LVEA Laser Hazard

Apollo - Install HAM1 door
Hugh – End X to work on HEPI  

08:30 Keita transitioned LVEA to laser safe while Apollo crew installed the HAM1 door
09:45 Apollo finished installing HAM1 door
10:45 Keita transitioned the LVEA to laser hazard
11:00 Hugh & Mitch at End X to work on HEPI
11:50 Dave did a remote DAC recycle to pick up new Beckhoff channels

Merry Christmas to one and all

The photodiode amplifiers for the fiber transmitted and rejected beams were not behaving as expected. Changing the gain had seemingly no effect on the read voltage. The first problem was that the two diodes were crosswired in the slow controls system. However, this did not fix the problem, and it is the same for the IR DC power. It looks like the gain settings are not getting applied to the concentrator. The main suspects are the 5V supply, DC_6, in the end 2 chassis, or another of these DB37 cables with pin 19 conveniently left unconnected. This supply is used to power the binary IO terminals for auxiliary concentrator 5. It also controls the gain in the REFL PD DC path.

Combined volumes of HAM2, HAM3, YBM, BSC1, BSC2, BSC3, XBM now pumped by both YBM and XBM turbos backed by QDP80s

Andres R. & Jeff B.

   We suspended H1-SR2 with the metal dummy mass installed. Checked several of the critical measurements to make sure nothing was disturbed during the transport of the suspension to the LVEA. All measurements are within specifications. 

   We centered the BOSEMs and took a set of transfer functions for phase 1b testing.
 
   The TF plots are attached below. There is some noise below 1Hz. However, as we are going to swap out the bottom wires, the M3 mass, and rework the suspension anyway, spending much time tracking down and fixing this noise is not a high priority.     

I saw no sign of real work in BS M2 coil balancing, I had some time, no SUS person was around, so I started doing it manually.

Coil gains before/after the adjustment:

Seems like the balance was not that bad anyway. I removed funny overall factor of 1.23 as I and Jeff Kissel agreed last week.

It may not be a big deal depending on how HEPI is used but the Inductive Position Sensors are close to their limits.

With Keita applying -12000 somethings offsets in the Blend for Ry, V1 & V2 are close to 30k counts on the IPS.  I increased this to -13000 to check that we still had some headroom.  First attempt tripped as the IPS watchdog is set at 30000.  Why isn't this 32000?  I increased the trip level and went to -13000 again.  All the IPS moved in response and the spread in readings was around 10% of the change so it didn't seem any one actuator was stuck.  Looking at the Dial Indicators though, the SW corner (2) moved down 6 mils while the NE corner (4) went up only 1mil.  The other corners shift 3mils each.  The magnitude of the moves make sense, the DIs average 3.25mils & the IPS average 2.76mils.  But the IPS are much more uniform than the DIs...  Could the V4 be hitting a stop, hard to tell but it didn't look closer than the others.

While at -13000 Ry I checked the Actuators and they all looked pretty close to hitting their mechanical stops.

Removed the -13000 offset and checks the DIs & Actuators.  The actuators looked decently centered but the South side rebounded up more than the North side rebounded down by ~2x. There was also several mils of Rz displacement seen at the DIs.  Returned the -12000 offset an the IPS return to almost exactly where we started.

Couple things:

Much further actuation and possibly damping/isolation coud trigger the IPS watchdog with the current 30k limit.

Correcting the input matrix, installing the symmetrization filters and commissioning the loops would be good to get done.

I restarted the DAQ to accomplish two goals: install the latest Beckhoff slow channel configuration (including baffle pds and the return of EY) and reconnecting to the PSL Centroid channels.

I was successful with the former, not successful with the latter.

The PSL Centroid channels are still not connected, and the reason is there is no EPICS Gateway between the H1AUX and H1FE VLANS. I am not comfortable installing a brand new EPICS gateway on Christmas Eve afternoon, so I'll delay this install until later in the week when I am physically on site.

The number of slow channels the EDCU is acquiring went up from 19,311 to 21,328. Both of these numbers are 8 less that the total ini channel count due to the missing 8 centroid channels.

Yesterday Keita tilted the ETMx HEPI in -Ry to pitch the TMS system down to bring the ALS green beam down back at the ITMx.  Attached is a plot showing the tilt around 1pm Monday pst.  About an hour later, the SUS tripped triggering the ISI and HEPI.  We restored the HEPI tilt but did not restore the ISI.  It isn't that we forgot but we just didn't think it mattered.  However there are DC bias steering offsets on the ISI as well although these are much smaller than the HEPI tilts.  The second plot shows the changes in the ISI system with the watchdog tripped.

Couple things--this plot serves as a pretty good record for the steering offsets.

There is pretty significant off diagonal elements from the Ry tilting.  Why? Primary is probably the lack of symmetrization filters evenning out the actuator drives.  Also, so near the limits of IPS senssing (30/32), the actuators could actually be hitting mechanical stops.  The -12000 ct offset in the blend path calcs to a 0.9mrad tilt according to the incorrect IPS2CART matrix.  This is actually closer to 0.45mrads but at 2m distance to the Piers, the actuator and IPS are nearly railed.  This also gives ~0.17mrads Rx and 10urads Rz corrected.  The X Y Z values are correct at .1, .08, & .2um respectively.

Looking at the second plot showing the CPS LocationMons, when the ISI trips and the locations are free to go hang where they may, you see largest motions on Stage1 X, 70um; Stage2 X, 30um and the Ry numbers ~4urads.  There are some problems with the CPS matrices too but I think they are mostly sign errors.  Anyway it is interesting to see the ISI respond as you'd expect: Tilt the HEPI Ry and see the free hanging ISI tilt Ry and shift X, cool.  You might think the ISI would tilt as much as the HEPI but if these numbers are right you'd have to admit they do not.  Is that the stiffness of the flexures?  How does it impact the Isolation performance?

After Keita aligned ITMX (see 9071), I aligned the corner PRMI using ITMX as a reference. It is flashing now.

Sadly, I still don't see the POP beam either on HAM1 or ISCT1. Also, I looked at the POP penetration hole (swiss cheese baffle) with the camera at HAM3 spool, but no sign of a clipping or scattering was found.

The screenshot below is the current best alignment:

The alignment of the day:

• I restored the IM alignments back to that of the last week (alog 9016) because I needed the REFL beam for aligning PRM.
• I  centered the beam on PR2. I used a HAM2 spool camera to look at PR2.
  • Because IM4 was not able to bring the beam from an edge to another edge of the aperture on the scraper baffle, I offloaded the DC bias to IM3 both in pitch and yaw.
  • The centering was done by taking the middle point between points where I saw a bright scattering from the aperture of the scraper baffle.
• PRM was aligned such that the REFLAIR_A_LF was maxmiazed.
• I centered the beam on PR3 by steering PR2. I used a HAM3 spool camera to look at PR3.
  • By introducing a big misalignment in pitch, I could let the beam hit the lower earthquake stops. The horizontal alignment was adjusted to be the mid-point of the two earthquake stops.
  • The vertical alignment was done by taking the middle point of points where the beam illuminated either lower or upper side of the mirror edge (perhaps the cage).
• I steered PR3 until PRX flashed with ITMX untouched.
• I steered ITMY until PRY flashed.

Soft-closed GV7, valved-out IP5, valved-in XBM turbo -> Soft-closed GV20 (ran motor closed for 4 minutes and 16 seconds - until "squeek" of O-rings heard with ear pressed against valve body), valved-out IP12 valved-in X-end turbo

So, ETMx was aligned ~31 Oct, alog 8356.  Location monitor channels were not available until ~23 Nov.  Attached is a trend graph showing the HEPI IPS signals from the alignment time until the location monitor channels became available.  See alog 8504 why the shifts seen are not signifcant.

Second plot attached shows trends of the Location monitor channels to the present.  On Dec 5 the HEPI was locked, pump down of the chamber began ~11 Dec and the HEPI was unlocked on the 12th.  The lock period is in the middle of the graphs.  The lock/unlock times are apparent although pumpdown trends are hidden in the unlock.  The shifts in Rx & Ry since the alignment are the most worth noting with 40 to 60urads observed.  But don't worry, the input matrix values for these channels are 2x too large so the actual motion is 1/2 this.  We'll get those matrix values correct soon!  Further, the Rz matrix values is 4x too large so the 30urads recorded is really about 8urads.

So, with these two plots we can track the HEPI position back to alignment.  Sorry for not adding the value of telling you where we are now.  Not sure how useful that really is since pump down has distorted the floor therefore the piers corrupting the numbers.  When we correct the matrix values, I'll have to go through this again as well.

- Kyle, to LVEA, open GV7, and to X-End station, open GV20, see his aLOG.
- Kiwamu, to LVEA, to FIX PSL, working now.
- Jeff and Andres, to LVEA, work by HAM04 area.
- Daniel, to X-End station.
- Sprage was on site today.
- Keita, CR, working with GL, from the X-End to the corner.

In HAM2:

- by changing IM1 alignment, beam on IM2 moved about (0, -1.2mm), (pitch, yaw)

- by changing IM2 alignment, beam on IM3 moved about (-1.1mm, -1.8mm), (pitch, yaw)

- by changing IM3 alignment, beam on IM4 moved about (1.3mm, 0.3mm), (pitch, yaw)

None of these numbers themselves is large enough to be of concern.  

In HAM3:

- by changing IM3 alignment, beam on PR2 moved about (20mm, 4mm), (pitch, yaw)

- by changing IM4 alignment, beam on PR2 moved about (0, 18mm), (pitch, yaw)

Doug,Travis, Mark Barton
We ran into issues with the fiber profiler. We are unable to get the proper results and ended up with bogus numbers and graphs. Travis emailed Angus who had seen this similar problem before, but wasn't certain of the cause either. We ran 2 different programs and tested them with both new and old data sets yielding the same out come. Mark worked with us later in the day but found nothing obvious either. He will look at the programs, data base and spreadsheets tonight to continue to debugging. Rebooting the computer had its own problems as it took several tries to get it back online. We did manage to tweak the profiler mechanical alignment which allowed us to run continuous passes without having to stop and refocus several times.

In conclusion if Mark does not find an obvious problem we will wait until Jan to proceed. The puller is ready, just waiting for the profiler evaluations before the production run. The micrometer is fixed in place and alignment rechecked. I made up several more substrates and cleaned up some more clamp blocks and supports.
If Mark finds a fix we may hit it again tomorrow.

For the record, the following are the nominal values used for the large ion pump controllers (listed in the order queried by the MultiVac firmware Flow 7):  

Torr
Spare
7000V 
200mA 
200watt 
Protect
10mA 
STEP 
5000V 
1.0 x 10-3amps 
3000V 
4.0 x 10-5amps 
(StPt 1) 1.0 x 10-5torr (not used?) 
(StPt 2) 1.0 x 10-6torr (not used?) 
1.0 x 10-10 
1.7 x 10-9 
8.0 x 10-7 
2.0 x 10-4 

Summary: Green injection hits the center of ITMX, comes back to the center of ETMX, and then back again to the center of ITMX. The alignment is good, with one caveat that HEPI should be tilted significantly in  PIT to help TMS. Since EX PIT is unaffected by the HEPI, we're using EX sus bias to point it down by 330 urad.

1. Green beam from TMSX to ITMY

After Kyle opened the GVs we started scanning TMS to find the green beam on ITMX baffle diodes. Somehow PD4 amplifier was busted so we reconnected PD4 to PD3  amplifier.

At first TMSX was pointing up too much, and I had to give HEPI a PIT (RY) offset of -12000 counts to H1:HPI-ETMX_BLND_IPS_RY_OFFSET with a gain of 1. HEPI loops were all open, so that just gave a DC offset to the HEPI angle. After that treatment, we were able to maximize the output of three baffle diodes using the following offsets for TMS bias:

See E1300634, figures 12 and 13, for the diode layout. PD1 and PD4 are two diagonal ones around the baffle hole, PD2 and PD3 are far from the mirror. "Center" is the mean of PD1 and PD4 and should be close to the real center of the optic.

Baffle diode channel names are H1:AOS-ITMX_BAFFLEPD_1_POWER etc., but they are not trended as of now. Also note that H1:AOS-ITMX_BAFFLEPD_3_POWER is actually reading PD4.

Transimpedance for the PDs were set to 20 kOhm, and when maximized the outputs were about 2.5V for PD2 and PD3, and about 2.3V for PD1.