LVEA: Laser Hazard
Observation Bit: Commissioning  

09:10 Cris – Delivering garb to End-X
09:10 Karen – Cleaning in the LVEA
09:37 Gerardo – In LVEA doing viewport checks
09:37 Hugh & Mitch – To unlock HEPI at End-Y
09:47 Aaron – PEM cabling work between HAM2 and Beer Garden
09:50 Travis – Open the High Bay rollup door in LVEA to bring in equipment from the end stations
10:22 Hugh & Mitch – Back from End-Y -  HEPI is now unlocked
10:25 Bubba – Going to End-X to check on cleanrooms
10:51 Karen – Going to End-Y to check on garb and clean
11:10 Bubba – Shutdown cleanrooms at End-Y and turn on heaters
11:30 Karen – Finished at End-Y
12:37 King Soft Water on site to drop off parts
13:17 Aaron – Pulling OpLev cables in the LVEA
14:54 Robert S. – Delivering equipment to End-Y
15:40 Daniel – Transitioning both End-X and End-Y to laser hazard

Rich, Hugh, Fabrice:

Continuing the investigation to solve HAM3 noise issues. Last tests on Fridays doing the sensor correction to HEPI instead of ISI show that the noise line is still visible in the CPS, but not in the GS13. Rich suggested it might mean that the noise is introduced in the sensor correction channels (still disturbing Stage 0, but rejected by Stage 1 isolation). So we have looked at the coherence bewteen the FIR channels:

H1:ISI-HAM2_SENSCOR_GND_STS_X_FIR_IN1_DQ,

H1:ISI-HAM3_SENSCOR_GND_STS_X_FIR_IN1_DQ,

...

H1:ISI-HAM6_SENSCOR_GND_STS_X_FIR_IN1_DQ

for the X, Y and Z directions. 

The coherence from HAM2  to the other channels is shown in the plot attached. It is pretty bad in the Y direction, but we don't see the coherence droping at 0.6 Hz. Next step is to look at the output of the sensor correction filters (not sure whether they are in the DAQs, I might need someone on site to look at it)

Elli, Daniel, Evan

Summary

We tried adding a dc bias to the PSL EOM in order to reduce the RFAM, with little success.

Details

At the top of ISC R1, we inserted a minicircuits bias tee into the 9 MHz drive that goes to the PSL EOM. With a DMM, we measured the input impedance of the 9 MHz drive to be an open, and the input impedance of the analogous point in the 45 MHz drive was 70 Ω. We take this to mean that the 9 MHz drive goes directly to the EOM, with no intervening amplifier.

To see the effect of dc bias, we first hooked up the dc port of the tee to ISC-EXTRA_C_AS_AO_4, which is a slow DAC channel on the ISC rack. We applied ±10 V dc offset while watching the time series of REFL_A 9I&Q, but saw no obvious changes.

So instead, we hooked up the dc port of the tee to LSC-EXTRA_AO_2 (a fast channel) and drove it with a 32700 ct, 444 Hz sine wave. Then we looked for this excitation in spectra of REFL_A RF9I&Q.

• We found that the signal showed up mostly in Q, at 0.014 ct/rtHz,with a bandwidth of 0.187 Hz. This corresponds to 6.1×10⁻³ ct_rms.
• Using 4.7×10⁶ ct/W as the end-to-end calibration of the PD (measured by Kiwamu), this is 1.3×10⁻⁹ W_rms.
• The DC power was 81 mW_dc, according to the calibrated output of LSC-REFL_A_LF. Since our bias voltage is V_bias = 32700 ct ≈ 10 V, the effect of our excitation is (1.6×10⁻⁹ W_rms/W_dc) / V_bias.

Previously (LHO#15681), the RFAM level has been pegged at 1.1×10⁻³ W_rms/W_dc. That means that the fractional RFAM change that can be effected by this bias tee configuration appears to be something like 1×10⁻⁶ / V_bias, which is way too small to be practical.

J. Kissel

I've taken a full set of top-to-top transfer functions on H1 SUS ETMX to complete the quick assessment performed on Friday (LHO aLOG 15748) and confirm all is free and good after the recent optic cleaning (LHO aLOG 15744) and door re-install (LHO aLOG 15750). The chamber is still at air, but the doors are on, the ISI is damped, HEPI is floating and position controlled.

Results look great. 

The only thing of interest is that the 2nd pitch mode, previously reported to be a lower frequency than expected (see LHO aLOG 8822) remains low in frequency, and has not changed since the previous assessment. Again, we've controlled this suspension admirably, so no problems. Just one of life's mysteries that remains unsolved.

All data, and updated scripts have been committed to the repository (see below for details).

-----------------
Raw Data:
/ligo/svncommon/SusSVN/sus/trunk/QUAD/H1/ETMX/
SAGM0/Data/2014-12-22_1710_H1SUSETMX_M0_Mono_L_WhiteNoise.xml
SAGM0/Data/2014-12-22_1710_H1SUSETMX_M0_Mono_P_WhiteNoise.xml
SAGM0/Data/2014-12-22_1710_H1SUSETMX_M0_Mono_R_WhiteNoise.xml
SAGM0/Data/2014-12-22_1710_H1SUSETMX_M0_Mono_T_WhiteNoise.xml
SAGM0/Data/2014-12-22_1710_H1SUSETMX_M0_Mono_V_WhiteNoise.xml
SAGM0/Data/2014-12-22_1710_H1SUSETMX_M0_Mono_Y_WhiteNoise.xml
SAGR0/Data/2014-12-22_1720_H1SUSETMX_R0_L_WhiteNoise.xml
SAGR0/Data/2014-12-22_1720_H1SUSETMX_R0_P_WhiteNoise.xml
SAGR0/Data/2014-12-22_1720_H1SUSETMX_R0_R_WhiteNoise.xml
SAGR0/Data/2014-12-22_1720_H1SUSETMX_R0_T_WhiteNoise.xml
SAGR0/Data/2014-12-22_1720_H1SUSETMX_R0_V_WhiteNoise.xml
SAGR0/Data/2014-12-22_1720_H1SUSETMX_R0_Y_WhiteNoise.xml

Processed and saved .mat files of measurements:
SAGM0/Results/2014-12-22_1710_H1SUSETMX_M0_DTTTF.mat
SAGR0/Results/2014-12-22_1720_H1SUSETMX_R0_DTTTF.mat

Updated scripts:
/ligo/svncommon/SusSVN/sus/trunk/QUAD/Common/MatlabTools/
plotquad_dtttfs.m
plotallquad_tfs.m

PSL Status: 
SysStat: All Green, except VB program offline 
Output power: 33.0w  
Frontend Watch: Green
HPO Watch: Red

PMC:
Locked: 5 days, 14 hours, 35 minutes
Reflected power:    2.3w
Power Transmitted: 23.3w 
Total Power:       25.6w 

FSS:
Locked: 2 days, 15 hours, 58 minutes
Trans PD: 1.944v

ISS:
Diffracted power: 7.44%
Last saturation event: 2 days, 19 hours, 11 minutes  

Will run a couple DC tests to insure clearance.

broken by people starting to go into the LVEA.

Start:   2014/12/22/01:05
Stop:    2014/12/22/17:25
Duration:16h20min

We do see O(1%) power drifts, including a step arounbd 8:30am local - presumably due to human activity. We will chase down where this comes from.

Seismic : Working on ITM configurations
	  Need to take Safe.Snap of BSC1, BSC2, BSC3
	  Calibration of HEPI system pressures	

Suspensions: Clean up after ETM optics work

no restarts reported for both days. Conlog frequently changing channels reports attached.

Evan, Stefan

With the winds calming down again, we did some more SR3 alignment work:
- We noticed that for SCR1_Y AS B 36 I is still the best signal. It has
   - less "phase lag", presumably due to a reduced coupling to the BS. This allows us to do a high bandwith loop.
   - a small enough offset that servoing it to zero makes sense for reducing build-up fluctuations.
- Thus we closed the yaw loop with a UGF of 3.3Hz. Engaging it is in the Guardian.
- We tried to play the same game for the pitch loop, with less sucess.
   - all signals have some RF offset.
   - none of the signals seem to have low enough "phase lag" for a high BW loop. We should make sure this phase lag is not due to some broken whitening filter.
- Thus for now we left pitch in the configuration described in alog 15769.

Evan is now also updating the WFS relieve.

We will leave DRMI locked for the night.

I went into the PSL to check out possibilities for redoing the top periscope piezo mirror mount, which I think is responsible for the 250 Hz peak in DARM at LLO (Link). The secondary purpose was to check the recovery time for a 10 minute incursion. The IMC did not loose lock but suffered intensity spikes beginning when I went in, and quickly dissapating so that they were gone by an hour after I left. The plots show MC2 TRANS and ISS_AOM_DRIVER_MON in an overview and a zoom into one of the intensity spikes. The zoom suggests ISS oscillations. The step in MC2 TRANS was when Evan, seeing the spikes, shut down the gaurdian. 

Robert, Evan

Elli, Thomas, Stefan

- We found that the DRMI build-up fluctuations reported in alog 15765 were mostly due to a small offset in the WFS locking point for the SRC (feed back to SRM yesterday, switched to SR3 today).
- We fine-tweaked the input matrix mixing signals from AS36 A (orthogonal to the BS signal) and AS36 B (I&Q), such that we maximize the SR3 signal and get a good locking-point offset.
  The matrix is:
    AS A RF36I -0.45
    AS A RF36Q  0.89
    AS B RF36I  1.1
    AS B RF36Q -0.77
  This was found for pitch. Yaw was confirmed to be close, but wind prevented further fine-tuning. Using this significantly reduced the build-up fluctuations.

- Next we commissioned the a high BW loop for SR3. The filters are
    PIT: zpk([0.06+i*0.815;0.06-i*0.815;0.3+i*3.25;0.3-i*3.25],[0.3+i*2.87;0.3-i*2.87;11.1111+i*38.4258;11.1111-i*38.4258],1,"n")
    YAW: zpk([0.13+i*1.24;0.13-i*1.24;0.15+i*2.88;0.15-i*2.88],[0.15+i*2.48;0.15-i*2.48;11.1111+i*38.4258;11.1111-i*38.4258],1,"n")
  They were successfully tested up to a UGF of 6Hz using an optical lever. However, on the WFS we could not go that high because there was significant cross-talk from the other loops.
  Thomas will attach a measured transfer function.

- We left the feed-back on SR3 (the guardian sets this up), but with maybe 10 times lower BW.

- We also noticed that the high BW WFS cause more violent lock losses. We thus put (generous) limiters to all the top stages.

Unfortunately the winds are at 60mph again, so we won't leave it locked tonight.

I have reconfigured conlog to remove the constantly noisy H1:ALS-Y_VCO_TUNEOFS and the 2 disconnected channels. Details are:

+ H1:ALS-X_WFS_AUTOC_SWITCH

+ H1:ALS-Y_WFS_AUTOC_SWITCH

- H1:ALS-X_WFS_AUTOC_SWTCH

- H1:ALS-Y_VCO_TUNEOFS

- H1:ALS-Y_WFS_AUTOC_SWTCH

inserted 2 pv names

deleted 3 pv names

model restarts logged for Fri 19/Dec/2014
2014_12_19 11:28 h1fw1
2014_12_19 14:48 h1hpiham3
2014_12_19 14:49 h1isiham3

h1fw1 unexpected restart, SEI HAM3 restarted to see if it would fix a problem. Conlog frequently changing channels report attached.

Stefan, Kiwamu,

We did some more ASC optimizations tonight in DRMI. We are leaving the DRMI locked overnight to see what drfits on a time scale of hours.

Here is a list of what we did:

• High bandwidth PR3 and PRM ASC loops were engaged. Both use the M3 bottom stage with an almost 1/f open-loop shape.
  • PR3 loops = 6 Hz UGF,
  • PRM loops = 1 Hz UGF (going above this UGF causes instability at 10 Hz for some unknown reason )
• Off-loading to top stage on PRM, PR3 and BS are newly implemented. The top stages have an integrator so that they keep the DC value when the DRMI drops lock.
• IM4 pointing slow loop is newly engaged. It uses ASC-POP_B. The output matrix is diagonalized with an off-diagonal element for PRM.
  • for pitch output matrix, IM4 = 1 and PRM=22.
  • for yaw output matrix, IM4 = 1 and PRM = 129.
  • The servo points to a non-zero point on POP_B as we were not sure whether it was a good idea to servo it to zero without confirming the arm pointing. In addition, we saw the build-up dropping when we went further away from the nominal offset point, which is another reason why we did not servo it to zero. For now, we put an offset in ASC-POP_B_PIT(YAW)_OFFSET such that we don't loose the current IM4 pointing.
• We moved SR3 (which is one of the uncontrolled mirrors) to see what signal responds to it. It seems that REFL_B_45I is sensitive to this mirror, but currently SRM is suppressing this sensor with a slow bandwidth. Stefan will look into this mirror during the weekend.

All the modifications and new loops are coded in not only in the ISC_DRMI guardian but also ISC_DOF guardian so that they do not mess up the initial alignment WFSing.