Krishna, Michael

While noise hunting for the cBRS, we noticed that our piezos were singing at a high frequencies. After further investigation, we found ~8 kHz noise on all four of our channels coming out of the PEM anti-imaging chassis whenever we assert a value to the DAC. We ended up installing some 100 Hz low pass filters just before the cBRS electronics box to fix the issue on our end.

Attached is a scope view of the noise. The signal is on channel 2 of the scope.

J. Kissel

Betsy and Koji have left the chamber this evening with what they though should be a freely suspended collection of SUS in HAM6 (see more details of their work in LHO aLOG 28882), so I volunteered to run a health check, comparing transfer functions to the reference measurements I'd taken just before the vent. 

In short:
- the OMs all look identical to how they looked before the vent: free and with resonance frequencies and Qs where expected.  
- The OMC looks to have its top mass locked up in the Transverse / Roll direction (probably just a forgotten set of earthquake stops), but otherwise all modes look to have nicely high Qs. The resonant frequencies of all modes of the L, P, and V DOFs have all decreased slightly. It's as of yet unclear if this is because of the tiny addition of mass (6 [g] out of the old 7161 [g], or new 7167 [g]), or because of some other mechanism (like the top mass being locked in Transverse).

I've informed Koji of this assessment, but there's still plenty of in-chamber work to do, so we can continue to iterate to improve / restore the suspension dynamics.

I attach screenshots of the OMC transfer functions from DTT showing the locked M1 mass. BLACK is reference in-air measurements, and RED is the current state of the suspension. The PDF attachments are comparing the OMs with previous results; as mentioned above, nothing exciting in there.

Data templates:
/ligo/svncommon/SusSVN/sus/trunk/OMCS/H1/OMC/SAGM1/Data/
2016-08-05_0128_H1SUSOMC_WhiteNoise_L_0p2to50Hz.xml   ***
2016-08-05_0128_H1SUSOMC_WhiteNoise_P_0p2to50Hz.xml   ***
2016-08-05_0128_H1SUSOMC_WhiteNoise_R_0p2to50Hz.xml   ***
2016-08-05_0128_H1SUSOMC_WhiteNoise_T_0p2to50Hz.xml   ***
2016-08-05_0128_H1SUSOMC_WhiteNoise_V_0p2to50Hz.xml   ***
2016-08-05_0128_H1SUSOMC_WhiteNoise_Y_0p2to50Hz.xml   ***

OM1/SAGM1/Data/2016-08-05_0133_H1SUSOM1_M1_WhiteNoise_L_0p2to50Hz.xml
OM1/SAGM1/Data/2016-08-05_0133_H1SUSOM1_M1_WhiteNoise_P_0p2to50Hz.xml
OM1/SAGM1/Data/2016-08-05_0133_H1SUSOM1_M1_WhiteNoise_Y_0p2to50Hz.xml

OM2/SAGM1/Data/2016-08-05_0145_H1SUSOM2_M1_WhiteNoise_L_0p2to50Hz.xml
OM2/SAGM1/Data/2016-08-05_0145_H1SUSOM2_M1_WhiteNoise_P_0p2to50Hz.xml
OM2/SAGM1/Data/2016-08-05_0145_H1SUSOM2_M1_WhiteNoise_Y_0p2to50Hz.xml

OM3/SAGM1/Data/2016-08-05_0201_H1SUSOM3_M1_WhiteNoise_L_0p2to50Hz.xml
OM3/SAGM1/Data/2016-08-05_0201_H1SUSOM3_M1_WhiteNoise_P_0p2to50Hz.xml
OM3/SAGM1/Data/2016-08-05_0201_H1SUSOM3_M1_WhiteNoise_Y_0p2to50Hz.xml

All have been committed to the svn.

*** I don't recommend using the 2016-08-05_0128 templates for the OMC transfer function, because I paid no attention to drive strength or frequency resolution. They were older in-air templates, so I wanted to make sure I was comparing in-air references to the current in-air state. But unfortunately they have different requested frequency resolutions so matlab post-processing analysis is painful, and the drive has no low-frequency boost so coherence is less than it could be. In the future, I would use the templates that I tuned for in-vacuum from LHO aLOG 28736.

[Betsy, Corey, TJ, Koji]

- Now the OMC cavity is flashing!

- The OM1~3 and OMC suspensions have been debiased, and the OSEMs were tweaked to have the flags at the center of them.

- The optical paths such as the OMC incident path, OM1 transmission path, OMC refl path ahve been aligned.
  We still need to align the WFS and OMCT paths and confirm viewport paths if the beams are hitting the viewport.

- Currently the OMC PZT HV is ON.

=== Details ===

Shutter mirror inspection

The surface of the shutter mirror was checked with the green lantern. We didn't observe any sign of degradation.

Mass balance

- We adjusted the weight of the new OMC to match with the old one as much as possible. Then the mass was moved to have reasonable flag positions in the OMC suspension.

- The lateral position of OMCS RT OSEM was adjusted to have the flag at the center in the OSEM.
- The centering of the OMCS OSEMs were checked to be within the tolerance range.
- Along with the mass balancing, the positions of the EQ stops for the OMC breadboard were checked. We found several EQ stops were too close or too far. The EQ stop holders were adjusted to have them reasonable gaps to the glass breadboard.

Electrical functionality check

- The DCPDs were illuminated by a white flash light to check which DCPD responds to which channel. DCPDA and DCPDB are related to the DCPD on the transmission anfd reflection sides of the BS prism, respectively. (DCPD(T) = DCPDA, DCPD(R) = DCPDB). This seemed opposite to the case with the previous OMC. It was found that the difference in the internal cabling on the OMC caused this difference. This will be noted in the OMC testing procedure document (T1500060) athough this does not affect the calibration.

- The OMC QPDs were illuminated by the flash light. QPD1 (short arm) and QPD2 (long arm) correspond to QPDA and QPDB, as nominal.

Incident beam alignment & suspension debiasing

- Prep: IMC was locked at 2W. The beam was aligned on to the center of AS_C QPD.
- At this point, we already could observe the beams were on the OMC QPDs. Very good reproducibility.
  The signal ratios between OMC_QPD_A/B_SUM and AS_C_QPD_SUM (0.56 and 0.59 today) were confirmed with the ones with the numbers on Jul 28 (0.48 and 0.45).
  These ratios were enough similar to convince ourselves that they are the real spots.

From this point, we could follow the procedure in T1400588 (sec 2.3.3 and later).

- OMCS and OM3 were debiased to have (0,0), and used OM1 and 2 to align the spots on the OMC QPDs.

- This made OM1 Yaw ~-2000, and the OMC2 Pitch ~1500.

- The OM1 suspension cage was twisted to remove the OM1 Yaw bias.
- The OM2 suspension pitch adjustment screw was adjusted to remove the OM2 Pitch bias.

- The resulting offsets were: OM1 (116.9, -229.0), OM2 (94.5, 113.0), OM3 (0,0), OMCS (0,0) => Requirement <250 = 1/10th of the full scale => OK!

- We quickly checked some suspension transfer functions for OM1/OM2 and OMCS. OM1 and OM2 showed consistent TFs as the previous measurements. OMCS had the same resonant structures as before except for the resonant frequency of the lowest frequency mode. JeffK is checking the TFs more carefully.

- We turned on the PZT HV and scanned the PZT2 voltage. We confirmed that the OMC DCPDA and DCPDB were observing the OMC flahses.

Optical path check

- Main path: The spot positions on OM1/2/3 were checked. They looked fine.

- Shutter path: The mechanical shutter path was checked. It is still nicely aligned.

- OM1 trans path: The beam alignment in the OM1 transmission was checked. They looked fine. We still need to check the AS AIR viewport path with the viewport emulator.

- OMCR path: The beam spots on the OMCR steering mirrors were checked. The beam was not on the center of the steering mirrors. The first steering mirror (so-called M8) in the OMCR path was moved. The reflection path for 90:10 BS and the beam diverter path was checked. They looked just fine. M10 and M11 were used to align the spots on the OMCR QPDs. We didn't use M9 this time. We'll check this path again once the viewport emulator is attached on the chamber tomorrow.

- WFS path / OMCT path: We will work on these paths tomorrow.

Next steps

- Restore OMC blackglass shroud if the OMCS TFs look OK.

- Restore OMCT steering mirror

- Place the viewport emulator

- Confirm spot locations on the viewport

- We want to check the calibration between AS_C QPD SUM, the incident power on OM1, and the incident power on the OMC breadboard.

- Ground loop check

- Other SUS/SEI exit check

J. Kissel

I've processed yesterday's measurements, found that the ETMX data was junk anyway, so I retook both test mass charge measurements. Attached are the result. The trend of charge accumulation continues, without fail. I wish I had thought of this sooner, but for the duration of the vent, I've turned the BIAS on both end station's ESDs OFF. This way they at least won't accumulate any more charge for a ~week. It won't make a big difference but it's something. 

Immediately after we've recorvered the IFO and we're satisfied with its operation, we *need* to flip the BIAS sign to begin to mitigate what charge has accumulated.

Also -- it would be really nice if we identified the source of the residual free ions in the chambers and reduced the accumulation that way. A while back, I'd started to work with the VE team to identify the remaining potential sources (see LHO aLOG 23906), but it feel off my radar to continue to push when I found so little documentation of the gauge array. Also, though we'd ruled out photoelectric emmission from the ALS system early on, it might be worth a reconfirmation, but I'm not sure we can go as long as we'd need to see an effect without the ALS system. Anyways, here's hoping someone out there gets re-excited about this.

Jason, Nutsinee

Mirror replacement -- Success!

-------------------------------------------

Quick conclusion: We swapped all the silver coated mirrors on HWS X and Y table (18 total, 9 per table). Stream images now look better compared to what we used to have (alog28624)

-------------------------------------------

Details:

Livingston found their mirrors to be contaminated (alog27041) so we went out to check ours and discovered similar (if not the same) issue (alog28624). Today we swapped out all the silver coated mirrors and realign them following procedure in T1600329. The old mirrors are covered with dust and tiny particulates that won't get blown away by compressed air. Some mirrors are covered with scratches that couldn't have happened naturally (not just by sitting on the table). Some have tiny holes that almost look like damages from laser. Tomorrow Jason will try to drag wipe some of the mirrors to see if the particulates can be cleaned.

Below are some pictures of the old mirrors we pulled out.

We inspected every new mirrors for dust and scratches. They didn't come perfect. Some have tiny holes in them and dust that couldn't be blowned away. But overall the new mirror set is a huge improvement of what we pulled out.

Here are some photos of the new mirrors. These defects pretty much represent the whole batch. Only a few came without any defects at all.

Below are screenshots of the stream images after the mirror swap. Much better compared to alog28624

ITMX

ITMY

-------------------------------------------

HWS code status

Since I will be gone for a whlie and the thinning code isn't quite ready for action, I removed a bunch of old ETMS data to make room enough for 3+ weeks. None of the HWS codes are running right now since it wouldn't be writing useful data. Somebody will have to restart the code once the IFO is ready to go again.

At 15:00 PDT all the user models on h1susey stopped running. They showed DAC errors. The IOP model continued to run, so SWWD did not trip. We suspect power cycling of the optical lever system which was occuring around this time could be the culprit. I restarted all the models, they all restarted with no problems.

Hugh, Dave:

We drafted a seismic IO Chassis power up sequence to protect the HEPI system from any non-zero DAC output voltage. The procedure document is DCC-T1600332. I labeled all Seismic IO Chassis and AI chassis in conformance to the document.

These had been energized yesterday so as to keep mag-lev batteries charged.  

NOTE: Pressure in Vertex Turbo 1.4 torr.  Pressure in Diagonal, XBM and YBM Turbos ~0.4 torr -> Would like to investigate at some point.

~1515 hrs. local -> As measured at the check-valve @ HAM6, dew point <-35C. 

Kobelco compressor and drying tower units -> no alarms, temps and pressures as expected for conditions.

Phil, Marc

ECR E1600230-v1

WP 6053

We removed the ETM ESD Drivers from the X and Y end stations and upgraded them with the ability to handle PI Correction while in HV mode per ECR E1600230-v1.  Both drivers were reinstalled into their respective enclosures, all cables were reconnected and the power was turned on.

Note CP7's LLCV setting is high (91%). This could be due to a combination of low Dewar level (23%) and high outside temperatures.

State of H1: OMC alignment work with IR beam started today, other parasitic work continues

Assistance: Stefan, Kiwamu, Sheila, JeffK

Alignment issue encountered and resolved:

Alignment of the IR beam to the OMC took a 200urad change in SR2 pitch, which Stefan and Kiwamu tracked down to a change on SR3 pitch driven by the cage servo, which read OSEM values.  

The SR3 OSEMs had gotten some extra light and the servo moved the optic. Reseting SR3 restored the alignment to the OMC with only a reasonable (much less that 200urad) change on SR2.

OMC issue encountered and resolved:

Koji was unable to change the output of OMC-PZT2, which Sheila tracked down to a dependency on PZT1.  Once the setting for PZT1 was changed, it was possible to manually control PZT2.

Activity: all times UTC

15:00-19:00:

• kyle -ey - baking rga
• joe - y arm - beam tube maintenance
• ed - lvea - tracking down a cable
• richard/ed - ecr - 
• fil/mark - ey - esd drive
• travis - ex - pcal - laser hazard
• krishna/michael - lvea vertex - seismometer
• robert - ey - timing
• betsy - ham6 - omc
• tj - ham6 - omc
• fil/mark - ex - esd drive
• jimw - itmy - sei tests
• nutsinee/jason - lvea - tcs hartman
• jimw - ex - sei tests
• daveb - ex, ey, lvea - sei labeling
• fil/mark - ex - esd drive

everyone back for lunch ~19:00-20:00

20:00-23:00

• koji - ham6 - omc
• betsy - ham6 - omc
• corey - ham6 - omc
• fil/mark - ex - esd drive
• jeffk - ex - charge
• karen - ey - cleaning
• nutsinee/jason - lvea - tcs hartman
• mikel - lvea - tour
• daveb - lvea - labeling sei
• sudarshan/miranda - ey - pcal - laser hazard
• kyle - ey - baking rga
• fil/mark - ey - esd drive
• robert - ey - timing

Currently: - people at these locations

• robert - ey - timing
• koji - lvea - ham6
• betsy - lvea -  ham6
• corey - lvea - ham6
• nutsinee - lvea - tcs
• jason - lvea - tcs
• krishna - lvea - seismometer/vertex
• fil - ex - esd drive
• mikel - lvea - tour

Currently: - issues with H1

• ey front end is down, went down at 22:00utc - daveb working on it

~1050 hrs. local -> Started pumps at West end of BSC6 

~1110 hrs. local -> Began heating RGA.  

RGA is isolated from BSC6 via a closed 2 1/2" metal-sealed valve.  The RGA is being pumped via a small (bolted to RGA) turbo (4.5" CFF) backed by a 2nd turbo which is backed by a scroll pump.  Vent protection is provided via an electropneumatic isolation valve in-line between the two turbos.  This valve closes upon a pressure signal or a loss of power.  A second isolation valve (spring/electric solenoid) is mounted at the scroll inlet.  This valve closes only at the loss of power.  Neither turbo utilizes a vent valve.  Backing pumps are clamped to each other and to BSC6 stand weldment.

The following readbacks are missing:

• MCL controllers for the green WFS auto-centering in the ends, see fault 6023.
• The green WFS demod readbacks are funky, see fault 6024.
• TCS RF amp readback, see fault 6025.

The list of high frequency calibartion lines injected before and during ER9. These are not necessarily the times when IFO was locked but only the time when the particular excitations were on.

Frequency    Amplitude   Start Time      Stop Time       
(Hz)               (ct)                (UTC)             (UTC)       
--------------------------------------------------------------------
1000.3           35k         06-27 23:03    06-28 23:51         

1501.3          35k         06-29  00:16    07-01 04:48         

2001.3          35k         07-01 04:50     07-01 15:08         

2501.3          40k         07-01 15:20     07-05 19:04     
 
3001.3          39k         07-05 19:00     07-09 17:41            

3501.3          39k         07-09 18:32     end

Analysis to follow.

J. Kissel

I was able to grab some charge measurements yesterday afternoon. Will process in good time. Only 4 and 3 of the data points for ETMX and ETMY were free of problems, so though there are 5 and 4 folders, I suspect only the first for will process correctly. Folders are quoted below lest we forget:

/ligo/svncommon/SusSVN/sus/trunk/QUAD/H1/ETMX/SAGL3/Data/
data_2016-08-03-19-47-12
data_2016-08-03-19-59-06
data_2016-08-03-20-10-54
data_2016-08-03-20-22-36
data_2016-08-03-20-34-21

/ligo/svncommon/SusSVN/sus/trunk/QUAD/H1/ETMY/SAGL3/Data/
data_2016-08-03-19-55-57
data_2016-08-03-20-07-41
data_2016-08-03-20-19-26
data_2016-08-03-20-31-11

The HV power cable for the Y2-8 ion pump has been repaired. The damaged section was cut off, and the cable was spliced together. Cable was tested with the HI-POT tester to 5KV.