I again looked at the cross-correlation of POP and POPAIR 45Q during full lock, in order to find out what the vertex LSC noise looks like below the shot noise level.

This time, I added a bandstop filter to PRCL, MICH, and SRCL that gives ≥40 dB attenuation between 82 and 101 Hz. This ensures that shot noise is not impressed on the vertex dofs in this band, so that we can get a true estimate of the freerunning displacement/sensing noises.

The result of 1 hour of cross-correlation is attached. In the case of POP 9I (used for PRCL) and POP 45I (used for SRCL), there is significant coherence between the two PDs. For 9I this is not so surprising, since the same (unknown) structure can be seen in both spectra. For 45I, a similar irregular structure is seen in both PDs. The coherence in the notched portion is 0.01.

For POP 45Q (used for the Michelson), the coherence seems remarkably free of the irregular structures seen in 9I and 45I. The notched portion appears to be at the noise floor of the correlation measurement, with a coherence <0.001. The coherence of 0.01 around 130 Hz probably comes from noise being injected into the Michelson loop.

The uncontrolled quadrature (9Q) shows some evidence of irregular structure, despite the fact that POP 9 and POPAIR 9 were both phased to mimize the apperance of PRCL in Q.

Time is from 2016-02-01 04:18:00 to 05:18:00 Z.

Title: 2/1 Eve Shift 22:00-6:00 UTC (14:00-22:00 PST).  All times in UTC.

State of H1: Lock acquisition.  Lost lock in the last 15 minutes of my shift.

Shift Summary:  Several locklosses at various stages and from various causes (commissioning activities notwithstanding).  Locked at NLN for ~2 hours, but in Commissioning mode, while Jenne and Evan do their thing. 

Incoming operator: None

Activity log:

22:44 TCS crew to CO2Y table

23:11 Joe D back from beam tube sealing

23:26 reset H1SUSETMY tim error

0:21 TCS crew done

I pushed the numbers from Gabriele's Saturday alog (25265) through the beam position calculating / calibrating script, and see that the ETMY pitch spot was moved by 2.4mm.

I'm not sure why this happened.  I need to think some more on this.

The HWS SLED temperature (H1:TCS-ITMX_HWS_SLEDTEMPERATUREMON) has never read back correctly. I tracked down the problem to a missing wire in a 15-pin cable.

1. The SLED driver chassis, (D1200600) expects to see the SLED temperature sensor (a 10K RTD) connected across pins 7 and 8 of the 15-pin D-SUB connector on the front (labeled SLED 1 TEC OUT for SLED1)
2. Turns out the 15-pin DSub cable connected to this does not have a wire attached to pin 8 on the inside
3. It does have a wire attached to pin 15
4. Nothing was using pin 15, so I shorted it to pin 8 on the SLED driver chassis (S1301925) and made a note on the DCC.
5. Lastly, on the other end of the cable, we changed the internal wiring of the Newport 742 diode mount such that the wire that was connected to pin 8 on the 15-pin Dsub connector is now connected to pin 15.

Lo and behold, the thermistor was correctly wired to the SLED driver chassis and now reads back a sensible temperature. What's more, turning on the SLED with 100mA going through it shows a 2.5C increase in temperature - as expected.

However ... I could now finally check if the SLED temperature changed as I changed the setpoint temperature to drive the TEC on-board in the diode package.

Changing the setpoint temperature had no response on the actual temperature.

I want to get this fixed as it will increase the lifetime and output power of the diodes.

(All of this was repeated for SLED 2).

[Alastair, Aidan]

The Y-arm CO2 laser, which has not been getting injected to the CP, has now had its beam block removed so that we can perform the alignment proceedure.  The AOM drive from the DAC has a very low frequency pole that would stop us from injecting a large enough signal to do the alignment this way, so we have directly bypassed the module that has this filter.

Instead we put an oscillator directly on top of the enclosure set to 23.8Hz, 0.1V pk-pk, 0.1V offset.  This oscillator is running on AC power and has quite a noisy fan.  The oscillator is being fed through to the table and directly connected to the AOM driver, bypassing the DAC and all other electronics.

The laser has its rotation stage set to output the minimum power we could achieve (11mW) so this signal shouldn't be visible in the interferometer at the moment.  If it is critical to stop it doing this then the laser can be turned off from MEDM, however I would request that if at all possible we leave the laser running because I am still working on the long-term stability of the locking loops.

Installed the table interlock box from Richard on the shelf inside the X and Y tables.  I installed all the cables that seemed to be meant to attach to this.  Not sure if it was meant to have anything in the connectors for Status or Monitor

[Alastair, Aidan]

Today we added the chiller loop to the laser servo on Y-arm.  It takes an error signal from the PZT output voltage minus 35V, to set the PZT to the middle of it's range.  From the step function measurement the time constant for a temperature change request to actually change the laser temperature is around 110s.  Gain was taken from previous measurements of power as a function of pzt voltage and chiller temperature https://alog.ligo-wa.caltech.edu/aLOG/index.php?callRep=11625.

We initially added a servo with unity gain at 0.001Hz, which should have given a reasonable phase margin, however we found that it was oscillating (very slowly), so we altered the unity gain down to 0.0003Hz and it now seems, from a few hours of operation, to be stable.

Attached is a graph of the 3hrs of laser power with the laser unlocked.  The pk-pk is roughly 0.17W.  Also attached is a chart of the laser with the PZT and chiller locked, showing pk-pk of around 0.02W, which in the full data plot looks to be the noise floor.  This plot starts just after the chiller servo has been engaged and shows it bringing the PZT voltage down from 55V, and actuating on the chiller temperature.

Attached are the OpLev trends from the past week. 

Laser Status:
SysStat is good
Front End power is 33.19W (should be around 30 W)
Frontend Watch is GREEN
HPO Watch is RED

PMC:
It has been locked 5.0 days, 22.0 hr 26.0 minutes (should be days/weeks)
Reflected power is 3.105Watts and PowerSum = 26.24Watts.

FSS:
It has been locked for 0.0 days 1.0 h and 43.0 min (should be days/weeks)
TPD[V] = 1.522V (min 0.9V)

ISS:
The diffracted power is around 7.575% (should be 5-9%)
Last saturation event was 0.0 days 2.0 hours and 10.0 minutes ago (should be days/weeks)
 

Activity Log: All Times in UTC (PT)

16:00 (08:00) Reset IPC error on H1SUSETMY
16:15 (08:15) Adjust ISS Diffracted power from -1.99v 9.4% to -2.0v 8.2%
16:20 (08:20) Goodwill on site for pickup – Bubba escorted
17:00 (09:00) Filiberto & Manny – Pulling cables at End-Y
17:03 (09:03) Christina – Opening OSB rollup door
17:51 (09:51) Corey – Working in the Optics Lab
17:57 (09:57) Chris & Joe – Beam tube sealing on X-Arm - ~800m from End station
18:00 (10:00) Filiberto – Back from End-Y
18:17 (10:17) Kyle – Going to End-X will be in compressor room
18:18 (10:18) Platt Electrical on site – Delivery for Richard
18:18 (10:18) Kiwamu – Transition LVEA to Laser Hazard
19:11 (11:11) Aidan & Nutsinee – Going into LVEA to IO table near HAM4 
19:48 (11:48) Joe & Chris – Back from X-Arm
20:00 (12:00) Dale – Big tour in the control room 
20:05 (12:05) Aidan & Nutsinee – Out of the LVEA
20:09 (12:09) Corey – Out of the Optics lab
20:10 (12:10) Dale – Another big tour in the control room
20:11 (12:11) Kyle – Back from X-Arm
20:11 (12:11) After initial alignment – Locked at DC_READOUT
20:15 (12:15) Start ASC-CHARD transfer functions for Jenne
20:21 (12:21) Lockloss – Unknown
20:37 (12:37) Kyle – Going to End-Y compressor room
21:11 (13:11) Locked at DC_READOUT for commissioning work
21:12 (13:12) GRB – Ignored alert due to status of IFO
21:20 (13:20) Joe & Chris – Bean tube sealing on X-Arm
21:30 (13:30) CW Injection running & CW Injection inactive messages
21:57 (13:57) Kyle – Back from End-Y
21:59 (13:59) Aidan – Going into LVEA
22:15 (14:15) Turn over to Travis
 

End of Shift Summary:

Title:  02/01/2015, Day Shift 16:00 – 00:00 (08:00 – 16:00) All times in UTC (PT)

Support: Jenne, 
 
Incoming Operator: Travis

Shift Detail Summary:  After running an initial alignment relocked the IFO at DC_RREADOUT for commissioning work. Started TFs for Jenne. Lockloss after about 10 minutes not related to Jenne’s TFs. Relocked at DC_READOUT. Jenne is running her TFs. Hand off to Travis. 

We had two occassions on Sunday where CRC errors showed up on certain front ends. Sunday 07:12 PST a single error showed up on some SUS, and ISI models, plus PSL DBB. Later at 18:05 PST all PSL models showed 8-10 errors. Normally CRC errors would be associated with model restarts, but no restarts happened on Sunday.

Attached are spectra comparing the SUS ETM L3 LV ESD channels from lock segments before (Jan 24, 2016 03:35:00 UTC) and after (Feb 1, 2016 01:50:00 UTC) the ESD Driver update last Tuesday alog 25175 (and the subsequent ESD fixes on Wed 25204).  Before the install, the channels looked like ADC noise, while they look live now.  The ETMx plot is included, but of course the ETMx ESD is not ON during either lock stretch, so all the plot really says is that something happened to the channels.  Whether or not the ETMy channels look like they actually should, according to various ECRs, is to be determined.

Feb. 1 2016 18:31 UTC Stopped Conlog on conlog-test-master. Had been started 19:42 UTC Jan 27 2016 (alog 25201). Shutdown conlog-test-master to install Spectracom card.

Kiwamu transitioned the LVEA to laser hazard

Pulled in new CPS Sync cabling from SUS-R1 to CPS units on BSC10.

Work still needed for install (EX/EY):

1. Install fanout chassis in SUS-R1
2. Run RF cable from Electronics Ebay to VEA SUS-R1 (71MHz)
3. Modifications to some of the CPS units (Converting units from masters to slaves)

Aftef improving the angular decouplig and the feedforward, the noise curve looks quite smooth to me, except for a small bump betwen 15 and 20 Hz and some other bumps between 55 and 80 Hz, to be investigated.

So I played the noise slope fitting game, to see what kind of noise shape we would need to explain the curve. At high frequency there's shot noise (flat) and Kiwamu's 1/f noise. At very low frequency (below 14 Hz) the noise curve looks very steep, and it seems to be something like 1/f^9, although it's very difficult to properly estimate the slope here, it could easily be 1/f^10. 

What's most interesting to me is that between 20 and 40 Hz, the noise floor is explanable with a 1/f^4 slope. I find this interesting because it points to suspension displacement or actuation noise in the second to last stage, for example excess noise in a DAC or coil driver in one of the test masses, or even in the BS.

Caveat: this is just a hint, the slopes and amplitudes I estimated might be very wrong, and there's no real indication that we only have three or four separate noise contributions. 

P.S. I wanted to upload the MATLAB fig file, but it's 21 Mb and so it seems I can't attach it here.

SEI – OK
SUS – Charge measurements
CDS – OK
FMP – Final carpet installation on Wednesday. Ongoing shimming the LVEA main crane. 
VAC – OK
PSL – High Power checkout work 
TCS – Guardian updates, Check out and commissioning. Prep work to turn on TCS-Y laser
General commissioning work continues. Commissioning meeting at 09:00 in control room
Outreach – Dale will conduct two tours through the control room around noon 

Outstanding work permits were reviewed. 
Reviewed planned work for Tuesday maintenance 

Attached are 14-day plots from turning up the front end laser pump diode current(s) and adjusting their
temperatures.

Note that even though the NPRO output power plot reads that the NPRO power is ~0.81W.  As measured by a
power meter placed after the phase-correcting EOM, the power is 1.46W.  The NPRO power monitoring photodiode
measures the power into the power amplifier.

Diodes 1 & 2: 51 A -> 55 A
Diodes 3 & 4: 51.6 A -> 57 A

Diode 1: 17 degC -> 16.5 degC
Diode 2: 17.5 degC -> 16.5 degC
Diode 3: 18 degC -> 16.5 degC
Diode 4: 18 degC -> 16.5 degC

I remeasured the 45 MHz phase noise coupling into DARM, this time with broadband excitation. No surprises here; it looks the same as the swept-sine TF that we took before O1 (20783).

Setup is similar to the previous measurement, although in this case the PLL has a UGF around 20 kHz, so that the control signal going to the IFR can be read out directly in order to get the frequency deviation.