As a curiosity, here are some projections comparing the current H1 noise with SRM T = 20% (nominal aLIGO design) and no SRM (power recycling only). The SRM T=20% and no SRM curves are obtained simply by replacing the modeled H1 quantum noise in the present configuration (SRM T equivalent = 39%) with the quantum noise calculated for these alternative configurations, assuming the rest of the noise the same.

We would have detected GW150914 no matter what; the SNR could have been 30% worse. 


GWINC output for corresponding theoretical curves:

Current H1

BNS Inspiral Range:      159.65 Mpc
BBH Inspiral Range:        3.04 Gpc (z = 1.0)

SRM T = 20%

BNS Inspiral Range:      131.75 Mpc
BBH Inspiral Range:        2.35 Gpc (z = 0.8)

NO SRM

BNS Inspiral Range:      155.89 Mpc
BBH Inspiral Range:        2.95 Gpc (z = 1.0)

Patrick, Sheila

Since we are getting high wind tonigh, we are not trying to lock and it seemed like a good chance to try to speed up the green WFS.  For the X arm I've turned the gains up as high as they can go before oscillating then turned them down a factor of 3.  We will have to reshape the loop to make things faster. 

Just as patrick got the Y arm aligned the wind picked up to above 60 mph, and we can't hold the green arm lock anymore.  

Evan, Matt, Lisa

While IFO realignment work was in progress yesterday, we spent sometime looking into the H1 quantum noise.

There are a couple of known issues when trying to explain the measured H1 shot noise level:

1) the H1 measured cavity pole (~340 Hz, see  the calibration companion paper ) is actually lower than expected from the nominal IFO parameters, so you can't get the right shape with the current GWINC parameter model (nominal parameters give a higher pole frequency);

2) beside that, higher losses and/or lower power are needed to explain the actual measured shot noise level.

Evan calculated the H1 shot noise contribution in the H1 noise budget (fig 2 in the detector companion paper) from the shot noise on the DCPD sum (8e-8 mA/rtHz), and then referred to displacement noise using the GDS channels for optical gain and cavity pole (optical gain = 3.24 mA/pm). This measurement well explains the H1 noise level at high frequency.

When trying to match the measured shot noise level with GWINC, we realized that an easy way to match the frequency dependence caused by the low H1 cavity pole frequency is to increase the transmission of the SRM to 39% (nominally 37%). We believe the real mechanism is actually a mismatch of the SRC cavity wrt to the arms, translating in a lower "effective" reflectivity of the SRM mirror (i.e., less efficient signal extraction). 

Still, even after fixing the frequency dependence with the higher SRM transmission, if one tries to reproduce the shot noise level with GWINC by using parameters inferred from measurements of loss/power at the various IFO ports, it is evident that extra losses (or lower powers) are actually needed. 

With power entering the IFO ~19W, recycling gain ~37, intra cavity power ~95kW, we need ~15% extra losses in the readout chain wrt to the measured ones (25%) in order to reproduce the observed shot noise level. One obvious way of getting that is if the OMC throughput and mode matching are not as good as inferred from  previous measurements .

A 10 degree mistuning of the homdoyne phase wrt to the "nominal" (pi/2) could explain up to ~5% of the observed loss. 

Bottom line: while one can see many ways to improve this analysis, either powers / recycling gain are not what we think they are, or, most likely, we have higher loss in the readout chain that we think we have (and an imperfect homodyne phase). 

The plot shows the best H1 noise, the H1 measured shot noise, and the GWINC quantum noise model including radiation pressure noise corresponding to 95kW in the arms.


% GWINC parameters
ifo.Laser.Power = 21 * 0.88;
ifo.Optics.Loss = 45e-6;  %Arm loss = 90 ppm
ifo.Optics.BSLoss  = 0.5e-3;  
ifo.Optics.PhotoDetectorEfficiency  = 0.65; %Readout loss tuned to match measured shot noise level
ifo.Optics.SRM.Transmittance  = 0.39;    % "Effective" Transmittance of SRM    
ifo.Optics.SRM.Tunephase = 0;            % SRM tuning
ifo.Optics.Quadrature.dc = 90 * pi/180;  % demod/detection/homodyne phase pi/2  

%GWINC Output
Laser Power:              18.48 Watt
SRM transmission:          0.3900
Finesse:                  445.93
Power Recycling Factor:   36.83
Arm power:                95.26 kW

Hardware Watchdog Swap-Out WP5750

Hugh, Jim, Dave:

We swapped out the older HWWD units in the corner station CER and the EY CER with newer models.

The corner station CER old unit was S1301712, it was unpowered and did not have the two long DB37 cables connecting it to the ITMY top stage satellite amps. It did have both binary in/out cables attached to SUS ITMY binary chassis. We replaced with the new unit S1301708 and connected both satellite amp monitor cables. We removed the binary control line, leaving just the binary monitoring line. This unit does not control the power to the ISI coil drivers for BSC1.

The EY old unit was S1301709. It was fully operational and controlling the three ISI coil drivers. Hugh put ISI into a safe state so we could de-energize the ISI coil drivers when the HWWD was powered down. We replaced with unit S1301701. We reattached all cables except for the binary control of the HWWD from the sus model (monitoring only).

The new HWWD units have different binary monitor voltage levels (low = FAULT, high = GOOD). The HWWD status is read by the SUS QUAD model via its binary input. The new hwwd-part code is in the RCG trunk version, so rather than risk building h1susitmy and h1susetmy against trunk, I made a simple model change to invert the four input binary lines to reflect to new binary levels. Both h1susetmy and h1susitmy models were restarted, no DAQ restart was required. SVN version of new sus models = r12764.

h1guardian0 reboot

Dave:

To resync all guardian nodes with recent file changes, I elected to reboot h1guardian0 to check that all nodes start automatically. First I rebooted the machine, and the nodes did not start automatically. Second I power cycled the machine and the guardian nodes did start.

h1tcscs new SIM model parts WP5749

Aidan, Dave, Jim:

Aidan made changes to his SIM parts of the h1tcscs model. Jim and I helped in getting the new code compiled. The model h1tcscs on h1oaf0 was restarted, followed by a DAQ restart.

ISI HAM4,5 model change

Hugh, Jim:

the models h1isiham4 and h1isiham5 were restarted with new models. No DAQ restart was required.

Timing System IRIG-B units handling leap year

Jim:

Jim checked that our IRIG-B fanout units in MSR, EX, EY and DTS have handled this year's Feb 29th inclusion correctly, they have.

DAQ Minute trends offload from h1tw1. WP5747

Jim:

The minute trends offload from h1tw1 was completed today. During this afternoon's DAQ restart h1nds1 was configured to use the new minute trend archive.

DAQ Restart

Dave:

The daq was restarted at 15:30 to resync with the new h1tcscs model and reconfigure h1nds1 to use the new minute trends archive. This was a clean restart. h1fw0 started sufficiently in advance of h1fw1 to write a 64 second frame before h1fw1 wrote its first frame.

Added 423 channels. Removed 272 channels. Changes attached.

WP 5751 FRS 4424

Jim logged the problem, 25713 on Thursday.  Today I swapped in another board (probe 13440) but the performance was much worse.  Microsense did not tell me that would be the case so I don't know what that says about this 13440 unit.  Maybe it says a lot or perhaps nothing.

After seeing that this replacement was not going to cut it, I swapped the original back in.  Funny now, the performance is much better but still not a good as the other sensors--see the attached.  In this uncalibrated spectra, the cluster of fine traces at the bottom are all the other stage2 CPSs.  The black trace is H3 before the swap.  The high green trace is H3 with the alternate board (not good) and the yellow is H3 with its original board back in place.

So is it the power cycle, maybe a contact scraping/cleanup, that has recovered the performance?  Maybe the board should be removed and plugged back in a number of time.

1/2 open LLCV bypass valve, and the exhaust bypass valve fully open.

Flow was noted after 20 seconds, closed LLCV valve, and 3 minutes later the exhaust bypass valve was closed.

Next over-fill on Thursday, March 3rd before 23:59 utc.

After a LN2 delivery to CP3, Kyle suggested to visit the Y-Mid station to see how CP3 was doing, there was LN2 being spilled out of the exhaust pipe.  At 22:23 utc I decreased the LLCV valve setting to 15%, previous setting was 18%.

Maintenance list in earlier alog.

DAC reboots by DaveB since that post.

Currently TCS is working with heating on ITMs.

Alignment and locking resume after their work.

(Chandra, Gerardo and Kyle)

Regenerated NEG pump with the aid of an aux cart.

Valved out NEG pump from X-End, then started regeneration of NEG pump ~19:00 utc.
2 hours later heating was complete, waited for temperature to drop down, valved in NEG pump to X-End volume at 21:45 utc and @ 92 deg C.

Finished adding Caps to the Negative regulator per latest dwg. Today we completed the ITMx,ITMy,BS, and all of Ham5 and Ham6 Suspensions.  Also verified and corrected were needed Ham2 optics.
This should stem any oscillations caused by the long cables from the SAT amp side.

IM2 signals changed behavior on 23 Feb around 19:00UTC.

Pitch and Yaw signals sent from about 1 count pp to 6 counts pp.

Looking at OSEM signals, UL and LL decreased in pp counts, UR remained about the same, and LR increased it's pp counts.

Plots attached: power spectrums look very similar to the "good" values, time series shows the OSEMs and the increased pitch and yaw signals.

Monday: Noise hunting (sort of)

Tuesday: ITM preloading, SRC work, get back to locking

Wednesday: WFS (morning) & noise hunting (later in the afternoon)

Thursday: Noise hunting (all day)

Nairwita and Jeff found yesterday that the foton file for HAM5 did not show the same controller that the seismic matlab commissioning scripts said were installed. The changes weren't huge (some very different low frequency gains, but only factors of a couple at a few hz), and are shown in the two attached plots. First figure is the old filters, second is the new filters. While everything was down this afternoon I've installed the Matlab filters. I don't expect any difference in the performance at HAM5, the diffrences are not huge, this was mostly a housekeeping task, to make offline modeling work easier. I still haven't figured out why the difference, but it would likely take digging through months of archived foton files. This also makes the controllers at HAM5 more similar to HAMs 4&6 over 1-10hz.

(Fil Keita Daniel)

OMC PZT dither: change cap for 1000 less analog gain. Issue 1208, ECR TBD. Done

OMC DCPD bias voltage: increase bypass caps on power supply. Issued 1207, ECR E1600061. Done

Cao, Nutsinee, Elli

We replaced the ITMX HWS SLED with a spare.

We remeasured power coming out of the SLEDs using an Ophir power meterhelp directly in front of the fiber.

The ITMX SLED power was 1.35mW (running at 98mA current)

The ITMY SLED power was 2.90mW (running at 103mA current.)

The SLED power channel H1:TCS-ITMX/Y_HWS_SLEDPOWERMON was recalibrated using new gains and dark offsets

H1:TCS-ITMY_HWS_SLEDPOWERMON=0.48*intput-0.0071

H1:TCS-ITMX_HWS_SLEDPOWERMON=1.089*input-0.154

Site activities: some started before 16:00UTC (08:00PT)

- 15:14 Richard - SUS work, ITMs, BS, and MMT1
- 15:23 JeffB - both end stations for Dust Monitor install
- 15:30 ChrisS to mid-X to retrieve items, no VEA entry
- 16:11 Fire Department - testing in OSB
- 16:11 Filiberto/TJ - EY then EX RF cable pulling
- 16:27 Christina - EX and mids
- 16:28 Hugh - restarted HAM4 and HAM5 models, all working
- 16:43 Ryan - restarting Remote Access, alog
- 17:00 GRB test alert
- 17:30 ChrisS - resumes beam tube sealing on X-arm roughly 300 yards from corner station
- 18:00 Gerardo - BSC5 recharge canister outside of chamber, 6 hours
- 18:00 Cheryl - H1 PSL Anti Room access for parts
- 18:02 Brynley/Vinny - heading to EY to get their magnetometer equipment
- 18:10-18:43 DaveB - SUS hardware wd swap out (CERitmy & EY ETMy)
- 18:10 portapotty service
- 18:12 ITMx sattelite back
- 18:13 Paradise water
- 18:23 Elli, Nutsinee - looking for TCS sled in west bay
- 18:44 Dave - ETMy SUS hardware wd swap
- 18:45 Ken - variacs work for bubba
- 18:45 JeffB - completed dust monitor work at end stations
- 18:57 Ed, JoeD - HAM5/6re-install sattelite amps
- 19:21 DaveB - done at EY with SUS hardware watchdog
- 19:21 JimB going to EX to look at electronics
- 19:50 Kiwamu - CO2 laser heating tests using ITMs and SRC