioned to laser safe

ITMX RH heating/measurement test successful

The heating test of the ITMX with the RH and coincident HWS measurement was successful. The usual negative thermal lens was observed to form in ITMX in response to 4.035W total electrical power into the RH.

t = 0 is defined as when the RH was turned on. tmax is defined as when the value of spherical power peaks.

• The difference in SPHERICAL_POWER from t0 to tmax was -135 micro-diopters
• The difference in PRISM_X (YAW) from t0 to tmax was approximately  -0.25 micro-radians.
• The difference in PRISM_Y (PITCH) from t0 to tmax was approximately +2.1 micro-radians

The center of the lens is located at -[+2.1, -0.25]/(-135) m = [+16, -2]mm 

CDS model and DAQ restart report, Monday and Tuesday 27th,28th October 2014

model restarts logged for Mon 27/Oct/2014
2014_10_27 09:15 h1iopseih45
2014_10_27 09:17 h1hpiham4
2014_10_27 09:17 h1hpiham5
2014_10_27 09:17 h1isiham4
2014_10_27 09:17 h1isiham5

restart of IOP to reset DAC enable error. No unexpected restarts.

model restarts logged for Tue 28/Oct/2014
2014_10_28 07:08 h1lsc
2014_10_28 07:14 h1susetmx
2014_10_28 07:14 h1susitmx
2014_10_28 07:16 h1susetmy
2014_10_28 07:16 h1susitmy
2014_10_28 07:30 h1broadcast0
2014_10_28 07:30 h1dc0
2014_10_28 07:30 h1fw0
2014_10_28 07:30 h1nds0
2014_10_28 07:30 h1nds1
2014_10_28 07:31 h1fw1
2014_10_28 08:03 h1susauxex
2014_10_28 08:04 h1susauxey
2014_10_28 10:09 h1hpiitmx
2014_10_28 10:09 h1iopseib3
2014_10_28 10:09 h1isiitmx
2014_10_28 10:24 h1hpiitmx
2014_10_28 10:24 h1iopseib3
2014_10_28 10:24 h1isiitmx
2014_10_28 10:41 h1hpiitmx
2014_10_28 10:41 h1iopseib3
2014_10_28 10:41 h1isiitmx
2014_10_28 13:14 h1fw1
2014_10_28 13:14 h1nds1
2014_10_28 13:15 h1nds1
2014_10_28 16:11 h1broadcast0
2014_10_28 16:11 h1dc0
2014_10_28 16:11 h1fw0
2014_10_28 16:11 h1fw1
2014_10_28 16:11 h1nds0
2014_10_28 16:11 h1nds1
2014_10_28 16:35 h1broadcast0
2014_10_28 16:35 h1dc0
2014_10_28 16:35 h1fw0
2014_10_28 16:35 h1fw1
2014_10_28 16:35 h1nds0
2014_10_28 16:35 h1nds1

Maintenance day: SUS, LSC and SUSAUX model work (with DAQ restart). h1seib3 bad ADC interface card/cable investigation. h1ldasgw1 raid work. DAQ restart to support HEPI pump ctrl and Beckhoff changes.

ETMX ISI is in a test configuration

I ran the script that Hugo prepared for me at around 7:34:30 in UTC or 0:34:30 in PDT. I confirmed that it successfully switched the blend filter for Z in ETMX ISI to the one he wanted to test. I am leaving it in this configuration as requested by Hugo.

Those who perform X arm comissioning tomorrow should not forget to switch it back to the nominal configuration by running:

/ligo/svncommon/SeiSVN/seismic/BSC-ISI/H1/Common/Misc/Test_Configuration_Scripts/Switch_To_Comm.py

 

Note:

before running the script, I steered ETMX to an angle which is far enough from the aligned value so that it does not interfer with the corner locking but still gives an OK centering for oplev. This resulted in  (PIT bias, YAW bias) = (403, 86).

arm cavities increases SRC mode hops ?

Alexa, Sheila, Kiwamu,

We are concluding that the DRMI seems to have a high rate of the SRC mode hops when the arm cavities are present. At this point, it is unclear why.

 

(A comparison test with and without arm cavities)

We locked the DRMI while holding the arm cavities at a off resonance point (750 Hz away from resonance in IR) by ALSs. The number of the mode hop was as high as once a second or so. As usual, a SRCL offset of -800 cnts could help reducing the mode hops and also aligning the DRMI helped it as well. However we could not completely get rid of the mode hops at the end. So we quickly switched back to a simple DRMI by misaligning ETMs to determin whether if it is an issue only when the arms are resent. Indeed, the simple DRMI locked and stayed without a mode hop. So the arm cavities really increase the rate of the mode hops.

Note that there was a good DRMI stretch starting at Oct-29 7:00 UTC.

We also tried engaging the ASC loop that had been tuned up for a simple DRMI. This did not look very promising as it was not able to reduce the number of mode hops. It may have been a situation where the ASC was not able to correctly work because of too many hoppings. We don't know what exactly was going on yet.

(Some ETM suspension adjustment for DIFF loop)

The roll mode rang up tonight as well in ETMY. We decided to use only ETMX until the roll mode settles down. Also we changed the L3 gain from 0.8 to 1.1 in ETMX because we saw an oscillation at the cross over frequency at around 2-ish Hz when the gain was at 0.8 and ETMY was disabled. We could not push the UGF of the DIFF loop to 10 Hz because of saturation in the ETMX ESD supposedly due to the roll mode dominating the rms. We decreased the overall LSC UGF by a factor of 2 or so in order to avoid the saturation.

At some point, we were suffering by an issue of the X arm being misaligned as the LSC feedback got bigger. This turned out to be a bad L2P decoupling in the L2 stage which Sheila turned off (alog 14428) because the filter was thought to be bad. We have no idea what has changed since then, but it was obvious tonight that the L2P decoupling filter really helped the decoupling and improved the stability of the DIFF loop a lot. We now enabled it.

(SR3 opelv damping loop was off)

When locking the DRMI, we noticed that a pitch mode of an optic was too large that it was inducing more mode hop in the SRC. We identified it to be SR3 whose oplev pitch loop had been switched off. So we switched it back on and this helped the stability of the DRMI.

peek at PR2 baffle

Alexa, Kiwamu,

In response to Keita's alog about the PR2 baffle, we took a peek at the PR2 baffle by opening some of the viewports on HAM3 and HAM2 spool.

Conclusions:

• The aperture hole on the baffle looks centered.
• The baffle in front of PR2 looks the right one.

 

(PR2 baffle check out)

We opened up a viewport on the East side of HAM3 which the leftmost one with an illuminator attached on. This was the only available viewport to open up. We removed the illuminator and looked at the baffle through the viewport. We confirmed that there was no cross bar structure on the side of the baffle unit as shown in the DCC document (D1000328). We could not see the top part of the baffle where it supposed to have a cross bar structure. We took some pictures and I attach them to this entry.

(Peek at the aperture position)

Then we tried a different zooming in the PR2 digital camera in order to have a better view so that we can determine if the aperture hole is in the middle of the baffle unit or not. With a help of flash light illuminating the PR2 baffle from the HAM2 East side viewport, we could clearly see the edge on both right and left sides of the unit as well as the edge of the aperture. It looked like the hole is centered with respect to the right and left edges of the unit. We took several pictures of it via the digital camera so that one can evaluate the position later if necessary.

(MC2 scraper baffle check out)

Then we opened up another viewport on the West side of HAM3 in order to see both MC2 and PR2 baffles. Though, the MC2 baffle was completely occulting the PR2 baffle and therefore we could not see it. We could still confirm that the MC2 baffle has a cross bar structure on the side as shown in the design document (D1000327).