Yesterday, Travis and I worked on finishing the reaction chain cabling now that the ESD connection is back to working.  We also fixed the noisy signal on the L2 UL OSEM by swapping the short quadrapus cable D1002524 that connects to all 4 L2 (PenRe) AOSEMs.

D1002524 s/n 904 was removed and 905 was installed.  Note, there are no more spares at LHO of this type of cable.  Will look into getting spares. 

While at it, we swapped 2 AOSEMs which had open light voltages which decayed down to 15k (from 30k).

We then aligned the L2 AOSEMs to the flags on the PUM, in a few iterations.

We made a few more alignment tweaks to both chains and then ran a series of transfer functions to make sure all 8 masses were fully suspended and free from mechanical interference.  

Details of this were posted by Travis on the original alog associated with the L2 UL signal, below.

HAM 6 pressure is at 4.9e-6 Torr, well below the 1e-5 Torr HV interlock set point. I gave Jenne and Sheila permission to turn HV ON.

We will continue to pump HAM 6 with turbo. If for some reason the turbo trips, the pressure gauge on HAM 6 is interlocked with HV.

This morning, a leak sprung on the TCSy CO2 table.  One of the dry break fittings on the supply manifold lost its seal and dumped just about the entire contents of the chiller onto the table.  With a quick initial assessment, I don't see any optics that were contaminated (the water manifolds are in the SE corner of the table, away from the optics).  Jeff Bartlett is currently cleaning up the water and repairing the broken fitting; if he can find a spare it will be replaced, if not it will simply be capped as it was an unused port on the manifold.

Edited to add: I took a couple quick pictures of the broken fitting, see attached.

[Aidan, Marie, Dan B, Alexei, Keita]

Yesterday morning we realigned the ALS beam into the vacuum system, confirmed it was centered on the TMS QPDs, confirmed it was coming out again and was centered on the in-air WFS and confirmed that it was getting back to the ALS length PD. The two irises installed after the PBS were centered on this ALS beam.

We then aligned the LED beam through the PBS and through the two irises. By carefully fine-tuning this alignment as best we could by eye, we found that there was a return beam coming back to the Hartmann sensor.

The return beam is quite sensitive to alignment. There is a narrow window of adjustment of the pitch and yaw on the final two HWS mirrors. Small changes (fractions of a turn) can make the beam disappear entirely. We don't have picomotors on these actuators so we can't easily quantify what "small" means here.

We were able to get images of the return beam on the Hartmann sensor camera. We started with the Hartmann plate in place but eventually took it off and saw the intensity distribution of the return beam. It looks quite mottled and smaller than expected. 

We spent the remainder of the day trying to improve the spatial quality of the return beam. It looks like it might be clipped in multiple places or is experiencing some diffraction off particulates on optics - we're still investigating. We experimented with trying to change the divergence of the beam coming from the fiber launcher as well as removing the iris that was in front to get more of the beam through.

Due to concerns about clipping, we temporarily removed the PBS so that the HWS beam didn't have to contend with that small aperture.

The goals today are to:

• Confirm that the Hartmann sensor is at the conjugate plane of the ETM and move it to that plane if it is not. This will be done by injecting a YAW modulation in the ETM and moving the Hartmann sensor longitudinally along the axis until the position modulation is minimized or zeroed in the sensor.
• Try reducing the beam size coming out of the fiber launcher for some of this initial work
• Measure the beam divergence on the return beam and compare to the beam from the fiber launcher. These should be well matched as the beam is supposed to be retro-reflected from the ETM.
• After optimizing the return beam. Install the Hartmann plate and quantify the spatial distribution and noise in the reconstructed wavefront.

TITLE: 05/23 Day Shift: 15:00-23:00 UTC (08:00-16:00 PST), all times posted in UTC
STATE of H1: Planned Engineering
OUTGOING OPERATOR: None
CURRENT ENVIRONMENT:
    Wind: 11mph Gusts, 8mph 5min avg
    Primary useism: 0.03 μm/s
    Secondary useism: 0.13 μm/s
QUICK SUMMARY:

Chandra R., Gerardo M., Kyle R.. Ken D.

Today we helium leak tested the CFF joints on CP4.  With the 55 L/s ion pump valved-out and the leak detector backing the 450 L/s turbo pump (which was valved-in for this exercise), each CFF joint was sprayed with an audible flow of helium for 10s of seconds each.  The nominal helium background signal was < 2 x 10-9 Torr*L/sec during testing.  Additionally, Chandra partially filled the (now empty) inner LN2 vessel with helium via applying helium to the bottom level sensing line and allowing the displaced air to exit the upper sensing line.  This test was incomplete in that the exhaust exiting the upper level sensing line was not monitored for O2 concentration and thus the helium concentration within the inner LN2 vessel could not be determined. 

A pressure accumulation test was also done.  For this test, all pumps were valved-out and the pressure within CP4 was allowed to rise (see attached graph). 

By all indications, CP4 seems to have survived the months-long bake exercise unscathed.  Of note too was that, while being pumped by only the turbo during leak testing today, that the pressure achieved nearly the same value as had been observed just prior to the unexpected turbo shut down last Thursday. 

Ken D. is well on the way to restoring the electrical connections that had been removed to accommodate the heated enclosure.  He also reminded us to consult with him later in the week prior to operating GV11 so as to review the details pertaining to the limit switches and motor rotation etc...

Gerardo M. and I have started to re-hang the annulus ion pump plumbing on GV11.  Chandra R. intends to be ready to open GV11 as soon as EOB Friday - stay tuned.  GV12 won't be opened until later.

This morning ~16:45 utc the NEG pump attached to the south door on BSC6 was valved in to the chamber, see attachment for pressure change.

Yesterday I measured the IMC input beam (measurement location: in front of the bottom periscope mirror), and compared that to the reading on the IMC IN PD.

• measured beam power = 1.63W (power meter)
• PD reading = 1.88W
• difference of +0.25W on the PD
• calibration needs to be evaluated
• unknown state of dark offsets
• this is true for the IMC IN PD and all PDs in the IO path
• true for all PDs on the PSL (Jason)

IO path PD Status:

• PD layout in the IO path is currently being reworked
• the ISS PD was moved back into the ISS box today
• where it was located, there is one new PD to add: the large area DC PD
  • this new DC PD  is on site, and is in Jason's office
  • it came with an AC power supply
  • other options for powering the PD are being looked at
  • other IO PDs are being powered with a box that is under the PSL table, so this may be an option
• while the ISS PD was in the IO path, it was looking at the transmitted beam from IO_AB_W1 (where the new large area PD will be installed)
• there was a Thorlabs DC PD on the reflected beam from IO_AB_W1, and it's unknown if this is intended to stay
• the Thorlabs DC PD on the transmitted beam of the PMC is a temporary setup, and will not stay (since it's not in the planned O3 configuration)
• NOTE : this PD, looking at the PMC transmitted beam, was being read into the DAQ through a channel labeled EOM power PD, starting when the ISS PD moved out of it's box

The pressure in corner station is 6.5e-7 Torr. Attached is a projection of *rough* dates at lower pressures. Ideally, we want to wait to open to the arms until the corner pressure is 1e-7 Torr on the turbos alone, and then valve in IPs and CPs. Last May when we vented corner for one day, we opened back up to arms at 2e-7 Torr in 16 days. Will consult Vacuum Review Board on how to proceed with opening up GV5 for y-arm commissioning.

J. Oberling, P. King

Today we worked on recovering the PSL ISS, and began by re-installing the ISS AOM.  The AOM mount was moved to a place where the beam was ~1mm in diameter (unfortunately I forgot to take pictures, will take some tomorrow and upload as a comment) and installed the AOM.  The mirror that sits downstream of the AOM and reflects the 1st order diffracted beam into a beam dump was also re-installed and aligned.  A power meter was placed in this beam path and the alignment of the AOM tweaked to maximize the power in the 1st order beam.  We then adjusted the ISS offset to find the point where the AOM was diffracting ~2W; this was found at an offset of 8.0.  The offset was then set to 0, and increased to 20 in steps of 1; a power reading for the 1st order beam was taken at each step.  This allows for calibration of the diffracted power graph on the ISS MEDM screen.  Peter has the data and is analyzing it.

The beam from the PMC to the ISS box had to be re-aligned, as we had not re-aligned this path since moving the ISS box to accommodate the damping bars for the new PMC.  This complete, we then roughly aligned ISS PDB.  The PD assembly was then removed from the ISS box so we could re-install ISS PDA (recall that PDA had been removed from the ISS box and installed in place of IO_AB_PD3 prior to O2).  With PDA back on the PD assembly, this was installed back in the ISS box, and both PDs aligned.  They both now read ~10.0 V.  Next step on the ISS (for tomorrow) is to get the loop to close and measure TFs to optimize its operation.

15:00 JeffB to LVEA

15:45 Fil to MSR 

16:15 Betsy, Travis to EX

16:15 Gerardo to EY

17:00 Jason to PSL

18:00 Marc to HAM6

20:15 Jason Peter to PSL

20:45 JeffB to ITMX camera

21:15 Betsy, Travis to EX

21:30 Aidan, Marie, Dan, Alexei to EY

files saved in:

• .../QUAD/H1/ITMX/SAGM0/Data
• .../QUAD/H1/ITMY/SAGM0/Data
• all TFs looked acceptable, with some noise, but nothing missing or added

   I added 100ml water to crystal chiller and no water to the diode chiller. Both filters are clean and clear. 

Rough pump down was faster than normal.  Implies that the majority of the gas load comes from the O-ring sealed QF flex lines that connect the scroll pump assembly to the HAM6 connection as these were pumped overnight.  Typically, these get pumped simultaneous with HAM6.  In other words, it seems that the time needed to rough pump HAM6 down to the point of switching over to the turbo pump is significantly determined by how wet the connecting flex lines are.  We have always suspected this but never realized to what degree. 

Large units over HAM3, HAM4, HAM5, HAM6 and the Beer Garden, as well as, the small change rooms etc. on north side of OMC tube.

[Gary T, Danny S, Matt H, Stuart A, Norna R]

During the close-out work of the BSC9 chamber (see LHO aLOG entry 13085) we were able to further investigate the source of the excess noise that had previously been observed on the ETMX (QUAD) L2 (PUM) UL channel (see LHO aLOG entry 13047).

Previously, I had swapped field cables at the Satellite Box between ETMX L1 and L2 stages running to the chamber. This indicated that the noise was downstream, i.e. with the field cables themselves or in-chamber. We repeated this test, but this time swapping field cables at the air side of the vacuum flange. Further measurements then eliminated the field cables and confirmed the issue resided in-chamber.

Gary inspected and re-seated the in-chamber connectors from the vacuum flange to the OSEM, but this offered no improvement. Finally, the L2 UL AOSEM (s/n #270) was removed and a spare unit connected up in it's place, but again, unfortunately this offered no improvement.

This indicates that the excess noise is most likely a in-vacuum harness problem, which would be invasive to attempt to replace. Therefore, it was decided to generate an integration issue and proceed with the close-out of the chamber, with the excess sensor noise on this channel.