Displaying reports 70221-70240 of 85980.Go to page Start 3508 3509 3510 3511 3512 3513 3514 3515 3516 End
Reports until 16:01, Wednesday 21 January 2015
H1 General
travis.sadecki@LIGO.ORG - posted 16:01, Wednesday 21 January 2015 (16193)
OPS shift summary

8:51 Kiwamu to IOT2L

9:05 Bubba to EX

9:06 Karen to EY

9:08 Corey to Squeezer Bay working on 3IFO ISC

9:15 Cris to MX

9:37 Corey to EY looking at ALS optics on table

9:38 Andres working on 3IFO storage cleanup in LVEA

9:44 Kiwamu done in LVEA

9:53 Gerardo X beam tube ion pump work

10:11 Kiwamu and Elli to ISCT6

10:11 Corey back from EY

10:24 Karen done at EY

10:27 Bubba done at EX

10:43 Corey back to Squeezer Bay

10:47 Andres out of LVEA

11:02 Jeff and Andres to LVEA for more cleanup

11:10 Rick and Sudarshan to LVEA PSL area

11:20 Jodi to LVEA taking pics

11:22 Jeff and Andres out of LVEA

11:32 Jodi out of LVEA

12:02 Gerardo out of LVEA

12:22 Corey out of Squeezer Bay/LVEA

14:02 Corey back to Squeezer Bay for 20 min.

LHO VE (VE)
gerardo.moreno@LIGO.ORG - posted 15:14, Wednesday 21 January 2015 - last comment - 17:53, Wednesday 21 January 2015(16192)
XBM annulus ion pump

(Kyle R, Gerardo M)

The new ion pump became railed sometime after decoupling the pump cart yesterday, and remained railed overnight.
This morning after pumping down the annulus system with the pump cart, we determined that the main valve was leaking.
So, to minimize exposure of the annulus system to atmosphere, we decided to add another valve in series with the leaky valve.
After pumping down on the system for about 25 minutes, the Ion pump started operating as it should, and is currently at 1.5 amps.

Comments related to this report
john.worden@LIGO.ORG - 17:53, Wednesday 21 January 2015 (16195)

or perhaps 1.5 mA

H1 SEI
hugh.radkins@LIGO.ORG - posted 14:49, Wednesday 21 January 2015 (16191)
ETMY BSC10 EndY HEPI Guardian reload for all dof restore

Just like ETMX earlier, restarted the HEPI guardian at ETMY to restore the same position for all dofs.  No problems again.  Attached is similar plot showing how different the alignment is after the restart.  Again, the HEPI is exactly the same, cause we made it so.  And the ISI, even though it restores no dofs, holds to its previous position to within 1 urad ( worst is RX=Pitch at ETMY,) all other dofs much less.

Images attached to this report
H1 TCS
kiwamu.izumi@LIGO.ORG - posted 13:50, Wednesday 21 January 2015 (16189)
TCSX calibration filter was off, we switched it back on

As a part of the DRMI investigation, we checked the laser power of CO2X and found that the power had dropped by a factor of two or so a week ago. However it turned out that this was due to a calibration filter (FM2 of TCS-ITMX_CO2_LSRPWR_MTR) which had turned off at that time for some reason. We switched it back on and also edited safe.snap accordingly. The attached is a 100days trend of relevant channels. As shown, the input of the monitor channel stayed at a constant value approximately in the past month or so while the output suddenly changed a week ago, indicating that the calibration filter was taken out.

Images attached to this report
H1 SEI (SEI)
sebastien.biscans@LIGO.ORG - posted 13:07, Wednesday 21 January 2015 (16187)
Script for the sensor correction gain calculation fixed

I found a small mistake in the HAM_gain_matching_calculation script.

The Q of the GS13 model was wrong by a factor a few, causing a slight phase delay around the frequencies that matter for the sensor correction ([0.1Hz-0.4Hz]).  The overall amplitude was thus altered.

This has been fixed and committed into the SVN:

/ligo/svncommon/SeiSVN/seismic/HAM-ISI/Common/Misc/HAM_gain_matching_calculation.m

 

Here's the correct values that we have so far (I though we had done HAM2 as well, but I can't find a good set of data):

  HAM4 HAM5 HAM6
X 0.945 1.001 1.035
Y 0.929 0.991 1.027
Z 0.918 1.039 1.103

 

We still need to do HAM2&3, plus all the BSCs. Don't forget to put the ISI in high blend mode with sensor correction OFF when you want to calculate the gain.

H1 PSL (DetChar)
edmond.merilh@LIGO.ORG - posted 13:05, Wednesday 21 January 2015 (16186)
PSL Diagnostic Breadboard Reports w/ISS RPN
Non-image files attached to this report
H1 SEI
hugh.radkins@LIGO.ORG - posted 12:24, Wednesday 21 January 2015 (16183)
EndX ETMX BSC9 HEPI Guardian restarted wp 5019

Using the Guardian manager, brought down the entire ETMX SEI after capturing the current held position for HEPI.  The Guardian code has been changed to restore all 8 dofs on HEPI to reduce or nearly eliminate alignment changes from lock to lock.  Before HEPI only restored the RZ and Pitch at the ETMs.

The Guardian smoothly brought the system down with no trips.  Restarted the Guardian code and then went directly to fully isolated first time.  No problems with the idea then.  I'll step this through all the platforms as commissioners allow.

Of note, none of the DOFs on the BSC-ISI are restored like this (As opposed to the HAM-ISI where all dofs are restored.)  So, I attach a plot showing the before and after of this morning's restart.  The op-levs are shown and the HEPI RZ.  Additionally, all the rotational dofs of the two ETMX ISI stagesare show to reveal at least one lock to lock alignment change on the ISI.  All the SEI channels are in nano units, Oplevs are urads I believe.  The Stage1pitch is worst at 600nrad tilt, all others are much smaller.

Images attached to this report
H1 General
travis.sadecki@LIGO.ORG - posted 11:30, Wednesday 21 January 2015 (16182)
Morning meeting notes
H1 PSL (DetChar)
edmond.merilh@LIGO.ORG - posted 10:53, Wednesday 21 January 2015 (16181)
PSL Weekly Report
Images attached to this report
H1 PSL
edmond.merilh@LIGO.ORG - posted 10:33, Wednesday 21 January 2015 (16180)
PSL Chiller Water

250ml of water added to chiller.

H1 IOO (ISC)
kiwamu.izumi@LIGO.ORG - posted 10:01, Wednesday 21 January 2015 (16179)
a lens inserted in IMC refl camera on IOT2L

As we found that the beam was too big on the IMC refl camera (alog 16166), I inserted a focusing lens (PLCX-25.4-20.6-UV) in front of it in order to obtain a better and wider view. The belows are pictures before and after the lens insertion.

Before

After

Both pictures were taken with the nominal exposure time of 19444 usec. In the second image, the main 00 mode is seen at the lower right. I am not sure whether if the upper part of the image is explainable by spatial higher order modes. It maybe a ghost beam. Note that this ghost-ish structure was visible with a laser card.

Images attached to this report
H1 CDS (DAQ)
david.barker@LIGO.ORG - posted 09:02, Wednesday 21 January 2015 (16178)
CDS model and DAQ restart report, Tuesday 20th January 2015

model restarts logged for Tue 20/Jan/2015
2015_01_20 00:05 h1fw0
2015_01_20 04:07 h1fw0

2015_01_20 10:29 h1iopsusex
2015_01_20 10:30 h1iopsusex
2015_01_20 10:31 h1susetmx
2015_01_20 10:31 h1sustmsx
2015_01_20 10:32 h1susetmx
2015_01_20 10:35 h1iopsusex
2015_01_20 10:35 h1susetmx
2015_01_20 10:37 h1sustmsx
2015_01_20 10:44 h1susetmx
2015_01_20 10:51 h1iopsusey
2015_01_20 10:51 h1susetmy
2015_01_20 10:51 h1sustmsy

2015_01_20 11:31 h1hpiham2
2015_01_20 11:31 h1hpiham3
2015_01_20 11:31 h1iopseih23
2015_01_20 11:31 h1isiham2
2015_01_20 11:32 h1hpiham2
2015_01_20 11:32 h1hpiham3
2015_01_20 11:32 h1iopseih23
2015_01_20 11:32 h1isiham2
2015_01_20 11:32 h1isiham3

2015_01_20 11:58 h1fw0
2015_01_20 11:58 h1nds0
2015_01_20 12:49 h1fw1
2015_01_20 12:49 h1nds1
2015_01_20 12:57 h1broadcast0
2015_01_20 12:57 h1dc0
2015_01_20 12:57 h1fw0
2015_01_20 12:57 h1fw1
2015_01_20 12:57 h1nds0
2015_01_20 12:57 h1nds1

maintance day preceded with two unexpected restarts. Restart tests on SUS ETMs. Power cycle of h1seih23 for noise hunting. Power cycle of DAQ solaris boxes, followed by DAQ restart for new slow controls ini files. Conlog frequently changing channels report attached.

Non-image files attached to this report
H1 ISC
sheila.dwyer@LIGO.ORG - posted 00:27, Wednesday 21 January 2015 - last comment - 12:36, Wednesday 21 January 2015(16175)
DRMI +arms tonight

Alexa, Evan, Koji, Arnaud, Sheila, Rana

The good news is that ALS is quite stable tonight, staying locked for up to 2 hours.  

We have been having trouble transitioning to 3F tonight.  We can transition MICH and PRCL fine, but we have seen a lot of noise at 300 Hz when we try to transition SRCL to 3F.  When we try to transition we see noise at 23.5Hz.  

ALS lock loss times: (all Jan 21st UTC) 0:03:02, 0:34:26

ALS lock loss +HEPI, ISI and sus trips: 7:30:15, 5:15:26 

Lockloss and bad misalingment of IMC due to DOF4: 6:35

Images attached to this report
Comments related to this report
alexan.staley@LIGO.ORG - 00:33, Wednesday 21 January 2015 (16176)

DRMI  + arms off resonance lock loss due to SRCL 3f transition at 01/21/14 08:06:00 UTC

sheila.dwyer@LIGO.ORG - 12:36, Wednesday 21 January 2015 (16185)

Keita, Sheila, Daniel, Alexa

Here is a screen shot of what happened that caused HEPI and ISI trips on DIFF lockloss last night.  First, the arms loose the green lock, at that time the DARM output becomes very large, the gaurdian ramps this down over ten seconds, durring which time the integrator in L1 is still integrating.  The guardian eventually clears this integrator.  Before the integrator was cleared, the arm cavity flashes, although the suspension was still swinging so this produced a momentary lock.  The tidal comes on, with a large output because the integrator in L1 has not been cleared yet.  

We have done 4 things to help prevent this in the future:

  • added a limiter of 3x10^6 in the DARM filter bank
  • added a limiter of 10 um in the LSC-X_TIDAL_ERR filter module (and Y)
  • fixed a mistake in the guardian that meant only one of the boosts in L1_LOCK_L was being turned off on a lock loss.
  • increased the speed of the ramping down of the DARM gain, so that the suspension history clearing will happen sooner.  

The last thing that we need to do is add a delay to the logic for the tidal feedback, so that it does not engage prematurely on these momentary locks.  

Images attached to this comment
H1 ISC (ISC)
rana.adhikari@LIGO.ORG - posted 20:05, Tuesday 20 January 2015 - last comment - 14:14, Wednesday 21 January 2015(16171)
UGF Servo math problem

Math puzzle: What's wrong with this UGF Servo?

its installed for use in the OMC and LSC at the moment, and could be used in the ASC if we find we want to hold the UGFs constant during TCS tuning.

Images attached to this report
Comments related to this report
nicolas.smith@LIGO.ORG - 12:59, Wednesday 21 January 2015 (16184)

loop diagram

We want to measure G. The algebra tells us that

b=frac{1}{1-G}e+n,

a=frac{G}{1-G}e+n.

When the excitation is sufficiently large that the noise is negligible, we get G=a/b.

a and b are complex quantities, and the real and imaginary parts are the I and Q outputs of the demods, or

a=a_I+i a_Q,

b=b_I+ib_Q.

In the version of the UGF servo that Rana posted, the phases would be chosen such that the imaginary (Q) outputs are zero, thus

G = frac{a}{b} = frac{a_I}{b_I}.

This is OK as long as G only ever changes in magnitude, otherwise G 
e frac{a_I}{b_I}.

To get the correct measurement in the case of a changing phase, one must do the following:

G = frac{a}{b} = frac{ab*}{|b|^2} = frac{a_I b_I+a_Q b_Q}{b_I^2+b_Q^2} + i frac{a_q b_I-a_I b_Q}{b_I^2+b_Q^2}=G_I+iG_Q

This is implemented in the attached simulink model.

simulink model

Images attached to this comment
Non-image files attached to this comment
koji.arai@LIGO.ORG - 13:40, Wednesday 21 January 2015 (16188)

(First of all I don't know the answer yet)

I believe G only changes the gain most of the case.

The problem was

a/e = G/(1-G) and b/e = 1/(1-G) change their phase as you change the gain of G. 

We usually don't care the phase of G, but only care the magnitude of G as the phase of G is fixed.

Therefore what we need is to take the ratio of the magnitude of a and b

|a| = |G|/|1-G|, |b| = 1/|1-G|

|a|/|b| = |G|, where |a| = sqrt(aI2+aQ2) and |b| = sqrt(bI2+bQ2)

(Ed: I'm suggesting to take SQRT(I^2+Q^2) to eliminate the frequently-omitted-effort of adjusting the demod phase correctly.)

william.korth@LIGO.ORG - 14:14, Wednesday 21 January 2015 (16190)

Meh, I say it's overkill. As Nic mentions, this works just fine if the UGF phase is not changing, so long as you set the demod phase correctly. As Koji mentions, the UGF phase should not be expected to change that much. It is already a second-order effect, so what is there now should be fine, unless we really want to accommodate wild loop phase fluctuations at the UGF. Is there a reason that's ever something we want?

H1 IOO (ISC)
kiwamu.izumi@LIGO.ORG - posted 15:35, Tuesday 20 January 2015 - last comment - 08:53, Wednesday 21 January 2015(16166)
IMC ASC maintenance

Rana, JeffK, Kiwamu,

We did some maintenance items on IMC ASC. The major activities are:

Also, tomorrow or sometime this week, we might insert a lens in the REFL gigE path as the REFL beam now is a bit too big to be able to cover the spatial higher order modes.

Comments related to this report
rana.adhikari@LIGO.ORG - 18:32, Tuesday 20 January 2015 (16170)IOO, ISC

Some issues with the current implementation:

  1. Its not clear that DOF4 servo makes any sense. Using the extinguished field (dark, messy HOM stuff) seems like a not stable way to make a centering loop. Certainly we cannot assume that putting digital offsets into these loops will be stable in the long run. The MC REFL image visibly changes week-to-week. If the carrier contrast defect was symmetric or if the SB power was larger or if we used 2f RF centering, this might be better.
  2. We had two low pass filters in all of these loops. This is now replaced with a single 4th order low pass at 7 Hz. Since we have no noise budget or noise estimate its not clear what these filters were for.
  3. There was a 'not1' filter in these filter banks which seems like a hacky way to inverting the plant, but only would be so if we were driving single pendula. We'll now look at modifying the MC SUS damping filters and then making the pendulum Q's lower and inverting the pendulum response (M1 P -> M3 P).
  4. Not sure when the Input Matrix was measured or diagonalized. This ought to be done to make sure we're not shooting ourselves in the foot.
  5. The FM2 (1:0) integrator was getting clicked off during each lock loss and sending the full control signals as a transient to the suspensions. This FM triggering is now turned OFF and things seem better. No DOF4 transients have happened after turning these off.
  6. The beam sizes on these MC WFS seem too small. According to Kiwamu (log #6560) the beam diameter is ~0.7 mm on both of them. According to Hartmut, they are ~1.5 mm at LLO.
sheila.dwyer@LIGO.ORG - 22:45, Tuesday 20 January 2015 (16173)

Tonight we have twice had MC lock losses where MC1+MC3 got completely misalinged, although they didn't trip.  The second one of these was at the same time as a lockloss of the ALS, but we don't know if the IMC caused it or ALS.  This was at 6:35 UTC, Jan 21st.  

daniel.sigg@LIGO.ORG - 08:53, Wednesday 21 January 2015 (16177)

We made the decision not to increase the spot size. This was done at LLO to decrease the jitter coupling into the ISS. The in-vacuum ISS doesn't require this.

The IMC seem to have worked much more reliably, before we added DOF4. Please turn it off for good.

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