(Richard M, Filiberto C, Kyle R, Gerardo M)
"New" high voltage cable was pulled yesterday along with new fiber.
The cable was tested yesterday, hi-POT tested up to 5k, then both ends terminated.
Fiber was tested today, all good.
Today the power supply was setup on the shelf and powered on, ion pump is working good thus far.
Thank you Fil, Richard and Gerardo - your efforts saved us $7k
Day Shift Summary: Title: 04/08/2016, Day Shift 15:00 – 23:00 (08:00 – 16:00) All times in UTC (PT) State of H1: IFO unlocked. HAM6 vented for ISI upgrade. Commissioning: Outgoing Operator: N/A Activity Log: All Times in UTC (PT) 15:00 (08:00) – Start of shift 15:45 (08:45) Jeff k., Jim, Corey – Working at HAM6 15:55 (08:55) Peter, Jason, Ed – Working in the PSL 16:15 (09:15) Patrick – Working on the End-X vacuum computer for new gauge install 16:30 (09:30) Patrick – Restarted the End-X vacuum computer 16:35 (09:35) Jeff K., & Evan – Confirmed the fast shutter is operating & out of LVEA 16:40 (09:40) Filiberto & Manny – Going to End-X to recover tools 16:42 (09:42) Jim & Corey – Finished at HAM6 – Out of LVEA 17:37 (10:37) Patrick – Restarted the End-X vacuum computer 18:00 (11:00) Kyle, Chandra, Gerardo, Jeff B. – Reinstall north and south HAM6 doors 22:00 (15:00) Kyle, Chandra, Gerardo, Jeff B. – Out of the LVEA 22:40 (15:40) Kyle, Chandra – Starting pumping and leak checks on HAM6 End of Shift Summary: Title: 04/08/2016, Day Shift 15:00 – 23:00 (08:00 – 16:00) All times in UTC (PT) Support: Incoming Operator: Shift Detail Summary: SEI upgrades are finished. TFs for HAM6 look good. Reinstalled the north and south doors on HAM6. Vacuum group is pumping down and doing leak checks.
Took many particle samples inside the chamber and inside the cleanroom while installing the north and south doors on HAM6. There was one spike of over 2000 counts of 0.5um particles while putting in the bolts on the bottom of the north door. There were also a couple of elevated counts when covers were removed. All other readings (inside and outside of the chamber) were below 100 0.5um particles, with most below 50 0.5um particles. A 4" witness optic was placed on a mass stack just to the -X, -Y side of the OMC. The cleanrooms from the north and east side have been powered down and returned to their parking spot. The Main cleanroom over HAM5/6 has been shutdown; the power cable has been disconnected. The temporary power cords for the cleanrooms have been removed from under the chamber. The small garb room and cleanroom on the south side are still running. I have some work to do on Monday that requires a cleanroom. These will be shutdown and removed when the leak checks are finished.
Ymid: 3:40-3:50pm local time Took 2:34 min. to overfill CP3 today with half turn on bypass valve. Next fill due Monday, April 11th.
Top plot:
IM2 LR OSEM noise rises above other IM OSEMS around 135Hz.
At 570Hz, IM2 LR OSEM in blue in top plot is ~15x the noise of the IM3 LL, ~60x the noise of IM1 UR, and ~90x the noise of IM4 LR
Bottom Plot:
OSEM noise shows up in pitch signal
Kyle, Gerardo, Jeff B., Chandra East door was installed on Thursday. North and South doors were installed today. Two of three are torqued. We will torque the South and start the rough pump down after late lunch. NOTES: 1. North door has a questionable scratch along the o-ring sealing surfaces (but not wide enough to cross both o-rings at same time, we think). Scratch is in fourth quadrant (when looking at door). 2. Inner o-ring of South door was bad. We replaced with one from 1998 processed stock. We will leak check all doors before COB today.
Excellent - although east door was installed Thursday. or -Y door as some would prefer.
Fixed the log entry, John. :) Kyle has photos of the scratch.
Filiberto, Patrick We did two things, and it is not clear which or if both were necessary. We swapped the transmit/receive fiber pair into the CU1521 media converter at X2-8. After that the link lights started blinking. At the end station we changed the rotary dial on the CU1521 media converter from 0 to 5. This dial sets the direction of the media converter as seen from the EtherCAT master. 0 is from fiber to copper. 5 is from copper to fiber. (pg. 22 of http://download.beckhoff.com/download/document/io/infrastructure-components/cu15xxen.pdf) So it had been incorrectly set as from fiber to copper. We then power cycled just the CU1521. We had checked the dial on the media converter at X2-8 and it was correctly set to 0 (fiber to copper). I had to restart the Beckhoff controls and IOC again to scan and add the gauges. I called Cheryl from the end station and she ran a script on the vacuum computer in the control room to set the IOC values. She also set the CP LLCV control to manual. I just set it back to PID.
My watch on Operations: approx. 18:00-20:00UTC (11:00-1:00PT) - as of 20:56UTC:
The h1nds1 computer died with a kernel panic. I powered the computer off, then powered it back on at about 11:53 PDT. Monit needed to be told to monitor the daqd process once the computer booted.
Corey and I did the last few ISI items this morning in HAM6. Check for tools, wiped down areas where people were working, pulled the septum cover, unlocked the ISI and closed the chamber. While we were doing that Evan, JeffK and Fil checked the operation of the beam diverter and fast shutter (Jeff just alogged that). I've now taken closeout ISI measurements and the ISI looks ok. I think my measurements are made a little noisy by high purge flow in the chamber, so I may take longer measurements after the chamber closes. But I think we are good to put doors on.
J. Kissel, E. Hall, F. Clara As per this April HAM6 vent's plan, E1600092, we've confirmed the functionality of the AS AIR and OMC REFL beam diverters, as well as the HAM6 fast shutter. Details of the test below. The tests required turning on the HAM6 High Voltage for the shutter, but we since have turned it off again now that or tests are complete. All mobile ISC components are functional; ISC is a go for chamber closeout. ------------------ Beam Diverters: - The AS AIR and OMC REFL beam diverters did not need to be moved or disconnected at all during this vent, so testing their functionality was as simple as exercising the OPEN/CLOSE buttons on the corresponding Beckhoff MEDM screen and watching as the shutters cycled through the two positions. We were able to cycle both several times without issue. Fast shutter: To test the fast shutter we did the following (informed by LHO aLOG 17831) This scenario: The chamber doors are open, the shutter is clearly visible, ISCT6 has been pulled away from the chamber, the trigger PD's input has been disconnected from the remote chassis, and the high voltage has been turned off. Gather ahead of time: a portable DC voltage supply (it need only be capable of +5V) and associated BNC cable and adapter. Process: (1) Confirm that the HAM6 fast shutter remote chassis's power is OFF (both that the front-panel "HV Enable" little silver dip-switch is set to "disable", and the back panel power rocker switch is OFF). This chassis is located in the field rack just -Y of HAM6 at the bottom of the rack. (2) Turn on the high voltage power supply in the Computer Electronics Room (CER) Mezzanine. Since the voltage and current adjust are analog dials, they are typically left at the right setting, so one only needs to turn on the power switch to the power supply. Once on, the voltage readback should show 250V, and the current readback should be hovering just above 0 A (i.e. *very* little current should be drawn). (3) Return to the field rack, and turn on the back panel chassis power rocker switch. (4) On the front panel, you should see the +/-15V light green, the computer screen light up, and after a few seconds the fault light will go red. (5) Enable the HV from the front panel silver dip switch. The computer screen will indicate that the capacitator is charging up for ~10 sec or so. The fault light will remain on. (6) Connect the DC voltage supply (with no voltage output) to the Fast Trigger Input. (7) As soon as you give the voltage supply 5 V, the shutter should pop up, and the fault light will go off. (8) Cycle the 5V a couple of times to confirm expected functionality. If the shutter pops up and down as expected, then the shutter is functional. (9) Disconnect the 5V voltage supply, flip the sliver dip switch back to "disable," turn off the power to the chassis via the back panel rocker switch, and turn OFF the high voltage power supply in the CER mezzanine. NOTE This only tests the mobility of the shutter, it does not test the shutter logic or the timing. This requires ISCT6 to be in place, and light on a trigger PD, as per LHO aLOG 17831 cited above. We will test these critical components as soon as possible.
The Diagonal Volume is currently being pumped by the Turbo, IP7 and IP8. IP7's voltage setting is not optimal, I'll fix it later. Unless otherwise directed, will leave this way over the weekend and shut down the Turbo Monday.
I put the TwinCAT system into configuration mode at end X and scanned for devices. The media converter and X2-8 EtherCAT gauge did not show up. I put it back to run mode. The LLCV is in manual mode until the PID recovers.
PSL – The leaking coolant manifold was replaced yesterday. Coolant has been circulating since then with no apparent problems. Today efforts will concentrate on getting the PMC relocked. SEI – The new hardware has been installed and tested. The crew is closing out some final cleanup tasks; then will run a final set of transfer functions. If everything checks out OK, the plan is to hang the last two doors after lunch. Vac – Pumping will start on HAM6 as soon as the doors are back on. Gate Valves should be opened on Monday. FRS – Reviewed and closed out completed FRS tickets.
The output of the 4 flow sensors - one per laser head - from the past 24 hours is attached. The sensor for head 1 was replaced yesterday. Not obvious to me why it did not settle down as rapidly as the other 3 sensors. But we will keep an eye on it. The crystal chiller water level was lower this morning than what it was yesterday afternoon. This might be due to the air bubbles working its way out of the plumbing. We will continue to monitor for leaks.
J. Kissel As per this April HAM6 vent's plan, E1600092, I've checked that the SUS have not been affected by this week's vent activities by measuring all DOFs of all SUS in the chamber -- the OMC and OMs 1 through 3. Attached are the results of the transfer functions compared against the last in-vacuum results. All SUS are A-OK; SUS is a go for chamber close out. New data sets live here: /ligo/svncommon/SusSVN/sus/trunk/OMCS/H1/OMC/SAGM1/Data/2016-04-08*.xml /ligo/svncommon/SusSVN/sus/trunk/HTTS/H1/OM1/SAGM1/Data/2016-04-08*.xml /ligo/svncommon/SusSVN/sus/trunk/HTTS/H1/OM2/SAGM1/Data/2016-04-08*.xml /ligo/svncommon/SusSVN/sus/trunk/HTTS/H1/OM3/SAGM1/Data/2016-04-08*.xml Note, I've improved the OM templates by tuning the drive and adding a boost to the low-frequency drive. The OMC's template didn't need it.
I did some follow-up tests today to understand the behavior of the DARM cavity pole. I put an offset in some ASC error points to see how they affect the DARM cavity pole without changing the CO2 settings.
I conlude that the SRC1 ASC loop is nominally locked on a non-optimal point (when PSL is 2 W) and it can easily and drastically changes the cavity pole. The highest cavity pole I could get today was 362 +/- a few Hz by manually optimizing the SRC alignment.
[The tests]
This time I did not change the TCS CO2 settings at all. In order to make a fair comparison against the past TCS measurements (26264, 26245), I let the PSL stay at 2 W. The interferometer was fully locked with the DC readout, and the ASC loops were all engaged. The TCS settings are as follows, TCSX = 350 mW, TCSY = 100 mW. I put an offset in the error point of each of some ASC loops at a time. I did so for SRC1, SRC2, CSOFT, DSOFT and PRC1. Additionally, I have moved around IM3 and SR3 which were not under control of ASC. All the tests are for the PIT degrees of freedom and I did not do for the YAWs. During the tests, I had an excitation line on the ETMX suspension at 331.9 Hz with a notch in the DARM loop in order to monitor the cavity pole. Before any of the tests, the DARM cavity pole was confirmed to be at 338 Hz by running a Pcal swept sine measurement.
The results are summarized below:
The QPD loops -- namely CSOFT, DSOFT, PRC1 and SRC2 loops -- showed almost no impact on the cavity pole. The SOFTs and PRC1 tended to quickly degrade the power recycling gain rather than the cavity pole. I then further investigated SRC1 as written below.
[Optimizing SRC alignment]
I then focused on SRC1 which controlled SRM using AS36. I switched off the SRC1 servo and started manually aligning it in order to maximize the cavity pole. By touching PIT and YAW by roughly 10 urads for both, I was able to reach a cavity pole of 362 Hz. As I aligned it by hand, I saw POP90 decreasing and POP18 increasing as expected -- these indicate a better alignment of SRC. However, strangely AS90 dropped a little bit by a few %. I don't know why. At the same time, I saw the fluctuation of POP90 became smaller on the StrioTool in the middle screen on control room's wall.
In order to double check the measured cavity pole from the excitation line, I ran another Pcal swept sine measurement. I confirmed that the DARM cavity pole was indeed at 362 Hz. The attached is the measured DARM sensing function with the loop suppression taken out. The unit of the magnitude is in [cnts @ DARM IN1 / meters]. I used liso to fit the measurement as usual using a weighted least square method.
By the way, in order to keep the cavity pole at its highest during the swept sine measurements, I servoed SRM to the manually adjusted operating point by running a hacky dither loop using awg, lockin demodulators and ezcaservos. I have used POP90 as a sensor signal for them. The two loops seemingly had ugf of about 0.1 Hz according to 1/e settling time. A screenshot of the dither loop setting is attached.
Probably interestinmg to take a look at ASC_ASA/B_36/90/DC, and see, if there is a better combintion available.
It occurs to me that we might try putting some offsets into the centering loops for the SRC WFS. Can we find a pointing location where the AS36 signals give us an optimal alignment for the SRC?
On a somewhat parallel thought, Evan and I wonder if we could set offsets in the SRC1 loops after choosing an alignment based on some dither lines? Maybe we don't want always-on dither lines, but we could use them to help us figure out what our optimal alignment is.
Here are some more data.
In this plot, full lock was achieved at some point between 0 and 500 sec. A small change in the SRM alignment offsets are due to the DRMI guardian completing the ASC offload to the top mass before decreasing the CARM offset. The measurement of the cavity pole and optical gain is valid only after 500 sec or so.
As I mentioned in the last ISC call, the cavity pole frequency and optical gain are anti-correlated -- one goes up and the other goes down.
The below shows a summary of my manual SRM alignment.
Before | After | Difference (after - before) | |
SRM PIT | -727 urad | -737 urad | -10 urad |
SRM YAW | 908 urad | 901 urad | -7 urad |
As I wrote in the original entry, I steered SRM PIT and YAW by -10 and -7 urad respectively.
Also I attach a screen shot of trends showing the 2f RF signals during the same period.
As the cavity pole increases the POP90 consistently decreases. This is what we expected because SRC sucks more light into it. POP18 also increased at the beginning which is good. However it decreased slightly after I aligned SRM yaw for some reason. The most outrageous one is AS90. As the cavity pole increased, the AS90 kept decreasing. I have no idea why.
Conclusion (again): it is the SRC alignment that changes the cavity pole.
[SRM and SR2 alignments]
I completely forgot about the SRC2 loop which controls the pointing of the output beam on to ASC_AS_C. This loop was active during my measurement silently correcting SR2 and SRM as I manually moved SRM. So I checked the witness sensors to see how much they actually moved instead of looking at my adjustment of the SRM alignment.
As you can see, SRM actually moved to the opposite direction in its angles due to the SRC2 loop counteracting on my adjustment. In total they have moved by the amounts listed in the table below.
before | after | difference (after-before) | |
SRM pit | -105 urad | -95 urad | 10 urad |
SRM yaw | 873 urad | 876 urad | 3 urad |
SR2 pit | 2603 urad | 2600 urad | -3 urad |
SR2 yaw | 790 urad | 791 urad | 1 urad |
[A finesse simulation also suggests that the cavity pole is a strong function of SRs' alignment]
With the above misalignment values in hand, I then ran a finesse simulation to see if I can reproduce a similar result. Indeed, I could change the cavity pole from an optimum of 366 Hz to 344 Hz in the simulation (while my measurement was from 360-ish Hz to 345-ish Hz). The attached is a simulated DARM response with and without these misalignment.
Because I was too lazy to fit out the effect of the time delay and next FSR peak, I simply searched for a frequency point where the phase rotates by 45 deg as a cavity pole frequency. This probably makes the absolute calibration of the cavity pole somewhat inaccurate, but the difference between the two cavity pole frequencies should be moreorless accurate.
Also I attach the finesse code in pdf format.
Addendum:
In the finesse simulation, the DARM response showed some difference at low frequencies between the two results. So I re-ran the same code and extended the frequency range to 0.1 Hz. It is seemingly due to a radiation pressure effect. I don't have a good explanation why it changed by SRs' alignment.
This is an update of the DCPD cross correlated spectra. This time I have added the one from Livingston which was integrated over 1266 hours using the O1 data. High noise durations (e.g. LLO 23453) are excluded from the integration.
The fig and mat files are attached.
Similar to previous entries, I put in the coating thermal noise and some oscillator AM to see how things look (plot 1). I also made a similar plot with higher thermal noise (by 1.4) and a 1/f^2 mystery noise to show what the limits are on these types of added noises (plot 2). Plot 3 shows the "uncorrelated noise budget", which required a 350Hz DARM cavity pole, and leaves something unexplained below 100Hz. There is something strange happening around 700Hz, but maybe I have overestimated the oscilator AM.