We have a short cut for front end code developers. On the h2build machine as user controls, if you type "core" it will send you to the /opt/rtcds/lho/h2/core/release directory. This directory is a symbolic link to the RCG version we are running H2 at, currently branch-2.3.
Here is a glimpse of the testing done on the ISI BSC8: Electronic, we changed: - 1 coil driver - 1 anti-image chassis - 1 sensor electronic board (and the sensor that goes with it) Instruments: - We replaced on coarse CPS sensor (and the electronic board). We stole two sets from unit2. Spares will be shipped from M.I.T in the coming days. - We had to open a GS13 can to adjust the 3 main springs holding the moving mass. This mass was resting at the bottom. We should receive replacement GS13 from LLO in about 2 weeks - There is a gain of 2 between the front panel and the back panel of the CPS satellite box. Software: - We had a couple of issues with watchdogs tripping when threshold were set up higher than the 2^15 bit (40K for instance). This problem might be coming from the decimation filters from the IOP to the model (64K to 4K). We will investigate later. - The Matlab transfer functions measurement program uses the decimate function (8 order Chebychev low pass filters at 0.8 x Nyquist frequency) to downsample the excitation signal. The decimation filters used to record signals on the frame builder have a corner frequency at ~0.7 x Nyquist frequency (with an order lower than 8). The Transfer functions are strongly affected over 700Hz for the geophones and 300Hz for the CPS. It will be fixed in the coming days. - In attachment, you will find a list the (101) channels recorded on the DAQ with their datarate. This list is the minimum required for testing and commissioning. The Overall datarate is 1.4MB/s. The allowed datarate is 2MB/s. Main results: - Stage1 is closed to a final balance - First resonance is at 215Hz on stage 1 (blades resonance? Need to be investigated) - First resonance is over 150 Hz on stage 2 (poor quality measurements at high frequency) I have attached few figures - The ISI with the cabling - Powerspectra of the sensors - Linearity test - Transfer functions (L2L main coupling)
B. Bland, J. Kissel, N. Roberston, T. Sadecki
As discussed yesterday, today in one last bit of effort to understand which the lowest pitch mode frequency is lower than expected, we flipped the M3 dummy mass upside-down, in efforts to change the height of the suspension point between M2 and M3 at that mass ("d4"). The solid works model predicted that this flip would increase d4 from 1 mm above the COM to 2 mm above the center of mass. However, recall from yesterday that a model that best fit the measured data showed that d4 was in fact ~0 +/- 0.1 mm, i.e. dead even with the center of mass.
The attached plot shows the results of the flipped M3. The result is that the pitch frequency did increase, but only by 0.01 Hz up to 0.47 Hz, as opposed to the expected 0.50 Hz. Hence, as with adjusting the M1 blade tip heights, the lowest pitch frequency moved quite a good deal less than expected. Further, a model matching the data shows that d4 had actually increased only from -0.1 mm (GREEN/PURPLE) to 0.4 mm (CYAN/GOLD), a 0.5 mm change, where a 1 mm change (from 1 mm (BLUE) to 2 mm (RED)) was expected.
This concludes our foray into investigating this particular mode, as achieving a 0.48 Hz lowest pitch mode (where the lowest longitudinal mode remains at 0.41 Hz) was a goal, not a requirement. Hence, we will settle for the first pitch mode being at 0.46 Hz, in which the M3 mass is returned right-side up, and the M1 blade tip heights are set to 23.6 mm from the M1 base plate, making that the new baseline.
Because we're going with a M1 lower blade tip height, we must now recalculate the appropriate wire lengths for the stages below M1, to restore the nominal heights of M2 and M2. We will do so, and remeasure the pitch frequency response to ensure that the lowest mode frequency remains *at least* above 0.46 Hz.
(Corey G, Jeff G, Jim W, Mike V)
Yesterday, we focused on subassemblies and getting them installed on the system.
Horizontal Small Actuators
All three of these were installed. A couple of notes:
1) The bolt on the "Base" (i.e. Magnet Mount) which is closest to the center of the ISI is really in a tough location to get a wrech at. Yoga poses are needed to tighten this bolt down (a torque wrench will not work back there).
2) The Actuator is pre-assembled with a Tooling Bracket which holes the coil & magnet in an ideal position. The magnet & coil sides are then carefully bolted down to Stage2 & Stage1 respectively. Coil/Magnet gaps are measured and then the Tooling is removed. Repeatedly, when the Tooling is removed, it was observed that the coil would drop on the order of 0.010-0.015"! Not sure what the trick is here to prevent this. For two of the Actuators this shift kept the gaps under the NO-GO value (we didn't want to have gaps over 0.115"). But on one, we had a gap of 0.118". This one had to be removed, Tooling re-attached, and then it was re-installed. With re-installation, this one fit in like a charm. It's gaps were balanced and no major shift was observed. It should be noted on this last Actuator that it's Pin Carrier Tooling were left in the Assembly during installation. perhaps this helped keeping things together.
3) It should also be noted that even with the Tooling, the Actuator gaps weren't always balanced (saw this with the Large Actuators). I thought this was the point of the Tooling! Is there a trick to putting these guys together. Perhaps keeping the Pin Carriers in place during the whole installation process is important.
Here are notes on biggest gap observed after Tooling removed (and also "before" gap measurements):
CORNER 1 Biggest gap (on top) = 0.111 (originally 0.098)
CORNER 2 Biggest gap (on top) = 0.118 (originally 0.109)
-----Reinstalled tooling and was balanced around 0.091"
CORNER 3 Biggest gap (on top) = 0.114 (originally 0.099)
Vertical Small Actuators
Just started installing one of these toward the end of the day. The Actuator Magnet Mounts (D0902191) were installed early, and it was noticed some of the bolts had somewhat tight fits into their helicoils. Perhaps these are electro-polished bolt candidates. Able to get the standard bolts to drop in by jiggling them a bit as you screwed them in.
Large & Small Lockers
The Small Lockers were installed with no issues. The Large Lockers were installed and then it was noticed that we blocked out access for the Spring Barrel Nuts(!). So, we had to remove all (3) Large Lockers, slip all Barrel Nuts into their holes, and then re-install the Lockers.
Locker Drawing Bolt NOTE:
So on the Assembly Drawings for both the Large (D1000854) & Small Lockers D(1000855), there are some items which aren't pointed out & are also just wrong. The issue we had were with bolts---the ones which bolt the Housing Locker Sleeve to the Stage/Plate above it (for both Lockers) and for the Large Lockers, the bolts which clamp Pin Caps down.
On the Large Actuators it is not pointed out which bolt should be used for the Pin Caps. By elimination, one would think it was the 3/8-16 x 1.5" bolts, BUT holes aren't tapped deep enough to take these bolts. So on BSC ISI#1, 1-3/8" bolts were used here. Unfortunately, the bolts used for Housing Locker Sleeves are also not pointed out in the drawing. By the process of elimination, we assume the 1-3/8" bolts were used here! (for both Large & Small Lockers).
So on BSC ISI#1, the 1-3/8" bolts were used for the Large/Small Sleeves & also on the Large Pin Caps. Unfortunately, we had a limited amount of these bolts and this left us short for BSC ISI#2! This is what we did for #2:
We saw for the Large/Small Housing Sleeves, that the 1-3/8" bolt provide LOTS of thread. We also saw that the 1-1/4" long bolt also provided plenty of thread as well. So, 1-1/4" bolts were used here for both Large/Small Lockers on BSCISI#2. Since the 1.5" bolt didn't work on the Large Locker Pin Cap, we put the 1-3/8" bolt here (as we did on #1).
Drawings changed to note this issue.
Temperatures in the LVEA have fallen dramatically overnight - average temps are ~60F. This is due to a broken wall temperature sensor which was sending back a reading of 256F - as a result the control system has been doing it's best to reduce that one zone temperature. I have disabled this sensor until it is repaired. Temps should begin to return to normal.
(G. Tellez, E. James, E. Black) Installation of the X-Y stage for the RX is complete. Both piers are in their final positions, leveled, and ready to be grouted. The laser (red, class II) was tested and the beam diameter will be measured to confirm the expected 2mm spot size. Telescope will not be used for test; opted to use commercial beam expander. A breakout box was built for preliminary tests of the QPD readout.
R. Lane, A. Ramirez Testing ITMY (QUAD 2) Took the Top Mass OSEM Coil Resistances, Photo Diode Voltages, and LED Voltages today. Took measurements at the connection between the octopus cables (D1000234) and the top mass extension cable. The OSEMS meet the requirements.* Coil Resistances: 39±1Ω PD Voltages: 1.01±0.05V LED Voltages: 0.53±0.05V Main Chain OSEM S/N Cable Coil(Ω) LED(V) PD(V) Face 1 481 695 36.3 1.017 0.554 Face 2 638 695 36.0 1.018 0.551 Face 3 501 695 36.4 1.018 0.558 Left 496 695 36.0 1.017 0.551 Right 499 698 36.5 1.018 0.558 Side 445 698 36.7 1.017 0.558 Reaction Chain OSEM S/N Cable Coil(Ω) LED(V) PD(V) Face 1 471 698 35.9 1.018 0.553 Face 2 484 698 36.4 1.018 0.554 Face 3 472 707 36.9 1.016 0.554 Left 630 707 36.8 1.017 0.562 Right 466 707 36.7 1.019 0.558 Side 415 707 36.0 1.018 0.559 *The requirement for the coil resistance to be 39±1Ω was defined at LLO using "extra long" non final cables. This requirement is not sufficient to determine if the resistance is within standard. I will inquire with the correct authorities to determine what the new value should be for the in-vacuum final cables. However, they do meet the tolerance of ±1Ω. We took the measurement at the octopus cable, not at the vacuum feed through simulator as specified. We did not have the cables available. Although this should not add more than a few tenths of an ohm to the final resistance and would not make up the difference.
The "M0 F2" OSEM now has a S/N 261. This is the current list on the H2 ITMY QUAD in the LVEA.
It turned out there was no dust monitor at MY to move.
Jonathan Berliner, Rolf Minton, Gerardo Moreno MichaelR (thanks!) tipped me off this morning that Pcal at MX was in the way of the upcoming BSC removal. RickS assigned me to remove the Pcal box. I conferred with DaniA and DougC about locks and tags that were there (none extant). JohnW was concerned about exposing the viewport window. Sure enough, the viewport window did not have a viewport protector (see photo), so I called GerardoM over to cover the exposed viewport. It truly was a 3-person job moving the support structure out due to weight and awkward shapes. New homes for parts: - Support structure - metal disposal by Big Red's parking spot - Clamps, bellows, and assembly - Vacuum shop - Pcal Box, bolts, fasteners, etc. - LSB Optics Lab. We blocked the opening of the box with a dump.
The SUS Team We've found welded repair plugs (by quick visual inspection) in the prism mounting holes of an M2/M3 metal mass (D080368) used in BSFM triple suspensions. See attached photos. Though we replace the lowest stage (M3) of the BSFM's metal mass with fused silica for final in-chamber suspensions, the M2 mass is identical to the M3 mass, and remains in the suspension. In addition, for the H2 OAC, we are to leave FMY's M3 as a metal mass. Two other masses have been checked for similarly visible repairs and none were found. Stay tuned for further details.
B. Bland, J. Kissel, R. Lane, J. O'Dell, N. Robertson, T. Sadecki As was mentioned in Monday's aLOG entry, in order to increase the lowest pitch frequency of the X1 SUS BSFM01, we lowered the M1 Blade Tip heights, such that the measurement between the M1 Base Plate and the Blade Tip break off point is 23.6 mm, (i.e. a d1 = nominal + 3 mm = 4 mm below the COM) as opposed to 26.6 mm ( a d1 = 1 mm below the COM). This *did* increase the pitch frequency, but not as much as predicted by the model -- The pitch frequency moved from 0.44 Hz to 0.46 Hz, where we expect from the model to be at 0.49 Hz. We are still confused as to why this is the case, and the attachment plots several models with the respect to the two measurements, adjusting parameters to try to explain the pitch transfer function. The conclusion is that, without redesign of the mechanical components of the suspension we cannot increase the lowest pitch frequency to more that 0.46 Hz, which is a reasonable 12% above from the first longitudinal mode at 0.41 Hz. We'll consult with other experts as to whether such a deviation from "requirements" is acceptable (though our first impression is that it is). ------------------------ The story (expanded legend) is as follows: BLUE - Nominal Model. This is what we expect the M1 P to P transfer function to look like. Note here, the lowest pitch mode is 0.488 Hz. This is what we *expect* a measurement to show if the blade tip heights are set to 26.6 mm, which the SolidWorks model claims sets d1 to the nominal 1 mm. PURPLE - 110620 Measurement, with the blade tip heights set to 26.6 mm. One immediately sees that the lowest pitch frequency is lower than expected, at 0.449 Hz. GREEN - Modified model, *decreasing* d1 by 3 mm, to 2mm above the center of mass. This implies a blade tip height of 29.6 mm. We see that this model nails the first pitch mode, though fails to precisely predict the upper two pitch modes. Since the 110620 measurement and model imply that the M1 blade tip heights are too high by 3 mm, we then lowered them by 3 mm, to 23.6 mm, ideally setting d1 back to the nominal 1 mm below the center of mass. YELLOW - 110621 Measurement, with the blade tip heights set to 23.6 mm. Here, we have increased the lowest pitch mode frequency to 0.461 Hz, and better matched the upper two frequencies to the nominal BLUE model. Confused as to why we didn't get all the way up to 0.48 Hz by adjusting d1 (the M1 blade tip heights), we began exploring other model parameters that might be different from nominal. Norna explored changing all of the d's: d0 - the suspension point to M1 connection at M1, d2 - the M1 to M2 connection at M2, d3 - the M2 to M3 connection at M2, and d4 - the M2 to M3 connection at M3. Note that in reality, only d1 may be adjusted "on the fly," to change the remaining d's would require new mechanical parts. However, varying d4 most accurately replicates what has been measured: RED - Modified model, *decreasing* d4 by 1 mm, to aligned with the center of mass (i.e. d4 = 0 mm). This model implies the prism height, with respect to the center of mass is incorrect. Joe took some physical measurements, and compared them against the solid works model and respective drawings, and while doing so discovered that the prisms (D080583) are version "F" when the production units should be at version "G". Although this needs to be fixed, the difference between version "F" and "G" is only in the distance to which it protrudes from the M3 mass, and therefore does not effect d4, and consequently would not effect the pitch mode. Interestingly, if we *increase* the nominal d4 by 1 mm (to 2 mm above the center of mass), the model predicts that we might get a much stiffer first pendulum mode, without effecting the frequency of the upper pitch modes: CYAN - Modified model, *increasing* d4 by 1 mm. This gets us a particularly stiff lowest pitch mode, without compromising the upper pitch mode frequencies. It turns out, that *flipping M3 upside down* (rotating 180 degrees about the transverse axis) will accomplish exactly this increase in d4, according to Joe's calculations using the SolidWorks model. Thus, in order to confirm that d4 effects this particular transfer function -- and to get another data point -- we will flip M3 over tomorrow (a reportedly simple task), and remeasure the pitch mode. We have no intention of making this change to the production units, as (we believe, though it has not yet been confirmed) it's too late to make such a change to the glass BSs and/or FMs, and given that the "requirements" for this particular mode are defined in away that is merely to get the first pitch mode away from the first longitudinal mode to simplify local damping. Stay tuned!! Note that we have strong evidence against two other "problems" (1) The modeled M1 blade spring stiffness is incorrect. We measured a separate M1's 4 blades, and their stiffness matches the model within the uncertainty of the measurement. See sub-entry to follow. (2) The trim mass distribution of M1 is unbalanced. Joe redistributed the trim mass to be more balanced, and a quick transfer function, and subsequent overnight spectra revealed no change in the lowest pitch frequency.
J. Kissel, J. O'Dell, R. Lane, T. Sadecki
In order to rule out a variant in the BSFM modelling, that might explain the unexpected results from X1 SUS BSFM01 pitch transfer functions, we quickly measured the vertical stiffness of 4 M1 blade springs on another assembled M1 mass. The model predicts a vertical blade spring stiffness of 1460 N/m, and the measured stiffness for each blade matches the model to within the measurements' uncertainty. This rules out the possibility that an error in the model's blade stiffness is causing the discrepancy between what has been measured and what is modelled.
Details
----------------
Measurement Setup (see second attachment): with a M1 mass dog clamped to an optical table, we loaded a single blade with the nominal weight of the lower stages experienced by a single blade. Then, we measured the displacement of the blade tip using a dial indicator after adding (and then removing) 50, 100, and 150 grams of trim mass to the load (and took the mean).
The Physics: It's always a good day when you can fall back on good 'ol Hooke's law, F = (-)k . x. We calculated the stiffness using
F = k x
m g = k x
k = m g / x
and calculated the uncertainty in stiffness, assuming a 0.002 in uncertainty in displacement, and that the uncertainty in force (and g) was negligible:
k = F / x
dk^2 = |dk/dF|^2 dF^2 + |dk/dx|^2 dx^2
(dF == 0)
dk^2 = |dk/dx|^2 dx^2
dk = |dk/dx| dx
( |dk/dx| = F / x^2 )
dk = (F / x^2) dx
where the displacement uncertainty came from a sticky dial indicator, and any addition force that it might have added (or prevented).
The ICC Crew today: Mark Layne, Zack Haux, Chris Soike We started the morning by inspecting the compressors with John W. and Michael L. The ICC crew had noticed moisture in the air hoses attached to the compressors. After checking the hoses and the filters, John was convinced that the moisture was water condensate and not a threat to our work. He did suggest blowing out the lines both before the beginning and end of work each day so that will be added to the procedure. John and Michael were in agreement that work should proceed. Tasks accomplished today -West beamtube dust barrier (iLIGO) installed -Gaps at the top of north and south dust barriers were filled in -Condition of chamber documented (pix) -Pre-work particulate samples taken -Particulate depletion samples taken -Soft dome cover removed and soft roof retracted -2 sections of the collar area cleaned -Soft door/dome covers re-installed -Hoses blown out at end of work -Materials consolidated to provide room for HAM 5/6 door lay-down
Leaving GV5 soft-closed
- Cleanroom moving to HAM5, bolts taken off north door by OMC TT1 - Quad 3 being moved to EY - Greg to break cement under HAM9 piers because aLIGO piers are slightly bigger than eLIGO piers - Squeezer electronics being moved to between HAM5 and HAM6 - Gregorio Tellez, Eric Black, and Eric James, inspect HEPI piers in LVEA - h2adcumy needs to be rebooted and it's MEDM needs to be fixed so that it shows red not black. Black is ambiguous. - Reibold, MikeL, MattE to EY for penetration and drilling. Vacuum cleaner brought to keep dust down - Kyle vents vertex and HAM6 - Deliver from Conway for Hugh to the warehouse - Oxarc delivery for Kyle - Small rodent found under Control Room big table during safety meeting. It crawled under the FMCS workstation and disappeared...it will return, no doubt. - SUS people working on test stand in the LVEA - LVEA is currently transitioning to laser hazard. Keita will lock mode cleaner (?) and Squeezers will work from there. - MattW will be leading efforts at the lab in EY. The phone extension there is x175 (posted on white board).
(Corey, Jeff, Jim, Mick V.)
Today consisted of lots of helicoiling and torquing. One team torqued down the Stage1 Close-Out Plate, while another team (mainly Jeff) worked on helicoiling the Top-Facing Keel Plate. Once the Stage1 Close Out Plate was torqued down some other Gussets and hardware were installed on the system (such as the Outer Upper Walls for Stage2.
The Bottom-Facing Keel Plate was installed on the system. Once the Top-facing Keel Plate was helicoiled, the day ended with us dropping this Keel Plate on it's respective plate. We now have all big plates on Assy#2!!
A background activity was building the Sensor Assemblies.
Sub-Assembly Status:
Jonathan and Dave.
We have installed ligo.org authentication on all the H2 CDS Workstations in the control room and the LVEA. In addition to the "controls" generic account, you may log in using your "albert.einstein" ligo.org account. Note if you dont already have a CDS account I will need to create your home directory before this will work for you.
Access to CDS from outside of CDS is still strictly controlled and is not ligo.org authenticated. If you need a remote access account, please contact me.
Please email Jonathan and myself if any problems are found with the new scheme.
(Corey, Eric, Jeff, Jim, Mick V.)
Stage2 Work
After part of Stage1 was put on the Optics Table, continued to build up Stage2. The Mid-Plate was installed, Upper Hex Assembly installed, and then we moved back to Stage1 work....
Stage1 Work
After the Stage2 Mid-Plate/Upper Hex Assembly was installed, the Stage1 Close-out Plate & Close-Out Plate Cover were installed (still need to put in bolts and torque the latter).
Subassembly Status
Misc.
Top-Facing Keel plate was put on the Granite Table (lots of helicoiling for it!)
Gerardo assisted- Dumped gate annulus then opened GV10. Dumped gate annulus then cycled GV18, cycled GV5, dumped all annulus volumes then cycled GV1, cycled IP1, IP2, IP3, IP4, and IP11.
(Corey, Eric, Fabrice, Greg, Jeff, Jim, Mitch, Myron, Sebastian, Vincent, et. al.)
It's been a while since progress has been posted, but tons of work has occurred; so here's a rough summary of the main assembly points of the last week or two.
BSC ISI#1
Notes: The L4C's & GS13's we recently received from LLO had noticeable dark powder/marks on them (believe this is the typical Aluminum Oxide we've seen before).
WHAT'S NEXT ON #1: Goal is to float the assembly today (which means tossing lots of mass on the Assembly!), and hopefully start some testing soon (Vincent could atleast play with the Horizontal GS13's)
Circuit Overload?
We have been overloading one of the electrical circuits in the Staging Building (noticed this when we hooked up Rai's helicoil machine and vacuum). When this circuit trips, it would shut every thing on this circuit down: including both the BSC/HAM Test Stand AND SUS Test Stand (!!!). Several times Vincent had to deal with losing all of his work and it would generally take a few hours to get everything back on-line.
I believe there are the two plugs which are on the wall with the circuit in question. Do not plug anything into these circuits which could overload the system (i.e. vacuum for example). Perhaps we should put up some signs, or tape over the plugs, or have some killer moths guard the plugs (more on them below).
BSC ISI#2
Roughly 75% done with helicoiling Optics Table
Staging parts for this assembly
Attack Of The Moths (& Tropical Temperatures)
Over the last month or so, we've noticed a deluge of moths within the cleanroom area of the Staging Building (attached is a photo of a pile of dead ones on the floor). They've been spotted inside and outside of our big cleanrooms (and we found a dead one on a large BSC plate under a cleanroom cloth cover!). This is just to note if we come across any questionable particulates.
On Monday it was downright tropical in the Staging Building (can't remember but it was in the mid to high 80s). John was able to give us tolerable temperatures by the afternoon (perhaps the moths like warm weather & learned how to futz with our thermostat!)
Shims Used For Locker Installation
(this is from email from Sebastian)
. Shim thickness for the lockers between stage0-1 (big lockers) :
Corner 1 : 0.127"
Corner 2 : 0.125"
Corner 3 : 0.127"
. Shim thickness for the lockers between stage1-2 (small lockers) :
Corner 1 : 0.126"
Corner 2 : 0.122"
Corner 3 : 0.130"