Evan, Lisa

This entry is to clarify the fact that the impact of  this excess of high frequency noise  is actually bigger than the coherence with the ASC channels suggests, as it can clearly be seen by comparing OMC NULL and SUM.

For example, around 2 kHz, the discrepancy in the noise floor between OMC SUM (total noise) and OMC NULL (shot + dark noise) is about 15%, so corresponding to a noise which is 0.6 times shot + dark.

The attachment shows OMC SUM/NULL in H1 at low noise (left) compared to L1 (right). 

So, the message is that we are looking for something quite big here..

After 17:30 UTC the interferometer was not undisturbed: I was making PEM injections.

 Measured temps of heated areas of RGA -> 95C < temps < 120C -> Made slight changes to variac settings -> Aux. cart @ 2.5 x 10-5 torr (seems high for this configuration)

Its been a week since the DAQ reconfiguration which reduced the NFS/QFS disk loading and both framewriters continue to be 100% stable. The attached plot shows the restarts of h1fw0 (red circles), h1fw1 (green circles) and the DAQ system as a whole (blue squares) for the month of July. The Magenta lines show when h1fw0 and h1fw1 were modified. In the past 7 days, the only restarts of the framewriters are associated with complete DAQ restarts.

Matt, Lisa, Evan

Tonight we looked at the coherences between the OMC DCPD channels and ASC AS C, this time at several different interferometer powers. In the attached plots, green is at 11 W, violet is at 17 W, and apricot is at 24 W.

Evidently, the appearance of excess high-frequency noise in OMC DCPD sum (and the coherence of OMC DCPD sum with ASC AS C) grows as the power is increased. We believe that this behavior rules out the possibility that this is excess noise is caused by RIN in the AS port carrier, assuming that any such RIN is independent of the DARM offset and of the PSL power. Since the DARM offset is adjusted during power-up to maintain a constant dc current on the DCPDs, RIN in the AS carrier should result in an optical power fluctuation whose ASD (in W/rtHz) does not vary during the power-up. This is the behavior that we see in the null stream, where the constant DCPD dc currents ensure that the shot-noise-induced power fluctuation is independent of the PSL power.

I modified the ISC_LOCK guardian to revert the DOWN state back to being a 'goto'.  This allows you to select the state directly, without having to go to MANUAL.

The reason it had been removed as a 'goto' was because occaissionally someone would accidentally request a lower state while the IFO is locked, which would cause the IFO to go back through DOWN to get to the errantly requested state.  To avoid this I implemented some graph shenanigans:  I disconnected DOWN from the rest of the graph, but told it to jump to a new READY state at the bottom of the main connected part of the graph once it's done:

This allows DOWN to be a goto, so it's always directly requestable, but prevents guardian from seeing a path through it to the rest of the graph.  Once DOWN is done, though, it jumps into the main part of the graph at which point guardian will pick up with the last request and move on up as expected.

J. Kissel
WP 5395
ECR E1500230
II 1054

I've removed all redundant IPC Error EPICs channels from the top-lvel models of all SUS this evening. This is in accordance with ECR E1500230. The models compile, and have been committed to the SVN. They will be installed this coming Tuesday.

Once installed, this closes out the ECR and Integration Issue for LHO.

Jeff, Sheila

We have had three locklosses in the last 2 days that were caused by the ETMX UIM coil driver rocker switch tripping.  The only solution is to drive to the end station, and flip the rocker switch back on.  Something is wrong with this coil driver (Jeff thinks it should just be replaced).

The only way to notice this is looking at the OSEM centering medm screen.  It would be great to add it to SYS DIAG (its not caught by the current noisemon check), and the ops overview screen, and the quad overview in a more obvious way.

Over the past two days h1susey has IOP glitched 10 times compared with only two times the previous two days. Here is a log of the recent glitches

With the IMC unlocked, these are some numbers for power on the IMC REFL PD (S1203775):

• PSL power: 2.52 W
• DC power on IMC REFL: 4.65(5) mW
• DC power on IMC REFL: 1223(3) ct

Evan, Kiwamu, Stefan

Evan reported that he observed a sudden drop in several AS poer signals, including 
H1:ASC-AS_C_SUM_OUT_DQ
H1:LSC-ASAIR_B_RF90_I_ERR_DQ
around Jul 31 2015 11:23:32 UTC

We found a corresponding drop of the 9MHz main oscillator feed, monitored by:
H1:ISC-RF_C_REFLAMP9M1_OUTPUTMON
H1:ISC-RF_C_AMP9M1_OUTPUTMON

attached is a file listing the channel differences between the L1 and H1 science frames.

During the period of bad IFO state which started at approx 12:12 PDT, the ITMX SWWD triped the SEI-B3 system. In the plot below, Ch1 shows the ITMX SUS top stage F1 OSEM signal, which rapidly exceeded its 95mV trip limit. This started the SUS SWWD counter. Five minutes later, Ch2 shows the signal going to the SEI-B3 drop to zero (the BAD state). This started the SEI SWWD counter, shown in Ch3 as going from one (GOOD) to three (1ST COUNTER). Four minutes later the SEI SWWD transitioned to four (2ND COUNTER) and one minute later tripped the SWWD, which zeroed all SEI-B3 DAC outputs. This shows up on the RMS plot as a slightly elevated signal, but SUS continues to be rung up. At 12:27 the operator intervened and manually panic'ed the SUS SWWD, at which point the RFM started decreasing.

Kyle, Gerardo

In and out of X-end VEA 

~1030 - 1230 hrs. local

Added 1.5" O-ring valve in-series with existing 1.5" metal angle valve -> Wrapped RGA with heater tapes and foil -> Elevated pump cart off of floor (resting on foam) -> NW40 inlet 50 L/s turbo (no vent valve) backed by aux. cart (no vent valve) -> Begin 100C bake 

In and out of X-end VEA between 

1405 - 1425 hrs. local, 

1450 - 1455 hrs. local and 

1600 - 1605 hrs. local. 

NOTE:  Will need to enter X-end VEA to make adjustments Saturday morning

Something happened at lock loss and the IFO did not reach the defined DOWN state.

Symptoms:

• SUS: ITMX, ITMY, ETMY - driven and rung up, watchdogs tripped, I had to adjust the RMS limit on ETMY from 8000 to 10000 to reset watchdog
• SEI: ITMY ISI tripped - Jim rest
• IO: MC WFS left pushing optics to a bad place and needed to be cleared by hand
• PSL: ISS and FSS in oscillation - outer loop on while IMC was unlock, throwing inner loop into oscillation
• GRD: ISC_LOCK - red for a while, cleared after INIT

Dave, Jaime, Sheila, operators, and others are investigating.

Matt, Evan

Why do the TMSX RT and SD OSEMs have such huge spikes at 1821 Hz and harmonics? These spikes are about 4000 ct pp in the time series. In comparison, the other OSEMs on TMSX are 100 ct pp or less (F1 and LF shown for comparison).

Also attached are the spectra and time series of the corresponding IOP channels.

Summary

To decrease uncertainty in calculation of actuation function correction factor, kappa_A, sensing function correction factor, kappa_C, and CC pole frequency, f_c, we've recently increased calibration line amplitudes to give SNR of 100 with 10s FFT (see LHO alog #19792). Earlier Kiwamu posted his investigation of CC pole frequency over the last weekend in LHO alog comment #19988. In this alog we show kappa_A, kappa_C and f_c calculated according to the method described in T1500377-v3 for the same time interval (2015-07-25 00:00 UTC to 2015-07-27 UTC, when GRD-ISC_LOCK_STATE_N >= 501, 1 min FFTs).

Statistical uncertainties of kappa_A, kappa_C and f_c within 1.5 hours time interval highlighted with green are:

Xctrl(34.7) and PcalX(33.1), std(kappa_A) = +/- 0.45 % (1 sigma)
PcalX(325.1), std(kappa_C) = +/- 1.12 % (1 sigma); std(f_c) = +/- 5.20 Hz (1 sigma)
PcalY(331.9), std(kappa_C) = +/- 1.43 % (1 sigma); std(f_c) = +/- 5.55 Hz (1 sigma)
PcalX(534.7), std(kappa_C) = +/- 0.70 % (1 sigma); std(f_c) = +/- 2.08 Hz (1 sigma)
PcalY(540.7), std(kappa_C) = +/- 0.78 % (1 sigma); std(f_c) = +/- 2.68 Hz (1 sigma)

Notice that kappa_C and f_c on the left subplots were calculated from low SNR 325.1 Hz and 331.9 Hz Pcal lines set by Evan (see LHO alog comment #19823). Calculation of these parameters using higher SNR 534.7 Hz and 540.7 Hz Pcal lines (right subplots) gave less noisy results.

Details

C_0, D_0 and A_0 were taken from LHO ER7 DARM model.

To make kappa_C calcluations consistent between results from 4 Pcal lines, a manual correction to phases of Pcal lines that correspond to 130us of time advance was applied. On the plot we report only changes in f_c by subtracting mean value of about 300 Hz. In order to receive an absolute value of f_c using this method, we must take into account exact time delay/advance of PCAL RXPD channel w.r.t. DARM_ERR; possibly a frequency independent phase shift (however we do now know any reason for that); and the DARM model TFs at the reference time, C_0, D_0 and A_0.

Plots of 1 min FFT dewhitened calibration line amplitudes and phases are given below.

Calibration line uncertainties in DARM_ERR readout in a 1.5 hours interval (highlighted with green color) are as follows:

Xctrl( 34.7) = 2.2000e-01 (+/- 0.00 %); Derr( 34.7) = 2.9738e-10 (+/- 0.15 %)
PcalX( 33.1) = 2.4587e-02 (+/- 0.00 %); Derr( 33.1) = 3.0817e-10 (+/- 0.26 %)
PcalX(325.1) = 1.0724e-01 (+/- 0.00 %); Derr(325.1) = 2.0593e-10 (+/- 1.48 %)
PcalY(331.9) = 9.3791e-02 (+/- 0.01 %); Derr(331.9) = 2.0150e-10 (+/- 1.55 %)
PcalX(534.7) = 7.1100e-01 (+/- 0.00 %); Derr(534.7) = 5.8223e-10 (+/- 0.52 %)
PcalY(540.7) = 6.3845e-01 (+/- 0.01 %); Derr(540.7) = 5.8948e-10 (+/- 0.45 %)

P.S.

After today's calibration telecon we've changed calibration lines that will be used for estimation of kappa_A, kappa_C and f_c to (see LHO alog #20063):

• PCALY 36.7 Hz, SNR ~100;
• DARM_CTRL 37.3 Hz, SNR ~90;
• PCALY 331.9 Hz, SNR~100;
• PCALY 1083.7 Hz, SNR~40;

We are also planning to add an ESD line close to low frequency PCALY line and another high frequency low SNR PCALX line at 3001.3 Hz after completing power budget investigations of PCALX module.