Still processing the TFs but likely okay.  Put the HEPI back to cartesian alignment with the Iso offsets.  The hysteresis of HEPI is evident as I had to change the offsets to get back to position.  So if commissioners lose the HAM5 HEPI they may need to again adjust these offsets.  I've got the Rot DoFs to +-500nrads and the Tran DoFs to +-40umeters.

no restarts reported

Follow up analysis of the OMC scan by Dan (ALOG entry13660)

I believe this was done with a single bounce of ITMX.
ITMY had an oplev issue at the time as you can seen in https://alog.ligo-wa.caltech.edu/aLOG/index.php?callRep=13654

Frequency calibration

Calibratre data points using 0th- to 3rd-order carrier resonances and 0th- and 2nd-order sideband resonances as a frequency reference

Interpolate the frequency calibration by 11th order polynomials (see attachment "OMC_mode_scan_freq_calib.pdf")

Mode identification

Once the frequency is calibrated, the modes can be identified. As the beam is not filtered, it contains all of the sidebands and the sidebands of the sidebands including their higher-order spatial modes. (Attachment "OMC_modes.png" or "OMC_modes.pdf")

In the figure "USB/LSBn" indicates nth-order higher-order mode for upper or lower sidebands for 45MHz modulation.
"usb/lsb" indicates upper or lower sidebands for 9MHz modulation.
"2xUSB0" and "2xUSB0" means 2nd-order modulation sidebands for the 45MHz modulation (i.e. 90MHz sidebands).

Peak fitting

Peak heights of most of the modes are fitted (by hand). (Attachment "OMC_scan_LHO.pdf")

The decomposition of the modes are listed at the end of this entry

Mode matching

From the mode decomposition, the mode matching of the carrier is 0.86 +/- 0.01

Modulation depth

From the ratio of the sideband photocurrent and the carrier photocurrent, the modulation depth for each modulation was estimated

Modulation depth for f1 (9MHz): 0.198+/- 0.006

Modulation depth for f2 (45MHz): 0.305+/-0.003
 

Wiggling some RF cables for the ASAIR_A_RF45 demodulation, I found a bad SMA connector that was for the LO signal at the fied rack. Depending on stress on the connector, it could rotate the phase by about 90 deg. I attempted to fix it, but I could not find the crimping tool kit in the EE lab. We will do it tomorrow once the tools are found. The RF cable is currently disconnected.

I measured the spot position on PRM by using the usual angular dither technique (see for example LLO alog 5010) with PRY locked. It turned out to be pretty good.

• measured vertical off-centering = too low by 2.0 mm
• measured horizontal off-centering = off toward PR3 by 1.0 mm

(some settings):

• ITMX and SRM are intentionally misaligned.
• PRY is locked on the carrier light by REFL_A_RF45_I with a demod phase of 6.9 deg
• No whitening gain, but whitening stage 1 and 2 are engaged to obtain better signal-to-noise ratio.
• Feedback on PRM and PR2 as usual
• servo gain in LSC = -50 which should give a UGF of 30-60 Hz.
• Excitation in SUS-PRM_LOCK_P(Y) with an amplitude of 1000 counts at 10.1 Hz
• I used dtt to take a transfer function of (REFL_A_RF45_I) / (PRM_LOCK_P(Y)) 
• Before the measurement, PRM was tweaked to maximize the intracavity power

(results)

See the plot below.

(some notes)

• At the beginning of the measurement, the beam on REFL_A was at the edge of REFL_A. This resulted in bogus data because it introduced some kind of wave-front-sensing effect as the PRM angle was modulated.
  • This was fixed by moving the tip-tilt mirrors in HAM1, namely RM1 and RM2.
• I used a conversion factor of 42.2 mm for converting the imbalance alpha (see 40m elog 2863 for the definition) into the position of the rotational nodes.
  • According to D1101377-v2,  I used the following numbers to derive the conversion factor:
    • radius of the mirror: R = 75 mm
    • mirror thickness: L = 75 mm
    • magnet separation D = 95.45 mm

Please don't disturb the Matlab session.  -Hugh

WHAM4 only has level 1 robust controllers and we should build Level 2 & 3 controllers as well.  Now that the system is really complete and we only have in-air TFs, it makes sense to run new TFs.  We need to do this just about everywhere.

See the two attached plots to see the new CPS TF completed Wednesday, the response is nicely smooth (in vacuum) compared to the In-Air TFs with HEPI locked on May 23.  Notice the large dip in H3 as well as the shift down and smoothing of peaks between 10 and 50 hz.  Not sure what this means for controller development but it seems important.  I drove with DTT and these seem to still be present.  These features DO NOT appear in the GS13 signals but we do have good coherence here for the GS13.

Running down some funny business.

8:41 Safety audit committee to LVEA for tour

8:51 Jeff B to LVEA to shutdown dust monitors (2,3,4,5,13)

8:53 Filiberto to MidY on AOS parts hunt

9:31 Richard to MidY

9:34 Safety audit committee tour complete

9:36 Jeff B done with dust monitor work

9:41 Greg to EY

9:51 Christina to EX and EY for magnetometer install

10:00 Kyle to soft-close  GV7

10:05 Richard back from MY

11:00 Betsy to west bay on laser barrier hunt

12:00 Greg transitioning EY to laser hazard

12:06 Jim B to LVEA with security review tour

12:33 Jim B out of LVEA

12:44 Greg Mendell to roof with security review committee

12:57 Karen to EY

12:58 Jim to ITMx investigating issues with ISI

13:11 Karen done at EY

13:49 Gerardo to EX, replacing valve on purge air system

13:53 Bubba to LVEA to crane zamboni out

14:55 Jason realigned ITMy OpLev

15:10 Gerardo back from EX

15:10 Gerardo to LVEA west bay CR to FC ITM optic for charging measurements

Soft-closed GV7 (this valve will be opened again in a few weeks and we seek to minimize hard closures) -> Added scroll backing pumps to YBM and XBM turbos (in parallel to QDP80 pumps and independently isolatable) -> Valved-in aux. pump carts to HAM5/6 and HAM4 annulus' -> Valved-in YBM and XBM turbos backed only by scroll pumps -> Shut down QDP80s -> Valved out IP1, IP2 and IP6 

The pressure at the X-end is OK to leave open to BT (saves a cycle of GV20)

Removed and replaced the check valve for compressor No. 4.

Also, about 1 month ago the relief valve for this compressor was replaced.

I've been digging into why my new loops for ITMX won't run and I've found I have a bad CPS (St1-H3). Not really terrible, and probably not responsible for my difficulties. See plot, which was made with the H3 and V3 in-air cables switched, but the original way looked the same, indicating a likely bad board, not the cabling.

   Now that most of the installation work is complete and the over chamber cleanrooms are turned off, I have shutdown and removed the dust monitors from the HAM2, HAM3, HAM4, HAM5, and the X-Arm spool areas. We are currently monitoring the general air in the LVEA via dust monitors in the Beer Garden and the HAM6 end of the tube.  

   While removing the above mentioned dust monitors I found several that had been unplugged from A/C power. The extension cords unplugged from these dust monitors had other things plugged into them. These dust monitors were plugged into A/C power because their batteries are failing (and cannot be replaced). By unplugging these dust monitors they were taken off line and not monitoring the cleanroom environment.

   Please do not unplug dust monitors from A/C power without talking to Jeff B. first.     

model restarts logged for Wed 03/Sep/2014
2014_09_03 09:03 h1fw1

unexpected restart of h1fw1

Attached is a plot of the reference cavity transmission and pre-modecleaner reflection signals.  Both have drifted slightly since the re-alignment on Tuesday.

• Closing gate valve on X arm after successful look down arm
• SEI working on ITMx ISI
• Richard reconnecting cables to SUS test stand in LVEA
• Jason working on finding a return beam from HAM5 OpLev
• Richard working on cameras in the LVEA
• more charging measurements on ITM in LVEA West Bay (Mike, Gerardo)

Now that the ISS is back working after re-aligning into the pre-modecleaner, it makes sense to do a measurement.

The measurement looks better than the one performed on August 12th in that the hump out beyond 1 kHz is cleaner now than before.  The low frequency relative power noise appears to be a little better from 1-3 Hz.  One difference to note is that the diffracted light level is ~2% higher than before.  Also the first loop gain is lower at 8 dB versus 17 dB (old).  With the improved alignment, the power on the photodetector is ~10V versus ~8.6V.

Sheila, Kiwamu,

We locked the infrared main laser to the X arm this evening in order to improve the alignment of the input poointing.

Here are some settings we used for future reference:

• REFL_A_RF45_I is used
• demod phase = 6.9 deg
• whitening gain = 12 dB
• stage 1 and 2 whitenings are on.
•  REFL_A_RF45_I(Q)_GAIN = 0.275
• FM3 and FM4 of LSC-XARM are used. FM3 = p0:z1, FM4 = z41:p1e3.
• XARM_GAIN = 0.2. This gave us a UGF of 80-ish Hz according to a kink point in a spectrum of the error signal
• Once it grabs a fringe, FM1 boost, p0:z3 can be engaged, MCL can be turned off.
• disabled all the notches in MC2 SUS INF in order to have stable loop.
• I could not bring the UGF below 40 Hz by reducing the gain. This maybe because of a phase mergin, or not enough supression or perhaps something else.
• SInce the UGF was higher than a vertical mode of SUS_MC2 at 40 Hz, the locking loop kept rinring up this mode. It is visible in the attached dtt screenshot.
• The X arm trans sum stayed at about 800 counts, seen by ASC-X_TR_A_NSUM

At the request of local commissioners, I have modified the SUS guardian code to go back to handling the setting of alignment offset values for the ALIGNED state, and have re-introduced the MISALIGNED state which sets the alignment offset to saved misaligned values.  This all was originally in the SUS guardian code, but was removed at LLO due to precieved problems with the SUS guardians handling the offsets.  The LHO commissioners, on the other hand, prefer the SUS guardians to have separate ALIGNED and MISALIGNED states.

SUS guardians have not been restarted yet.  Only SR2 for testing.  We're waiting until after the arm alignment tests are done.

NOTE: ALIGNED and MISALIGNED offset values MUST BE SAVED in order for the SUS guardians to restore to them! This is the big change by going back to this configuration.  When the SUS guardians were not touching the offsets, there was no worry that they would accidentally be reset.  Now that they are being set by guardian, we have to remember to always save the offsets appropriately after tweaking them.  Forgetting to save them could result in the current alignment being lost if the suspension trips or the alignment state is cycled.

As a bonus, the SUS guardians will use the notification USERMSG to notify you if the alignment has been changed and not saved.

Here's the current SUS state graph:

This is all just a stop-gap until we get a better comprehensive solution to the alignment offset problem.  This will likely be discussed in the next SYS meeting, on 9/9/2014.

When Kiwamu locked PR-X (CH16), POP_A (CH1-7) saw some decent beam, about right in PIT and off in YAW.

POP_B (CH9-15) also saw something, it's not clear if it was the real beam or some ghost, the power is about a factor of 10 smaller than POP_A, and mostly in seg1 and 2.

Anyway, the important thing is that the POP_A already see the beam and POP_B is close.

Don't use pico to center these, though, as POP sled might be a good initial alignment reference.

We should first align the IFO to the POP sled and see if it makes things better. POP sled was aligned perfectly in the last days of HIFO-X/Y. Though a beam splitter was inserted after the vent, the insertion procedure was written such that the sled centering is preserved.