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ID Date Author Type Category Subject
8462   Thu Apr 18 19:54:11 2013 JenneUpdateLSCLSC whitening triggering working

I have implemented automatic triggered switching of the analog whitening (and digital dewhitening).

The trigger is the same as the degree of freedom trigger.  On the LSC RFPD screen there is a space to enter the amount of time (in seconds) you would like to wait between receiving a trigger and actually having the whitening filter switch.

The trigger logic is as follows:

* For each column of the LSC input matrix (e.g. AS11 I), check if there is a non-zero element.  If there is a non-zero element (indicating that we are using that PD as the error signal for a degree of freedom), check if the corresponding DoF has been triggered.  Repeat for all columns of the matrix.

* If either the I or the Q signal from a single PD is being used, send a trigger in the direction of the PD signal conditioning / phase rotation blocks.  (Since the whitening happens before the phase rotation, we want to have the whitening state be the same for both the I and Q signals coming from the demod boards.

* Before actually changing the whitening state, wait for the amount of time indicated on the RFPD overview screen.

* Switch the digital dewhitening.  If the digital dewhitening is on, send a bit over to the binary I/O to switch the analog whitening on.

This required changing the LSC RF_PD library part so that you can send the trigger to the filter bank from outside that part..  This part is in use by all LSC models, so I'll make sure the LLO people are aware of this change before I commit it to the svn.

While I was working on the LSC model, I also put in a wait between the time that the filter module trigger is received, and when it actually switches the filter modules.  So far, this time is defined for a whole filter bank (so all filters for a given DoF still switch at the same time).  If I need to go back and make the timing individual for each filter module, I can do that.  This new EPICS variable (the WAIT) defaults to zero seconds, so the functionality will not change for anyone who uses this part.

These changes also require 2 pieces of c-code:  {userapps}/cds/common/src/wait.c and {userapps}/isc/c1/src/inmtrxparse.c

7184   Tue Aug 14 22:16:46 2012 JenneUpdateLSCLSC whitening triggers

I'm ~30% of the way through implementing LSC whitening filter triggers.  I think that everything I have done should be compile-able, but please don't compile c1lsc tonight.  I haven't tested it, and some channel names have changed, so I need to fix the LSC screen when I'm not falling asleep.

Also, Rana pointed out that we may not want the whitening to trigger on immediately upon acquiring lock - if there are other modes ringing down in the cavity, or some weird transients, we don't want to amplify those signals.  We want to wait a second or so for them to die down, then turn on analog whitening.  Jamie - do you know how long the "unit delay" delays things in the RCG?  Do those do what I naively think they do?  I'll ask you in the morning.

7188   Wed Aug 15 09:09:45 2012 jamieUpdateLSCLSC whitening triggers

 Quote: I'm ~30% of the way through implementing LSC whitening filter triggers.  I think that everything I have done should be compile-able, but please don't compile c1lsc tonight.  I haven't tested it, and some channel names have changed, so I need to fix the LSC screen when I'm not falling asleep. Also, Rana pointed out that we may not want the whitening to trigger on immediately upon acquiring lock - if there are other modes ringing down in the cavity, or some weird transients, we don't want to amplify those signals.  We want to wait a second or so for them to die down, then turn on analog whitening.  Jamie - do you know how long the "unit delay" delays things in the RCG?  Do those do what I naively think they do?  I'll ask you in the morning.

The unit delay delays for a single cycle, so I think that's not what you want.  I'm not sure that there's an existing part to add delays like that.

We also need to be a little clever about it, though, since we'll want it to flip off if we loose lock during the delay.

276   Sat Jan 26 22:00:03 2008 JohnUpdateGeneralLSC-TRY_OUT and ETMY-QPD
In the path from the ETM to the trans PD and QPD at the Y end I have replaced a BS1-1064-10-2037-45P with a polariser. The power falling on these diodes has been reduced. When the arm is locked in its nominal state the transmitted power is now less than 1.

This polariser should serve as an injection point for the auxiliary arm locking. I am attempting to use crossed polarisations to separate this loop from the main arm light.
11515   Wed Aug 19 00:55:35 2015 IgnacioUpdateLSCLSC-YARM-EXC to LSC-YARM-IN1 TF measurement + error analysis

Yesterday, Rana, Jessica and I measured the Transfer function from LSC-YARM-EXC to LSC-YARM-IN1.

The plot below shows the magnitude and the phase of the measured transfer function. It also shows the normalized standard error in the estimated transfer function magnitude; the same quantity can be applied to the phase, only in this case it is interpreted as its standard deviation (not normalized). It is given by

$\frac{[1-\gamma_{xy}^2(f)]^{1/2}}{|\gamma_{xy}(f)|\sqrt{2n_{d}}}$

where $\gamma_{xy}^2(f)$ is the ordinary coherence function and $n_{d}$ is the number of averages used at each point of the estimate, in the case here we used 9 averages. This quantity is of interest to us in order to understand how the accuracy of transfer function measurement affects the ammount of subtraction that can be achieved online.

Since this transfer function is flat from 1-10 Hz (out of phase by 180 deg), this means that we can apply our IIR wiener filters direclty into YARM without taking into account the TF by prefiltering our witnesses with it. Of course this is not the case if we care about subtractions at frequencies higher than 10 Hz, but since we are dealing with seismic noise this is not a concern.

The coherence for this transfer function measurement is shown below,

2946   Tue May 18 14:30:31 2010 josephbUpdateCDSLSC.mdl problem found and fixed

After having checked old possibilities and deciding I wasn't imagining the lsc.mdl file not working, but working as another name, I tracked Alex down and asked for help.

After scratching our heads, we finally tracked it down to the RCG code itself, as opposed to any existing code.

Apparently, the skeleton.st file (located in /home/controls/cds/advLigoRTS/src/epics/util/) has special additional behavior for models with the following names: lsc, asc, hepi, hepia, asc40m, ascmc, tchsh1, tchsh2.

Alex was unsure what this additional code was for.  To disable it, we went into the skeleton.st file, and changed the name "SEQUENCER_NAME_lsc" to "SEQUENCER_NAME_lsc_removed" where ever it occured.  These names were in #ifdef statements, so now these codes will only be used if the model is named lsc_removed.  This apparently fixed the problem.  Running startlsc now runs the code as it should, and I can proceed to testing the communication to the lsp model.

Alex said he'd try to figure out what these special #ifdef code pieces are intended for and hopefully completely remove them once we've determined we don't need it.

8553   Wed May 8 19:31:17 2013 JamieConfigurationLSCLSC: added new SQRT_SWITCH to power normalization DOF outputs

This removes the old sqrt'ing from the inputs to the POW_NORM matrix (was only on the POP110 I/Q) and moves it to the DOF outputs.  Koji wanted this so that he could use the DC signals for normalization both sqrt'd and not sqrt'd.

The POW_NORM medm screen was updated accordingly.

8501   Sat Apr 27 00:29:40 2013 KojiUpdateLSCLSCoffset script fixed

Prior to the locking trials...

scripts/LSC/LSCoffset script had behaved peculiarly:

This script spawns LSC/offset3 in order to remove the dark offset from the channels.
How ever the offsets had been nulled every other PDs
(i.e. The offsets REFL11 I&Q were nulled.
The offsets REFL33 I&Q had been left untouched
The offset REFL55 I&Q had been nulled
and so on.)

I found that the script run many instances of "offset3" scripts in background.
It seemed that tdsavg did not like too many averaging channels at once.

So the "&"s in the LSCoffsets were removed and now the script runs much more slowly,
but works for all of the PDs listed.

I think I have never seen the offsets in REFL33 and REFL165 nulled down to this level before.

9063   Mon Aug 26 18:59:08 2013 MasayukiUpdateLSCLSCoffset script updated

I made scripts/LSC/LSCoffsets2.py which is the script to zero the dark offset of all the LSC PD.  The list of PDs is same as the list in scripts/LSC/LSCoffsets. New script average all outputs of PDs parallelly, so we can zero the offsets much faster.

You can define the averaging time, and you can choose the channel for getting the dark offset from INMON or OUT16. You should know that if you use OUT16 channel, the effect of the unwhite filter is not taken into account.

Example usage (at scripts/LSC):

./LSCoffsets2.py -d 20 --out16

you can find the help by calling this script with option -h or --help

9064   Mon Aug 26 19:13:38 2013 KojiUpdateLSCLSCoffset script updated

What do you mean???

What is the effect of the anti-whitening filter?

 Quote: You should know that if you use OUT16 channel, the effect of the unwhite filter is not taken into account.

3062   Thu Jun 10 07:53:14 2010 AlbertoUpdatePEMLaTeXlabs

 Quote: BTW, latex launched this new thing for writing pdfs. doesnot require any installations.  check  http://docs.latexlab.org

so cool!

3063   Thu Jun 10 10:58:02 2010 KojiUpdateGeneralLaTeXlabs

I could not dare to share my google doc with this site...

Quote:

 Quote: BTW, latex launched this new thing for writing pdfs. doesnot require any installations.  check  http://docs.latexlab.org

so cool!

3064   Thu Jun 10 11:10:21 2010 AlbertoUpdateGeneralLaTeXlabs

Quote:

I could not dare to share my google doc with this site...

Quote:

 Quote: BTW, latex launched this new thing for writing pdfs. doesnot require any installations.  check  http://docs.latexlab.org

so cool!

Just in case,  granted access to Google docs can be revoked any time from here:

https://www.google.com/accounts/IssuedAuthSubTokens

17110   Mon Aug 29 13:33:09 2022 JCUpdateGeneralLab Cleanup

The machine shop looked a mess this morning, so I cleaned it up. All power tools are now placed in the drawers in the machine shop. Let me know if there are any questions of where anything here is placed.

Attachment 1: EDE63209-D556-41F1-9BF2-89CD78E3D7B7.jpeg
15629   Thu Oct 15 13:48:58 2020 anchalSummaryGeneralLab Entry Notification

I entered 40m today at around 1:20 pm and left by 1:45 pm. I entered 104 through the machine shop entry. I did the following:

• I took photos and videos of the PSL table with lights on.
• I uncovered the AP table, took photos and video, and covered it back.
• I went to the X End table and took a video without opening the enclosure.
• Apart from flipping light switches, nothing else should have changed.
15632   Fri Oct 16 19:44:41 2020 anchalSummaryGeneralLab Entry Notification

I entered 40m today at around 1:10 pm and left by 1:50 pm. I entered 104 through the machine shop entry. I took top view single picture photos of ITMY, BS, AP, ITMX, ETMX and ETMY tables. The latest photos will be put here on the wiki soon.

17135   Thu Sep 8 11:54:37 2022 JCConfigurationLab OrganizationLab Organization

The arms in the 40m laboratory have now been sectioned off. Each arm has been divided up into 15 sections. Along the Y arm, the section are labelled "Section Y1 - Section Y15". For the X arm, they are labelled "Section X1- Section X15". Anything changed or moved will now be updated into the elog with their appropriate section.

Below is an example of Section X6.

Attachment 1: 1A7026BC-82A9-49E9-BA22-1A700DFEC5D2.jpeg
Attachment 2: 2A904809-82F0-40C0-B907-B48C3A0E789E.jpeg
Attachment 3: CB4B8591-B769-454D-9A16-EE9176004099.jpeg
17136   Thu Sep 8 12:01:02 2022 JCConfigurationLab OrganizationLab Organization

The floor cable cover has been changed out for a new one. This is in Section X11.

Attachment 1: F41AD1DA-29E9-4449-99CB-5F43AE527CA6_1_105_c.jpeg
Attachment 2: FF5F2CE8-85E8-4B6F-8F8A-9045D978F670.jpeg
3318   Thu Jul 29 12:31:09 2010 KojiSummaryGeneralLab Schedule

July
29 Thu BS chamber work: Move cable towers / green steering mirrors / (2 TTs with TT charactrization) / Put the heavy door by 5PM.
30 Fri Pumping down
31 Sat WFS work by Nancy

Aug
1 Sun - 5 Thu WFS work by Nancy
5 Thu PSL Table prep
6 Fri PSL Table prep / Likely to shut down the PSL

9 Mon PSL Table prep / shutting down of the PSL (optional)
10 Tue PSL box Frame lifting
12 Thu PSL table tapping

16 Mon - 17 Tue concrete pouring preparation
19 Thu - 23 Fri Tripod placement
24 Tue - 26 Thu concrete pouring

Attachment 1: PSL_work_schedule.pdf
2496   Sun Jan 10 16:05:51 2010 AlbertoOmnistructureEnvironmentLab Thermostats Temperature Lowered by 1 deg F

Rana noticed that recently the temperature inside the lab has been a little bit too high. That might be causing some 'unease' to the computers with the result of making them crash more often.

Today I lowered the temperature of the three thermostats that we have inside the lab by one degree:
Y arm thermostat: from 71 to 70 F
X arm thermostat: from 70 to 69 F
Aisle thermostat: from 72 to 71 F.

For the next hours I'll be paying attention to the temperature inside the lab to make sure that it doesn't go out of control and that the environment gets too cold.

2501   Mon Jan 11 10:01:06 2010 AlbertoOmnistructureEnvironmentLab Thermostats Temperature Lowered by 1 deg F

 Quote: Rana noticed that recently the temperature inside the lab has been a little bit too high. That might be causing some 'unease' to the computers with the result of making them crash more often. Today I lowered the temperature of the three thermostats that we have inside the lab by one degree: Y arm thermostat: from 71 to 70 F X arm thermostat: from 70 to 69 F Aisle thermostat: from 72 to 71 F. For the next hours I'll be paying attention to the temperature inside the lab to make sure that it doesn't go out of control and that the environment gets too cold.

Today the lab is perceptibly cooler.

The temperature around the corner is 73 F.

15657   Tue Nov 3 09:06:50 2020 gautamUpdateGeneralLab alarm tripped

I got a call from Calum ~830am today saying some facilities people entered the lab, opened the south entrance door, and tripped the alarm in the process. I came to the lab shortly after and was able to reset the alarm by flipping the switch on the alarm box at the south end entrance to "Alarm OFF". Then, I double checked that the door is closed, and re-enabled the alarm. The particle count at the SP table is not unusually high and the lasers (Oplev HeNe and AUX X) were still on, so doesn't look like any lasting damage was done. The facilities people were apparently wearing laser safety goggles.

16240   Tue Jul 6 17:40:32 2021 KojiSummaryGeneralLab cleaning

We held the lab cleaning for the first time since the campus reopening (Attachment 1).
Now we can use some of the desks for the people to live! Thanks for the cooperation.

We relocated a lot of items into the lab.

• The entrance area was cleaned up. We believe that there is no 40m lab stuff left.
• BHD BS optics was moved to the south optics cabinet. (Attachment 2)
• DSUB feedthrough flanges were moved to the vacuum area (Attachment 3)
• Some instruments were moved into the lab.
• The Zurich instrument box
• KEPCO HV supplies
• Matsusada HV supplies
• We moved the large pile of SUPERMICROs in the lab. They are around MC2 while the PPE boxes there were moved behind the tube around MC2 area. (Attachment 4)
• We have moved PPE boxes behind the beam tube on XARM behind the SUPERMICRO computer boxes. (Attachment 7)
• ISC/WFS left over components were moved to the pile of the BHD electronics.
• Front panels (Attachment 5)
• Components in the boxes (Attachment 6)

We still want to make some more cleaning:

- Electronics workbenches
- Stray setup (cart/wagon in the lab)
- Some leftover on the desks
- Instruments scattered all over the lab
- Ewaste removal

Attachment 1: P_20210706_163456.jpg
Attachment 2: P_20210706_161725.jpg
Attachment 3: P_20210706_145210.jpg
Attachment 4: P_20210706_161255.jpg
Attachment 5: P_20210706_145815.jpg
Attachment 6: P_20210706_145805.jpg
Attachment 7: PXL_20210707_005717772.jpg
17132   Tue Sep 6 09:57:26 2022 JCSummaryGeneralLab cleaning

DB9 Cables have been assorted and placed behind the Y-Arm. Long BNC Cables and Ethernet Cables have been stored under the Y-Arm.

 Quote: We held the lab cleaning for the first time since the campus reopening (Attachment 1). Now we can use some of the desks for the people to live! Thanks for the cooperation. We relocated a lot of items into the lab. The entrance area was cleaned up. We believe that there is no 40m lab stuff left. BHD BS optics was moved to the south optics cabinet. (Attachment 2) DSUB feedthrough flanges were moved to the vacuum area (Attachment 3) Some instruments were moved into the lab. The Zurich instrument box KEPCO HV supplies Matsusada HV supplies We moved the large pile of SUPERMICROs in the lab. They are around MC2 while the PPE boxes there were moved behind the tube around MC2 area. (Attachment 4) We have moved PPE boxes behind the beam tube on XARM behind the SUPERMICRO computer boxes. (Attachment 7) ISC/WFS left over components were moved to the pile of the BHD electronics. Front panels (Attachment 5) Components in the boxes (Attachment 6) We still want to make some more cleaning: - Electronics workbenches - Stray setup (cart/wagon in the lab) - Some leftover on the desks - Instruments scattered all over the lab - Ewaste removal

Attachment 1: 982146B2-02E5-4C19-B137-E7CC598C262F.jpeg
Attachment 2: 0FBB61AC-E882-458D-A891-7B11F35588FF.jpeg
17072   Wed Aug 10 19:36:45 2022 KojiBureaucracyGeneralLab cleaning and discovery

During the cleaning today, we found many legacy lab items. Here are some policies what should be kept / what should be disposed

Dispose

• VME crates and VME electronics as long as they are not in use
• Eurocard SUS modules that are not in use.
• Eurocard crates (until we remove the last Eurocard module from the lab)
• Giant steel plate/palette (like a fork lift palette) along the Y arm. (Attachment 1)
• An overhead projector unit.

Keep

• Spare Eurocard crates / ISC/PZT Eurocard modules
• Boxes of old 40m logbooks behind the Y arm (see Attachment 2/3).
• Ink-plotter time-series data (paper rolls) of 1996 IFO locking (Attachment 4). Now stored in a logbook box.
• A/V type remnants: Video tapes / video cameras / casette tapes as long as they hold some information in it. i.e. Blank tapes/blank paper rolls can be disposed.
Attachment 1: steel_plate.jpg
Attachment 2: logbook1.jpg
Attachment 3: logbook2.jpg
Attachment 4: paper_plots.jpg
997   Fri Sep 26 14:10:21 2008 YoichiConfigurationComputersLab laptops maintenance
The linux laptops were unable to write to the NFS mounted directories.
That was because the UID of the controls account on those compters was different from linux1 and other control room computers.
I changed the UID of the controls account on the laptops. Of course it required not only editing /etc/password but also dealing with
numerous errors caused by the sudden change of the UID. I had to chown all the files/directories in the /home/controls.
I also had to remove /tmp/gconf-controls because it was assigned the old UID.

Whenever we add a new machine, we have to make sure the controls account has the same UID/GID as other machines, that is 1001/1001.

I did some cleanups of the laptop environment.
I made dataviewer work on the laptops *locally*. We no longer have to ssh -X to other computers to run dataviewer.
The trick was to install grace using Fedora package by
sudo yum install grace
Then i modified /usr/local/stow_pkgs/dataviewer/dataviewer to change the option to dc3 from "-s fb" to "-s fb40m".
16025   Wed Apr 14 12:27:10 2021 gautamUpdateGeneralLab left open again

Once again, I found the door to the outside in the control room open when I came in ~1215pm. I closed it.

14027   Wed Jun 27 21:18:00 2018 gautamUpdateCDSLab maintenance scripts from NODUS---->MEGATRON

I moved the N2 check script and the disk usage checking script from the (sudo) crontab of nodus to the controls user crontab on megatron .

3348   Mon Aug 2 17:12:28 2010 KojiUpdateGeneralLab schedule for the week of Aug. 2

Aug

2 Mon - 5 Thu WFS work (Nancy)

2 Mon - 4 Wed

Jenne: Seismometer fix / Seismic measurements on the PSL table
TT characterization (with Koji)
Preparations ETM suspensions (optional: may be in later weeks)

Kiwamu: CDS test for SUS (may be involving Koji)

Alberto: RF system prep.

All: For 5th and 6th: PSL cabling works Koji

5 Thu PSL Table prep
6 Fri PSL Table prep / Likely to shut down the PSL

9 Mon PSL Table prep / shutting down of the PSL (optional)
10 Tue PSL box Frame lifting
12 Thu PSL table tapping

16 Mon - 17 Tue concrete pouring preparation
19 Thu - 23 Fri Tripod placement
24 Tue - 26 Thu concrete pouring

Attachment 1: PSL_work_schedule.pdf
14545   Mon Apr 15 22:55:34 2019 gautamFrogsThermal CompensationLab thermostat adjusted

It is feeling cold in the office area. According to the digital wall clock near the coffee machine, it is 19C. Rana bumped the thermostat setpoint up by 2F (from 75F to 77F). We need to setup long-term monitoring.

15603   Tue Sep 29 17:07:25 2020 gautamUpdateGeneralLab visit for inventory location

I was in the lab from 1630-1830. I have located and visually inspected all the parts required for the magnet regluing / optic cleaning parts of the planned vent, except the fresh batches of scpectroscopic grade solvents. I was in the cleanroom part of the clean and bake lab from 1630-1700.

1231   Fri Jan 16 11:28:54 2009 YoichiUpdateComputersLab. laptop needs wireless lan driver update
One of the lab. laptops (belladonna) cannot connect to the network now.
I guess this was caused by someone clicked the update icon and unknowingly updated the kernel, which resulted in the wireless lan driver malfunctioning.
It was using a Windows driver through ndiswrapper.
Someone has to fix it.
14533   Thu Apr 11 01:10:05 2019 gautamUpdateALSLarge 2kHz peak (and harmonics) in ALS X

These weren't present last week. The peaks are present in the EX PDH error monitor signal, and so are presumably connected with the green locking system. My goal tonight was to see if the arm length control could be done using the ALS error signal as opposed to POX, but I was not successful.

Attachment 1: EX_PDH_2kNoise.pdf
14548   Wed Apr 17 00:50:17 2019 gautamUpdateALSLarge 2kHz peak (and harmonics) in ALS X no more

I looked into this issue today. Initially, my thinking was that I'd somehow caused clipping in the beampath somewhere which was causing this 2kHz excitation. However, on looking at the spectrum of the in-loop error signal today (Attachment #1), I found no evidence of the peak anymore!

Since the vacuum system is in a non-nominal state, and also because my IR ALS beat setup has been hijacked for the MZ interferometer, I don't have an ALS spectrum, but the next step is to try single arm locking using the ALS error signal. To investigate whether the 2kHz peak is a time-dependent feature, I left the EX green locked to the arm (with the SLOW temperature offloading servo ON), hopefully it stays locked overnight...

 Quote: These weren't present last week. The peaks are present in the EX PDH error monitor signal, and so are presumably connected with the green locking system. My goal tonight was to see if the arm length control could be done using the ALS error signal as opposed to POX, but I was not successful.
Attachment 1: EX_PDHnoise.pdf
14549   Wed Apr 17 11:01:49 2019 gautamUpdateALSLarge 2kHz peak (and harmonics) in ALS X no more

EX green stayed locked to XARM length overnight without a problem. The spectrogram doesn't show any alarming time varying features around 2 kHz (or at any other frequency).

Attachment 1: EX_PDH_specGram.pdf
4338   Tue Feb 22 14:37:24 2011 steveUpdateSAFETYLarisa received 40m safety training

Larisa Thorne received 40m lab specific, basic safety training. She will attend P. King's Basic Laser Safety Training Session tomorrow.

3588   Mon Sep 20 10:33:21 2010 josephbBureaucracyComputersLarry stopped by - GC machine had conflicting IP

Larry stopped by today and had to disconnect the m25 machine (this is the 1st GC machine on the left as you walk into the control room) because its IP was conflicting with a machine over in Downs.  Do not use 131.215.115.125 as the IP on this machine as this is already assigned to someone else.  They couldn't figure out the root password to change it which is why it is not currently plugged into the network, and is not to be until an appropriate IP is assigned.

They've asked that whoever set the machine up to please contact them (extension 2974).

6500   Fri Apr 6 19:40:57 2012 Mike J.SummaryGeneralLaser Emergency Shutoff

I accidently shut off the laser at 19:34 with the emergency shutoff button while trying to tap into a video line for the Sensoray device.

6501   Fri Apr 6 20:05:12 2012 JamieSummaryGeneralLaser Emergency Shutoff

We reset the interlock and restarted the PSL.  The end AUX lasers seem to have come back online fine.  PMC and mode cleaner locked back up quickly.

1465   Thu Apr 9 23:11:27 2009 robSummaryLockingLaser PM to PO-DC transfer functions at multiple CARM offsets

I've plotted some transfer functions showing the response at POB DC to laser frequency (phase) noise.  There are transfer functions for multiple CARM offsets.  Basically, the transfer function looks like the DARM transfer function when the CARM is at zero offset, and is super-wonky elsewhere.  POB-DC is not a good CARM signal for intermediate stages of lock acquisition in a dual-recycled interferometer.  We should look into switching back to REFL-DC.

Attachment 1: CARMoffs1.png
Attachment 2: CARMoffs2.png
Attachment 3: CARMcarpet.png
1466   Thu Apr 9 23:20:35 2009 robSummaryLockingLaser PM to REFL-DC transfer functions at multiple CARM offsets

 Quote: I've plotted some transfer functions showing the response at POB DC to laser frequency (phase) noise.  There are transfer functions for multiple CARM offsets.  Basically, the transfer function looks like the DARM transfer function when the CARM is at zero offset, and is super-wonky elsewhere.  POB-DC is not a good CARM signal for intermediate stages of lock acquisition in a dual-recycled interferometer.  We should look into switching back to REFL-DC.

Here are the corresponding transfer functions for REFL-DC.

Attachment 1: CARMoffs1_r.png
Attachment 2: CARMoffs2_r.png
Attachment 3: CARMcarpet_r.png
1468   Fri Apr 10 03:10:08 2009 ranaSummaryLockingLaser PM to REFL-DC transfer functions at multiple CARM offsets

I hereby award the previous rainbow transfer functions the plot innovation of the month award for its use of optical frequency to denote CARM offset.

The attached movie here shows the sensing matrix (minus MICH) as a function of CARM offset. There are 3 CARM signals plotted:

GREEN - tonights starting CARM signal - REFL_DC

RED - my favorite CARM signal - REFL 166 I

CYAN - runner up CARM signal - POX 33 I

1636   Mon Jun 1 13:56:52 2009 AlbertoUpdatePSLLaser Power after fixing the laser chiller

The laser power seems to have become more stable after fixing the laser chiller. The power is lower than it used to be (MOPA amplitude 2.5 versus 2.7) but, as shown in the attchement, it became more steady.

Attachment 1: MOPAtrend.jpg
1639   Mon Jun 1 15:01:31 2009 ranaUpdatePSLLaser Power after fixing the laser chiller: more traces
If you look at the correlation between RMTEMP and HTEMP, you see what we knew: namely that there
was a 1:1 correlation before. After the chiller fix, I can see no correlation between the room and
amplifier temperature at the resolution of 10:1. So the chiller loop has a gain > 10 at 24 hour time
scales.

I don't understand why the PMC looks more stable.
Attachment 1: Picture_7.png
552   Mon Jun 23 15:22:04 2008 ranaBureaucracySAFETYLaser Safety Walkthrough today
Attachment 1: Walkthrough08.jpg
16024   Tue Apr 13 20:45:16 2021 YehonathanUpdatePSLLaser amplifier

{Yehonathan, Rana}

We unpacked the content of the amplifier crate in front of the water fountain (see attachments). Inside we found:

1. Amplifier head. (attachment 1)
2. Amplifier electronics and pump diodes (attachment 2).
3. Optical fiber (attachment 3).
4. 2 Long water hoses (~2m) and 2 short ones.
5. Network cable.
6. A wooden plate.
7. Cable sleeve (attachment 2)?
8. Some manuals will be uploaded to the wiki soon.

Please don't move/touch any of that stuff

Things that we need to consider/obtain:
1. A suitable power cable (attachment 4) with suitable power ratings (800W according to the amplifier specs). The connector head is C19 I believe.
2. A chiller. Rana says Aidan knows where to find one. Should we chill the amplifier head as well?
3. A mounting plate for the amplifier head with good thermal conductivity.
4. The pump wavelength is 808nm, we need to get suitable safety goggles.
5. Where to put the big electronics box. Preferably on 1X1 or 1X2.
6. How do we arrange the different components on the table? We also need to mode match the beam into the amplifier.

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16032   Wed Apr 14 19:48:18 2021 gautamUpdatePSLLaser amplifier

A couple of years ago, I got some info about the amplifier setup at the sites from Terra - sharing here in case there is some useful info in there (our setup will be rather different, but it looked to me like our Amp is a 2017 vintage and it may be that the performance is not the same as reported in the 2019 paper).

collection of docs (table layout in 'Proposed....setup') : https://dcc.ligo.org/LIGO-T1700046

LVC 70W presentation: https://dcc.ligo.org/LIGO-G1800538

I guess we should double check that the beam size everywhere (in vacuum and on the PSL table) is such that we don't exceed any damage thresholds for the mirrors used.

16034   Thu Apr 15 09:46:24 2021 YehonathanUpdatePSLLaser amplifier

Some more relevant documents provided by Matt:

Phase III:70W amplifier integration at LIGO

70W amplifier External Shutter

aLIGO PSL high power attenuator

16044   Fri Apr 16 18:21:36 2021 YehonathanUpdatePSLLaser amplifier

I surveyed a bit the 1X1/2 area to plan for the installation of the laser amplifier.

There is a vacancy at the bottom of 1X2 (attachment 1). I measured the dimensions of the diode box (DB) and it should fit. The optical fiber bundle is 75m long and should reach the amplifier head on the table easily.

According to the specs, the maximum power consumption of the DB is 800W (typically 600W), it should probably have its own circuit breaker. It can easily draw more than a few amps. The rack power strips are connected to this 4 socket box (attachment 2), is this just another power strip? It is connected to a circuit breaker with a 30A rating. How do we proceed from here?

In any case, we will need at least 2 meters of power cable.

I also tried to find a suitable place for a water chiller. A few suggestions are in the attachments. Basically either between the electronics shelves and the small rack next to 1X2 or next to the small rack close to the optical table. Maybe put it where the ladder sits and find another place for the ladder. Other options?

We would also need a windows machine running the Beckhoff software. The idea is that all the different laser components (DB, chillers, interlocks, switches) are connected to the EtherCat (over the ethernet infrastructure) so that the Beckhoff code can recognize a failure and switch off everything.

The things that are monitored:

1. Is the NPRO on?

2. Is the flow rate from the chillers enough?

3. Is the temperature of the diodes in the normal range?

4. Is one of the interlocks open?

5. Was one of the emergency buttons pushed?

6. Was the key switch on the DB turned to OFF?

The DB is EtherCat ready but the rest of the signals need to be interfaced somehow. Do we have to buy these EtherCAT terminals?

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16046   Sun Apr 18 21:29:55 2021 ranaUpdatePSLLaser amplifier
• Ideally, we put the chiller outside of the interferometer area. The PSL chiller used to be in the control room near the door by IMC REFL. We could also put it in the drill press room.
• Once we figure out a couple of places where the Diode Box can go, we can ask facilities to make the appropriate power connections. They will have to eval the situation to figure out if the main power to the lab needs to be shut down.
• Can we put the laser diode box in the drill press room too? Then the hoses can be short. Perhaps less EMI getting into our sensitive places.
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