J. Garcia, J. Kissel, S. Steplewski

Tuesday's measurements showed severe cross coupling on the Main Chain, and only two vertical modes (where there should be three) on the reaction chain. Brett and Mark subsequently modeled that the R0 UIM and R0 PUM were moving as one, and Travis went in and found (a) that the M0 BOSEMs were all wonky, and (2) that the R0 UIM blade stops were locked. 

Since then, Travis has unlocked the R0 UIM blades, and re-aligned the M0 BOSEMs, and Jeff has remeasured all TFs. The results are attached. In summary, M0 (though the measurement was taken with damping loops ON*) looks good**; R0 still has some rubbing (likely at or near the top stage*** -- maybe the UIM blade stop was backed off too far and is contacting TOP to UIM SUS wires?), and its cables appear to be adding stiffness****.

Jeff, Szymon, and Travis are going in to investigate further as I write the aLOG update...  

Details / Further Explanation
-----------------------------
* The M0 TFs were taken with damping loops ON, simply because of a failed automated hand off between HEPI measurements and SUS Measurements. Nominally, we want to set up a system similar to the BSC-ISI and SUS, where there's an EPICs variable reserved for indicating "measurement ON" and "measurement OFF" that automated Matlab TF scripts would turn on and off appropriately. Unfortunately, for the HEPI / QUAD trade off that Vincent / Garcia tried last night, either the variable wasn't there yet, HEPI's automated scripts were set up to turn the EPICs variable or the SUS damping loops on/off, the QUAD script wasn't watching it to take the appropriate action, or something (I couldn't quite tell what happened from Garcia's description) because things were set up a little bit too quickly. So, the damping loops for the QUAD (required during the HEPI TF) were left ON after the HEPI TF had finished during the M0 TFs, but were turned OFF by the automated script by the time R0 TFs rolled around. No big deal, there's a first time for everything with these automated scripts, and it never works out the first time. Garcia's gunna make sure that either he gets the chamber for the evening, or the automation works better this time.

** Looking at pages 1 through 6 of the attachment comparing current to previous should-be-the-same measurements, you can see 
- If you by-eye undamp the transfer functions, you can see that "everything seems to be in the right place" compared with the previous measurements
- The cross coupling that was in the 2012-05-07 measurement looks to be gone
- We're inconsistently damping each degree of freedom; some way overdamped (P), and some poorly damped (e.g. L)
So, we say we think the dynamics look good from this eyeballing, but we know that damping signifcantly reduced cross-coupling, so we really need an undamped measurement to really confirm the dynamics are OK.

*** Pgs 7 to 12 show the reaction chain. As far as "rubbing at the top stage" I see that the data for low frequency modes of R, T, and V are low Q and noisy which we've found from experience usually means rubbing. Because the rubbing appears to be affecting only the low frequency modes, we know that the rubbing should be localized to the upper stages. (Remember: for low frequency modes, the QUAD masses are swinging as one, so the "pivot" for these mode will be high up in the suspension; for high frequency modes, the dynamics are more complicated, involving differential motion between the masses, so the dynamics involve the lower stages).

**** Pg 11 shows the P to P TF, and specifically that the large, second Pitch mode is stiffer that previous measurements. From past experience, we know that this mode is easily affected by cable stiffness (the higher the frequency of the mode, the stiff the cables are). We also know from past experience that we can arrange the cables in such a way that we can get the Pitch TF to be consistent between suspensions. We also also know that something has happened to the cable arrangement between the 2012-05-07 measurement and last night's measurement that has stiffened up the cabling. So, we should look at the cable arrangement again.

The control path takes input error signals from the CM PDH and PHASE servos, IMON, FMON, SMON.  These go into an input matrix, through an ARM_LONG filter, and then out to ETM_LONG control output.  In h2iscey, the ETM_LONG output is routed to the RFM sender to ETMY via h2susetmy.

I also added input filter modules for the other PD inputs (PDH_DC, {IR,GR,BB_PWR_MON).

h2iscey was recompiled, installed, and restarted.  The daq was also restarted to register the new channels.

I also updated the OAF medm screen to add links to the new filter modules.

Measurements have completed on H2 SUS ITMY as of ~10:30AM PST.

The following RFM senders (library part cdsIPCx_RFM) are now in h2iscey:

H2:ISCEY-SUSTMSY_PIT
H2:ISCEY-SUSTMSY_YAW
H2:ISCEY-SUSETMY_LONG
H2:ISCEY-SUSETMY_PIT
H2:ISCEY-SUSETMY_YAW

I have also added the corresponding receivers to h2sustmsy and h2susetmy.

All models have been recompiled, installed, and restarted.  I have tested the connections, by applying offsets to the filter modules that output to the senders, and the connections seem to be working fine.

I have left the outputs and inputs to the filter modules that connect to the RFM senders and receivers off for now.  The input to the H2:ISCEY-SUSETMY_LONG sender is just a constant at the moment (value = 666), since there is no control signal for that output yet.  That will likely be added today.

I note, since I forgot, the receivers need to have their inputs grounded to indicate they are receivers. Otherwise the model will fail to compile.  Similarly, you can not ground the input on a sender or it will be interpreted by the RCG as a sender.  If the input to the receiver needs to be set to a specific value the Simulink "constant" part can be used.

(corey, eric, jim)

Stage1

All the walls were torqued, 60deg Brackets installed, and Flexure Posts installed.  A shim was used to check for any gaps.  Lockers were installed under Stage1. 

Stage1 on Stage0

Stage1 was craned on to Stage0.  Lockers were torqued down on to Stage0.

Springs & Optics Table

Flexures were built and Springs were pulled down (with Spring Safety hardware in place). 

The Optics Table was inspected for any loose tangs or tangs which needed to be removed.

Next up:  Installing the Optics Table

- HAM3 cleaning and then septum installation
- BSC8's IOP was crashing intermittently
- Travis at BSC8 intermittently
- TF's at BSC8 at the end of the day
- DAQ rebooted several times
- People working in BSC6. Watchdogs going off frequently.
- OSB doors locked at ~4:00pm

H1: finished install of H1 PSL DBB TEST model. Later this was replaced by the actual DBB model and the ISS TEST model was activated. Work continues on the new PSL user account, specifically with regards to file sharing with the controls account. Start of DBB testing was delayed by the default-off behavior of the filter modules.

H2: New PEM models were installed on h2peml0 and h2pemey to conform to the new naming scheme.

Alignment of the main green path was mostly done.

We'll do the HWS pickoff path tomorrow.

Some serious problem for the red QPD and picomotors. Detailed alog to follow.

I've added the RFM inputs from h2iscey to the h2susetmy and h2sustmsy models.  These are the control inputs for ISC PIT and YAW.

I have not recompiled, installed, or restarted these models yet.  I will do so first thing tomorrow morning.

Looked at cabling coming from Red QPD (chamber) to QPD Transimpedance Amplifier Chassis D1002481(rack). Used voltmeter to do a diode measurement across QPD1 (four segments) and QPD2 (four segments). Was expecting to see around 0.6V for the forward voltage drop across the diodes. Did not see any voltage drop on cable ISC-BSC6-1. Performed test on cable ISC-BSC6-2 (green QPD) and saw the expected 0.6V across the diodes. Next we swapped ISC-BSC6-1 and ISC-BSC6-2 at the chamber vacuum feedthru. Retested at rack side, and cable 1 tested good, cable 2 did not pass. We had also noticed 
cable 1 had a short from Pin 13 (GND) and Pin 16. Reverified at chamber side.

The crew returned to In-Chamber Cleaning at BSC3 today after being pulled to work on viewport and feedthrough installations at HAM1-2-3 yesterday. Wipe down and second vacuum were completed by the end of the day. Tomorrow we'll do close-out work, including FTIR samples and inspection.

The west door was removed from HAM3 and held on the forklift boom while the following activities took place: pre-work wipe of chamber floor (which showed the expected black oxide), septum blank install, and fit check/install of modified HAM spacers. (*Note: The septum blank and spacers were NOT torqued down.) The door was returned to the chamber and the bolts were torqued and tightened. HAM3 should be ready for pumpdown. The cleanroom will be moved to HAM1 tomorrow so that the ion pump can be installed.

The assembly validation testing report for HAM-ISI Unit #5 is posted under the DCC for validation.

Reports regading the previous units tested/validated (Phase I) at LHO are also available on the DCC:

HAM-ISI Unit #1
HAM-ISI Unit #2
HAM-ISI Unit #3
HAM-ISI Unit #4

While the crew had the HAM3 door off and were installing the Septum Window Cover, they also installed the HAM ISI Spacer (type for WHAMs 2 & 3) D1101180-v2 Type 00.  They used the 5" long ISI-through-spacer-to-Support-Tube bolts to constrain the position while bolting down the Spacers to the Support Tubes (Separate 3" bolts.)  The 5" bolts were then removed.

Thanks to Mark, Scott, Slim and the Devil Dog.

PSL installation team

Injection locking:
We injection locked the oscillator. 
Total output power without corona aperture in place: 210 W
Total output power with corona aperture mount in place: 204 W
No measurement with corona aperture in place.
We lert the system running over night with power watchdogs turned on.

Other work in LAE:
Alignment of optical components on optical table: ongoing

Other:
Work on purple cable pulling / electronics: ongoing

This one is a no-brainer.

The emails of the log posts (L-mail) would be much more convenient if they actually just included the contents of the log post directly in the message.  One could just read the posts in their mail without having to click through.  So nice.

Furthermore, the emails subject lines should just be the title of the log post.  That way you could see if the post is relevant to you without even having to open the mail.

Links to the posts could of course still be provided in the message to provide direct access to the post for viewing images, etc.

B. Bland, J. Kissel

The results from the overnight TFs that Betsy started last night are attached. The lame news: the SUS is not yet ready for chamber close up. However, over the phone, Betsy informs me that more items on/around the suspended elements have changed and some other tweaking occurred today since the measurement and more will change tomorrow. Though this set of TFs is informative academically, we have to wait until we're "done" with mechanical stuff before a "final" close out measurement (which will hopefully show a clean bill of health).

From what we can [remember / piece back together / guess], the state of the chamber is:

- HEPI Floating, but OFF
- BSC-ISI Floating, but OFF
- QUAD
    - Free, OFF
    - One-off, wire loop, prisms, and glass optic main chain; Production ThinCP fully laced
    - EQ stops brought into 0.75 mm gap
    - One set of ECD magnets is removed (Betsy doesn't recall exactly which, but we think lower cluster below M0 F3)


Here's what I see, and what I think is going on:

Main Chain
Although the diagonal TFs (LtoL, TtoT, etc.) look OK, its obvious from the off-diagonal terms that there's a serious amount of cross coupling (see 2012-05-07_H2SUSITMY_M0_ALL_TFs.pdf). My guess is that this is because of the missing weight from the absent ECD magnet cluster. As mentioned in G1100865, pg 4, one of the possible VtoP / PtoV cross coupling mechanism is a static offset in pitch. The fact that PtoP looks "clean" (though a little bit low in overall magnitude), and both VtoV and RtoR show the 2nd pitch mode, my guess is that the missing ECD magnet cluster brought whichever corner of the mass up, creating both a static roll and pitch in the mass, causing the exact cross coupling described in G1100865.

We should get that ECD magnet back on there, do any other final tooling additions and removals, and measure again.

I use the "wire" model for this one-off, wire loop, prisms, and glass optic main chain, and it seems to predict it pretty well. In allquads_120507_H2SUSITMY_ALL_TFs.pdf I compare it against other metal mass wire SUS, and other than the cross-coupling mentioned about, and slightly less magnitude, it matches up pretty well. 

Reaction Chain
Here, the VtoV transfer function shows something new, fun, and bad. Notice there's only two resonances? My gut reaction, is that the lower two modes have shifted up in frequency due to increased stiffness, and the lower two masses are stiffened to the point on moving as one; cabling's the only thing I can think of off-hand. Either that or something's interfering with the lower blades. Remember, the higher frequency the resonance, the more it involves lower stages. Also, because other modes, and other degrees of freedom show little to no reduction in Q, implies that whatever's stiffening up the vertical DOF, likely isn't at the top stage. Looks like the high-frequency Roll / Trans modes have changed shape too, likely due to the same vertical stiffness issues.

I'd check around the blades, and re-assess cabling on this one.