Displaying reports 73721-73740 of 83317.Go to page Start 3683 3684 3685 3686 3687 3688 3689 3690 3691 End
Reports until 13:05, Thursday 06 February 2014
H1 General
patrick.thomas@LIGO.ORG - posted 13:05, Thursday 06 February 2014 (9894)
Richard, Arnaud to ETMX to troubleshoot ground loops


			
			
H1 SUS
jeffrey.bartlett@LIGO.ORG - posted 12:30, Thursday 06 February 2014 - last comment - 16:27, Thursday 06 February 2014(9892)
Pre-Glass Installation Measurements of H1-SR3
Jeff B & Andres R

   We moved the HLTS suspension SR3 into position to have the metal Bottom Mass replaced with the Glass Optic. We took height and blade tip breakoff measurements as a pre-installation base line. All measurements are within tolerances. 

Measurement Point            Target/Tolerance  	                         Measurement 
Top Blade Wire Breakoff       806.12mm	                                 804.93mm, 805.89mm 
Bottom of T-Block                 552.23mm	                                 552.60mm
Top of Intermediate Mass     461.63mm	                                 461.63mm
Lower Blade Wire Breakoff   608.84mm tip coplanar <0.5mm  607.75mm, 608.11mm, Coplanar = 0.36mm
Top of Bottom Mass              291.0mm +-1mm	                         291.17mm

   The next step is to center and adjust the OSEMs, and then run Phase 2A Transfer Functions.  
Comments related to this report
andres.ramirez@LIGO.ORG - 16:27, Thursday 06 February 2014 (9901)
The OSEMs have been re-centered and then retracted for taking the OLVs. A D1000234 quadruple cable needs to be attached before running the "PrettyOSEMgains" script.
H1 DAQ (CDS)
james.batch@LIGO.ORG - posted 12:25, Thursday 06 February 2014 (9893)
Restarted h1nds1 daqd
Corrected daqdrc file, restarted daqd on h1nds1.
H1 SEI (SEI)
richard.mittleman@LIGO.ORG - posted 12:18, Thursday 06 February 2014 (9891)
Sensor Correction for BS-BSC-ISI

  In preparation for installing sensor correction I took a ground to platform transfer function to see what kind of coherence we have, short answer is lots from 0,1 to a few hertz

 

Images attached to this report
Logbook Admin General
jonathan.hanks@LIGO.ORG - posted 11:40, Thursday 06 February 2014 - last comment - 12:03, Friday 07 February 2014(9890)
Scheduled downtime Friday 7 Feb 2014 noon Pacific
The aLOG will be down for maintenance tomorrow at noon (pacific time).

Please post or save your log entries before the maintenance.
Comments related to this report
jonathan.hanks@LIGO.ORG - 10:05, Friday 07 February 2014 (9905)
The downtime is being moved earlier in the day to 11:30am pacific.
jonathan.hanks@LIGO.ORG - 12:03, Friday 07 February 2014 (9915)
The work is completed
LHO General
patrick.thomas@LIGO.ORG - posted 11:35, Thursday 06 February 2014 (9889)
Mitchel out of LVEA west bay


			
			
H1 CDS
patrick.thomas@LIGO.ORG - posted 10:21, Thursday 06 February 2014 (9887)
updated alarm handler
I commented out the DC watchdog components in /opt/rtcds/userapps/release/cds/h1/alarmfiles/h1cds_iop_sus_watchdog_b123.alhConfig.
H1 General
patrick.thomas@LIGO.ORG - posted 10:05, Thursday 06 February 2014 - last comment - 11:23, Thursday 06 February 2014(9886)
Jeff B. working on test stand by HAM4,5


			
			
Comments related to this report
patrick.thomas@LIGO.ORG - 11:23, Thursday 06 February 2014 (9888)
Done.
H1 General
patrick.thomas@LIGO.ORG - posted 10:03, Thursday 06 February 2014 (9885)
Corey to end X, end Y
Getting alignment targets from end X and installing them on TMS at end Y.
H1 DAQ (CDS)
james.batch@LIGO.ORG - posted 09:55, Thursday 06 February 2014 (9884)
Restarted h1fw1 and h1nds1 daqd process
Frame writer 1 daqd and nds1 daqd were restarted to read new daqdrc files to allow writing of raw minute files in the proper place, following moving of old files to a different file system.  
H1 SYS
kaitlin.gushwa@LIGO.ORG - posted 09:20, Thursday 06 February 2014 - last comment - 10:29, Tuesday 11 February 2014(9850)
HAM4 witness plates & optics
Jeff B. & Kate G.

A horizontal 4" witness plate (wafer) and horizontal 1" optic (S/N 1247) were placed near the center of the SEI table on Feb 5th. A vertical 1" optic (S/N 1245) was mounted on the HR side of SR2. A vertical wafer still needs to be set near SR2. 

Important notes: Witness samples were not placed immediately after the chamber was opened. Jeff did some cleaning before SR2 was installed and the wafers and optics were placed. Also, the 1" optics were removed from their PET G containers, put in PEEK holders, double bagged, and stuck in a bag with other tools before going in chamber. I didn't see obvious scratches in the First Contact, so hopefully the samples weren't damaged. 
Images attached to this report
Comments related to this report
kaitlin.gushwa@LIGO.ORG - 10:29, Tuesday 11 February 2014 (9974)

On Feb 7th, I used a handheld particle counter in the cleanroom around HAM4 and in chamber before starting work. The counts seemed really high. The particle counter (used for trending data) on the +X side of the chamber was not working.

Size (um) Cleanroom Count Chamber Count
0.3 10725 17177
0.5 2518 3895
0.7 1075 1562
1.0 586 798
2.0 169 213
5.0 1 0

I placed a vertical wafer near the HR side of SR2, and inspected the cleanliness of the chamber with a flashlight array. There were a few particles on the witness samples (which had not seen work since they were placed two days earlier), and a lot of contamination on the TCS HWS optics and SEI table. The dark iPhone photos don't do it justice.There was only time for a quick cleaning using the TigerVac and IPA soaked wipes. It would be helpful to get a PET swipe sample the next time work is done in HAM4. 

Images attached to this comment
H1 SEI
hugh.radkins@LIGO.ORG - posted 07:58, Thursday 06 February 2014 - last comment - 08:03, Thursday 06 February 2014(9882)
WBSC 1 & 2, ITMY & BS ISI not Isolating this morning

Maybe Stefan turned these off, I didn't catch such in the alog.  I thought I left these in some Isolation state yesterday as Stefan wanted PRMI asap.

ITMY is damping with a Stage2 trip from GS13 limits.  The BS has no trip indicator but is damping only.

The HEPIs here are running normally.

Comments related to this report
hugh.radkins@LIGO.ORG - 08:03, Thursday 06 February 2014 (9883)

I just noted the detail in Kiwamu's log about turning them off but he did not note a specific problem.

H1 SUS (ISC)
stefan.ballmer@LIGO.ORG - posted 04:28, Thursday 06 February 2014 - last comment - 04:30, Thursday 06 February 2014(9878)
BS opleve was oscillating

Stefan and I found that the BS oplev was oscillating because of probably a loop instability. Disabling and enabling them at H1:SUS-BS_M2_OLDAMP_P(Y) made it stable again. It had been oscillating for more than 15 hours.sad The attached is the trend.

Images attached to this report
Comments related to this report
kiwamu.izumi@LIGO.ORG - 04:30, Thursday 06 February 2014 (9881)

posted by Kiwamu, not Stefan, sorry.

H1 PSL
stefan.ballmer@LIGO.ORG - posted 04:20, Thursday 06 February 2014 - last comment - 04:30, Thursday 06 February 2014(9877)
Ref cav transmitted light decreasing, the threshold lowered to 0.4
Stefan and I lowered the threshold value of the ref cav transmitted light because it was preventing FSS from a smooth recovery. It is now 0.4.
Comments related to this report
kiwamu.izumi@LIGO.ORG - 04:30, Thursday 06 February 2014 (9880)

Posted by Kiwamu, not Stefan.

H1 ISC
kiwamu.izumi@LIGO.ORG - posted 04:06, Thursday 06 February 2014 - last comment - 04:15, Thursday 06 February 2014(9874)
Unidentified oscillation at 40 Hz in PRMI

Stefan, Lisa, Kiwamu,

Our goal tonight was to lock PRMI with the 3f signals. However we didn't reach that point yet because of a (perhaps new) issue in the PRMI locking.

A good news is that the power build up was high because of the ring heater on ITMY which had been set at 4 W in total. POPAIR_B_RF18 went to 8000 counts.

 

40 Hz unidentified oscillation in PRMI signals:

After some tweak of alignment and gains, we managed to lock PRMI with the sidebands being resonant. However the PRMI lock was fragile for some reason. In particular, it lost the lock frequently when we changed the PRC gain. We took spectra of the signals and were surpprised by a huge peak in both PRC and MICH signals. This was causing a DAC saturation in the M2 stage of PRM which made the PRC loop unstable. This is something we didn't see before. We looked at some previous spectra from the last long stretch of 3rd of February (alog 9809) and confirmed that there was no such oscillation at that time. The attached shows spectrum of various signals from tonight. It is obvious that there is a broad and prominent oscillation at around 40 Hz in each signal. Note that when I took this data, I had a notch in PRM M2 stage to mitigate the saturation and that's why the PRM_M2 signal look a bit suppressed at around 30 Hz.

 

We tried to lower the UGF of PRCL, but the oscillation persisted. In fact the peak moves as we changes the UGF. For example, lowering the UGF also brings the peak frequency lower. We suspected a gain peaking and tried to move the UGF, but somehow the gain margin was so narrow that we could not move around so much. According to a quick swept sine measurement, the UGF was at around 40 Hz.. Another thing we suspected was a roll mode which is usually at around 40 Hz in the case of the small triple suspension. Since we failed to lower the UGF, we could not really try a notch technique to minimize unwanted excitation. We also looked at MC_F because we suspected the roll mode of MC2, but there was no visible oscillation at all. I also quickly tried the PRX locking to see if it still persists, but I didn't see any oscillation in PRX.

We are still unable to identify this oscillation.

Images attached to this report
Comments related to this report
kiwamu.izumi@LIGO.ORG - 04:15, Thursday 06 February 2014 (9875)

Some other notes:

  • We turned off the isolation loop of ITMY and BS ISIs at the beginning of the PRMI commissioning tonight.
  • The power recycling gain steadily kept dropping over 5 hours despite of our semi-automated alignment. See attached. I have no idea why.

Images attached to this comment
H1 ISC
kiwamu.izumi@LIGO.ORG - posted 03:33, Thursday 06 February 2014 - last comment - 04:16, Thursday 06 February 2014(9873)
ALS frequency fluctuation is bigger than the linewidth

Stefan, Lisa, Kiwamu,

The X arm is now quiter due to the oplev on ETMX and we are now becoming able to assess the noise performance.

Since Stefan got the oplev active loop running on ETMX and made the arm quitter, we wanted to measure the ALS infrared frequency noise by locking the PSL to the X arm using the green beatnote. The hand off process was very smooth tonight and we could try many times to bring the PSL frequency close to the arm resonance. Stefan engaged the additive offset path on top of the MCL feedback. We measured the UGF to be 3.6 kHz with a phase margin of about 64 deg.

It seems that the CARM noise is now suppressed to ~ a few 100 Hz which is unfortunately still greater than the arm linewidth of about 84 Hz. Because the fringe moved more than its linewidth, we could not confine it within the linear range. The below is a screenshot of the PDH signal in StripTool. You can see that the PDH signal, which in blue, goes back and forth around a resonance, resulting in a periodic funny shape. Also it looked like we need to have some more gain at low frequencies because we saw a low frequency excursion in the error signal.

 

Even though the PDH signal was pretty much out of the linear range, we calibrated REFLAIR_A_RF45 using Alexa's formula (see alog 7054) and tentatively made a noise spectrum which, of course, underestimated the actual noise due to a low optical gain. One thing we immediately noticed was that there is a 70 Hz broad peak which maybe a vibration of the periscope on ISCT1. It looks quite similar to what we had in HIFO-Y. We are not sure what this is at this point.

Images attached to this report
Comments related to this report
kiwamu.izumi@LIGO.ORG - 04:16, Thursday 06 February 2014 (9876)

Note that the ISCT1 hepa filter has been intentionally off in order to get low noise.

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