(All time in UTC)

23:00 Take over from Ed. IFO has been locking and observing. Dick's inside optics lab.

01:21 Dick out of the lab.

05:00 Dan's on site. Will be here for the rest of the night.

07:00 The ifo has been locking over 26 hours now! Handing off to Travis.

- Quiet shift. Wind still below 20 mph. No seismic activity. Saturation alarm hasn't been complaining about anything else other than ETMY, which has been the only source of big glitches on the DMT Omega.

- Camera 3 control was very slow. At one point I thought it was busted. Seems to be working fine again.

The interferometer is still locking and going strong. Wind below 20 mph. Quiet seismic activity. No one on site but me. I'm hoping for another record breaking lock stretch!

LLO has been locking and observing over the past two hours.

Summary:

• Shift was quiet. Wind starting picking up just a little but not more than 20mph. IFO locked the entire shift with only about 5 glitches noted in my activity log. Spoke to Tom Evans for a while to ask about their Observation Intent Bit issue. Their solution can be found in their aLog. Spoke to Dave Barker about “to clear or not to clear” the timing error that occurred in ETMY GDS TP. He will bring that up at the CDS meeting on Tues.  Handing off to Nutsinee.

ACTIVITY LOG:

• • 16:55 William from LLO hailed me to ask abut a problem he’s having with the Observation Intent Bit changing states by itself after a period of 30-40 minutes. I suggested he look to Jamie or Joe B. for his answer.

  • 17:03 ETMY saturation

  • 17:57 ETMY saturation

  • 19:31 ETMY saturation

  • 19:45 ETMY saturation

  • 20:01 Noticed a timing error in  H1SUSETMY. As I understand, this is due to the speed of the new computer and is of no consequence? I will leave it be until I hear otherwise. I’ve e-mailed Dave to ask wether I should come out of Observing to reset this error or just leave it as is.

  • 20:59  ETMY saturation

  • the wind picked up a few minutes ago to about just under 20mph

  • 21:38 Gustafson on site and going into the optics lab.

  • 22:55 Nutsinee here

Arrival:

• Taking over from Patrick. IFO locked in NOMINAL_LOW_NOISE-68.82MPC. Slight downward trend in range over the past 8 hours possibly due to slight upward trend in microseism. Wind and earthquake activity seem quiet. Lights are off everywhere that I can see on cameras. Landscapers are on site cleaning weeds. IP-9 A&B both reading 7KV/6.2e-09 and 1.8e-08 respectively. The rest of the vacuum system looks good. All other systems are GO. Steady as she goes.

~13:00 - 13:09 UTC Stepped out of control room.
14:49 UTC dust monitor invalid alarm at end X

Remainder of shift quiet. Range seems to be slightly dropping with slow increase in microseism.

Handing off the Ed.

07:12 UTC Handoff from Nutsinee. H1 in observing mode at around 70 Mpc. Kiwamu only other person here.
07:16 UTC Lights are off in the LVEA and PSL enclosure. Lights appear to be off at the mid and end stations.
07:17 UTC Checked IP9. Both A and B pumps HV around 7kV.
07:53 UTC Momentary end X HEPI pump station pressure minor alarm.
08:52 - 08:58 UTC Stepped out of control room.
09:06 UTC Kiwamu leaving site. I'm alone.
10:50 - 10:57 UTC Stepped out of control room.

No lock losses or changes in observing mode. SUS ETMY saturations at 08:44:54 and 11:00:19 UTC.

I worked a bit more on the analysis codes that Jeff has written (alog 21015 and alog 21049). I was not able to finish deriving the suspension scale factors. Tomorrow, Jeff and Darkhan will pick up them at the point where I left and will continue working on it.

Major updates:

• DARMOLGTFmodel now incorporates not only each ESD driver circuit measurement but also each PUM coil driver measurement.
  • Darkhan is going to alog some detail of the PUM driver measurement and fitting.
• The ALS Diff measurements are now analyzed using the latest DARMOLGTF model.
• Also, the Pcal measurements are now analyzed using the latest DARMOLGTF model.
  • By eyeballing the resultant plots, I see that the inclusion of the ESD driver and PUM coil driver circuits made the model more accurate. This is encouraging.

Next steps:

• We need to include the latest DARMOLGTF model in the free-swinging Michelson analysis.
• UIM driver circuit needs to be updated. DARMOLGTF still assumes a perfect cancelation between the digital and analog filters.

Some notes:

In the course of the code update, I changed the file organization structure of the ALS diff and Pcal scripts so that they have only one analysis code which can be invoked by specifying a set of data parameters. This organization approach is the same as those for the DARM open loop analysis.

As for ALS diff, the core analysis code is

aligocalibration/trunk/Runs/ER8/H1/Scripts/ALSDiff/Matlab/analyze_alsdiff.m

and the parameter files are in the same directory and named as

H1ALSDIFFparams_20150826.m

H1ALSDIFFparams_20150828.m

H1ALSDIFFparams_20150829.m

As for Pcal, the core analysis code is

aligocalibration/trunk/Runs/ER8/H1/Scripts/PCAL/analyze_pcal.m

and the parameter files are in the same directory and named as

H1PCALparams_20150826.m

H1PCALparams_20150828.m

H1PCALparams_20150829.m

Each parameter file loads H1DARMOLGTFmodel_ER8 with the latest electronics information and subsequently returns the parameter structure, or the familiar variable "par". As usual the parameter structure can be then fed to the analysis code (e.g. analyze_alsdiff.m or analyze_pcal.m) as an input argument. I have not carefully thought about the final return variables from the core analysis codes, but in principle we can write them such that they return the calibrated suspension transfer functions in meters/counts together with some error bars and also perhaps some statistical values. In this way, the final step of performing apple-to-apple comparison between various measurements from various dates can be less painful.

I tried propagating the same file organization structure to the free-swinging Michelson codes, but apparently I am running out my energy for the night and did not finish it yet.

(All time in UTC)

23:00 The interferometer is down. Take over from Ed.

23:51 Dick to optics lab

23:56 IMC had trouble locking. MC2 pitch seems to have moved the most from the time the ifo was still locking so I touched it and managed to get IMC locking again. Ed had to touch ITMY to get the green to lock, fearing that this might give me trouble during DRMI afterward I reverted his changes and tried adjusting ETMY and gave TMSY a small touch.

00:36 Wind reached 40 mph. I adjusted PR3 to maximize COMM beatnote. Can't really do much at this point. Waiting until the wind calm down.

01:20 Dick to LVEA.

01:38 Dick back

01:51 Robert to LVEA

01:55 Robert back

02:11 After trouble locking DRMI AND PRMI, I decided to do initial alignment. I didn't see that Patrick already did this last night.

03:24 After the inital alignment locking DRMI still seems hopeless. Locking PRMI.

03:48 PRMI also have difficulty locking. I adjusted BS, PRM, PR2. Adjusting PR2 seems to be the most effective. Maybe adjusting BS and PRM wasn't necessary...

04:20 PRMI is good but I still can't get the DRMI to lock.  I've been adjusting SRM pitch and yaw but no luck. Not sure what on earth is going on. POP18 and POP90 is flashing high so I know the PRMI is good.

04:25 I noticed that SR3_CAGE_SERVO wasn't engaged. I think it HASN'T been engaged this whole time that I was having problem with DRMI. It saw SR3 misaligned at some point and never turned itself back on. SR3_CAGE_SERVO supposed to correct SR3 misalignment due to interferometer heating/cooling. Otherwise locking DRMI will be a problem. So, note to self, MAKE SURE THE CAGE_SERVO IS ON!!!

04:29 ISC_DRMI Connection Error. I called Jenne and it was an easy fix. Just request STOP, and EXEC again at ISC_DRMI. DRMI is now locking again (thank goodness).

04:47 Locked at NOMINAL_LOW_NOISE. Back to Observing. 71 Mpc (hooray!).

05:00 Kiwamu arrived doing calibration work.

07:00 Wind below 20 mph. The saturation alarm hasn't been complaining much. Handing off to Patrick.

Note:

- I checked and the SR3_CAGE_SERVO wasn't turned off until I started the initial alignment. Whatever was giving me hell with DRMI and PRMI earlier wasn't the cage servo. But to be fair I didn't touch any optics in trying to fix PRMI before I went and did the initial alignment (PRMI never had trouble locking itself in my experience!). I guess I should have...

- I have been getting calls from an unknown number all day and nobody talks when I answered. The last call was just a few minutes ago. It's really annoying....

04:47 UTC at 71 Mpc.

ER8 Day 19, no restarts reported

After I got the IMC back up (it had trouble locking itself so I touched MC2 pitch a little), the wind picked up speed. It has just reached 40 mph and the forecast says it should come down in 3 hours or so. I'm waiting for the wind to calm down before moving on. Hopefully I don't have to wait 3 hours...

Kiwamu, Sheila, Evan

Durring the calibration activities last week Kiwamu noticed that there was upconversion of the drive from ETMY.  Specifically when he drove in the L3 LOCK filter, he saw a second harmonic. When he drove each stage individually, through the test filter bank with a similar amplitide he saw no evidence for upconversion.  This suggests that the upconversion might come about by driving mutliple stages, or through the length 2 angle paths. 

We went back through the data and looked at the relative heights of the peaks.  We also calculated a ratio of the amplitude of the second harmonic to the square of the amplitude at the fundamental :
  ASD(2f) = alpha * (ASD(1f))^2

If we ignore other frequencies which could mix and only consider the second harmonics of DARM control, we would expect this upconversion to be something like a factor of 10 below our measured noise at 20 Hz, and near the measured noise at 10 Hz.

The next step is probably to identify which stages contribute to this upconversion, for example it seems probable that this is only noticeable for frequencies where L2 get a significant fraction of the DARM control signal. 

Summary:

• Shift was mostly quiet. Some glitching. Wind starting picking up ~ 3 hours ago gusting to around 35mph. Recovery after Lockloss is proving to be a bit of a chore. Mode Cleaner is unlocked and trying to relock but the curious thing is while the REFL shows it trying to lock in flashes the TRANS isn’t showing sympathetic flashing. hmm. Handing off to Nutsinee.

ACTIVITY LOG:

• 16:21  a glitch occurred between 50Hz and 300Hz

• 16:25 Robert on site. He suggests that high frequency noise in an oscillator is causing the lack of normal range.

• 16:58 ETMY glitch

• 17:30 EX Pump differential pressure alarm going off.(yellow)

• 17:41 ETMY saturating for ~ 1 minute repeatedly.

• 17:42 OMC DCPD saturated a couple of times. WE SURVIVED THE GLITCHES.

• 17:43 Noticed the landscapers are here for tumbleweed/weed control. (as scheduled)

• 18:00 Landscapers moved their truck from the LSB to the OSB

• 18:03 LLO in Observing mode

• 18:15 Kiwamu on site

• 22:03  Lockloss

• 22:13 Locking ALS giving a bit of trouble in the X dept.

• 23:00  Still trying to get arms locked and setlled. Handing off to Nutsinee

LOCK LOG:

• 22:03 Lock Loss - PRM saturating

  • Strange thing is, Guardian tried to go straight to LOCK_DRMI_1F?? It then proceeded to LOCKLOSS and then DOWN. It then proceeded normally.

Stefan, Evan

This is an analysis that Daniel suggested a while ago.

When we increase the interferometer power from 3 W to 24 W, we increase the common-mode radiation force on the test masses. Since the suspensions are compliant, this produces an extra displacement in the test masses along the beamline relative to their suspension points. The CARM loop senses this common-mode displacement and compensates by applying a slow control voltage to the IMC VCO. This control voltage is offloaded to the UIMs of the end station suspensions, and then subsequently to the endstation HEPIs, thereby moving the suspension points of the ETMs forward so as to cancel the radiation-induced displacement. Therefore, an appropriately calibrated HEPI tidal signal can be used to estimate the amount of power circulating in the arms.

We looked at a data stretch from 2015-08-07, when we had been sitting at 3 W for a while and then powered up cleanly to 24 W, and found the following:

• The HEPI tidal signals show a nice, linear trend for the hour preceding and the hour following the power-up [first attachment].
• By fitting the linear trend [second attachment] and subtracting it off [third attachment], we can get an estimate of the HEPI displacement due to the radiation pressure alone. The displacements are 2.9 µm each for X and Y.
• During power up, the change in the force on the test mass due to the change in radiation pressure is ΔF = 2 ΔP / c. The dc compliance of each test mass is H = Δd/ΔF = 2.6×10⁻³ m/N, where Δd is the change in displacement of the end-station HEPI. Therefore, the power change is given by ΔP = c Δd / (4 H) [there is an extra factor of two here because there are two suspended masses per arm]. From this, the power change per arm is 85 kW.
• From the IMC input PD we know that the power ratio before and after powering up is P₂/P₁ = 10.3. This can be combined with the above power change to arrive at an absolute number for the circulating power: 94 kW.

On the other hand, when we make a similar estimate from the end-station QPDs, we have something like 24 W × 0.88 × 1/2 × 40 W/W × 283 W/W = 120 kW. [The factor of 0.88 is the modecleaner transmission.]

The calibration of the HEPI tidal signals into nanometers is sort of loose [to within 10%?], according to Hugh. Similarly, there is some spread in the power inferred from the endstation QPDs, which gives an uncertainty that is also on the order of 10%. With a more precise HEPI calibration, perhaps we could use this method to better constrain the optical calibration.