WP 7312

I updated and restarted the h0vacex and h0vacey PLCs to create separate sync units for each Inficon gauge. The X2-8 and Y2-8 Inficon gauges are still powered off, but no longer disabled in TwinCAT. With the addition of the separate sync units this no longer prevents the remainder of the system from running. I burtrestored both h0vacex and h0vacey to 6am local time this morning.

The high voltage at each end station has likely tripped off and will need to be reset.

TITLE: 01/26 Day Shift: 16:00-00:00 UTC (08:00-16:00 PST), all times posted in UTC
STATE of H1: Planned Engineering
OUTGOING OPERATOR: None
CURRENT ENVIRONMENT:
    Wind: 24mph Gusts, 20mph 5min avg
    Primary useism: 0.04 μm/s
    Secondary useism: 0.45 μm/s
QUICK SUMMARY:

Terry, Sheila

We seem to have a mix up with our fiber collimators.  We measured the beam profile out of our 532 nm collimator this afternoon, because our mode matching into the OPO is very poor, and found it to be 52 um.  This afternoon Terry and I measured the waist out of both of our collimators for both wavelengths. 

The 532 collimator that we have is SN4.  Maggie sent a link to a git where she has measured data from SN4 for 532nm, this data shows that the waist is 264 um 0.6 meters from the collimator.  I am not sure right now what the serial number of our 1064 collimator is, but the data on the git says SN01 has a waist of around 280um @0.3 meters while SN17 and 18 have waists around 315/320um.  

It seems like the most plausible explanation is that we have the collimators swapped somehow even though we have been careful not to do that since taking them out of the bag.  If the one that we think is the 532nm SN4 is really 1064nm SN01, these measurements aren't as crazy, although there is still a discrepancy between the waist position of the 1064 beam coming out of our SN4 collimator and what Maggie measured for SN01.  

The data for all four of the measurements that Terry and I took this afternoon are in the comments in the attached script. 

Jenne, Keita, TVo

Successful locking of the OMC on the 00-mode!

First, the OM1-OM2-OM3 path into the OMC using QPD_A and QPD_B as a reference and closing the loops.  This left OM1 pretty close to railing in yaw and so there were some attempts to offload OM1 onto the other two but it would rail the OMC actuators when the loops were engaged.  We remedied this by zeroing the OMC alignment sliders while the OMC_ASC loops were on (this worked pretty smoothly). So Jenne offloaded again so that we do the least amount of optics sliding/rotating on the HAM6 optics table.

Fil turned the high voltage on for the PZT so that we could try to lock. There was some confusion when the OMC_DC_IN1 was railing when sweeping the PZT_OFFSET, this is still not clear why so we turned off all stages of whitening to avoid saturating.  Then we were able to achieve lock after Keita turned off the purge air,  we've left the purge turned on but lower than the previous setting.

Jenne pointed out that having about 1mW of input power from HAM5 should register about 1mA on the OMC_DC_SUM_OUTPUT when on the right mode and we're getting about that with PZT_OFFSET = 1.8. 

Nutsinee, Marc, Terry, Daniel

We finally wrestled the new TTFSS to the ground. Ugf is around 500kHz with good phase margin and somewhat less good gain margin. The crossover is around 10kHz. It cannot be raised by much due to two smaller peaks in the 70-95kHz range. A couple of electronics modifications were needed.

For the frequency counter of the beat note to work we need >-12dBm pf RF power in the cable going towards the CER. Ideally we have at least 0dBm. The beat note strength from the photodiode was only around 30mV and we had to change the directional coupler in the TTFSS preamplifier to a splitter to give us more umpf.

Kyle, Gerardo 

We vented GV12's annulus volume (minus the gate volume) with bottled UHP N2 and observed no leaks into the CP4 volume.  Next, we pumped out the vented volume, combined the gate annulus volume and then administered UHP N2 into the entirety of the annulus volumes.  We observed pressure rises on both the Y2 module side of the closed gate valve as well as the CP4 side - thus indicating that both the inner and outer gate O-rings leak.  We evacuated the system, isolated the gate annulus volume, restarted the AIP (pumps all but gate volume in this configuration) then isolated and shut down the connected turbo+cart.  

Another useful test would be to fully vent the annulus volumes adjacent to the leaking gate annulus volume and then "dump" this gas all at once as a step change into the gate annulus volume and then observe how much time we would have to decouple plumbing and install a blank on one of the two gate annulus pump ports and a pump port valve on the other gate annlulus pump port as was done to GV11 yesterday.   

Today, we measured the violin modes of the new monolithic ETMy with the goal to determine what contributed to the large-ish pitch offset we were seeing.  Nothing egregious was found from violin modes themselves, so we decided to attempt to fix the pitch by re-stress-relieving the stock welded to the horns.  This technique has been done before, once here at LHO and once at LLO with success.  This time around, we went from ~5mRad differential pitch to ~500 uRad differential pitch.  Now, if only we could get a factor of 10 improvement in other aspects of LIGO in the course of a day. . . 

Jim and I went in today and tried our hand at some of the bolts on the periscope. We had high hopes since the 3IFO periscope looked good and the bolts freed easily. Unfortunately, these bolts had their hexes almost stripped on many, if not most, of the bolts (see attachments). With some breaker bars we managed to get out all of the ones we need for the vibration absorbers, and then we started on some for the baffle panel brackets with Betsy guiding us to the correct ones. Overall it was a good success with more work tomorrow. And we only bent 3 wrenches in the process!

Also, I didn't get any pictures of where we left off, check back tomorrow.

TITLE: 01/25 Day Shift: 16:00-00:00 UTC (08:00-16:00 PST), all times posted in UTC
STATE of H1: Planned Engineering
INCOMING OPERATOR: None
SHIFT SUMMARY:
LOG:

16:03 Christina out to LVEA

16:45 Hugh out to LVEA - working atop HAM6

16:50 Set Very Large EQ button because of 5.8mag of the coast of N Cali

16:53 reset ACT SEI trip at ETMX

16:57 reset MC1 wd,  HAM2 ISI CPS trip, and ITMY ACT trip. The latter has been problematic this morning.

18:03 Jeff K out to LVEA - talk to Hugh on top of HAM6

18:04 N out to squeezer bay

18:13 Marc out to LVEA - check on ZM1; pull TTFS unit from squeezer bay.

18:22 Betsy Tj Jeff K and Jim out to EY - B&K Hammer and Reaction chain

18:27 Sheila ou to optics lab

18:29 Travis called from EY - the welding team is out there (Danny, Angus and him)

19:43 Noticed Fil out on LVEA floor at output.

21:32 Richard into CER - HV supplies

21:36 Marc out to LVEA - SUS rack by HAM5

21:50 Sheila out to optics lab

21:54 Betsy out to EY

22:04 Jim and TJ out to EY

22:45 Kissel back

22:53 Marc back

23:13 Kyle out to MY and EY

23:38 Jeff B out

23:59 Greg out to TCSY table to reset the LASER

24:00 EOS

Commissioning - 

• aligned beam into OMC QPDs;
• PZT scan is up next.
• WFS still not aligned. 
• AS Air which requires viewport simulators.
• Need to figure out feedthroughs for  the top of HAM6.
• Talk of putting internal viewport covers on septum.
• ZM2 troubleshooting is over

Squeezer -

• Ongoing
  • No weekend work is scheduled

TCS - 

• one of the tables need a new panel

Vacuum - 

• Tyler and Mark putting magnets on new ION pump
• NGG pump commissioning
  • won't happen this week

Fiber Welding -

• ETMY is welded; has pitch problems
• working on violin mode 'spreading' 
  • not quite where they need to be

Pcal - 

• B&K hammering done
• Periscope vibration absorber issues ongoing

SEI -

• Maintenance is ongoing

CDS Electronics - 

• ITMY noise investigations are ongoing

Facilities - 

• HVAC work; ongoing

Terry, Nutsinee, Daniel, Sheila

LAYOUT

Attached is the current layout of ISCT6 at LHO that is an almost identical copy of LLO. Differences at time of writing are as follows:

1) A quarter wave plate was added after the laser to reduce the elliptical polarisation out of the Mephisto and increase the transmission through the isolator to > 95% and reduce the back reflection that is awkward to dump because the rejected beam from the isolator goes vertically down and is close to the isolator mounting post.

2) Two  100 mm &  two 150mm lenses were used to mode-match the LO  and PSL LO paths (instead of four 100 mm lenses) and the seed path has two 75 mm lenses instead of two 100 mm lenses as we had run out of 100 mm lenses. This made the LO path from the PSL about 50 cm longer and the seed path a few cm shorter. The seed path was routed as originally proposed in D1500297-V5 as a lens mount was in the way and made it difficult to keep an exact copy of the LLO beam path.

3) The SHG is about 5 inches closer to the fiber coupled output end of the table than at LLO. This was just a positioning error on the table and did not compromise the setup and once the SHG was mode matched I did not feel it was worth changing.

4) The fibre couplers are about 3 inches further away from the end of the table (I accidentally left myself a little too much room to play with).

5) The fast AOM has 70% diffraction efficiency (as opposed to 80% at LLO). 

6) To get more RF power on the TTFSS detector BS5 and BS9 have been swapped from their original positiions at LLO (alog 40249)

I'll post the mode-matching solutions shortly but the coupling efficiencies into all the fibres are about 80%.

PARTS LIST

The parts in red have to be replaced with superpolished mirrors and the parts in yellow are also not superpolished but are less critical. 

Still waiting for fibres from couplers on table to patch panel and fibre switch (using temporary patch cables at the moment).

After Jenne's experience with the Kamchatka earthquake last night, I've added the requested seismic recovery button the ISI_CONFIG screen, shown on attached image. The new, green Recover EQ button is just above the old, red Very Large EQ button, and mostly just reverses the operations of the red button. If any platforms are tripped, you'll have to reset watchdogs. There's also a long standing issue of the HAM2&3 GS13 gains, which for some reason can't be stably managed by the ISI guardians, so there will be SDF differences after recovering from an bad earthquake. I've also added the low frequency Z blrms for EX&EY STS2s to the stripchart on the lower right. If all 4 channels (LSC-CPS, & 3x .03-.1hz gnd blrms) on that display are headed off the stripchart, it's a pretty good indication of a large earthquake arriving.

Ed, Jim

Excursions in BRSX include Krishna's initial visit and a code crash at the end of December

TITLE: 01/25 Day Shift: 16:00-00:00 UTC (08:00-16:00 PST), all times posted in UTC
STATE of H1: Planned Engineering
OUTGOING OPERATOR: None
CURRENT ENVIRONMENT:
    Wind: 8mph Gusts, 7mph 5min avg
    Primary useism: 0.03 μm/s
    Secondary useism: 0.35 μm/s
QUICK SUMMARY:

The laser tripped around 1:20 am because of the Wachhund.  I increased the diode currents by 1A for heads 2, 3, and 4.
Things seemed to have come back okay.

A. Bell, J. Oberling, D. Sellers, T. Sadecki, K. Toland

The final 2 fibers were welded to the new ETMy.  The monolithic was successfully suspended and IAS measurements were taken.  I'll let Jason fill in the numbers, but the differential pitch is a bit larger than we generally hope for but not grossly so.  Good work team!

Violin mode measurements to commence tomorrow.

Turned the RF driver and the power supply on for the CO2Y laser, also connected the IR sensor, and was getting green lights for the control board. Using the PWM controller I tried to turn the laser on but wasn't getting any results on the power monitor. After double checking the power supply was set to 28V and 28A limit, and the RF driver was set to 40.68MHz, Fil and I found that the wrong RF cable was plugged in. After plugging the right one in the laser powered up in PWM mode and I was able to verify the rotation stage is working as well. Tomorrow I will check that the alignment hasn't changed significantly and that the periscope picomotors are operating correctly.