(corey, eric, hugo, jim)  [this is an entry for work on Tuesday]

#6

Installing more walls, several iterations of balancing system, measuring Lock/Unlock values.

And yet more serial number info for cables

Corner1

• Actuator H:  S1106673
• Actuator V:  S1104096
• GS13:  S1106665
• L4C:  S1106653

Corner2

• Actuator H:  S1104097
• Actuator V:  S1106676
• GS13:  S1106670
• L4C:  S1104709

Corner3

• Actuator H:  S1104099
• Actuator V:  S1104101
• GS13:  S1104701
• L4C:  S1104602

#7

Started staging for Pitchfork/Boxwork assembly.

Helicoiled Outer Walls

(corey, greg, hugo, jim, mitch)

#6

Performed ISI tilt measurements.  While doing this it was discovered that H1 (s/n094) was not acceptable.  It was removed and was replaced with the one spare horizontal GS13 on hand (s/n 018).  Then continued with performance measurements on the ISI with new H1 GS13.

#7

Ribs were prepped for Stage1 Assembly.  These Ribs were individually installed on the Stage1 Floor (vs. pre-assembling the Pitchfork/Boxworks and installing them on Stage1).  Keel Walls were installed, and other parts were also set up on Stage1.  Should have Stage1 on Stage0 tomorrow.

Attached are plots of dust counts > .5 microns.

Burped GV5 gate annulus into aux. pump cart and switched from Turbo to Ion pump pumping on the YBM -> Didn't valve YBM into CP1 yet as viewport work is still taking place on the YBM (op levs, camera).  

The support table was removed from HAM5 first thing this morning then the condition of the chamber was documented. The support tubes were wrapped and brushing was started. The crew got about a quarter of the chamber brushed before the end of the day.

[Stuart A, Travis S]

A request was made from Matt H and Jeff K to provide the distribution of addable mass used on the LHO PR3 (HLTS) suspension. Unfortunately, in this instance the paper-trail (and ICS trail) quickly ran cold. The distributions had been captured for subsequent suspensions, just not unfortunately for the first assembled PR3.

It was therefore necessary to conduct a visual inspection, and with the assistance of Travis, we were able to determine the following:-

M1 addable mass:-
M1 (upper) = 100+100+20+10 = 230g (+ nut)
M1 (lower) = 100+100+20+10 = 230g (+ nut)

M1 sliding masses:-
M1 roll adjustment, protruding ~11-12mm towards LF side
M1 pitch adjustment, ~centred

M2 addable masses:-
LF (front) = 100+20 = 120g, RT (front) = 20g (refer to pictures for fixing screws & nut arrangements)
LF (back) = 0g, RT (back) = 100+20 = 120g (refer to pictures for fixing screws & nut arrangements)

M2 sliding masses:-
M2 pitch adjustment, protruding ~2mm towards back

Many pictures have been taken during this inspection of PR3, a choice selection of which can be found attached below.

Image 836, PR3 storage barrel re-located to a chamber-side clean-room.
Image 866, Storage barrel lifted and removed, revealing PR3.
Image 851, M1 and M2 masses taken from front of suspension.
Image 857, Close-up of M2 taken from front of suspension.
Image 862, Close-up of M2 taken from back of suspension.

N.b. naming convention used is consistent with M1 stage BOSEMs, which are fitted to back of the suspension.

Activities throughout the day:

SURF students to End-Y

Recompilation of the 'h2susetmy' user model.  Subsequent reboots of 'h2sustmsy' and power-cycle of 'h2susb6' front-end. (Dave B. & Jeff G.)

Richard out the End-Y for cabling of end station camera.

PEM model reboots by Dave B.

35W beam

After Jeff G made his changes to the h2susetmy model to ingest the Optical Lever quad photodiode signals from the second ADC, we experienced strange "DAC channels already in use" errors between h2susetmy and h2sustmsy. We checked the models carefully, no conflict was apparent. I have recompiled (but not installed) all H2 models this morning against RTS Tag2.5, so I suspect I was the cause of the problem. I rebuilt all models on h2susb6 against the Tag2.5 and the suspensions for ETMY and TMSY are now working.

200W beam

After a serious round of fit checking on Monday (going through the motions on the wrong optic), Danny yesterday in my absence glued the first primary prism onto MC2.  It cured at room temperature overnight.  The fixture was removed this morning and the prism is now under a heat lamp cure until ~3pm this afternoon.

The setup for the fixture which requires the ability to use a horizonally mounted height guage is still flat out dumb.  After ~7 mods to parts, I've recreated Danny's setup at LLO (kudos for getting the poor design to work at there!), but we still find that the multlitude of bolted together stages do not hold the long lever arm of the height guage steady enough.  As well, we are still hand pushing the jig fixture around to acheive the 0.1mm tolerance on the placement of the prism (no micrometers!!).  I do not see how we can continue to use the exsisting fixtures for 13 more optics (H1 and I1), without sacrificing serious efficiency (and my mental health).  So, I'm going to try the iLIGO gluing fixture on a spare optic, in parallel with fussing through the cobbled together setup we have now for the 2nd MC2 prism.

Part of the Assembly Validation testing of HAM-ISIs (that happens in the staging building) consists in taking power spectra with the ISI tilted. It allows us to check that the sensors, especially the seismometers, work in tilted position as well. To do so, spectra are taken with a 10kg mass set at each of the 6 corners of the optical table (Locations A to F in ISI_Tilted) 

This test revealed that GS13-H1 (Pod #94) was not functioning correctly. Symptoms are the same as observed on previous failing GS13s. The response of the instrument drops dramatically below 60Hz (ISI_Not_Tilted) which is characteristic of a stuck seismic mass.

This instrument was tested OK at reception from LLO. It is very likely that the tilting of the ISI induced the sticking of the seismic mass.

We have one last spare horizontal GS13 (Pod #18). It will be installed as replacement today. Testing of this unit will start over with sensor spectra, as soon as it is installed. 

Mode Cleaner Tube baffles in MC1 installation alignment was verified as accurate for both MCA and MCB ends.

MCA1 - Fasteners were loosen to reposition center plates. The missing center clip and all fasteners (x2) were installed and tightened. Installation is complete as designed.

MCB1 - Fasteners were loosen to reposition center plates. The missing brackets (x4) and all fasteners were installed and tightened. Installation is complete as designed. NOTE: one broken fastener in lower middle center plate and one galled screw was left unmoved in upper right.

Work was performed by Apollo crew (Mark Dodson and Caleb), Tim Nguyen and Lisa Austin.

We left the HWS running overnight. Despite not properly imaging the ETM yet, we took spectra of the prism/tilt measured by the HWS and compared it to the OSEM signals for the penultimate mass of the ETM. There is a strong correlation between the two spectra just below 1Hz, verifying that the HWS is actually recording a real signal.

LHO CDS:

I've added more medm snapshots to the LHO CDS web page:

https://lhocds.ligo-wa.caltech.edu/screens/

Due to a 27 screen limit per virtual frame buffer, I am now running three frame buffers on script0 which correspond to the H0, H1 and H2 systems.

Jim and Dave.

now that h2susb78 (SUS FMY) is stable after the one-stop cable was replaced, we returned the original front end 2U supermicro computer Tuesday morning to show that the error was not in the computer. Also it will allow us to use the management port for remote control. h2susb78 remains stable 18 hours after this replacement.

LHO Mid station gate valve annulus ion pump response to daily temperature excursions.

[Thomas, Elli, Aidan]

We re-aligned the pick-off from the ETM HR surface onto the Hartmann Wavefront Sensor (HWS). Several wedged uncoated optics were used to attenuate the beam before the sensor. We adjusted the combination of these until the beam was not quite saturating the CCD on the sensor.

We removed the Hartmann plate from the CCD and recorded the beam profile. There were diffraction rings on the edges of the intensity distribution which we assumed was caused by clipping on a couple of optics. Tweaking the alignment removed some of these effects but there is still significant clipping on the right hand side of the image that we've yet to identify the cause for [see attached PDF].

The Gaussian beam radius in the vertical direction on the HWS is roughly 1.95mm. We expect a beam size of 1.57mm. We need to adjust the magnification in the HWS telescope and confirm that we're imaging the ETM HR surface.

We replaced the Hartmann plate and ran the sensor overnight.

Rana, Keita

We also found that the view of the ETM from the optical lever viewport is very nice. It would be good if we could use that one for the ETM face cam during OAT.

Also, in lieu of having a true TransMon beam for OAT, perhaps we can setup a scatter monitor PD on an ITM chamber viewport as Bill Kells used to do: a 2" diameter lens and a high gain Thorlabs Si PD with a short pass filter.

HAM6 was placed into a shipping container around January 27th, Corey's alog, and purged with a Nitrogen boil-off from a dewar. To the best of my knowledge it has not been purged since that time. To determine what the humidity levels inside the container were like, a super elaborate no expenses spared contraption was developed to capture the exhaust from the container during the purge (photos attached). Data logging using a testo 645 dew point probe was started as soon as the purge began and ran for about 19 hours (graph attached).

Direct LN2 boil-off read at -48.5 td°C, 9.2 °C; while ambient LVEA readings were at 4.4 td°C, 20.1 °C. Purge rate is ~10 L/m with ~5,442 L of empty volume inside the container.