ops

ETMx ISI Alignment changed

St1 Before	St1 After	St2 Before	St2 After
X 6959nm	41458	-9643	2702
Y 8935nm	9155	253	478
Z -22709nm	-22563	-10660	-10743
Rx 39467nrad	39195	10198	10083
Ry -7904nrad	-5523	5845	7101
Rz 19481nrad	20104	4123	4482

To help make the isolation of the ETMx less troublesome, this morning I reset the ETMX ISI position loop alignment targets to the tilted location.  This way the ISI will not drive back to the untilted position putting larger outputs on the ISI and reliably running up the trilliums, tripping the WDs.  If the local to cart matrices are somewhat correct, the position/alignment change is small & so far OK.  Adding theStage1 & Stage2 cart position changes gives a 46um position shift of the ISI Optical Table with <4urads on the Ry.  All the other dofs combine to 1um or 1 urad or less.  Sheila did spend some time realigning but the ITM wasn't in nominal isolation either so that might have been hampering efforts there.  Once the ITM was Isolated properly, the green locked much better.

So above is the before and afters.

Wiggling cables at ITMx CPS

From ~1400 to 1440--moving ladders, wiggling cables, general trouble making.

ETMy OL values

Betsy swapped all the BOSEMs and AOSEMs on ETMy and left them retracted for open light measurements. The resulting values with gains and offsets are:

prettyOSEMgains('H1','ETMY')

M0F1 30218 0.993 -15109
M0F2 29922 1.003 -14961
M0F3 29480 1.018 -14740
M0LF 31134 0.964 -15567
M0RT 30792 0.974 -15396
M0SD 31110 0.964 -15555
R0F1 31059 0.966 -15529
R0F2 30058 0.998 -15029
R0F3 29953 1.002 -14977
R0LF 30794 0.974 -15397
R0RT 31050 0.966 -15525
R0SD 30282 0.991 -15141
L1UL 29222 1.027 -14611
L1LL 30117 0.996 -15059
L1UR 25735 1.166 -12868
L1LR 22721 1.320 -11361
L2UL 21334 1.406 -10667
L2LL 24582 1.220 -12291
L2UR 21223 1.414 -10612
L2LR 20325 1.476 -10163

I entered the gains, checked that all the outputs were right (should be 15000*0.023333=350) and redid the safe.snap.

 

EX PDH Measurements

(Sheila, Alexa)

We made a few measurements at EX under the following configuration:

PLL Servo Board

• Input 1 pol: NEG
• Input 1 gain: 0dB
• Comm Comp: ON
• Generic Filter: ON
• Fast Option: ON
• Fast gain: -8dB
• Boost 1: OFF
• rest off

PDH Servo Board

• Input 1 pol: POS
• Input  1 gain: -1dB (this was adjusted due to the new modulation depth change...we inserted a 12dB attenuator...see alog 9466. The optical gain must be adjusted accordingly)
• Boost 1: ON
• Comm Comp: ON
• rest off

1. PDH open loop transfer function (EX_PDH_OpenLoopTF_mag/phase.TXT)
2. To calculate the arm cavity length we zoomed in around the FSR resonance (~37MHz) and took the open loop TF (EX_PDH_OpenLoopTF_mag/phase_zoom.TXT). We found FSR ~ 37.752 kHz, which gives a crude estimate of L~3970.6m for the arm cavity length.
3. PDH error signal power spectrum (EX_PDH_Noise.TXT, EX_PDH_Noise_High.TXT, EX_PDH_Noise_Low.TXT). When plotting the power spectrum at full span we noticed a lot of variation in the measurement (we tried to collect the high and low spectrum in this variation). This variation is due to an unstable cavity lock which causes a variation in the optical gain.
4. PDH shot noise (EX_PDH_ShotNoise.TXT)

PSL Change

Kiwamu is transitioning the H1 PSL from commissioning to science mode.

ETMX ISI running fine.

Stefan logged yesterday that he was unable to get the ISI into operation state without tripping.

First time I did this today, I did Stage2 one dof at a time and had no problem.  The ETMx blends at 750mHz on both Stages all dofs.  Pretty sure this isn't as well as can be squeaked from the ISI.  I took this opportunity to take spectra as I brought other blend filters to bare.  Attached is the Stage2 GS-13 X In1 with various filter combos.

Ref3, red: As found 750mHz all dofs both Stages.

Ref7, blue: T(rilliums)750mHz all dofs Stage1, 750mHz Stage2---Maybe a factor of 2 improvement below 0.5Hz

Ref11, green: T250mHz all dofs Stage1, 750mHz Stage2---Much better above 0.5Hz but worse between ~.1 and 0.5Hz.

Ref15,thick brown: T100mHz.44NO Stage1 X Y & Rz else T250s, Stage2 750mHz---Big win below 1Hz to about 0.1Hz.

Ref18, pink:T100mHz.44NO Stage1 X Y & Rz else T250s, Stage2 250mHz---Better ~x2 or 4 above 0.8 but worse below especially 0.2Hz.

Ref23, aqua: T100mHz.44NO Stage1 X Y & Rz plus Notch X Y else T250s, Stage2 750mHz---Lost improvement above 0.8Hz but improves over brown between 0.8 and 0.2Hz.

Ref28, black: T100mHz.44NO Stage1 X Y & Rz plus Notch X Y else T750s, Stage2 750mHz---Some improvements below 0.2Hz and some above 1Hz.

I'm not sure this is exactly the best configuration such as maybe the T250 is better than the T750 for both Stages.  Certainly incrementally there were tradeoffs.  We need to combine the benefits in a better way.

So I have the ISI in this final arrangement. I took the ISI out of Isolation (it triggered then!)  I then reset the ISI targets to the unisolated postions.  The ISI was then able to go into Isolation with 'One Button'.  Green team is evaluating if they can live with this minor alignment change.

ops

Sheila to EX

Commissioning calendar for next 2 weeks

Here is the list of commissioning task for the next 7-14 days:

Green team:

1. Measure difference between red and green locking offsets.
2. Commission the common mode hand-off including the AO path.
3. Make an exact measurement of the cavity length.
4. Complete the noise model for ALS X by adding PDH and COMM servos.
5. Commission a relief script for the angular offsets in the initial alignment controls.
6. Commission the length feedback path to the ETM top suspension point to suppress microseism.
7. Asses the status of the reference cavity temperature controls.

Red team:

1. Angular decoupling optimization for PR2 and PRM.
2. Lock the PRMI using 1f and 5f signals.
3. Lock the PRMI using the 3f signals.
4. Arm cavity alignment for the red beam.
5. Mode matching measurements using ISCT1 and maybe IOT2R.
6. Mode cleaner characterization: Absorption, heating and scattering.
7. Track down the 0.5 Hz feature in the seismic isolation system.
8. Investigate the REFLAIR45 whitening filter issue.

TMS:

1. Repair and exchange the in-vacuum cable for the beam diverter.

ISCTEY (starting next week):

1. Complete the feedthrough panels.
2. Install the on table cabling.
3. Prepare for move to the end station.
4. Check out ALS electronics in EY.

~1000 hrs. local stopped pumping Y-end dewar vacuum jacket -> ~1030 hrs. local started pumping CS CP1 dewar vacuum jacket

Another round of TF measurements on PRM and PR2

Stefan , Kiwamu

The following TFs are now being measured.

• PRM
  • M3 L to PY
  • M3 P to PY (automatically starts after the L to PY finishes)
  • M3 Y to PY (automatically starts after the P to PY finishes)
• PR2
  • M3 P to PY
  • M3 Y to PY (automatically starts after the P to PY finishes)

All of them runs on opsws5. They started at 10:20 am local.

Views of and from ITMX, its compensation plate, the BS, PR3, PR2, PRM, and MC1,2, and 3 for scatter evaluation

Summary: A camera with a flash right beside the lens was used to look for potential backscatter noise sites. Most baffles look good, and there was only one strong backscatter site within the arm cavities: the large gate valve seats by the ITMs.  There were also a few retro-reflective sites outside the arm cavities: for the compensation plates, the HAM3 ISI, and the supports for the elliptical baffles and the TCS mirror 2 were quite retro-reflective. As an aside, I also noticed that the TCS alignment port was partially blocked by a nozzle. In the lower sensitivity input arm, the MCA1 and 2 baffles had bright reflections, as did the HAM3 ISI.

ITMX. In Figure 1, the top image shows approximately what the beam spot on ITMX “sees”. I use these photos to look for potential scattering problems; the camera is placed very close to the center of the optic where the beam spot will be. The flash mimics the wide-angle scattering of interferometer light from the beam spot and lights up regions that will retro-reflect interferometer light back to the beam spot, where it can recombine with the main beam to produce scattering noise. Of course the technique is limited by different angular distributions of scattered IFO light and light from the flash, as well as by color differences, but it gives a rough idea and also shows glints, which are hard to predict. The camera is about 10 cm in front of ITMX, so it sees a little more through the hole in the baffle than the beam spot on the optic will. Nevertheless I expect that the baffle will not block the view of the gate valve seat, the shiny reflecting arc at the right of the view through the baffle aperture. This is the only site found in the high-intensity arm cavities. I think the first step is to double check that the valve seats are actually visible from the ITM beam spots.

The lower image in Figure 1 is the view from the X-manifold spool of ITMX, with the camera located in the IFO beam path (the camera is in the beam path when the flash retro-reflects off of the optic). The arm cavity baffle looks good: the small reflecting rectangle at the bottom center of the baffle is the connection for the safety lanyard and is actually under the bottom side of the baffle and thus should be outside the clear aperture from ETMX. It looks like it is inside the baffle because the far part of the baffle box sags down a little and we are seeing a little of the underside of the baffle.

ITMX RM (compensation plate).Figure 2 shows the view from the beam spot on the compensation plate (the reaction mass). There are strong retro-reflections from the HAM3 ISI. The glints are off of stage 1 of the ISI so there is some isolation of the reflecting surface. There are also glints off of the elliptical baffle, which has one stage of passive isolation like the ISI, and also off of the mount for TCS mirror 2, which is not seismically isolated.

The view in TCS mirror 2 (the copper-colored circle), shows that the TCS alignment port is partially blocked by the nozzle of the port. Thus there is not a complete view of the compensation plate from all parts of the port, which may make alignment more difficult. We also need to watch for backscatter sources on the TCS table.

BS.The first page of views from the beam splitter, Figure 3,  show bright reflections from the frames of the ITMs. I have reported this before (Link) and Mike Smith’s subsequent calculations suggested this would not be a problem, though I don’t think that specular reflection was considered.

Another potential source of retro-reflections to the spot on the BS are the reduction flanges for the tubes holding the gate valves between BSC1 & 8 and BSC3 & 7.

The second page of BS views shows the view back out the input arm. As with the view from the ITMX compensation plate, there are particularly bright glints from the HAM3 ISI (notice the beams of light shining on the floor of the tube), including one from the table edge, just a few centimeters below the path to/from PR3.

PR3. Figure 4; looking toward the BS, there are fairly strong reflections from the electro-polished aluminum baffle, MCA1, as well as from masses on the HAM3 tabletop.

PR2.The worst reflection in Figure 5 seems to be from the edge of the MCA2 baffle.

PRM.  Figure 6 shows a fairly bright reflection from the MCA1 baffle, a wide-angle reflection from the circular baffle, and reflections from objects on the HAM3 table.

MC1 & 3. Figure 7 shows that the MCA1 baffle again seems quite reflective and that there are also reflections from objects on the HAM3 table.

MC2. The reflection from the MCA1 electro-polished surface in Figure 8 does not appear as bad from this side, possibly because of the greater distance.

not able to engage ETMX ISI

When I came in today, the arm was unlocked. For some reason the tidal relieve to HPI ETMX was still integrating. When I cleared its history, all watchdogs on ETMX, its ISI and HPI tripped. 

HPI and SUS were easy to recover. When trying to re-engage state 1 for ISI stage 1 though, the ISI consistently tripped when trying to move it to the final alignment biases.

ALS CARM handoff successful - no additive offset path yet.

Daniel, Stefan

With the PLL running reliably, I successfully handed off the mode cleaner control to the ALS COMM signal.

 - I copied all old HIFOY scripts in /als/h1/scripts/ into /als/h1/scripts/HIFOY_safe
 - I updated the CARM_down script and started working on the CARM_handoff script.
 - The initial part of the CARM_handoff script ran fine, and I was able to turn off the MC feed-back to MC2.
 - The CARM loop before engaging the AO path has a UGF of 20Hz - rather low, and the phase margin is questionable (0deg margin at 100Hz)
 - Then I noticed that CARM FM6 was an outdated filter, which needed to be updated for the new PLL. I added FM10 "shape", which is a z1.4:p1000 with the gain matching the previous filters FM6 and FM7.
   This effectively got rid of a p40:z7k - a filter that we now have in analog in the PLL. With that I increased the UGF to 90Hz.
 - I tried ramping up the AO path, but always lost it before I was able to measure the OLG. More work to be done there.



Updates to the CARM_down and CARM_handoff scripts:
 - The MC2_M3_ISCINF_L FM6 used to be a z150:p500 lead filter for extending the actuation lead to 500Hz. I restored it.
 - We are now using H1:SUS-MC2_M3_LOCK_L FM9 instead of FM8. I adapted the scripts
 - Use CARM FM10 instead of FM6 and FM7.
 - I took all ARM HEPI feed-back engaging out of the script - that is handled by the ALS at the end station.
 - I took any reference to RFAIR_9 out of the down script.

Comm PLL work today

Sheila, Daniel, Stefan

I tuned up the beat note alignment this morning. 

With the arm locked we have 88uW total on the COMM_A_LF detector, 42uW from the arm and 47uW from the SHG.  This gives us a beatnote of 28mV pp, with the PFD RF power readback saying -35dBm. 

The Comm PLL locks for a few seconds and runs out of range (due to fluctuations at the microseism frequency).  One solution would be to feedback to the ETM  from the green laser at the microseim frequency ( right now we only have very low frequency feedback to HEPI), this would probably be nice in the end, because the PLL would lock nicely and we need to figure out out how to do this for HIFOXY anyway.  Another solution would be to engage COMM with the PLL partially locking, which does still give a useable error signal, which would be quicker to implement.

Dipelxers for REFL 3f and AS 2f installed

[Koji Yuta]

On Friday afternoon, an RF amplifier unit with 3f (27/135MHz) diplexer (D1300989) and a 4ch demodulator unit
with 2f (18/90MHz) diplexer mod (E1300899) were installed to R2U27 and R3U8, respectively.

- The RF diplexer amplifier D1300989 S1400079

The module was fixed at U27 of the R2 rack and cabled up. Test signals were applied from an RF signal source via the installed TNC-N cable.
Quick check of the 3f chain has been done:
1) Applied a -40dBm  (6.3mVpp) signal at ~27.5MHz to the input cable => obtained the output of 2.5Hz with the amplitude of ~1200Vpp (attachment 1)
2) Applied a -50dBm  (2.0mVpp) signal at ~136.5MHz to the input cable => obtained the output of 270Hz with the amplitude of ~11500Vpp (attachment 2)

There could have been the whitening filters turned on. So the response should be done again with more careful tuning of the input frequency.

- The RF diplexer amplifier D1300899

The demodulator was modified by Dick and tested by Yuta. The test proceduer is here. E1400033

The module is installed to the R3U8 for AS18 and AS90. There are LO signals labeled Ch1/2/3.
However, the diplexer channels for 9/18MHz are CH3 and CH4. So we need to confirm what the
correct channel assignment should be. This will affect the ADC channel assignment.