Ops DAY Summary

The main installation activity today is closing out HAM6 work.  In parallel a couple of tasks went on:  (1)  Balancing the ISI & (2) Retrofitting top glass plate so it can be installed. 

HAM6 work is done in the chamber.  The day ended with prep work (moving cleanrooms) so the doors can be installed on HAM6 on Monday.  Before HAM6 is closed, the Signature Approval for Chamber Closure  will need to be filled out (E1500273).

LVEA was transitioned to Laser SAFE this morning.

Day's Activities:

• 8:30:  ETMx & ETMy charge measurements (Leonid)
• 9:00  Install a PCal Chassis at EX (Sudarshan)
• 9:15:  HAM6ISI balancing beginning (Hugh & Greg)
• 9:30:  OMC glass retrofit (Matt)
• 9:30:  Grabbing AUX Cart from EY and bringing back to LVEA (Gerardo)
• 10:03:  Cable swap for Low Noise ESD at EY to clear negatively-railed signals (Richard, TJ)
• 10:05-11:15:  Troubleshooting PEM channels in LVEA (Jordan)
• 12:55:  Pepsi truck
• 1:43:  HAM6 in-vac work complete (OMC work done, ISI balanced, and SUS's given clean bill of health)
• 2:10:  Final checks/inspection inside HAM6 (Hugh)
• 2:15:  Ring Heater check (Nutsinee)
• 3:00:  Bubba giving Rebolt a tour of piers/pylons/places to grout.

FRS web link added to CDS LHO home page

FRS is now linked from the CDS home page.

Issues with HAM5, probably caused HAM6 activities. Now with free (better) feedforward data.

I noticed this morning (through the Detchar pages, very sad that last nights SEI data isn't available) that the HAM5 ISI has not been doing well since about the time HAM6 vent activities started. Sadly this casts some doubt on the feedforward data I posted the other day, so I re-evaluated the performance at HAM4 while I was digging into HAM5. My first image shows the difference between HAM's 4 & 5 in the Y direction, all the other DOFs look similar. Second image shows the rotational dof's of HEPI L4C's on the two chambers, and HAM5 sees al lot more motion than HAM4 (dashed lines are HAM5, solid are HAM4). The translations are messier, (third image) but still seem to indicate more motion at HAM5. Hugh reports finding a few mechanical contacts at the chamber while he was working on HAM6, so I'll wait to panic about HAM5 until after that mess is cleaned up. Jeff is filing a report with FRS on this.

On to doing a better evaluation of RY feedforward on HAM'S : the fourth image shows the healthy HAM4 RY feed forward, dashed lines are off, solid are on. Fifth image shows that turning RY FF on has not spoiled the X performance.

Last two images show HAM4's Y and Z feedforward performance, with the same dashed/solid off/on convention.

Opened FRS ticket #3240.

FRS web page inaccessible from CDS workstations

Jeff, Dave, Jonathan, Ryan:

Jeff K noted that the FRS web service was inaccessible from LHO CDS workstations this afternoon. We raised this as FRS-3241. Jonathan H and Ryan B did some analysis on the problem and suspect it is an issue with LLO DNS when clients use  root-DNS. I opened a LLO GC fault ticket  FRS-3242 and closed out FRS-3241 Until a fix has been implemented, I have reconfigured the internal CDS DNS server to resolve the fed.ligo-la.caltech.edu address internally. This is just a short term fix.

WHAM6 Further Status Update

With purge on and both door covers open 2' outside of -Y door plane:  Dust counts all zeros!

While Matt was prepping to cut glass, Greg & I did the major rebalance of the ISI.

After Matt got the modified OMC shroud pieces reinstalled, Greg and I completed the ISI rebalance--I'll detail next.

Just before recovering the openings, -X of South Door:

100/0/100/0/200/100 counts for 0.3/0.5/0.7/1.0/2/5/ particals

Got the covers secured and free of the Optical Table with the purge turned down.  Jim made quick TFs (will log seperately) and they look fine.

Dan took over next and reports the OMC is still in good shape.

I've completed a thorough visual inspection and as-built of the new mass layout.

Thanks to GregG who spend nearly four hours in chamber.

new tables installed in computer users room

Our new tables for the computer users room were installed today. This required the power cycling of several CDS workstations.

OMC glass black shroud install complete

Matt H, Bubba G, Greg G, Jeff B, Calum T (remotely), Eddie Sanchez (remotely)

 

If you remember from yesterday with all the glass pieces of the OMC shroud in we had a cable interference with the shroud (see pic 2424).
 After playing with the cables the decision was made to pull the two interfering panels out so that the cables would hang free (see pic 2431). This however leaves the to now open and exposed (pic 2459). So after some discussion last night we decided to try to score and snap part of the black glass to stop the interference but also so that we could get the plate back in.

 

By looking side on (pic 2469) we could use the holes that the capture screws go in a s a guide to where the cables interfere with the black glass and how much glass we wanted to remove.

 

We decided to remove around 2.25 " (see plate mod pdf)...so it should hopefully look like "OMC3D" pic

 

With a brand new glass cutter we practiced on some test piece bits of black glass Calum had sent Betsy. The trick is to only do one 'score" with a light but even pressure, and then put the pressure over a raised surface (say a small diameter smooth rod), and then with gentle and even pressure that is spread out, push down and will get it to snap along the score.

 

Once happy with our technique, we went out and did it to the two real pieces. After of course the old carpenters trick of "measuring twice cutting once" :-) Worked like a charm. John W, gave us a small file (diamond tipped I think) to just gently bevel the edges a tiny bit to take off the sharp corners. That also worked really well. We then cleaned it by blowing it down with top gun, and then in area that snapped giving it a methanol rinse.

 

It went back in no problems at all. Its done.

 

Pic 2497.....before pic of one of the glass pieces to be cut

Pic 2498......after its been "modified"

Pic 2504...drying after methanol rinse. Thats the AR coated side you see

Pic 2506 & 2510.....The now complete OMC black glass shroud installed

EY ESD power cycled reset

Leonid needed the ESD for some measurments, so Corey and I reset the EX ESD the usual way (toggle H1:ISC-EXTRA_X_BO_4, then click HI on the medm). We couldn't do this with EY since it is the newer low noise ESD, but Jeff showed showed us the SUS_CUST_QUAD_BIO.adl screen and the big reset button.

This worked, kinda, but the driver was railed negative. Richard and I went down the EY to power cycle the driver and this seemed to solve the issue.

Added missing leap second to EY IRIG-B, set leap second pending on EY, EX, MSR IRIG-Bs

Dave Barker

The IRIG-B in EY only had 15 leap seconds set as of yesterday. I manually added an extra leap second at around 12:30 PST and set a pending leap second. Dave and I confirmed that all three operational IRIG-Bs have 16 current leap seconds as well as a leap second pending for June 30th.

Fri Morning Detector Meeting

Morning Meeting Notes

• SEI:  HAM6 re-balance
• Hartman:  No luck last night.  May work if have laser hazard
• HAM6:  Try to re-install top glass plates (which requires cutting some glass off of them first), then can hand over to Hugh for balancing.  Will need to transfer to Laser SAFE.
• VAC:  Need to crane cart over tube in LVEA
• Office furniture getting installed
• Outreach:  "Particle Fever" viewing with Landry/Dwyer talks on Sat.  Mike will also have a tour on Sunday

X2 Beam Tube pressure during washing

The beam tube washers are nearing completion on X2 and are currently near the X end station.

The plot shows 30 days of pt 523.

OMC black glass shroud and beam diverter move update

Daniel H, Matt H (and help at various times from Hugh, Greg G, Kiwamu, Sheila, others)

 

Todays events

So a  quick summary of todays work as too tired to write a detailed one sorry.

The in-vacuum cables were connected back onto the OMC and we confirmed we had signals etc. Also had a go at roughly moving the beam diverter to the position Keita/Dan hoped they could sqeeze it so as to not to have to move optics/SEI balance masses. We also had a look at trying to strain relieve the cables on the OMC that touch the OMC black glass shroud. But it looks like these are very touchy and altering these alter the balance.

 

Decided to analyse more with a laser beam.

 

Had troubles locking the mode cleaner. Apparently it was chased down to some whitening problem (something that last appeared around May 2014 I think I overheard). Once input mode cleaner locked and Dan had it set in a single bounce configuration,  The "M8" mirror (near the tiptilt and OMC shroud) was replaced (as was the additional black glass beam dump we had to remove for the OMC shroud install). The septum viewport protector was removed.  Dan was estatic (okay maybe he wasnt estatic but he was happy) that immediately saw signals. Looking at the OMC glass shroud and the beams though it looks like they go through very close to the center. Well done to Eddie Sanchez and the SYS team for all their hard work with the design to make sure they did.

 

We played more with the cables but in the end I decided to pull the trigger on removing the two upper black glass plates that r the cables that go to the glass bench are touching (it pained me to do so after all the hard work putting it in). Playing with the cables more we were able to get it to a point that Dan was "happy" with....(he would like it better if could but we decided we were at the point that perfection was the evil of good enough).

Note: we have it so that no offsets on the OMC like used to have

 

Then checked beam aligment out of OMC. As M8 didnt go back exaclty in the same spot, some of the optics had to be tweaked to re-establish the alignment. Also had to move a beam splitter as part of the beam diverter move. We chacked that both beam diverters still work in air. They did.

 

Also turned down purge air and did some TF's and they all passed (see attached).

 

Below is Dans much more succint summary......

 

Beam diverter was moved succesfully
90-10 BS was moved upstream of the second OMCR pico mirror; power on the QPDs has not changed (when the diverter is open)
Beam dump for 90-10 splitter was moved next to OMC SUS, should be out of the way

Alignment of OMCR path is good
Tested both beam diverters
Alignment into / out of OMC is excellent
Flashed OMC and saw the OMC TRANS beam out of the vacuum

OMC SUS TFs are good!

Purge air is on and OMC PZT HV is off.

 

Going forward tomorrow and still trying to get two bit of black glass back in

However not yet ready to hand over to Hugh for balancing. We are still actively investigating at how we can try to get both plates back in. After talking to Calum tonight he wants me to try putting at least one of the plates back in and taking some measurements to see how we might be able to modify the plates (ie maybe score and snap a bit off.......)

Also we should take TF's of tip tilts at some stage (after doors are on probably though).

 

Oh particle counts were basically all 0 in all locations (if not zero then had a reading of 10). Sorry am usually better at recording these details.

 

Pics:

2403...before pic of the OMC before shroud work started

2426...OMC black glass shroud installed

2424..the two cables on the OMC that interfere with the OMC black glass

2435...The OMC glass shroud with the two upper glass plates removed. It doesnt look as impressive :-(

2431 & 2434..how close the cables are to the peek support with glass removed.

2410 & 2412....beam diverter, V glass beam dumps (both), and beam splitter before move of beam diverter

2441 & 2442....playing wiht cables on OMC and checking alignment of beams into and out of OMC shroud

2445, 2449, 2451 & 2453.....the beam diverter, V balck glass dumps (ne for beam diverter and one for beam splitter) and beam splitter after beam diverter move

2454 & 2455...the "holes" in the OMC black glass shroud that the beams go in and out of

2457, 2460, 2461...the OMC black glass shroud from a different angle (with the two glass panels missing)

High acoustic coupling likely due to HAM6 ISI blade spring and suspension wire resonances; wire damping demonstrated

Summary: Frequencies excited by tapping HAM6 ISI flexures while it was vented match frequencies excited in DARM by external acoustic and shaker injections.  A prototype damping clamp damped the wire resonances. We suggest development of a permanent damping clamp for the ISI suspension wires and tuned dampers for the blade springs in the 350-450 and 850-1000 Hz bands.

Ambient acoustic sound produces noise in DARM that is only a factor of 2 below our current sensitivity in the 850-1000 Hz band and not much lower in the 350-450 Hz band and several higher frequency bands (Link).  We got a chance to study HAM6 during the vent that started last week.  It turned out to be difficult to excite and monitor the resonances that dominate in vacuum when we were vented. I believe that this is because the dominant vibration coupling path to the ISI table surface during a vent is acoustic and not through the flexures, as it is in vacuum.  External shakers did not produce peaks in the geophone signals that matched the peaks in DARM. I ended up attaching a small shaker magnetically to one of the blade springs, and monitored the frequency with an accelerometer mounted close to where the flexure attached to stage 2 (see photos in Figure1).

I thought at the outset that the high-acoustic coupling bands were likely associated with modes of the ISI flexure because they lined up with ISI resonance bands characteristic of all ISIs, and all external vibration would have to be funneled through these flexures to shake the table. Figure 2 shows that I excited a number of peaks in my in-vacuum accelerometer spectra by flicking one of the 3 ISI suspension wires (number 3). The evidence that it was the wire resonances and not some other resonances that I excited by flicking the wire is strengthened by the fact that these peaks were not evident when I damped the wire by clamping a piece of Viton to it. Since flicking amplitude is not well controlled, Figure 2 shows that I went back and forth several times between clamp-on and clamp-off states. Figure 3 shows that the lowest of the excited wire resonances, 753 Hz, matches the frequency of a peak in DARM that is excited by shaking HAM6 with a shaker. Note that the peak at this frequency is not the largest feature in DARM in this region, the feature between 850-100 Hz is larger, but, resonances of the wires do seem to account for the coupling at higher frequencies.  Figure 4, for example, shows that at least two of the high frequency resonances excited by flicking the wire line up with peaks in DARM that were excited acoustically. 

Figure 5 shows that tapping on the blade spring rather than the wire produces peaks that line up with acoustically excited peaks in DARM, including the largest acoustically excited peaks in the 850-1000 Hz band. I tried clamping a small piece of Viton to the blade spring and it was not nearly as successful as the wire damping (a factor of 2 at most). Possibly a larger piece would help, but I am inclined to suggest a tuned damper like the one for the low frequency blade spring mode.

Thus I would suggest that we develop a wire clamp damper like the prototype that I made to damp the wire modes, and that we develop tuned dampers for the 350-450 Hz band and, most importantly, for the 850-1000 Hz band.

Robert S., Hugh R., Katie Banowetz, Nutsinee K.

just adding the SEI tag so I don't loose the entry.

RY FF on HAM ISI's

In an email conversation Norna had asked what we could do to reduce motion on the HAM's in the RX/RY dofs at 25-35 hz. This morning I took a few measurements to design a FF filter. I've taken a first pass at it and I think I have something that works. Attached spectra are of the ground STS X and GS13s in RY the first png, then both sensors in X on the second plot. The live measurements are with FF on, references are from a quiet time last night, FF off.

The third attachment is a plot from the script I used to do the filter fit. Blue is the filter, green is the ideal fit from the St0 L4C's to the ISI GS13's, red is the fit from the HEPI L4C's to the ISI. The design approach is exactly the same as I talked about in my alog 18045.

That was quick! Looking good.
Thanks.

J. Kissel, J. Warner

Some additional information and/or a "current status:"
ISIs HAM2 and HAM3 do not have any ST0 / HEPI L4C feed-forward running.
ISIs HAM4 and HAM5 have Y, Z, and RY ST0 L4C (not HEPI L4C) feed-forward running.
(HAM6 is currently vented and the ISI and HEPI are locked.)

The HAM4 and HAM5 filters, for Y, Z, and RY live in FMs 2, 3, and 4 respectively. The gain for all DOFs on both HAMs is 0.5.

Norna's designing / modelling how adding blades between the HSTS's lowest stages will improve performance in the SUS's vertical displacement. The input motion for the SUS's suspension point in vertical is composed of the ISI's center of mass moving in Z, RX, and RY (see T1100617). She noticed from the results Jim posted (T1500289), that at 25-30 [Hz], the input V motion was dominated by RX / RY of the table. So, among other ways to improve the performance at these frequencies (see them discussed in SWG aLOG 11327), Jim tried improving the RY DOFs today -- and won!

Nice work, as always, Jim!