chandra.romel@LIGO.ORG - posted 13:11, Thursday 31 March 2016 (26361)
The Master
Images attached to this report
[Fil, Jenne]
We've measured the distances from each Newtonian array sensor location (marked on the LVEA floor with green electrical tape) to the racks we'll use for signal concentration, so that we can order our cables soon.
The new Met One dust monitors have been installed in: The LVEA at HAM6 and in the Beer Garden, in the Optics Lab,End-X, and End-Y. They are and sampling for 60 seconds every 10 minutes. There are still a few minor issues being resolved, which do not effect the operation of the units or the particle counts. Attached is a quick operators guide to the new monitor. Fuller documentation will follow.
John, Chandra Pressures at IPs IP-7 & IP-8 on diagonal were ~10 Torr. Pumped out volumes with aux cart and opened gate valves to main diagonal volume. Connected HV cables, but did not activate IPs yet. Current diagonal pressure = 7e-7 Torr. IP-8 still needs cable strain relief.
h1fw1 froze up last night at 22:41 PDT with a kernel panic. It was restarted at 10:16 PDT today (I pressed the front panel reset button)
last part of the console error message was:
VFS: Close: file count is 0
Kernel panic - not syncing: CRED: put_cred_rcu() sees xxxxxxxxxxxxxx with usage -1
where xxxxxx is a large hex number.
We've had much more success tonight with the non-broken Xarm Trans QPD. We once again re-centered the spots on the ETMs, although they didn't need much moving. We are able to sit at 10W and 12W just fine now. Now, we're running into regular ol' loop oscillations, so we've been measuring loops at different powers, and trying to re-tune them.
CHARD Y seemed the most egregious, so we created a new control and boost filter combo, which live in FMs 4 and 5. Unfortunately, these filters are totally unuseable at 2W, although they improve our stability at 10W, so right now the guardian still only engages the old loop shape filters. We'll have to re-think the 2W filter situation to make sure we can transition between these filters. Right now, we were by-hand turning off the CHARDY loop, changing the filters, then re-engaging the loop. Attached is an open loop gain for the new loop.
PRC2 pitch we've decided is kind of okay if we use a factor of 2 less gain.
Now, we're seeing oscillations that also show up in AS 90, so we suspect either the MICH or SRC angular loops. Unfortunately, there's something going on with NDS/the lockloss plotter/something, such that I can't get data from the last ~5 locklosses. The ones before that, I can still get and plot, but it can't find data for the last several even if it's been an hour since that lockloss.
So, next up: Measure the MICH and SRC loops at 10W to see if they're close to unstable. Measure again at 15W, and then think about going from there.
I feel I should know this already, but what is known about the QPD failure (circumstance at failure, failure mode, etc.)
It's not totally clear to me yet what the exact problem was. R.McCarthy is looking into why (apparently) putting the PI chassis spoiled the signal. Removing the new PI chassis seems to have fixed our problems. See alog 26328 and comments for symptoms and Rich's comment.
The PI AA was off and its OpAmp inputs were probably 'shorted' to ground due to the input protection diodes.
I am designing the input circuitry for the ITM PI Driver using the same input chip as that used on the ETM PI AA, so I will hedge our bets by including some input protection circuitry (current limit and clamp) to avoid this if that turns out to be the case.
In the lab, Fil reproduced the situation at EX by connecting a function generator to a coil driver test box (D1000931) and only used the single to differential converter of the board inside (D1000879) to drive the input of unpowered PI bandpass, and daisy chained to powered AA board.
Things looked OK until the PI input reached about +-1V differential (that's +-500mV positive and -+500mV negative), anything larger than that and the voltage started to be pulled down. Looked like a diode and a small resistor in series to me. As soon as the PI bandpass was powered on, everything got back to normal.
Daniel is correct. The chips used on the input to the PI filters have internal input protection diodes that will (up to the limit of their current handling capacity, which is not much over 10mA or so) clamp the voltage from the QPD amplifier to something around a volt. This is not a problem if the PI BPF is powered, which is the normal state of the system. This event prompted a redesign of the differential input to the ITM ESD Driver to avoid this in the future. Another case of incremental learning.
I have updated the documentation in the DCC here,
https://dcc.ligo.org/LIGO-T1500502
about hoft generation for ER8/O1 to include information about C02 hoft.
In particular, these caveats are included:
* For the exact versions of filter files, code, and command lines used to generate C01 and C02 hoft see: https://wiki.ligo.org/Calibration/GDSCalibrationCon figurationsO1
* Users should check with their working group about which vetoes and which veto-de finer files to use with each type of data before producing fi nal results.
Michael, Krishna, Hugh, Jeff
This morning, we took out the piezo stacks from under the BRS-2 platform. We then turned on the ion pump. The current initially went up to 20 mA and slowly dropped down to ~300 microamps in ~1 hr. We then disconnected the Pump station. When we checkd it later after about 4 hrs, the pump current was ~200 microamps (P ~ 1e-6 torr) and steadily dropping.
Michael and I then hooked up the rest of the electronics, wrapped the vacuum can in several sheets of foam, and finally set up the thick-foam-box around the instrument.
Hugh had set up the EY_GND medm screen showing the BRS-2 data coming into the ISI frontends (similar to EX_GND). After correcting a cable connection mistake, we are now getting the BRS-2 angle data into CDS. Currently we are getting the following channels in to ISI AA Chasis:
ADC0, channel 27: Raw Tilt Signal : Calibration - to be worked out soon. This is a high-passed value of the raw angle measured by the autocollimator, high pass: 2 pole at ~0.5 mHz.
ADC0, channel 28: Drift Signal : Calibration: 58.33 nrad/ct. This is a scaled down version of the raw angle signal.
ADC0, channel 29: Ref Signal : Calibration: - to be worked out soon. This is the angle of the reference mirror. It is useful as a measure of the autocollimator noise. Unlike BRS-1, this signal has a higher noise floor and is useful only at very low frequencies, below ~ 5 mHz.
ADC0, channel 30: Status Signal : This is currently zero. The plan is to use this as an indication of the health of BRS-2.
The Tilt channel is currently noisy and we will investigate further tomorrow.
Introducing the new LASER_PWR Guardian node! Use it to change the power by selecting one of the three requestable powers (2W, 10W, 22W) or open the "ALL" screen to select any 'POWER_#W'. I attached a shot of the graph if you're curious. This node is nominally manged by ISC_LOCK and then ALIGN_IFO during initial alignment (though this has created some usermsg issues that I am trying to work around, more on that later).
I have also changed around some of the management for initial alignment. If the user wants to run initial alignment:
1. From READY in ISC_LOCK, go to manual and select INITIAL_ALIGNMENT
2. Wait for ALIGN_IFO to run through its DOWN state. This will temporarily take control of the ALS's, LASER_PWR, and IMC_LOCK nodes.
3. Run the green alignment from ALIGN_IFO instead of each of the ALS nodes. Offload the green WFS at the same ti.
4. Continue as usual, during SRC the LASER_PWR node will bring the power up to 10W and then back down after.
6. When done with initial alignment, make sure to go to INIT on ISC_LOCK to take back control of the nodes. then continue as usual.
I added the LASER_PWR, as well as the SR3_CAGE_SERVO nodes to the Guardian Overview screen (shot attached).
I also slightly changed the ISC_GUARDIANS medm to show who the managers are of each node and placed the new node on the bottom. (shot also attached).
As I mentioned above, there are some user messages that will pop up on ALIGN_IFO and ISC_LOCK about the nodes being stolen by one another. This isn't a big deal for ISC_LOCK to report this whie we are in the middle of initial alignment, but it isn't good for ALIGN_IFO to be continuously notifying during normal locking. I have something that I want to try next opportunity I get, hopefully tomorrow. And if that doesn't work, Jamie seemed to have an idea of how to solve these types of situations that will be in the next Guardian release. Until then we can not manage the nodes during initial alignment just as before.
Quick update on Initial Alignment procedure.
After switching to the INITIAL_ALIGNMENT state in ISC_LOCK, the nodes usually used for IA will no longer be automatically managed. These will stay UNmanaged just like before all of this.
I tried to make a go around for the management by redefining the list of nodes that were control by the NodeManager object. This was plan B since I could not create a second object like I had originally hoped. Plan B also did not work though. While it did manage to get rid of the user notifications, it would regularly get confused and say something like "Node X was in state A, now state B" even though it was the one that had set state A and B. Seems like we will just have to keep it this way until the next grd release, but since this is basically like it was before it's not a big deal.
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.
TITLE: 03/30 Day Shift: 15:00-23:00 UTC (08:00-16:00 PST), all times posted in UTC
STATE of H1: Planned Engineering
INCOMING OPERATOR: Jim
SHIFT SUMMARY: Good day for locking. Had the IFO as far as DC Readout by 16:30. Then some QPD and other work took me down. Since then, we have been back to locking consistently.
LOG:
15:16 Krishna and Michael to EY BRS work
15:41 Bubba driving inside of both arms checking tumbleweeds
16:05 Chandra pump cart work in diagonal
16:26 Fil to EX QPD work
16:27 Karen and Chris done in LVEA
16:40 John and Bubba to LVEA
16:58 John and Bubba out
17:42 Fil and Richard back
17:45 Fil and Ed to LVEA HAM3 cabling
18:08 Fil and Ed out
18:18 Ed to LVEA
18:50 Ed out
19:30 Fil to EX QPD
19:53 Fil done
19:54 Jeff B to both ends
20:11 DAQ restart
20:30 Jeff B back
20:36 Ed to LVEA
20:47 Bubba and Nicole to MY
(Tasked by Aidan)
We were curious of how the HWS sled power decrease over time so we know when to swap them out. Below I've attached plots of HWSX and HWSY sled power (corrected for gains) and input current. The start time is when we replaced the SLED (April 26, 2015 for YSLED and March 1, 2016 for XSLED). I only plotted the time when the SLEDs were turned on (displays in number of days). XSLED shows deteroration of ~2% per day and YSLED shows deterioration of ~1% per day (given 7mW to be 100%, I don't think we are shooting 7mW out though but the trend looks reasonable). YSLED power decreased slightly faster when the input current = 94 mA.
XSLED data can be found here and YSLED data can be found here. The column goes Time|Power (mW)|Current(mA). The script to fetch and plot data can be found in the same directory.
The fast decay in the beginning is a known problem.
Here are plots with correct Y-axes labels. Sorry about that.
WP 5799 FR 4694 (PKA II 1193)
Continuing the offload of SUS calculating the SUSPOINT motion from ISI GS13 cartesian motion, this has ISI doing the calculating. We'll stop the SUS doing the calcs as soon as we confirm that DetChar is happy with the ISI numbers.
All the HAM models were rebuilt & installed and FrontEnds restarted. safe and OBSERVE.snaps were checked and updated (lots of new channels.)
No issues with HAM ISIs reisolating.
Medm editing is ongoing for the SUSPOINT. Each medm is custom for the number of suspensions. HAM6 and HAM2 still need to be built.
Along these lines, the BSC Models were adjusted to put the SUSPOINT on IPC and at ENDY, the BRS was added as at ETMX.
SVN COMMITS:
hugh.radkins@opsws1:models 0$ svn commit -m "HAM SUSPOINT calcs moved to ISI and BSC SUSPOINT calcs added to IPC and BRS at ETMY"
Sending models/h1isibs.mdl
Sending models/h1isietmx.mdl
Sending models/h1isietmy.mdl
Sending models/h1isiham2.mdl
Sending models/h1isiham3.mdl
Sending models/h1isiham4.mdl
Sending models/h1isiham5.mdl
Sending models/h1isiham6.mdl
Sending models/h1isiitmx.mdl
Sending models/h1isiitmy.mdl
Transmitting file data ..........
Committed revision 12961.
hugh.radkins@opsws1:models 0$ pwd
/opt/rtcds/userapps/release/isi/h1/models
hugh.radkins@opsws1:hamisi 0$ svn commit -m "Added suspension OPTICs for medm generation"
Sending hamisi/H1_isiham2_overview_macro.txt
Sending hamisi/H1_isiham3_overview_macro.txt
Sending hamisi/H1_isiham4_overview_macro.txt
Sending hamisi/H1_isiham5_overview_macro.txt
Sending hamisi/H1_isiham6_overview_macro.txt
Transmitting file data .....
Committed revision 12962.
hugh.radkins@opsws1:hamisi 0$ pwd
/opt/rtcds/userapps/release/isi/h1/medm/hamisi
hugh.radkins@opsws1:burtfiles 0$ svn commit -m "Update snaps for SUSPOINT & commissioning"
Sending burtfiles/h1isibs_down.snap
Sending burtfiles/h1isibs_safe.snap
Sending burtfiles/h1isietmx_safe.snap
Sending burtfiles/h1isietmy_OBSERVE.snap
Sending burtfiles/h1isietmy_safe.snap
Sending burtfiles/h1isiham2_safe.snap
Sending burtfiles/h1isiham3_safe.snap
Sending burtfiles/h1isiham4_OBSERVE.snap
Sending burtfiles/h1isiham4_safe.snap
Sending burtfiles/h1isiham5_OBSERVE.snap
Sending burtfiles/h1isiham5_safe.snap
Sending burtfiles/h1isiham6_safe.snap
Sending burtfiles/h1isiitmx_safe.snap
Sending burtfiles/h1isiitmy_OBSERVE.snap
Sending burtfiles/h1isiitmy_safe.snap
Transmitting file data ...............
Committed revision 12963.
hugh.radkins@opsws1:burtfiles 0$ pwd
/opt/rtcds/userapps/release/isi/h1/burtfiles
I'll commit the medm adls once I'm finished with them.
A full description of the changes committed about can be found in G1600795.
J. Kissel, B. Weaver, H. Radkins, D. Barker, J. Batch Here's a list of all of the upgrades we were involved in today. There will be more details of the upgrade, more debugging, associated MEDM screen changes, svn commits, and other clean up tomorrow as we continue to explore what we've installed and debug. Bear with us, and thanks for your patience. 1) Fixed UIM coil driver path's automatic compensation bug by updating CD_STATE_MACHINE.c. See Int. Issue 1178. 2) Installed ISI GS13's projection to SUSPOINT Euler basis projection into the SEI models. See ECR E1600028. 3) Sent the Euler Basis Longitudinal DOF for each SUS involved in a cavity over various IPC (PCIE and RFM) and models (ISI, End-station PEM, H1OAF) to be collected in OAF. See ECR E1600028. 8) Removed the excess RFM channels from End-Station ALS models (noteably *not* the excess channels in the ISC models). This made room for 3). See LHO aLOG 25216 4) Added various rotational sensor correction paths to the BSC ISIs (GND BRS to ST1, and ST1 to ST2). (Prototyping, this stuff, no ECRs just yet) 5) Removed the L4C sensor correction path. See SEI aLOG 666 6) Added new infrastructure for the EY BRS. (Most Copied from EX, covered by ECR E1500246) 7) Reverted the BSC SUS's coil driver monitors to store the NOISEMON in the frames (and pushed the FASTIMON to the commissioning frames). Also, we put filter modules in front of the NOISEMONs (like was done for the FASTIMONs the last time we touched this) in case we ever wish to calibrate them. See ECR E1600033 and LHO aLOG 26313 Because we haven't built MEDM screens and actually *used* any of these paths yet, there's still potential for bugs and we haven't explored and/or fixed all of the collateral damage. Stay tuned as we continue to work on all of these updates tomorrow.
J. Kissel I've documented all of the front-end model changes that were necessary for items 2, 3, 5, 6, and 7 (i.e. all of the SEI model changes). Check out G1600795. As indicated in LHO aLOG 26321, all of the simulink model changes have been committed to the repository.
J. Kissel, H. Radkins Here're the updated MEDM screens that correspond to the above SEI model updates. I'll work on the Cavity Basis OAF MEDM screen tomorrow. The following screens where changed and/or added: /opt/rtcds/userapps/release/isi/common/medm/bscisi A ISI_CUST_CHAMBER_ST1_ROT_SENSCOR_FIR_ALL.adl A ISI_CUST_CHAMBER_ST1_ROT_SENSCOR_IIRHP_ALL.adl A ISI_CUST_CHAMBER_ST1_ROT_SENSCOR_MATCH_ALL.adl A ISI_CUST_CHAMBER_ST2_ROT_SENSCOR_FIR_ALL.adl A ISI_CUST_CHAMBER_ST2_ROT_SENSCOR_IIRHP_ALL.adl A ISI_CUST_CHAMBER_ST2_ROT_SENSCOR_MATCH_ALL.adl Sending ISI_CUST_CHAMBER_ST1_SENSCOR_OVERVIEW.adl Sending ISI_CUST_CHAMBER_ST2_SENSCOR_OVERVIEW.adl Sending ISI_CUST_CHAMBER_OVERVIEW.adl=
This is a quick summary of today's TCS joy. I ran another differential lensing test today. I went to the other side of the differential lensing (CO2X goes higher power).
The highest cavity pole was 352 Hz in this test.
This time, I also took many measurements of the intensity and frequency noise couplings periodically throughout the test using Evan's automated measurement script (20470). I will analyze and post them later. The second attachment is trend of some relevant channels.
This is a report on the intensity noise coupling measurement to DARM during the same TCS testing period.
The below is an animated plot showing how the intensity noise coupling evolved as a function of time during the test. The transfer function was measured from ISS-SECONDLOOP_SUM14_REL to CAL-DELTAL_EXTERNAL. DELTAL_EXTERNAL is unwhitened.
As shown in the above animated plot, the intensity noise increased at the beginning and then went back down to where it was. The overall spectral shape almost did not change, but the scaling factor has changed roughly by a factor of two comparing the minimum and maximum. The magnitude of the coupling rises in proportion to frequency -- if I plotted them for a coupling to DCPDs, they would be almost flat due to the cavity pole correction taken out.
Here is another plot showing the evolution of coupling as a function of time.
The upper plot shows the transfer coefficient at 2500 Hz (in arbitrary unit) as a function of time. The bottom plot shows the CO2 lensing from the same period. The transfer coefficient shows a clear correlation with the defocus of ITMs. I can not say for sure if the differential was a dominant cause of this effect because I had a few uD defocus as well in the same fashion.
Here is the same analysis for the frequency noise coupling to DARM. The variation in the coupling is more drastic than that of intensity noise.
The below is a same type of animated plot. The transfer function was measured from REFLA_RF9_I_ERR to CAL-DELTAL_EXTERNAL. Note that DELTAL_EXTERNAL is properly unwhitend.
It seems that the coupling has two different mechanisms, one for the coupling below 300 Hz and the other for the above. As the CO2 setting changed, the high frequency part increased at the beginning and decreased later while keeping the same spectral shape. On the other hand the low frequency part varied in an opposite fashion; it decreased as the high frequency part increased. The slope of the high frequency coupling seems to be almost proportional to f. If we convert it into [OMC DCPDs [A] / laser frequency [Hz]], it will be more like 1/f due to the cavity pole and REFL's transfer functinon against the laser frequency.
Here is another plot showing the evolution of the transfer coefficient at 2500 Hz. The coupling coefficient changed by a factor of 15 at this frequency. This is much more drastic than that of the intensity noise coupling which varied by a factor of two or so.
A preliminary conclusion:
With the 2 W PSL, the DARM cavity pole prefers a high CO2 differential lensing while the laser noise couplings prefer a low differential lensing.
This is a belated analysis on the intensity noise coupling. The punch lines are:
[Noise coupling v.s. differential lensing]
As seen in the plot above, the coupling coefficient shows a linear relation to the differentianl lensing. This likely indicates that the differential lensing is not optimized to minimize the intensity noise coupling. I should note that this measurement had used the badly clipped COY beam (27433) which was later fixed in May 2016; a smaller differential lensing means less power in CO2Y than CO2X.
[Intensity noise coupling]
Here is a plot showing the intensity noise coupling of the various TCS settings. This time the coupling coefficient is converted to OMC power [W] / input RIN. The dashed line in the magnitude represents the expected value calculated by
(coupling) = 2 * J1^2 * Pin * Tomc * Tifo [W/RIN] = 5.5e-6 [W/RIN],
where Pin = 2 W is the PSL input power, Tomc = 61.4 ppm is the OMC transmission for the 45 MHz RF sidebands, and Tifo is the transmission of the intereferometer for the 45 MHz RF sidebands which I have assumed to be 1 for quick calculation. As seen in the plot, the expected noise level (limited by the 45 MHz RF sidebands) is lower then the measurement by roughly a factor of 10. These two plots support the hypothesis that we are far from the optimum point.
Here are the beamsplitter angles as a function of differential lensing. (There are some data dropouts in the trends).
This seems to indicate that a differential lens change of a few tens of microdiopters causes the beamsplitter yaw to change by a few hundreds of nanoradians, presumably via changes in the 36 MHz angular plant. In pitch it is less clear whether we are seeing angular control effects or simply drift over time.
