ID |
Date |
Author |
Type |
Category |
Subject |
10567
|
Mon Oct 6 10:04:58 2014 |
manasa | Update | General | Unexpected power shutdown |
We had a unexpected power shutdown for 5 sec at ~ 9:15 AM.
Chiara had to be powered up and am in the process of getting everything else back up again.
Steve checked the vacuum and everything looks fine with the vacuum system. |
10569
|
Mon Oct 6 10:28:18 2014 |
manasa | Update | General | Unexpected power shutdown |
Quote: |
We had a unexpected power shutdown for 5 sec at ~ 9:15 AM.
Chiara had to be powered up and am in the process of getting everything else back up again.
Steve checked the vacuum and everything looks fine with the vacuum system.
|
The last time we had a power failure IFO recovery elog |
10570
|
Mon Oct 6 11:09:52 2014 |
Jenne | Update | General | Unexpected power shutdown: slow computers |
As per other slow computers, which Chris figured out in elog 10189, I added all the rest of the slow computers to Chiara's /etc/hosts file, so that they would come up when Manasa went and keyed the crates.
Computers that were already there:
Computers that I added today:
- c1susaux
- c1auxey
- c1iscaux2
- c1pem1
- c1aux
- c1iool0
- c1vac1
Manasa keyed all of these crates *except* for the vac computer, since Steve said that the vacuum system is up and running fine. |
10571
|
Mon Oct 6 17:04:51 2014 |
ericq | Update | General | Unexpected power shutdown |
I brought back the PMC, MC and Arms.
PMC:
- Same as when we replaced the busted sorensen, the kepco regulators in 1X1 (which power the FSS HV amp, PMC PZT and WFS) needed to be brought back up in the proper order. (Middle two are + and - for the FSS, need to be rolled up in unison). Also the same as that occasion, sticky sliders prevented the full voltage range on the PMC PZT from being accessible. I touched every button on the PMC and FSS screens, which seemed to fix it.
- I then realigned the PMC to ~0.80 transmission
MC:
- Needed to do some hand alignment to get a lock
- Measured spot positions, they were all under 2mm
- Despite centering the beams on the WFS and setting the offsets, WFS would not turn on successfully
- Also, the autolocker on megatron isn't doing anything but blinking
- Also also, MC2 is exhibiting some intermittent alignment wandering. The SUSDOF traces look like flat ramps lasting a few minutes.
Arms:
- No green was evident anywhere, but it didn't take to much alignment tweaking to get IR flashes
- No signals were evident on RFPDs, confirmed light on PDs and power to demod boards.
- Turned out the 11MHz Marconi was not doing anything, and needed to be reset to the modulation frequency in ELOG 10314 (which reminds me that I need to update the sticker on the marconi)
- Locked arms, ASS'ed, oplev spots were acceptable.
|
10572
|
Mon Oct 6 17:36:17 2014 |
ericq | Update | General | Unexpected power shutdown |
The autolocker is now working, but I didn't change anything to make it so. I was just putting in some echo statements, to see where it was getting hung up, and it started working... This isn't the first time I've had this experience.
It turns out IOO had a bad BURT restore. I restored from 5AM this morning, the WFS are ok now. |
10573
|
Mon Oct 6 18:15:12 2014 |
manasa | Update | General | Unexpected power shutdown: end green alignment |
After Q brought back the IR, I went to check the green situation.
1. The end lasers had to be turned ON.
2. The heaters for the doubler crystals had to be enabled. The heaters are at the set values.
3. The X arm PZTs for the steering mirrors had to be powered up (Set voltage 100V and current 6.7mA)
4. I aligned the green to the already IR-aligned arms.
Green PSL alignment has to be done after Q finishes his work on the MC WFS. |
10575
|
Tue Oct 7 10:09:07 2014 |
manasa | Update | General | Chiara not responding |
Chiara doesn't seem to be responding and I guess something happened 7 hrs ago.
I tried to hook up chiara to a monitor to reboot or atleast look for error messages; but it is not even detecting the external monitor (Tried changing monitors and vga cables; still see nothing).
I tried to ssh into it and only received errors :
NFS lookup failed for server XXX.XXX.XXX.XXX : error 5 (RPC: Timed out)
ssh: chiara: host/servname not known
Steve had the vacuum checked and everything seems fine with the status of the vacuum system atleast. |
10576
|
Tue Oct 7 16:17:15 2014 |
Steve | Update | General | reason for 8 sec power outage |
Quote: |
We had a unexpected power shutdown for 5 sec at ~ 9:15 AM.
Chiara had to be powered up and am in the process of getting everything else back up again.
Steve checked the vacuum and everything looks fine with the vacuum system.
|
There was an equipment malfunction in one of Pasadena's substation that caused the outage. After about an 8 second delay, back up circuits restored power. This affected about 1/2 of the campus.
Mike
-----Original Message-----
From: Steve Vass [mailto:steve@ligo.caltech.edu]
Sent: Tuesday, October 07, 2014 2:18 PM
To: Anchondo, Michael
Subject: 5s
Hi Mike,
Can you tell me about yesterday's power outage?
Thanks, Steve
|
10577
|
Tue Oct 7 16:19:50 2014 |
ericq | Update | General | Chiara not responding |
We're back! It was entirely my fault.
Some months ago I wrote a script that chiara calls every night, that rsyncs its hard drive to an external drive. With the power outage yesterday, the external drive didn't automatically mount, and thus chiara tried to rsync its disk to the mount point, which was at the time just a local folder, which made it go splat. 
I'm fixing the backup script to only run if the destination of the rsync job is not a local volume. |
10578
|
Tue Oct 7 16:41:12 2014 |
Jenne | Update | General | Chiara not responding |
I put a little script into ...../scripts/Admin that will check the fullness of Chiara's disk. We only have the mailx program installed on Nodus, so for now it runs on Nodus and sends and email when the chiara disk that nodus mounts is more than 97% full. |
10586
|
Thu Oct 9 10:52:37 2014 |
manasa | Update | General | Power outage II & recovery |
Post 30-40min unexpected power outage this morning, Steve checked the status of the vacuum and I powered up Chiara.
I brought back the FE machines and keyed all the crates to bring back the slow machines but for the vac computers.
c1vac1 is not responding as of now. All other computers have come back and are alive. |
10592
|
Thu Oct 9 19:14:04 2014 |
ericq | Update | General | Power outage II & recovery |
I touched up the PMC alignment.
While bringing back the MC, I realized IOO got a really old BURT restore again... Restored from midnight last night. WFS still working.
Now aligning IFO for tonight's work |
10610
|
Wed Oct 15 17:09:49 2014 |
manasa | Update | General | Diode laser test preparation |
[EricG, manasa]
The He-Ne laser oplev setup was swapped with a fiber-coupled diode laser from W Bridge. The laser module and its power supply are sitting on a bench in the east side of the SP table. |
10629
|
Tue Oct 21 18:40:46 2014 |
manasa | Update | General | End laser fiber setup |
[Manasa, Diego]
This is our first time touching tables for Frequency Offset Locking.
The goal was to couple the 1064nm that leaks after the SHG crystal and couple it into the fiber before we run it along the length of the arm.
The fiber has been mounted at the end but there is no light coupled into the fiber as yet.
In the process, the following were done:
1. ETMY oplev servo disabled. This was enabled after the work.
2. NPRO laser power was reduced so that nothing gets burnt accidently while putting things on the table. This was also reset after the work.
The arms could be locked to green and IR after the work. So I am hoping today's work will not affect locking. |
10635
|
Thu Oct 23 13:08:55 2014 |
ericq | Update | General | Gap in local Chiara backups |
After the second of the two recent power outages, the outlet powering Chiara's external drive for local backups didn't come back. The modification to the backup script I made correctly identified that the drive wasn't mounted, and happily logged its absence and didn't try to stuff the internal drive with a copy of itself. However, I hadn't checked the logs to see if the backups were proceeding until today... maybe I should set up an email alert for these, too.
I plugged the external drive into a live outlet, and mounted the 40mBackup drive with: sudo udisks --mount /dev/sdc1 , which is a helpful command that puts the drive at /media/40mBackup as it should be, based on the drive label.
The /cvs/cds backup is now proceeding, to make up for lost time. |
10636
|
Thu Oct 23 17:45:54 2014 |
Jenne | Update | General | Pianosa frozen |
Not sure why, but Pianosa was frozen. Also couldn't ssh or ping. So, I hard power cycled it. |
10638
|
Fri Oct 24 10:08:24 2014 |
manasa | Update | General | Y AUX laser - fiber coupled |
The Y end aux laser light leaking after the doubling crystal has been coupled into the 70m long PM fiber.
Input power = 250mW; Output after 70m = 20mW
The poor efficiency is partially due to the ellipticity of the beam itself and partially due to the compromise I had to make using a single lens to couple the light into the fiber (given the limitations in space). But 20mW should be more than sufficient for a beat note setup.
Light propagates as follows after the doubling crystal:
Doubler ---> Harmonic Separator (45deg) ---> Lens (f=12.5cm) --> Steering mirror (Y1) --> Fiber collimator ( Thor labs CFC-2X-C) --> FIber end
I will update photos of the setup shortly.
I have left the 70m fiber in its spool sitting at the Y end and blocked the light before the last Y1 steering mirror in the above setup. So it should be safe.
Other:
Through the course of the work, I disabled the ETMY oplev and enabled it before closing the enclosure. I also reduced the AUX laser power and brought it back up after the work.
I did a check to see if the arms are locking in both IR and green and they did.
|
10639
|
Fri Oct 24 18:53:23 2014 |
rana | Update | General | Y AUX laser - fiber coupled |
10% seems like a pretty bad coupling efficiency, even for a single lens. I know that the NPRO itself isn't so elliptical as that. Where is the other 230 mW going? random scattering?
Given that this is such an invasive process and, since its so painful to lose a whole night of locking due to end table business, I suggest that you always measure the out-of-loop ALS noise at the end of the end table work. Just checking that the green laser is locked to the arm is not sufficient to prove that the end table work won't prevent us from locking the interferometer.
We should insist on this anytime someone works on the optics or electronics at EX or EY. Don't have enough time to do an out-of-loop ALS spectrum? Then don't work at the end tables at all that day. We've got PZT alignment and mode matching work to do, as well as the rebuild of the EX table enclosure, so this is a good discipline to pick up now. |
10640
|
Mon Oct 27 12:17:46 2014 |
manasa | Update | General | Y AUX laser coupling telescope design |
Since I obtained a poor coupling efficiency from the earlier setup, I went back to calculate the coupling efficiency of the current setup.
For the current setup, I took the average of the x and y waist of the input beam and calculated the distance at which the input beam diameter would match the (fiber +collimator) beam diameter.
Average waist = 40.2um @-3.3mm from face of doubling crystal
(Fiber PM980 + Collimator f=2.0mm) beam waist = 205um
Distance(z) at which the input beam waist is 205um = 11.9cm
The closest available lens was f = 12.5cm. So I used it to couple the input beam by placing it at z ~12.5cm on a micrometer stage.
Since this gave only 10% coupling, I went back to calculate (using 'a la mode') the best possible coupling that can be obtained taking into consideration the ellipticity of the beam.
The maximum obtainable coupling (mode overlap) is 14.5% which is still poor.
Redesign
Taking into account the ellipticity of the input beam, the available lenses and the space restrictions (lens can be placed only between z= 8 to 28cm), I calculated the best possible coupling efficiency (using 'a la mode').
The maximum possible mode overlap that can be obtained is 58.6% (matlab code and plot attached)
>>auxmode
modematching = 0.58632
Optimized Path Component List:
label z (m) type parameters
----- ----- ---- ----------
L1 0.0923 lens focalLength: 0.0750
|
Attachment 1: AUXmode.zip
|
Attachment 2: AUXmode.png
|
|
10650
|
Wed Oct 29 11:45:11 2014 |
manasa | Update | General | Y AUX laser - fiber coupled (52%) |
Quote: |
Redesign
Taking into account the ellipticity of the input beam, the available lenses and the space restrictions (lens can be placed only between z= 8 to 28cm), I calculated the best possible coupling efficiency (using 'a la mode').
The maximum possible mode overlap that can be obtained is 58.6% (matlab code and plot attached)
>>auxmode
modematching = 0.58632
Optimized Path Component List:
label z (m) type parameters
----- ----- ---- ----------
L1 0.0923 lens focalLength: 0.0750
|
I used the above configuration and was able to obtain ~52% coupling.
Input power = 250mW
Output power with absorptive ND 1.0 = 13 mW
I used the absorptive ND filter before the lens to keep the coupled output power within the range of fiber power meter and also avoid scattering of enormous amount of uncoupled light all over the table.
I have attached the screenshot of the out of loop ALS noise before opening the table (BLUE) and after closing down (MAGENTA). The beat note frequency and amplitude before and after were (14.4MHz/-9.3dBm) and (20.9MHz/-10 dBm). |
Attachment 1: 31.png
|
|
10651
|
Wed Oct 29 18:07:28 2014 |
manasa | Update | General | Diode laser test preparation |
I ran 3 BNC cables from the SP table to 1X7 rack so that we can have 16 bit channels for the Ontrak PD that will be used to test oplev lasers. The BNC cables are plugged to the Ch 29, 30 & 31 that were already created for this purpose (elog 10488) |
10659
|
Fri Oct 31 19:59:26 2014 |
Koji | Update | General | Some locking work / PRMI analysis |
Preparations
- According to Diego's report, the MC WFS gains were too high. We'll fix this later by tweaking the servo shapes.
But for now, all of the WFS gains were reduced by 40%.
i.e. WFS(1|2)(PIT|YAW) gains from 5 to 3, MC2TRANS(PIT|YAW) gains from 50 to 30.
- Aligned IMC carefully and ran the offset nulling script. MC REFL became 0.435~0.445 and MC TRANS was ~16600.
- Locked the arms and ran ASS.
PRMI
- Started locking PRMI. I just used REFL33I&Q as suggested by the configure script. The PRMI locking was not so robust.
Particularly, the third violin mode of PRM and BS seemed to get excited and dominated the signals.
I modified Vio3 filter in the violin filter for BS and PRM to include zero at 1921Hz where the growing peak was seen.
- We probably want to start from the 1f signals for DRMI lock acquisition. So I wanted to check how REFL11s are.
Measured the demod phase and relative gain between 33I and 11I. (By the way, REFL11I whitening gain was lowered to 0dB).
REFL11I had about x10 gain and the same phase compared to REFL33I. The demod phase for REFL11 was +21deg.
Also checked REFL55 phase and gain. 55Q has almost the same gain as 33Q. And the adjusted phase was 25deg.
These were just rough adjustment of the demod phases.
- Then the servo configuration was transtioned to Configuration 1 (below), and then Configuration 2.
- This configuration was very stable and the PRMI stayed locked about ~1 hour. During this long lock, I could measure
PSDs, sensing matrix, and etc. Also I could play with the PRM ASC. I wasn't sure if the POP is actually stabilized or not.
(I have no data)
- I noticed that something was ringinging up at 1883Hz. Another 3rd order viloin mode???
- The lock was lost due to too strong injection. But also it reacquired without touching.
- Precise demod phase adjustment has been done by elliminating PRCL from the Q signals.
REFL11 16.75
REFL33 133.0
REFL55 31.0
REFL165 -142
AS55 -53
- Configiration1 (REFL11I&REFL55Q)
REFL11: WTN 0dB PHASE 21deg, REFL11I x0.1 -> PRCL
REFL33: WTN 30dB PHASE 145deg
REFL55: WTN 21dB PHASE 25deg, REFL55Q x1 -> MICH
PRCL: GAIN -0.04 FM4/5 ON, Triggered FM 2/3/6/9, Servo trigger: POP22I 50up 10down, No Normaization.
MICH: GAIN 10 FM4/5 ON, Triggered FM 2/3/6/9, Servo trigger: POP22I 50up 10down, No Normaization.
PRCL -> PRM +1
MICH -> PRM -0.2625, BS +0.50 BS
- Configuration 2 (REFL11I&Q)
Same as above except:
REFL11Q x-0.1 -> MICH
Calibration
Let's use these entries
PRM: http://nodus.ligo.caltech.edu:8080/40m/8255
PRM: (19.6 +/- 0.3) x 10^{-9} (Hz/f)^2 m/counts
BS/ITMs http://nodus.ligo.caltech.edu:8080/40m/8242
BS = (20.7 +/- 0.1) x 10 -9 / f2
ITMX = (4.70 +/- 0.02) x 10 -9/ f2
ITMY = (4.66 +/- 0.02) x 10 -9/ f2
- PRCL Calibration
Lockin oscillator module 675.13Hz 100 -> +1 PRM
Measurement bandwidth 0.1Hz -> Signal power BW 0.471232 (FLATTOP window)
C1:SUS-PRM_LSC_IN1: 118.99 cnt/rtHz => 5.12pm/rtHz
REFL11I: 17.84 cnt/rtHz => 3.49e12 cnt/m
REFL33I: 2.28 cnt/rtHz => 4.46e11 cnt/m
REFL55I: 0.158 cnt/rtHz => 3.09e10 cnt/m
REFL165I: 1.63 cnt/rtHz => 3.19e11 cnt/m
- MICH Calibration
Lockin oscillator module 675.13Hz 100 -> -1 ITMX +1 ITMY
Measurement bandwidth 0.1Hz -> Signal power BW 0.471232 (FLATTOP window)
C1:SUS-ITMX_LSC_IN1: 121.79 cnt/rtHz => 1.26pm/rtHz
C1:SUS-ITMY_LSC_IN1: 121.79 cnt/rtHz => 1.25pm/rtHz
REFL11Q: 0.0329 cnt/rtHz => 1.32e10 cnt/m (PRCL/MICH ratio 265)
REFL33Q: 0.00773 cnt/rtHz => 3.09e9 cnt/m (144)
REFL55Q: 0.001645 cnt/rtHz => 6.58e8 cnt/m (47)
REFL165Q: 0.00374 cnt/rtHz => 1.50e9 cnt/m (213) !?
AS55Q: 0.0696 cnt/rtHz => 2.78e10 cnt/m
Openloop TF measurements
Servo filter TF measuremnts
The UGFs were ~250Hz for PRCL and ~120Hz for MICH, respectively.
The OLTF was modelled by the servo and violin filters TF from foton, estimated TF of the AA/AI filters, and the constant time delay.
Displacement spectra measurement
SELF NOTE: DON'T FORGET TO TURN ON the whitening of the unused signals! (USE MC DOF or manual switch)
- PRCL
The PRCL displacement was measured with REFL I signals. In the attachment 3, the in-loop and free-run equivalent displacements are shown (red and blue).
Other out-of-loop sensors (33/55/165) were also plotted together.
FIrst of all, the uncompensated displacement noise level of PRCL is around 1e-7 m/rtHz. This is a good indication that the calibration was not crazy.
The sensing noise of REFL11 seems to be 1e-15~1e-16 m/rtHz at high frequency which is enough for now.
As expected, REFL11I has the best noise level among the REFLs. At low frequency, it seemed that the noise level is limited by something at 1e-12 m/rtHz.
Of course, we can't say this is just the sensing noise of the other REFLs or the noise of the REFL11I. But this noise level is enough small for the locking of
the low finesse (F<100) PRCL cavity.
Remembering we had no trouble locking PRCL with REFL33/55/165, this plot indicates that the PRCL was suppressed too much below 2Hz.
And we want more supression between 5Hz to 30Hz. We have resonant gains in ther PRCL servo but not sure how effective they were.
If we consider the contamination of PRCL in MICH, we should try to optimize the PRCL servo.
- MICH
The MICH displacement was similary calibrated to PRCL. The signal sources were the REFL Qs and AS55Q.
In the attachment 4, the in-loop and free-run equivalent displacements are shown (red and blue).
Other out-of-loop sensors were also plotted together.
The problem here is that the out-of-loop levels (REFL33/55/165 and AS55) show almost the same levels
and thus it is likely that the actual (out-of-loop) stability of MICH is this kind of level. If we believe it, we only have
~1/100 supression between 1-10Hz and ~1/10Hz below 0.5Hz. The strong servo control does nothing to stablize
MICH. From the out-of-loop noise level of MICH, this comes for the contamination from leakage PRCL.
We really need to improve the signal quality of MICH.
The MICH servo filter has quite complicated shape, but is not necessary according to the estimated free-runing MICH.
The MICH free-running motion is quieter than the PRCL one between 1Hz to 30Hz. The reasonable explanation is
that it comes from poor vibration isolation of the tip-tilts. It means that SRCL also has the similar noise level to PRCL. |
Attachment 1: PRMIsb_PRCL_OLTF.pdf
|
|
Attachment 2: PRMIsb_MICH_OLTF.pdf
|
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Attachment 3: PRMIsb_PRCL_SPE.pdf
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Attachment 4: PRMIsb_MICH_SPE.pdf
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|
10670
|
Wed Nov 5 11:37:29 2014 |
manasa | Update | General | Light from Y end reaches PSL table |
[Steve, Diego, Manasa]
Since the beatnotes have disappeared, I am taking this as a chance to put the FOL setup together hoping it might help us find them.
Two 70m long fibers now run along the length of the Y arm and reach the PSL table.
The fibers are running through armaflex insulating tubes on the cable racks. The excess length ~6m sits in its spool on the top of the PSL table enclosure.
Both the fibers were tested OK using the fiber fault locator. We had to remove the coupled end of the fiber from the mount and put it back in the process. So there is only 8mW of end laser power at the PSL table after this activity as opposed to ~13mW. This will be recovered with some alignment tweaking.
After the activity I found that the ETMY wouldn't damp. I traced the problem to the ETMY SUS model not running in c1iscey. Restarting the models in c1iscey solved the problem.
|
10671
|
Wed Nov 5 17:50:29 2014 |
manasa | Update | General | PSL and AUXY beatnote in IR found |
Found the IR beatnote between PSL and Y end laser.
Since our goal was to find the beatnote ASAP to recover ALS, I ignored the fine details in alignment. I will revisit the setup to make some improvements in the near future.
1. Coupled the PSL IR beam leaking after the doubler into the fiber. We have only 10% coupling into the fiber at the PSL table right now (6mw); but this will be improved once I get a suitable translation stage for the telescope.
2. PSL IR --> PM980 fiber --->50-50 fiber beam splitter ---> 50-50 fiber beam combiner
AUX Y ---> PM980 fiber ---> 50-50 fiber beam combiner
The output port of the fiber beam combiner is connected to the fiber coupled broadband RF PD.
3. The RF output of the PD when connected to a spectrum analyzer shows a beatnote of -50dBm. The small amplitude of the beatnote is due to the laser power being attenuated before coupling into the fiber to keep the PD safe.
Attached is photo of how the setup is put on the PSL table. We will put all the stuff in a box once the X setup is also in place. |
Attachment 1: PSLsetup.jpg
|
|
10677
|
Thu Nov 6 10:18:12 2014 |
Steve | Update | General | fiber insulation in cable tray |
Quote: |
[Steve, Diego, Manasa]
Since the beatnotes have disappeared, I am taking this as a chance to put the FOL setup together hoping it might help us find them.
Two 70m long fibers now run along the length of the Y arm and reach the PSL table.
The fibers are running through armaflex insulating tubes on the cable racks. The excess length ~6m sits in its spool on the top of the PSL table enclosure.
Both the fibers were tested OK using the fiber fault locator. We had to remove the coupled end of the fiber from the mount and put it back in the process. So there is only 8mW of end laser power at the PSL table after this activity as opposed to ~13mW. This will be recovered with some alignment tweaking.
After the activity I found that the ETMY wouldn't damp. I traced the problem to the ETMY SUS model not running in c1iscey. Restarting the models in c1iscey solved the problem.
|
AP Armaflex tube 7/8" ID X 1" wall insulation for the long fiber in wall mounted cable trays installed yesterday.
The 6 ft long sections are not glued. Cable tied into the tray pressed against one an other, so they are air tight. This will allow us adding more fibers later.
Atm2: Fiber PSL ends protection added on Friday.
|
Attachment 1: APT07810.jpg
|
|
Attachment 2: fromYend.jpg
|
|
10678
|
Thu Nov 6 11:40:58 2014 |
Steve | Update | General | He/Ne telescope |
Liyuan is measuring the He/Ne telescopes in the Y arm between the tube and CES wall. He'll be here till 1pm |
10684
|
Fri Nov 7 10:29:56 2014 |
Steve | Update | General | He/Ne telescope |
Quote: |
Liyuan is measuring the He/Ne telescopes in the Y arm between the tube and CES wall. He'll be here till 1pm
|
Liyuan is continuing his measurement in the Y arm till noon today. |
10702
|
Wed Nov 12 15:14:09 2014 |
manasa | Update | General | X end AUX laser fiber setup |
I looked at the endtable for possible space to setup optics in order to couple the X end laser into a PM fiber.
Attached is the layout of where the setup will go and what are the existing stuff that will be moved.

|
10730
|
Fri Nov 21 11:41:24 2014 |
manasa | Update | General | X end fiber insulated and on cable tray |
Quote: |
Quote: |
[Steve, Diego, Manasa]
Since the beatnotes have disappeared, I am taking this as a chance to put the FOL setup together hoping it might help us find them.
Two 70m long fibers now run along the length of the Y arm and reach the PSL table.
The fibers are running through armaflex insulating tubes on the cable racks. The excess length ~6m sits in its spool on the top of the PSL table enclosure.
Both the fibers were tested OK using the fiber fault locator. We had to remove the coupled end of the fiber from the mount and put it back in the process. So there is only 8mW of end laser power at the PSL table after this activity as opposed to ~13mW. This will be recovered with some alignment tweaking.
After the activity I found that the ETMY wouldn't damp. I traced the problem to the ETMY SUS model not running in c1iscey. Restarting the models in c1iscey solved the problem.
|
AP Armaflex tube 7/8" ID X 1" wall insulation for the long fiber in wall mounted cable trays installed yesterday.
The 6 ft long sections are not glued. Cable tied into the tray pressed against one an other, so they are air tight. This will allow us adding more fibers later.
Atm2: Fiber PSL ends protection added on Friday.
|
[Steve, Manasa]
Two 70m long fibers are now running through armaflex insulating tubes along the X arm on the cable racks. The excess length of the fiber sits in its spool on top of the PSL enclosure.
Fibers were checked after this with the fiber fault locator (red laser) and found OK. |
10739
|
Mon Dec 1 15:41:38 2014 |
Steve | Update | General | X end fiber insulated and on cable tray |
Quote: |
Quote: |
Quote: |
[Steve, Diego, Manasa]
Since the beatnotes have disappeared, I am taking this as a chance to put the FOL setup together hoping it might help us find them.
Two 70m long fibers now run along the length of the Y arm and reach the PSL table.
The fibers are running through armaflex insulating tubes on the cable racks. The excess length ~6m sits in its spool on the top of the PSL table enclosure.
Both the fibers were tested OK using the fiber fault locator. We had to remove the coupled end of the fiber from the mount and put it back in the process. So there is only 8mW of end laser power at the PSL table after this activity as opposed to ~13mW. This will be recovered with some alignment tweaking.
After the activity I found that the ETMY wouldn't damp. I traced the problem to the ETMY SUS model not running in c1iscey. Restarting the models in c1iscey solved the problem.
|
AP Armaflex tube 7/8" ID X 1" wall insulation for the long fiber in wall mounted cable trays installed yesterday.
The 6 ft long sections are not glued. Cable tied into the tray pressed against one an other, so they are air tight. This will allow us adding more fibers later.
Atm2: Fiber PSL ends protection added on Friday.
|
[Steve, Manasa]
Two 70m long fibers are now running through armaflex insulating tubes along the X arm on the cable racks. The excess length of the fiber sits in its spool on top of the PSL enclosure.
Fibers were checked after this with the fiber fault locator (red laser) and found OK.
|
X-arm AP Armaflex tube insulation is cable tightened into cable tray. Only turning 6 ft sections are taped together.
Remaining things to do: install ends protection tubing |
10740
|
Mon Dec 1 16:34:20 2014 |
Jenne | Update | General | IFO wake-up |
After its' several days of rest, it is time to wake up the IFO.
- FSS temp was railed at +10, which was making the MC not want to lock. Set it to zero, locked the MC, and ran the MC WFS relief scripts.
- PMC trans is down to 0.686, so I'll probably want to tweak that up before I get too carried away for tonight.
- c1iscex computer was frozen, which I suspect is why Steve found ETMX tripped this morning. Soft reboot, and we're back to normal.
With that, it's time for a new week of locking, and trying to catch up with the big kids at the sites. |
10742
|
Mon Dec 1 17:19:22 2014 |
Jenne | Update | General | PMC align |
[Diego, Jenne]
Tweaked up the input alignment to the PMC. Now we're at 0.785. |
10758
|
Fri Dec 5 02:44:43 2014 |
Jenne | Update | General | IFO alignment shenanigans |
[Jenne, Q, Diego]
OMG, today sucked alignment-wise. Like, wow.
I think that the problem with the ASS is with the input pointing part of the system. I found that if I disable the TTs for the Yarm (iin practice, the outputs are held at zero), I could run the Yarm ASS at full gain of 1, and it would do an awesome job. The first time I did this, I by-hand optimized the TTs by running the test mass loops to make them follow the input pointing. After that, I haven't touched the TT pointing at all, and we've just been running the test mass loops for the Yarm ASS. The Xarm seems to not have this problem (or at least not as drastically), so I left it as it was, touching BS as well as ITMX and ITMY, although the gain still needs to be about 0.3.
I feel pretty good about the IFO alignment now, although it is slightly different than it has been. The transmitted arm powers are higher than they were before I changed the ASS procedure, and there seems to be a little less power fluctuation with alignment. Q points out that I don't have concrete evidence that this is a good alignment, but it feels right.
It was a significant enough change that I had to go down to the Yend to realign the green to the new arm axis. Xgreen we did with the remote PZTs. I also realigned both of the beatnotes on the PSL table.
While I was on the PSL table, I quickly touched up the PMC alignment.
The biggest problem, the one that sucked up more hours and energy than I'd like to admit, is ETMX's jumping. So frustrating. Sometimes it is time-coincident with engaging the LSC, sometimes not. I thought that it might be because there are too many violin filters, but even if I turn off all violin filters to ETMX, it jumped a few times while the cavity was locked. Sometimes it moves when the cavity is just locked and seems happy, sometimes it moves when nothing is resonating except for the green. It takes a few minutes to recover the alignment enough to lock, and then it'll jump again a few minutes later. I haven't gone down to squish the cables today, although I did it yesterday and that didn't seem to do anything.
We had a few hours of time when it wasn't jumping, so we tried a few times to lock the IFO. The last several times we have lost lock because the PRC loop rang up. We measured the loop at low-ish arm powers, but it kept losing lock at higher powers before we could measure. At least 3 times, the PRC lockloss took out CARM and DARM too.
Anyhow, it has been a long day of not accomplishing anything interesting, but hopefully the IFO will feel better tomorrow. |
10760
|
Sun Dec 7 13:11:57 2014 |
manasa | Summary | General | Frequency Offset Locking - To Do List |
Attached is the timeline for Frequency Offset Locking related activities. All activities will be done mostly in morning and early afternoon hours. |
Attachment 1: FOLtodolist.pdf
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|
10765
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Mon Dec 8 15:54:39 2014 |
manasa | Summary | General | Dec 8 - Check Frequency Counter module |
Quote: |
Attached is the timeline for Frequency Offset Locking related activities. All activities will be done mostly in morning and early afternoon hours.
|
[Diego, Manasa]
We looked into the configuration and settings that the frequency counters (FC) and Domenica (the R pi to which the FCs talk to) were left at . After poking around for a few hours, we were able to readout the FC output and see it on StripTool as well.
We have made a list of modifications that should be done on Domenica and to the readout scripts to make the FC module automated and user-friendly.
I will prepare a user manual that will go on the wiki once these changes are made.
|
10766
|
Mon Dec 8 20:53:51 2014 |
diego | Summary | General | Dec 8 - Check Frequency Counter module |
Quote: |
Quote: |
Attached is the timeline for Frequency Offset Locking related activities. All activities will be done mostly in morning and early afternoon hours.
|
[Diego, Manasa]
We looked into the configuration and settings that the frequency counters (FC) and Domenica (the R pi to which the FCs talk to) were left at . After poking around for a few hours, we were able to readout the FC output and see it on StripTool as well.
We have made a list of modifications that should be done on Domenica and to the readout scripts to make the FC module automated and user-friendly.
I will prepare a user manual that will go on the wiki once these changes are made.
|
I started working on the scripts/FOL directory (I did a backup before tampering around!):
- I still need to make some serious polishing in the folder, and into the Raspberry Pi itself, in order to have a clean and understandable environment;
- as of now, I created an single armFC.c program, which takes as arguments the device (/dev/hidraw0 for the X arm, and /dev/hidraw1 for the Y arm) and the value to write into the frequency counter (0x3 for initialization and 0x2 for actual use); hence, no more need for recompilation!
- I improved the codetorun.py script (and gave the fellow a proper name, epics_channels.py) which handles the initialization AND the availability of the channels;
- On the Raspberry Pi, I created two init scripts, /etc/init.d/epics_server.sh and /etc/init.d/epics_channels.sh, which start at the end of the boot process with default runlevels; the former starts the softIOc process (epics itself), while the latter executes the constantly running epics_channels.py script; as they are services, they can be started/stopped with the usual sudo /etc/init.d/NAME start|stop|restart
As a result, as soon as the Raspberry Pi completes its boot process, the two beatnote channels are immediately available.
|
10767
|
Tue Dec 9 00:30:27 2014 |
manasa | Summary | General | Dec 9 - Elaborate to do list |
Quote: |
Attached is the timeline for Frequency Offset Locking related activities. All activities will be done mostly in morning and early afternoon hours.
|
Elaborate to do list:
1. The FC module should be mounted on the IOO rack. Domenica has to be powered up appropriately to the rack power supply.
2. The fiber chassis needs to be built. This will hold all the fiber components and will sit inside the PSL enclosure.
Fiber connectors and fiber couplers need to be installed in the chassis. Attached is the cartoon sketch of layout in the chassis.
3. User guide for FC module (work in progress) |
Attachment 1: FOL_FiberChassis.pdf
|
|
10770
|
Tue Dec 9 16:06:46 2014 |
diego | Summary | General | Dec 8 - Check Frequency Counter module |
Quote: |
Quote: |
Quote: |
Attached is the timeline for Frequency Offset Locking related activities. All activities will be done mostly in morning and early afternoon hours.
|
[Diego, Manasa]
We looked into the configuration and settings that the frequency counters (FC) and Domenica (the R pi to which the FCs talk to) were left at . After poking around for a few hours, we were able to readout the FC output and see it on StripTool as well.
We have made a list of modifications that should be done on Domenica and to the readout scripts to make the FC module automated and user-friendly.
I will prepare a user manual that will go on the wiki once these changes are made.
|
I started working on the scripts/FOL directory (I did a backup before tampering around!):
- I still need to make some serious polishing in the folder, and into the Raspberry Pi itself, in order to have a clean and understandable environment;
- as of now, I created an single armFC.c program, which takes as arguments the device (/dev/hidraw0 for the X arm, and /dev/hidraw1 for the Y arm) and the value to write into the frequency counter (0x3 for initialization and 0x2 for actual use); hence, no more need for recompilation!
- I improved the codetorun.py script (and gave the fellow a proper name, epics_channels.py) which handles the initialization AND the availability of the channels;
- On the Raspberry Pi, I created two init scripts, /etc/init.d/epics_server.sh and /etc/init.d/epics_channels.sh, which start at the end of the boot process with default runlevels; the former starts the softIOc process (epics itself), while the latter executes the constantly running epics_channels.py script; as they are services, they can be started/stopped with the usual sudo /etc/init.d/NAME start|stop|restart
As a result, as soon as the Raspberry Pi completes its boot process, the two beatnote channels are immediately available.
|
Update and corrections:
- I forgot to log that I added a udev rule in /etc/udev/rules.d/98-hidraw-permissions.rules in order to let the controls user access the devices without having to sudo all the time;
- I updated the ~/.bashrc and /opt/epics/epics-euser-env.sh files to fix syntax errors and add some aliases we usually use;
- since /etc/init.d/ doesn't support automatic respawn of processes, I purged the two scripts I did yesterday and added two lines to /etc/inittab. This works just as fine (I tried a couple of reboots to verify that) and the two processes now respawn automatically even if killed (and, I assume, if they die for any other reason)
- Another thing I forgot: for the time being, during the cleanup, the Raspberry Pi works on the network share script directory. Once cleaning is done and everything is fixed, everything will run locally on the RPi, and the scripts/FOL directory on chiara will be used as backup/repository.
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10771
|
Tue Dec 9 16:07:16 2014 |
manasa | Summary | General | Dec 9 - FC module and fiber chassis |
Quote: |
Quote: |
Attached is the timeline for Frequency Offset Locking related activities. All activities will be done mostly in morning and early afternoon hours.
|
Elaborate to do list:
1. The FC module should be mounted on the IOO rack. Domenica has to be powered up appropriately to the rack power supply.
2. The fiber chassis needs to be built. This will hold all the fiber components and will sit inside the PSL enclosure.
Fiber connectors and fiber couplers need to be installed in the chassis. Attached is the cartoon sketch of layout in the chassis.
3. User guide for FC module (work in progress)
|
1. FC module has been mounted on the IOO rack. The module gets it AC supply from the powerstrip already installed on the back side of the rack.

2. The fiber chassis has not been put together completely. We have still not received the front and back panels for the chassis; which is keeping me on hold. Diego is almost done with his housekeeping on Domenica. He will post an elog with all the details.
3. User guide for FC module (work in progress) |
10775
|
Wed Dec 10 16:12:29 2014 |
manasa | Summary | General | Dec 10 - PSL table |
Quote: |
Attached is the timeline for Frequency Offset Locking related activities. All activities will be done mostly in morning and early afternoon hours.
|
I was working around the PSL table today.
I wanted to modify the telescope that couples PSL light into the fiber; now that I have the translation stages for the lenses. I could not finish it as the locking work started earlier than usual this afternoon. I measured the out of loop noise for ALS error signals before I opened the PSL enclosure. X and Y beat notes were at -18dBm at 49.3MHz and -29.56dBm at 62.2MHz for this measurement. DTT data can be found in /users/manasa/data/141210/ALSoutLoop.xml; so there is reference to go back to in case of any damage done due to the work on the PSL table.
Also, I received the front and back panels for the Fiber chassis and put it together. Find photos (front panel and inside) of chassis in attachment. This will go inside the PSL enclosure tomorrow.

|
10778
|
Thu Dec 11 10:08:10 2014 |
manasa | Update | General | IFO update |
Status of IFO:
1. The X end slow computer is down. ETMX sliders and buttons on the ETMX suspension screens have gone white. I have disabled the ETMX oplev because it is largely misaligned in yaw. I am not poking it and leaving it as is for the time being.
2. The Y arm green alignment had drifted and GTRY was down to 0.15 . I tweaked the alignment using the last two steering mirrors and brought GTRY to 0.7 which gives a beat note of -14dBm. |
10780
|
Thu Dec 11 12:50:12 2014 |
manasa | Summary | General | PSL table optical layout |
I assembled the telescope to couple PSL light into the fiber. The maximum coupling that I could obtain was 10mW out of 65mW (~15%).
I was expecting to achieve 80-90% coupling from my design estimates. It makes me wonder if the beam waist measurements made by Harry during summer were correct in the first place. I would like to go back and check the beam waist at the PSL table.
Also, we need a pair of 8m (~25 feet) long SMA cables to carry the RF signal from the beat PD on the PSL table to frequency counter module on the IOO rack.
Steve says that we had a spool of SMA cable and it was borrowed by someone a few months ago. Any updates on either who is holding it or if it has been used up already would help.
The X end slow computer was down this morning. So I used only the Y arm ALS to record the noise level for reference. DTT data for ALSY out of loop noise before opening PSL enclosure is saved in /users/manasa/data/141211/ALSYoutLoop.xml
|
10787
|
Thu Dec 11 23:34:06 2014 |
manasa | Summary | General | PSL table optical layout |
Quote: |
I assembled the telescope to couple PSL light into the fiber. The maximum coupling that I could obtain was 10mW out of 65mW (~15%).
I was expecting to achieve 80-90% coupling from my design estimates. It makes me wonder if the beam waist measurements made by Harry during summer were correct in the first place. I would like to go back and check the beam waist at the PSL table.
Also, we need a pair of 8m (~25 feet) long SMA cables to carry the RF signal from the beat PD on the PSL table to frequency counter module on the IOO rack.
Steve says that we had a spool of SMA cable and it was borrowed by someone a few months ago. Any updates on either who is holding it or if it has been used up already would help.
The X end slow computer was down this morning. So I used only the Y arm ALS to record the noise level for reference. DTT data for ALSY out of loop noise before opening PSL enclosure is saved in /users/manasa/data/141211/ALSYoutLoop.xml
|
I missed to elog this earlier. I have temporarily removed the DC photodiode for GTRY to install the fiber holder on the PSL table. So GTRY will not be seeing anything right now.
|
10788
|
Fri Dec 12 02:30:25 2014 |
Jenne | Summary | General | PSL table optical layout |
Quote: |
I missed to elog this earlier. I have temporarily removed the DC photodiode for GTRY to install the fiber holder on the PSL table. So GTRY will not be seeing anything right now.
|
After some confusion, I discovered this a few hours ago. |
10791
|
Fri Dec 12 14:38:39 2014 |
manasa | Summary | General | Frequency Offset Locking - To Do List (Revised) |
Unfortunately the order placed for beam samplers last week did not go through. These will be used at the X and Y end tables to dump the unwanted light appropriately. Since they will not be here until Tuesday, I revised the timeline for FOL related activities accordingly. |
Attachment 1: FOLtodolist.pdf
|
|
10792
|
Fri Dec 12 15:19:04 2014 |
manasa | Summary | General | Dec 12 - PSL table |
Quote: |
Unfortunately the order placed for beam samplers last week did not go through. These will be used at the X and Y end tables to dump the unwanted light appropriately. Since they will not be here until Tuesday, I revised the timeline for FOL related activities accordingly.
|
I was working on the PSL table today.
Since the rejected 1064nm light after the SHG crystal is not easily reachable to measure beam widths close to the waist, I put a lens f=300mm and measured the beam size around its focus. I used this data and redesigned the telescope using 'a la mode'.
I used a beam splitter to attenuate the beam directed towards the fiber. The reflected beam from BS has been dumped (I need to find a better beam dump than what is being used right now.
I have only ~200uW at the input of the fiber coupler after the BS and 86uW at the output of the fiber (43% coupling).
I moved the GTRY DC photodiode and the lens in front of it to make space for the fiber coupler mount.
The layout on the PSL table right now is as shown below.
I have also put the fiber chassis inside the PSL enclosure on the rack. I moved the coherent spectrum analyser controller that is not being used to make space on the rack.

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Attachment 2: PSLfiberChassis.png
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|
10808
|
Wed Dec 17 11:57:56 2014 |
manasa | Summary | General | Y arm optical layout |
I was working around the PSL table and Y endtable today.
I modified the Y arm optical layout that couples the 1064nm light leaking from the SHG crystal into the fiber for frequency offset locking.
The ND filter that was used to attenuate the power coupled into the fiber has been replaced with a beam sampler (Thor labs BSF-10C). The reflected power after this optic is ~1.3mW and the trasmitted power has been dumped to a razor blade beam dump (~210mW).
Since we have a spare fiber running from the Y end to the PSL table, I installed an FC/APC fiber connector on the PSL table to connect them and monitored the output power at the Y end itself. After setting up, I have ~620uW of Y arm light on the PSL table (~48% coupling).
During the course of the alignment, I lowered the power of the Y end NPRO and disengaged the ETMY oplev. These were reset after I closed the end table.
Attached is the out of loop noise measurement of the Y arm ALS error signal before (ref plots) and after.
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Attachment 1: 58.png
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10831
|
Mon Dec 22 17:06:14 2014 |
manasa | Update | General | X end AUX laser fiber setup |
Quote: |
I looked at the endtable for possible space to setup optics in order to couple the X end laser into a PM fiber.
Attached is the layout of where the setup will go and what are the existing stuff that will be moved.

|
Since we will not be doing any major locking, I am taking this chance to move things on the X end table and install the fiber coupler.
The first steering mirror shown in the earlier elog will be a Y1 (HR mirror) and the second one will be a beam sampler (similar to the one installed at the Y endtable for the fiber setup).
Configuration:
Doubler --> Y1 ---> Lens (f=12.5cm) ---> Beam sampler --->Fiber coupler
The fiber coupler mount will be installed in the green region to the right of the TRX camera.
This work will involve moving around the TRX camera and the optic that brings the trans image on it.
Let me know if this work should not be done tomorrow morning for any reason. |
10834
|
Tue Dec 23 13:18:37 2014 |
manasa | Update | General | X end AUX laser fiber setup |
Quote: |
Since we will not be doing any major locking, I am taking this chance to move things on the X end table and install the fiber coupler.
The first steering mirror shown in the earlier elog will be a Y1 (HR mirror) and the second one will be a beam sampler (similar to the one installed at the Y endtable for the fiber setup).
Configuration:
Doubler --> Y1 ---> Lens (f=12.5cm) ---> Beam sampler --->Fiber coupler
The fiber coupler mount will be installed in the green region to the right of the TRX camera.
This work will involve moving around the TRX camera and the optic that brings the trans image on it.
Let me know if this work should not be done tomorrow morning for any reason.
|
I was working around the X endtable and PSL table today.
1. Y1 mirror, beam sampler and the fiber coupler have been installed.
2. Removed TRX camera temporarily. The camera will be put back on the table once we have the filter for 532nm that can go with it.
3. Removed an old fiber mount that was not being used from the table.
4. Lowered the current for X end NPRO while working and put it back up at 2A before closing.
5. The fibers running from the X end to the PSL table are connected at an FC/APC connector on the PSL table.
6. Found the HEPA left on high (probably from yesterday's work around the PSL table). I have brought it back down and left it that way.
I have not installed the coupling lens as yet owing to the space restrictions - not enough space for footprint of the lens. I have to revisit the telescope design again. |
10846
|
Mon Dec 29 21:30:25 2014 |
rana | Update | General | recovery |
- Control room is at +66 F. Brrrr.
- Alignment of input beam into the IMC was wacky; locked on HOM.
- Re-aligned beam into the PMC first.
- Restarted mxstream for c1sus.
- Power cycled Martian router; all laptops were lost. Now better.
- Aligned launch beam from PSL to get onto the MCWFS better, MC is locking OK now. Moved MC SUS a little to get back to OSEM values from 6 days ago.
- Fixed LOCK_MC screen quad displays to be cooler.
- changed many of the ezcawrite calls in the mcup / mcdown to be 'caput -l' for more robustness. Still need ezcawrite for the binbary calls.
- I didn't touch the mirrors on the MC REFL path, so we can still use that as a reference once the temperature returns to normal; the PSL room temp is down to 20C from 22 C a couple days ago.
- TRX values coming in to the LSC were frozen and the TRY_OUT16 was going to huge values even though camera flashes were reasonable. Tried restarting c1lsc model. No luck.
- Also tried shutdown -r now on c1lsc. No luck. Probably needs a RFM boot.
- Increased the FSS SLOW servo threshold to 9999 counts to avoid it running on some misaligned TEM01 mode locks. Increased the PID's I gain from 0.05 to 0.356 by tuning on some step responses as usual.
- By midnight the control room temperature is back around 71 F.
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