Ellie, Evan and Dave
It has been noticed that the H1 Inteferometer has a tendency to spatial mode-hope between TEMOO and TEMO1 modes whilst L1 does not have this tendency. We have been setting up to characterize the SRC cavity length and Gouy phase to see whether it differs from the design settings.

To do this we set-up the auxillary laser and improved the focusing of the light onto the high speed 1611 diode of ISCT6 on the OMC_REFl_Air periscope. As a first step we repeated the previous measurement describe in AlOG 16084 with considerably higher signal to noise. 

With a bright Michelson lock we observed the reflection maximum on the either side of the Michelson. By eyeballing this data we can see that these occurred at -790+/-10 MHz and 905 +/- 10 MHz. Assuming that these are difference because of an offset in lock. The Michelson Reflection Dip is peaked at 847 MHz +/- 7 MHz.
This corresponds to a Schnupp Asymetry = 8.9 cm +/- 1mm. A more rigorous analysis of this data will follow.

J. Kissel 

Changing the clock-rate and PID parameters of the corner station's HEPI Pump Servo (LHo aLOG 16796) has removed most of the noise from the corner station SEI systems, while still maintaining a 10 [mHz] UGF loop suppression on the pump pressure (for design, see 16782). 

Notes on the current impact on chamber performance, compared with what was measured when the problem was initially discovered (LHO aLOG 16239):
- The Beam Splitter remains as the worst chamber, with coupling in X, RZ (as measured by the ISI ST1 T240s) and HP (as measured by the HPI L4Cs) between 5-50 [mHz], 5-50 [mHz] and 50-150 [mHz], respectively. Even still, the amplitude of displacement for these DOFs has been reduced by a factor of a few, with the best reduction being RZ from 20-90 [mHz] where the amplitude dropped by a factor of 5 -- should be great for yaw alignment drift of the BS.
- For all HAM chambers, any coherence, in any DOF -- except for HP -- has disappeared or, at least it's below the HEPI L4C sensor noise floor. 
- For the BSCs, all DOFs but for what's mentioned above, show little coherence even with the T240s, indicating we're also not limited by this noise there either. 
- Of the tanks that still show coherence with HP, their noise amplitude has also reduce by factors of 2 to 3, reducing the coherence by similar factors. HAM2 is the worst offender for HP, with still obvious coherence between 0.1 [Hz] and 1 [Hz].

I think we've got what we can out of the pump servo's stinky computers, tuning the parameters to account for its inherent badness -- and got factors of 2-3 reduction in ISI input noise between 10 [mHz] and 1 [Hz] motion. Any further efforts on improving the remaining coupling should be dedicated to installing a better pressure readout system.

For the attached plots, I've focused on the DOFs that still have some coherence, and new information where I've gathered T240 information. For the entire collection of plots showing all DOFs for all tanks, check out .pdf files tagged with the date 2015-02-20 in the 
/ligo/svncommon/SeiSVN/seismic/HEPI/H1/Common/
folder in the SeiSVN.
The DTT template used to make the thousands of plots can be found here:
/ligo/svncommon/SeiSVN/seismic/HEPI/H1/Common/2015-02-18_H1HPI_PumpControllerNoise.xml

Will post similar results for the ETMs tomorrow -- I expect the same goodness there.

no restarts reported. Conlog frequently changing channels report attached.

I am concluding that the scale factor in the original calibration (alog 16698) was underestimated by a factor of about 2.4 in 2 - 20 Hz frequency band (meaning, the DARM spectra we had collected were too good). This was due to my inaccurate estimation of the ESD actuation response.

For the frequency region above 20 Hz, it has been underestimated by a factor of 3.2 when the PSL power stayed at 2.8 W and the same DARM offset was used. This was due to the inaccuracy in the ESD propagating into the sensing factor and also inaccuracy in the UGF location. I did not try to track how the sensing calibration should have been compensated as a function of the PSL power or the DARM offset (alog 16726).

I have updated the CAL-CS online calibration coefficients accordingly in both the sensing and actuation paths.

Pcal_Y seems to still indicate that the DARM spectrum is consistently too good by 40-65 %.

(ETMX response agreed the sus model by 40 %)

The day before yesterday, I had a chance to repeat the calibration of the ESD response of ETMX by locking the X arm with the IR laser. Comparison with ITMX at 13 Hz gave me an ESD response of 6.32 x 10^-16 m/cnts in ETMX at 13 Hz. This is 1.4 times larger than the expected than the suspension model. Since I used alpha of 2.0 x10^-10 N/V² in the model, the measured response corresponds to a slightly larger alpha of 2.8x10^-10 N/V². With the right force coefficient of -124518.4 cnts applied on ETMX, I tested both the linearized actuation and non-linearized. They showed almost same strength in a frequency band of 10 - 59 Hz as expected but with the linearized version somewhat stronger by 3-ish % (see the attached) presumably due to the charge on the test mass.

Since the change between the linearized and non-linerized actuations is so small, I neglected this effect and kept using the transfer coefficient of the non-linarized version at 13 Hz.

(Estimation of the DARM optical gain)

Using the measured data taken by Alexa (alog 16805), I estimated the optical gain of the DC read out to be 9.09x10^-7 cnts/m. To get this number, I first extrapolated the ESD response to some frequencies at around 20 Hz. Since the loop shape is already known, fitting of the open loop gives me the optical gain. I did eye-fitting this time. The UGF was at around 23 Hz in this particular data.

Since I was able to lock the interferometer at 2.8 W with the DC read out tonight, I cross-checked the DARM open loop. Running a swept sine, I confirmed that it sill kept the same UGF (see the attached below). Good.

(Comparison with Pcal)

First of all, one thing I have to mention is that, in an alog (alog 16781) describing the comparison between LSC-DARM_IN1 and PCAL is not a fair comparison because we know that LSC_DARM_IN1 was not well-calibrated. I checked the CAL-DELTAL_EXTERNAL_DQ at this particular time, but unfortunately the spectrum did not look reasonable probably because I was in the middle of changing some parameters in the CAL-CS. Instead, I looked into a different lock stretch at Feb-02, 5:13:11 UTC with the same IMC incident power of 2.8 W. The Pcal reported greater displacement by a factor of approximately 4.6 (see the attached below).

If I applied the new accurate sensing calibration, the discrepancy would have been a factor of 1.45 or 45% with the Pcal higher than the DARM spectrum.

To double check it, I checked the Pcal again during one of today's lock stretches at Feb-21, 10:04:05 UTC. One thing we have to pay attention is that the Pcal excitation frequency is now shifted to 540.7 Hz (alog 16815). I used the Pcal calibration formula that Sudartian posted in alog 16718 to get the displacement. The ratio between the Pcal and DARM spectrum was about 1.65 or 65% with the Pcal greater than the DARM spectrum. Even though the ratio is slightly different from 8 days ago or so, it still indicates that the DARM calibration is too good by several 10%.

The other excitation at 36.7 Hz (alog 16815) did not have signal-to-noise ratio more than 2 in the DARM spectrum due to high noise in this frequency region and therefore I did not use it this time. Nevertheless, the Pcal at this frequency was also greater as well. So the relation between Pcal and DARM spectrum is qualitatively consistent.

Alexa, Sheila, Dan, Evan, Kiwamu

Tonight we have had good locking.  The take home message tonight was that our noise changes with aligment, and so we think that we need to spend some time getting some ASC going (or at least a reproducible alingment)  before we can make much progress on noise hunting.  (see alog 16839)

 We moved SR2, the difference between the noise spectrum before and after can probably be explained by the alignment depent noise rather than by reducing the rubbing (see alogs 16831 and 16811).  The new positions are shown in the attahed screen shot.  The SR3 OPLEV is not alinged any more.     If someone wants to use the OpLev over the weekend, you will have to go back to the old alingment of SR2+3. 

Turning on the OMC dither alingment improved the spectrum from 20-70 Hz in a way that is reproducble.  The main improvement in the noise tonight came from alinging IM4, which resulted in the best spectrum we have had so far around 100 Hz.  Note, the attached spectra are not calibrated!

Sheila, Alexa, Dan, Evan

Summary

Tonight on dc readout, we started to reduce the coupling of alignment fluctuations into DARM by closing some more ASC loops. We focused mainly on the input and power-recycling optics.

During this work, the lowest value of REFL_A_LF observed was 0.4 ct (compared with 21 ct on resonance), meaning the interferometer visibility is 98%. The highest arm power observed was 1150× single-arm buildup, meaning the interferometer recycling gain is 34 W/W.

Details

List of loops, and things tried:

• We were able to close REFLB9I → IM4 pitch with an OK bandwidth (> 0.1 Hz, based on step response). Here we have a 1/f loop shape everywhere (FM2+FM3 in INP1), and a gain of −1.0 ct/ct. We may want to use REFLA9I − REFLB9I instead (see below). Closing the loop had an immediate improvement on the mode seen on the REFL camera.
• For IM4 yaw, we noticed that the combination REFLA9I − REFLB9I gave a sensible error signal (as was the experience at Livingston [LLO#16254]). But the lock broke while trying to close the loop, and we did not pursue it further. The most egregeous alignment fluctuations in the corner appear to be in pitch anyway.
• At one point were able to close REFLA9I →PRM pitch, but it seems this error signal is only good intermittently. Possibly it requires the input pointing into the PRC to be good already (i.e., we may need to close it after the IM4 loops).
• We looked for a while for a good signal for the common ETM motion, but none of the responses in REFL9 or REFL45 seemed immediately good.
• The situation with AS36 → BS is still mysterious; neither ASA36Q nor ASB36Q seemed to give good error signals.
• The differential ETM loops ("DHARD", but not actually DHARD) seem to have more optical gain now that the SR2 position has been moved. Good filter module gains are 8 ct/ct for pitch and 80 ct/ct for yaw; these are possibly conservative for the 2.8 W lock. For the 8 W lock they may need to be reduced a bit further still. Otherwise they continue to work fine.

Alexa, Sheila, Evan, Dan

Peter had noted that our suspension compenstation for the LSC DARM filter was different than the one used at LLO. In his plot LHO#16728 he had actually missed a Lead filter at 200 Hz (FM9) that we turn on once we are on RF DARM. See new sus compenstation comparison plot. Even with this lead filer on, we still do not have as much phase as Livingston.

Today, I loaded LLO's suspension compenstation filter into FM1 of LSC DARM. We tried enaging this for ALS DIFF but immediately saturared L3. Our next plan in attempt to acquire more phase margin is to develop a filter which can be engaged along with the lead filter (FM9) once we are on RF DARM with our original sus compensation filter (FM8), and see if this causes saturation. TBD.

Before tuesday, we had been listening to IFO channels through the computer speakers using z audio.  It seems like z audio has disapeared. 

Since Betsy found out that SR2 is rubbing at its nominal alignment, (alog 16811), I've tried to investigate if we can move SR2 so that it is not rubbing without introducing clipping.  This was done by moving SR2 pitch, then adjusting SR3 to center on AS_C.  The attached plot shows the power on each of the PDs we have at the AS port, each PD is normalized to the mean powers at different alingments so they can be displayed on the same plot.  While we get some clipping on AS_C and AS_A when we are in the non rubbing zone, happily the best location for the OMC QPDs are in the middle of the SR2 alingments where betsy says there should not be clipping. 

Keita had previoulsy set the alingment of the SRC cavity and the pios to AS_C (alog 15145 ).

Dave O, Evan, Elli

This morning we prepared for a measurement of the SRC length we plan to take tomorrow.  We were working on IOT2R.  We realigned the Auxiliary laser beam going into HAM1 so that in follows the reflection of the carrier from the PRM onto IOT2R.  This realigned the Aux laser beam returning frm HAM1 onto the 1611 photodiode on IOT2R.  The beat note of the Aux laser and carrier is -34dBm, the same as what we saw in December.  We tried locking the beat note to the spectrum analyser but ran out of LVEA time, so this is a job for tomorrow the settings were the same as used in December.

While we had been playing with things, I kept the alarm levels a little sloppy but now that we'll likely leave this alone for a time, I've closed down the range of operating pressures.

The alarm handler will alarm (as it has for some time) at differential pressures outside of +-2PSI.  The servo should have no problems keeping the pressure within that range.  Further it will alarm MAJOR at +- 5 psi.  If the minor alarm goes off and stays out of major alarm, it is likely the servo has frozen or someone left it in manual mode.  Please address asap and feel free to seek realtime help from me.  There is an OPS wiki too.  If the alarm is ignored, an avoidable HEPI trip will likely be the result.

LVEA: Laser Hazard
Observation Bit: Commissioning  

07:15 Cris & Karen – Cleaning in the LVEA
07:15 Jodi – In the LVEA
07:52 Corey – Working in the Squeezer Bay
08:05 Elli & Dave – Working on IOT2R 
08:20 Jim – Running TFs on HAM4
10:00 Corey – Out of the Squeezer Bay
11:00 Kyle – Going to HAM5 area to get bolts for HAM1
11:14 Kyle – Out of the LVEA
11:17 Keita – Going into the LVEA to look for 3IFO parts
11:21 - Adjusted the ISS diffracted power from 5.2% to 8.1%
11:35 Keita – Out of the LVEA
12:13 Elli & Dave – Out of the LVEA
12:49 Ed – Retrieving totes from Mid-Y
13:21 John, Bubba, & Kyle – Going to Mid stations and end stations to check the weather stations
13:42 Dan & UM Students – Going to LVEA roof. 
13:54 Ed – Opening high-bay roll-up door to bring in totes. 
14:10 Ed – Going back to Mid-Y
14:30 Ed – Back from Mid-Y
15:05 John, Bubba, & Kyle – Back from mid and end stations

Looking for missing VE chamber door bolts! -> Also, noticed X-end turbo pump controller still energized from most recent pump down (fan has been running unnecessarily) -> Turned off controller and brushed up against OPLEV pier accidentally in the process

Several commissioners feel that our new seismic defenses leave H1 insensitive enough to truck traffic that our Hanford site contacts no longer need to email me weekly with reports of their levels of activity.  A quick glance at the 1-3Hz seismic trace in the control room will always settle the question of whether the trucks are hauling or not.    

We've built up a good bank of contacts related to site operations.  Feel free to email me any time if you have questions about the possibility of earth-shaking things occurring near LHO.