Displaying reports 57941-57960 of 85361.Go to page Start 2894 2895 2896 2897 2898 2899 2900 2901 2902 End
Reports until 06:30, Wednesday 06 July 2016
H1 PSL (PSL)
peter.king@LIGO.ORG - posted 06:30, Wednesday 06 July 2016 (28189)
ISS
Came in and engaged the ISS.  Found it was in manual mode.  Left it in auto.  The integrator engaged straight
away.  This was before I did any temperature tuning of the laser diodes.

    Attached is the average diffraction over the past week.  I don't know why the spread was larger over the
past ~4 days and wonder if it was/is a portent of diode troubles.  Things seem okay at the moment.
Images attached to this report
H1 PSL (PSL)
peter.king@LIGO.ORG - posted 05:53, Wednesday 06 July 2016 (28188)
Front end laser temperature tuning
After yesterday's front end diode box replacement, the diode temperatures were left at the values
from the old diode box.  The diodes are now temperature tuned for what I think is close to the
optimum values.  Optimum being decided by the output power of the front end.
Images attached to this report
LHO General
patrick.thomas@LIGO.ORG - posted 23:53, Tuesday 05 July 2016 (28186)
Ops Evening Summary
Trouble keeping MC and FSS locked.

23:14 UTC Chandra to CP3
23:17 UTC Jenne and Sheila to LVEA to measure MC open loop gain
00:07 UTC Jenne and Sheila back
00:37 UTC Sheila to LVEA to plug in SR785 for analog measurement of MC open loop gain
00:44 UTC Sheila back
00:50 UTC Sheila to LVEA
00:54 UTC Sheila back
01:44 UTC Sheila to LVEA to set up RF analyzer
01:59 UTC Sheila back
H1 PSL (PSL)
jenne.driggers@LIGO.ORG - posted 21:51, Tuesday 05 July 2016 - last comment - 05:28, Wednesday 06 July 2016(28182)
ISS noisy since Friday

[Sheila, Keita, Jenne, Patrick]

We have been struggling to lock anything at all today.  Sheila is going to post about the loop measurements that we made today, but this alog is a cry for help with regard to the ISS. 

The ISS average diffracted power has been much more noisy than usual, ever since Friday.  Since today's PSL work, it's even worse.  We suspect that this may be bad enough that we are unable to lock.  We can no longer keep the integrator for the first ISS loop engaged for more than a few minutes before the loop starts to oscillate.  But, with or without the integrator on, the diffracted power is moving around like crazy.

At this point, we are leaving the IFO in Down, and hopefully someone from Team PSL will come in and look at the ISS tomorrow, and then maybe locking will be possible.

As a side note, it appears that everything in the PSL is misaligned by a bit.  Both the PMC and RefCav transmissions are about 25% lower than normal, with corresponding increases in their reflected powers.  This is probably the reason that we've had to increase the FSS loop gain earlier today to make locking even the IMC possible (see Sheila's alog).

Images attached to this report
Comments related to this report
sheila.dwyer@LIGO.ORG - 22:22, Tuesday 05 July 2016 (28183)

Attached are measruements of the IMC open loop gain.  We cannot measure the FSS gain without going into the PSL, but Peter King posted some measurements from May

The first attached plot shows that the IMC goes unstable around 200 kHz when the FSS gain drops by only 2dB.  Since the power transmitted by the reference cavity droped 25% after the laser problem, this probably explains why we were having trouble keeping the IMC locked with our old FSS gain of 14dB.  (see Hoacun's measurement of the time when we reduced the fast gain from 20 to 14 dB for a comparison.)  It seems like we want more than 2dB of gain margin though...  The orange trace shows that the IMC OLG continues to improve as we turn the common gain up to 20dB, but in this configuration the FSS cannot recover from a lockloss.  If this is the reason we keep the FSS gain marginal, we could write a gaurdian to automate relocking at a lower gain and turning up the gain once locked.

We checked that the IMC optical gain has not changed since Evan H's mid June measurement. (taken on the day the IMC gain was reduced by 4 dB from a IN1 gain of 20dB for 2 Watts to 16 dB at 2Watts which gives us a UGF of about 65kHz).

The second plot shows what happens when we change the fast gain by +/- 4 dB, reducing the gain makes gain peaking at 200 kHz.  

The data attached is for the configuration we are leaving, IMC locked at 2 Watts with 16dB IN1 gain, FSS common gain 16 dB, FSS fast gain of 22 dB.

Non-image files attached to this comment
sheila.dwyer@LIGO.ORG - 22:25, Tuesday 05 July 2016 (28184)

Also, there seems to be a problem with ALS DIFF after today's maintence.  We tried flipping the bias sign back, but that didn't help.  Since we still have laser/FSS/IMC problems we didn't investigate much further.

matthew.heintze@LIGO.ORG - 05:28, Wednesday 06 July 2016 (28187)

My guess based on the LLO experience of late is its the ISS AOM. My suggestion (from afar) is to realign and recalibrate the ISS AOM (its something that Christina B from AEI suggested should be done each time laser alignment could change). Since Ive done ours, our fluctuations that were on the order of %'s during O1 and before has really settled down to barely vary at all (hopefully I haven't jinxed myself now).

 

However doing this to the ISS AOM will probably misalign the PMC a bit (but if its already misaligned and need to redo the alignment anyway, now is maybe a good time to try realigning and recalibrating the ISS AOM)

H1 CAL
evan.goetz@LIGO.ORG - posted 21:22, Tuesday 05 July 2016 (28179)
DARM open loop gain, sensing function, actuator coefficient measurements for ER9

Evan G., Jeff K., Kiwamu I., Darkhan T.

Summary:
We have processed the DARM open loop gain and sensing function measurements and built a model of the loop that we believe sufficiently represents our knowledge of the parameters. In addition, the actuator coefficients have been remeasured using the Pcal. In summary, our model reproduces the DARM open loop transfer function to within +/-10% in magnitude and within +/-5 degrees in phase from 10 Hz to 1 kHz. Caveat: we have not yet assessed how this translates to the overall calibration uncertainty. Actuation coefficients for L1, L2, and L3 are within +/-5% of their O1 values. This model is used in the recently updated CAL-CS model (alog 28178).

Details:
The DARM measurements made recently (alog 28107) were processed using the updated DARM model code. Included in this new model is a functional form for the SRC detuning (alog 28150), and the fit to the measured data gives updated cavity gain, cavity pole frequency, time delay, and detuning spring frequency. The uncompensated OMC whitening filters are updated (alog 28087). Since the L1, L2, and L3 driver compensation has been updated (alogs 27150 and 27180), we removed all the measured and compensation zeros and poles, except for the uncompensated high frequency zeros and poles of the L3 stage (alog 27619). The AA/AI downsampling filters are using the RCG 3.0 64-16k filter coefficients (alog 27173).

Attached are figures showing (in order) the measurement and model comparison DARM open loop gain transfer function, the measurement and model comparison of the sensing function, and the L1/L2/L3 actuation coefficient measurements calibrated using the Pcal.

It was realized that since we no longer read out H1:CAL-DARM_ERR_WHITEN_OUT_DQ for the for the Pcal to DARM transfer functions--instead we are reading out H1:LSC-DARM1_IN1_DQ--the measurement to model comparison for the sensing function should not include the 1 16k clock cycle delay. However, the model for the sensing function should include this 1 16k clock cycle delay.

We tried a few different values for unknown sensing and actuation delays but did not attempt to optimize this any further.

Non-image files attached to this report
H1 SEI
patrick.thomas@LIGO.ORG - posted 20:59, Tuesday 05 July 2016 (28181)
SEI ground seismometer mass position check
There are 1 STS proof masses out of range ( > 2.0 [V] )!
STS EY DOF X/U = -2.072 [V]

(full results attached)
Non-image files attached to this report
H1 CAL (CAL)
darkhan.tuyenbayev@LIGO.ORG - posted 18:25, Tuesday 05 July 2016 (28180)
Updated EPICS records for tracking DARM time-dependent parameters (param. set for ER9)

Evan G, Darkhan,

Summary

EPICS records that will be used by GDS pipeline for calculation of the DARM time-dependent parameters in ER9 were updated on 05-Jul-2016 17:44:57 PDT (06-Jul-2016 00:44:57 UTC).

Details

The H1 DARM model parameters used for generation of the EPICS values are

Output files: raw epics values, a verbose log and a Matlab file with EP# variables (see T1500377-08, Table 2) were committed to the calibration SVN directory (the verbose log is also attached to this alog):

Runs/PreER9/H1/Scripts/CAL_EPICS

./20160705_H1_CAL_EPICS_VALUES.txt
./20160705_H1_CAL_EPICS_verbose.log
./D20160705_H1_CAL_EPICS_VALUES.m
./callineParams_20160705.m
./writeH1_CAL_EPICS.m

Runs/O2/Common/Scripts/CAL_EPICS/writeO2_TDEP_EPICS.m

H1 CAL
jeffrey.kissel@LIGO.ORG - posted 18:13, Tuesday 05 July 2016 - last comment - 12:37, Wednesday 06 July 2016(28178)
H1 CAL CS Front End Calibration Updated for ER9
J. Kissel, E. Goetz, K. Izumi, D. Tuyenbayev

Evan will post the details of the work we've had to do to get the model running, but in the interest of time, I've taken what we needed from the Matlab model to update the CAL-CS front-end filters. Since early results indicate that the only low-frequency (sub-Nyquist) things that have changed from the O1 model are in the sensing function (see LHO aLOG 28171):
   - Lower optical gain = 9.071e5 [ct/m],
   - Lower frequency DARM coupled cavity pole frequency, f_c = 328.7 Hz, and
   - New SRC-detuned optical spring frequency, f_s = 9.831 Hz.
I only needed to update the H1:CAL-CS_DARM_ERR inverse sensing function filter (see further discussion below). 

The new settings have been captured in the SDF system.

Details of the design:
Foton Design String --
       zpk([9.831;-9.831;328.7],[0.1; 0.1;7000],1,"n")gain(9574.81)*gain(1.102e-6)
The gain of 1.102e-6 is 1 / 9.071e5 [ct/m], this lives separately in FM4, called "ER9gain." In FM3, in the filter called "SRC D-2N" for "Signal Recycling Cavity De-Two-Ne" there lies:
- The pair of real poles at 9.831 Hz, one of which is in the right-half-plane, reflect the detuning dynamics. Note that we've rolled of these inversion zeros at low frequency of two real poles 0.1 Hz. 
- The 328.7 Hz is the new f_c, and we retain the same high-frequency roll off of 7000 Hz.  
- The gain of gain(9574.81) which is the correct normalization gain to get the over-all gain to be unity at 100 Hz, which is the frequency at which I matched the no-detuning gain of the (unused) 329:7000 filter in FM3.
The attached PDF shows that the ER9 gains agree between detuning and no detuning, and as expected, the overall optical gain is ~20% lower that O1 because we've not yet digitally compensated for the ~20% lower optical gain (because of 20% lower PRC gain; see LHO aLOG 28133) in the DARM loop.


Further Discussion on why I've only updated the Sensing Function:
All actuation strengths are within ~5% of there O1 values (see LHO aLOG 28130), and we've compensated all electronics better (see LHO aLOGs 27180, 27150, and 28087), so we need not update anything in the actuation chain. Rana and Evan H. have changed the local, top-mass damping loop filters for the QUADs, so nominally the QUAD dynamics have been changed, but that should be a small effect in the GW band. We'll update for O2, but no need for ER9. There have been several changes to effects at high-frequency, but all of those are covered in the GDS FIR filters which absorb the CAL-CS output and acausaly correct for these super-Nyquist frequency effects.
Images attached to this report
Non-image files attached to this report
Comments related to this report
jeffrey.kissel@LIGO.ORG - 12:37, Wednesday 06 July 2016 (28195)
J. Kissel, E. Goetz

After exporting the above SRCD-2N filter from foton and importing it back into matlab to compare against the matlab model of the sensing function, we discovered that my gain normalization was not perfect, and had a ~1% systematic error. This is likely because there is still some influence of the 9.8 Hz detuning poles at 100 Hz where I chose to normalize to the no-detuning filter. 

As such, instead, I've re-normalized to the gain at 500 Hz above the DARM coupled cavity pole. This results in a now-better-than-0.01% agreement with the matlab model in gain at all frequencies. I've updated the design string to
     zpk([9.831;-9.831;328.7],[0.1; 0.1;7000],1,"n")gain(9674.74)
and loaded coefficients.
H1 DAQ (CDS)
james.batch@LIGO.ORG - posted 17:04, Tuesday 05 July 2016 (28177)
Restarted h1tw0 trend writing
Carlos, Jim

After installing Ubuntu 12 on h1tw0 and performing a file system check, the h1tw0 is now writing minute trend files.
LHO VE
chandra.romel@LIGO.ORG - posted 16:35, Tuesday 05 July 2016 (28175)
CP3 overfill
4pm local

1/2 turn open on bypass LLCV - took 1:08 min. until LN2 came out the exhaust.
H1 CDS
david.barker@LIGO.ORG - posted 16:35, Tuesday 05 July 2016 (28174)
Restarted CW hardware injection process on h1hwinj1

I noticed that the CW hardware injection excitation had stopped running at 15:47PDT Thursday 6/30. Using monit I have just restarted it.

H1 General
cheryl.vorvick@LIGO.ORG - posted 16:26, Tuesday 05 July 2016 (28173)
Ops Day Summary:

State of H1: did not make it through Initial Alignment, Sheila and Jenne working on it

Activities:

listed in previous alog 28149

Since that alog:

Current Activities:  Jenne and Sheila out to LVEA to measure MC open loop gain

H1 CDS (DAQ)
david.barker@LIGO.ORG - posted 14:49, Tuesday 05 July 2016 - last comment - 16:42, Tuesday 05 July 2016(28168)
CDS maintenance summary

h1iscex lost timing

Jim, Dave:

at 09:41 PDT h1iscex lost its timing sync. Possibly due to a power cord being moved which drives the independent DC powered timing slave in the IO Chassis. Models were restarted at 11:50 PDT.

h1susetm and h1omcpi new models

Jeff, Carl, Dave

New h1susetm[x,y] and h1omcpi models were installed. DAQ was restarted

New Vacuum Controls code

Patrick, Dave

New Vacuum controls Beckhoff code was installed at all 7 locations. Required a DAQ restart.

alog tiny font fixed

an entry made this morning set the font size to x-small. This was fixed.

Ready to upgrade h1fw0 to 10 GigE if it becomes unstable WP5985

Jim, Dave

If h1fw0 becomes unstable, we will upgrade its CDS-LDAS link from 1GE to 10GE using borrowed LDAS cards. The next time it crashes it will not restart. We'll wait until 4pm PDT and then allow a restart.

Comments related to this report
david.barker@LIGO.ORG - 16:42, Tuesday 05 July 2016 (28176)

will keep h1fw0 running overnight. the 4pm deadline passed, all daq systems have been running for 3 hours now. Reminder, difference now is that two 64kHz channels have been removed from the commissioning frame, six 512Hz channels added to science frame.

LHO VE
patrick.thomas@LIGO.ORG - posted 14:46, Tuesday 05 July 2016 - last comment - 15:06, Tuesday 05 July 2016(28167)
Updated Beckhoff vacuum controls code
The code on each Beckhoff vacuum controls computer has been updated to incorporate the new PI controller. All of the cryopumps are back on PID control. TJ and I turned back on the ESD high voltage at end X and end Y. Dave has updated the DAQ. This completes WP 5972.
Comments related to this report
patrick.thomas@LIGO.ORG - 15:06, Tuesday 05 July 2016 (28169)
The PT100 cold cathode is no longer forced on. Since Gerardo changed the wiring it should no longer need to be. (alog 28024)

I noticed that the PT110 cold cathode stays on whether or not it is requested to be. I can't recall if this was hardwired to remain on?
LHO VE
kyle.ryan@LIGO.ORG - posted 13:05, Tuesday 05 July 2016 - last comment - 16:15, Tuesday 05 July 2016(28155)
1240 hrs. local -> Connected electronics and energized Y-end RGA filament
As found, RGA was valved-in to Y-end -> Will take a few scans in an hour or so
Comments related to this report
kyle.ryan@LIGO.ORG - 16:15, Tuesday 05 July 2016 (28172)
I am short pwr supplies for the electronics so I had to de-energize the filamnet, i.e. leaving the configuration as found.
H1 CAL
kiwamu.izumi@LIGO.ORG - posted 11:36, Tuesday 05 July 2016 - last comment - 14:16, Friday 08 July 2016(28150)
Fit of sensing function completed

With the measured sensing function (28123) in hand, we did an MCMC-based numerical fitting for the sensing function (see E. Hall, T1500553).

The fitting results are


[New sensing function form]

As reported by Evan (27675), it seems that the extra roll off in the DARM response at low frequencies are due to an SRC detuning (or something equivalent). While such detuning should be suppressed by some control loop ideally, we decided to include the detuning-induced functional form in addition to the ordinary single-pole response. We use the following approximated form for the DARM response

S(f) = H / (1 + i f / fc ) * exp( -2 * pi * f * tau) * f^2/(f^2 + fs^2)

where H, fc, tau and fs are the optical gain, DARM cavity pole, time delay and spring frequency. Some details of the derivation will be reported later. Apparently, we now have an additional quantity (i.e., fs) to fit.

Note that since H1 seems to be in (unintentionally) an anti-spring detuning, fs should be a real number whereas it should be an imaginary number for a pro-spring case. Obviously, Q is set to infinity for simplicity.

[MCMC-based numerical fitting]

Following the work by Evan (T1500553), we adapted his code to include the spring frequency as well. In short, it is a Bayesian analysis to obtain posteriors for the parameters that we want to estimate. We gave a simple set of priors as follows for this particular analysis.

The quad plot below shows the fitting result. The estimated parameters are obtained by taking the mean values of the resutling probability distribution. As usual, the two plots on the left hand side show a bode plot of the measured and fitted data. The two plots on the right hand side show the residual of the fit. As shown in the residuals, there are several points which are as big as 20% in magnitude and 6 deg in phase below 10 Hz. Otherwise, the residual data points seem to be within 10-ish % and 4 deg. The code is attached in pdf format.

EDIT: I am attaching the actual code as well.

Images attached to this report
Non-image files attached to this report
Comments related to this report
kiwamu.izumi@LIGO.ORG - 15:15, Tuesday 05 July 2016 (28170)

A detailed derivation of the new functional form can be found at https://dcc.ligo.org/LIGO-T1600278

kiwamu.izumi@LIGO.ORG - 16:03, Tuesday 05 July 2016 (28171)

EvanG noticed that we have unintentionally included high frequency poles in the previous analysis (28157). So we made the same fitting for the data with all the high frequency poles removed.

Here are the fitting results for the latest data:

  • Optical gain = 9.070764e+05 +/- 8.071988e+02 [cnts/m]
  • Cavity pole = 3.287361e+02 +/- 5.692504e-01 [Hz]
  • Time delay = 5.554816e+00 +/- 3.424867e-01 [usec]
  • Spring frequency = 9.831483e+00 +/- 5.434934e-02 [Hz]

Since the bode plot looks very similar to the one posted above, I skip showing it here. Observe that the time delay is now smaller than it was because we now don't have the high frequency poles.

craig.cahillane@LIGO.ORG - 14:16, Friday 08 July 2016 (28274)CAL
C. Cahillane, K. Izumi

I have added in a new term to our sensing function fit, an optical spring Q factor to gain back phase information.

From the functional form f^2/(f^2 + f_s^2) we only get a magnitude correction from detuning, but we also expect detuning to slightly affect phase in the sensing function response.

This can be clearly seen in lower right subplot Figure 1 of this comment, where Kiwamu originally plotted the full RSE sensing function.  Here we see that when we have 1 degree of detuning we also have +1.5 degree phase difference at 10 Hz when compared to the sensing function without detuning. 

In the phase residual plot in the original post you can see this phase loss in the actual ER9 sensing measurement.  

In order to try and gain back some of this phase information, we have added in an additional term to the detuning function:

    f^2                        f^2
-----------    ===>  -----------------------
f^2 + f_s^2          f^2 + f_s^2 - i*f*f_s/Q

This adds another parameter to our fit, but lets us get back phase information lost to detuning.

**********

Figure 2 shows Kiwamu's original fit parameters posted above in red alongside my new results in green.
I argue that including the optical spring Q factor has improved the phase fit significantly.  
Quantitatively, here are the phase Χ-Square values:

With Optical Spring Q Χ-Square    = 85.104
Without Optical Spring Q Χ-Square = 819.28

**********

I have modified Kiwamu's SensingFunction.ipynb into a SensingFunctionSimulation.ipynb which fits to both phase and magnitude of the sensing function.  SensingFunctionSimulation.ipynb is attached as a zipped file in this aLOG and is also in a Git repo called RadiationPressureDARM owned by Kiwamu.

Fit parameters:

Optical gain = 9.124805e+05 +/- 8.152381e+02 [cnts/m]
Cavity pole = 3.234361e+02 +/- 5.545748e-01 [Hz]
Time delay = 5.460838e+00 +/- 3.475198e-01 [usec]
Spring frequency = 9.975837e+00 +/- 5.477828e-02 [Hz]
Spring Inverse Q = 1.369124e-01 +/- 3.522990e-03

(I choose to parametrize using inverse Q = Q^{-1} because Q^{-1} can be zero.)
Images attached to this comment
Non-image files attached to this comment
Displaying reports 57941-57960 of 85361.Go to page Start 2894 2895 2896 2897 2898 2899 2900 2901 2902 End