ID |
Date |
Author |
Type |
Category |
Subject |
16210
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Thu Jun 17 16:37:23 2021 |
Anchal, Paco | Update | SUS | c1susaux computer rebooted |
Jon suggested to reboot the acromag chassis, then the computer, and we did this without success. Then, Koji suggested we try running ifup eth0, so we ran `sudo /sbin/ifup eth0` and it worked to put c1susaux back in the martian network, but the modbus service was still down. We switched off the chassis and rebooted the computer and we had to do sudo /sbin/ifup eth0` again (why do we need to do this manually everytime?). Switched on the chassis but still no channels. `sudo systemctl status modbusioc.service' gave us inactive (dead) status. So we ran sudo systemctl restart modbusioc.service'.
The status became:
● modbusIOC.service - ModbusIOC Service via procServ
Loaded: loaded (/etc/systemd/system/modbusIOC.service; enabled)
Active: inactive (dead)
start condition failed at Thu 2021-06-17 16:10:42 PDT; 12min ago
ConditionPathExists=/opt/rtcds/caltech/c1/burt/autoburt/latest/c1susaux.snap was not met`
After another iteration we finally got a modbusIOC.service OK status, and we then repeated Jon's reboot procedure. This time, the acromags were on but reading 0.0, so we just needed to run `sudo /sbin/ifup eth1`and finally some sweet slow channels were read. As a final step we burt restored to 05:19 AM today c1susaux.snap file and managed to relock the IMC >> will keep an eye on it.... Finally, in the process of damping all the suspended optics, we noticed some OSEM channels on BS and PRM are reading 0.0 (they are red as we browse them)... We succeeded in locking both arms, but this remains an unknown for us. |
16213
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Fri Jun 18 10:07:23 2021 |
Anchal, Paco | Summary | AUX | Xend Green Laser PDH OLTF with coherence |
We did the measurement of OLTF for Xend green laser PDH loop with excitation added at control point using a SR560 as shown in attachment 1 of 16202. We also measured coherence in our measurement, see attachment 1.
Measurement details:
- We took the
measurement as per 16202.
- We did measurement in two pieces. First in High frequency region, from 1 kHz to 100 kHz.
- In this setup, the excitation amplitude was kept constant to 5 mV.
- In this region, the OLTF is small enough that signal to noise ratio is maintained in
(SR560 sum output, measured on CH1). The coherence can be seen to be constant 1 throughout for CH1 in this region.
- But for
(PZT Mon, measured on CH2), the low OLTF actually starts damping both signal and noise and to elevate it above SR785 noise floor, we had a high pass (z:0Hz, p:100kHz, k:1000) SR560 amplifying before measurement (see attachment 2). This amplification has been corrected in Attachment 1. This allowed us to improve the coherence on CH2 to above 0.5 mostly.
- Second region is from 3 Hz to 1 kHz.
- In this setup, the excitation was shaped with a low pass (p: 1Hz, k:5) SR560 filter with SR785 source amplitude as 1V.
- We took 40 averaging cycles in this measurement to improve the coherence further.
- In this freqeuency region,
is mostly coherent as we shaped the excitation as and due to constant cycle number averaging, the integrated noise goes as (see 16202 for math).
- We still lost coherence in
(CH1) for frequencyes below 100 Hz. the reason is that the excitation is suppressed by OLTF while the noise is not for this channel. So the shaping of excitation only helps fight against the suppression of OLTF somewhat and not against the noise.

- We need
shaping for this purpose but we were loosing lock with that shaping so we shifted back to shaping and captured whatever we could.
- It is clear that the noise takes over below 100 Hz and coherence in CH1 is lost there.
Inferences:
- Yes, the OLTF does not look how it should look but:
- The green region in attachment 1 shows the data points where coherence on both CH1 and CH2 was higher than 0.75. So the saturation measured below 1 kHz, particularly in 100 Hz to 500 Hz (where coherence on both channels is almost 1) is real.
- This brings the question, what is saturating. As has been suggested before, our excitation signal is probably saturating some internal stage in the uPDH box. We need to investigate this next.
- It is however very non-intuitive to why this saturation is so non-uniform (zig-zaggy) in both magnitude and phase.
- In past experiences, whenever I saw somehting saturating, it would cause a flat top response in transfer function.
- Another interesting thing to note is the reduced UGF in this measurement.
- UGF is about 40-45 kHz. This we believe is due to reduced mode matching of the green light to the XARM when temperature of the end increases too much. We took the measurement at 6 pm and Koji posted the Xend's temperature to be 30 C at 7 pm in 16206. It certainly becomes harder to lock at hot temperatures, probably due to reduced phase margin and loop gain.
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Attachment 1: XEND_PDH_OLTF_with_Coherence.pdf
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Attachment 2: Beta_Amp.pdf
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16218
|
Tue Jun 22 11:56:16 2021 |
Anchal, Paco | Update | SUS | ADC/Slow channels issues |
We checked back in time to see how the BS and PRM OSEM slow channels are zero. It was clear that they became zero when we worked on this issue on June 17th, Thursday. So we simply went back and power cycled the c1susaux acromag chassis. After that, we had to log in to c1susaux computer and run
sudo /sbin/ifdown eth1
sudo /sbin/ifup eth1
This restarted the ethernet port acromag chassis is connected to. This solved this issue and we were able to see all the slow channels in BS and PRM.
But then, we noticed that the OPLEV of ITMX is unable to read the position of the beam on the QPD at all. No light was reaching the QPD. We went in, opened the ITMX table cover and confirmed that the return OPLEV beam is way off and is not even hitting one of the steering mirrors that brings it to the QPD. We switched off the OPLEV contribution to the damping.
We did burt restore to 16th June morning using
burtwb -f /opt/rtcds/caltech/c1/burt/autoburt/snapshots/2021/Jun/16/06:19/c1susaux.snap -l /tmp/controls_1210622_095432_0.write.log -o /tmp/controls_1210622_095432_0.nowrite.snap -v
This did not solve the issue.
Then we noticed that the OSEM signals from ITMX were saturated in opposite directions for Left and Right OSEMs. The Left OSEM fast channels are saturated to 1.918 um for UL and 1.399 um for LL, while both right OSEM channels are bottomed to 0 um. On the other hand, the acromag slow PD monitors are showing 0 on the right channels but 1097 cts on UL PDMon and 802 cts in LL PD Mon. We actually went in and checked the DC voltages from the PD input monitor LEMO ports on the ITMX dewhitening board D000210-A1 and measured non-zero voltages across all the channels. Following is a summary:
ITMX OSEM readouts
|
C1-SUS-ITMX_XXSEN_OUT
(Fast ADC Channels) (um) |
C1-SUS-ITMX_xxPDMon
(Slow Acromag Monitors) (cts) |
Multimeter measurements at input to Dewhitening Boards
(V) |
UL |
1.918 |
1097 |
0.901 |
LL |
1.399 |
802 |
0.998 |
UR |
0 |
0 |
0.856 |
LR |
0 |
0 |
0.792 |
SD |
0.035 |
20 |
0.883 |
We even took out the 4-pin LEMO outputs from the dewhitening boards that go to the anti-aliasing chassis and checked the voltages. They are same as the input voltages as expected. So the dewhitening board is doing its job fine and the OSEMs are doing their jobs fine.
It is weird that both the ADC and the acromags are reading these values wrong. We believe this is causing a big yaw offset in the ITMX control signal causing the ITMX to turn enough make OPLEV go out of range. We checked the CDS FE status (attachment 1). Other than c1rfm showing a yellow bar (bit 2 = GE FANUC RFM card 0) in RT Net Status, nothing else seems wrong in c1sus computer. c1sus FE model is running fine. c1x02 (the lower level model) does show a red bar in TIM which suggests some timing issue. This is present in c1x04 too.
Bottomline:
Currently, the ITMX coil outputs are disabled as we can't trust the OSEM channels. We're investigating more why any of this is happening. Any input is welcome.
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Attachment 1: CDS_FE_Status.png
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16445
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Tue Nov 2 18:54:41 2021 |
Anchal, Paco | Update | BHD | Optical fibres laid for BHD upgrade |
We successfully laid down all required optical fibre fiber cables from 1X4-1X7 region to 1Y1-1Y3 region today. This includes following cables:
- Timing
fibre fiber from Master Timing Synchornizer D050239 on 1X6 to C1SU2 I/O chassis on 1Y1.
- Timing
fibre fiber from Master Timing Synchornizer D050239 on 1X6 to C1BHD I/O chassis on 1Y3.
- CX4 cable from Dolphin Card on 1X4 to C1SU2 FE on 1Y1 for IPC.
- CX4 cable from Dolphin Card on 1X4 to C1BHD FE on 1Y3 for IPC.
- DAQ Network extension
fibre fiber optic cable from DAQ Network Switch on 1X7 to another switch we mounted on 1Y3 for local DAQ network distribution.
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16228
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Tue Jun 29 17:42:06 2021 |
Anchal, Paco, Gautam | Summary | LSC | MICH locking tutorial with Gautam |
Today we went through LSC locking mechanics with Gautam and as a "Hello World" example, worked on locking michelson cavity.
MICH settings changed:
- Gautam at some point added 9 dB attenuation filters in MICH filter module in LSC to match the 9 dB pre-amplifier before digitization.
- This required changing teh trigger thresholds, C1:LSC-MICH_TRIG_THRESH_ON and C1:LSC-MICH_TRIG_THRESH_OFF.
- We looked at C1:LSC-AS55_Q_ERR_DQ and C1:LSC-ASDC_OUT_DQ on ndscope.
- The zero crossings in AS55_Q correspond to ASDC going to zero. We found the threshold values of ASDC by finding the linear region in zero crossing of AS55_Q.
- We changed the thresold values to UP: -0.3mW and DOWN -0.05mW. The thresholds were also changed in C1LSC_FM_TRIG.
- We also set FM2,3,6 and 8 to be triggered on threshold.
We characterized the loop OLTF, found the UGF to be 90 Hz and measured the noise at error and control points.
gautam: one aim of this work was to demonstrate that the "Lock Michelson (dark)" script call from the IFOconfigure screen worked - it did, reliably, after the setting changes mentioned above. |
16237
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Fri Jul 2 12:42:56 2021 |
Anchal, Paco, Gautam | Summary | LSC | snap file changed for MICH |
We corrected the MICH locking snap file C1configure_MI.req and saved an updated C1configure_MI.snap. Now the 'Restore MICH' script in IFO_CONFIGURE>!MICH>Restore MICH works. The corrections included adding the correct rows of PD_DOF matrices to be at the right settings (use AS55 as error signal). The MICH_A_GAIN and MICH_B_GAIN needed to be saved as well.
We also were able to get to PRMI SB resonance. PRM was misalgined earlier from optimal position and after some manual aligning, we were able to get it to lock just by hitting IFO_CONFIGURE>!PRMI>Restore PRMI SB (3f). |
16239
|
Tue Jul 6 16:35:04 2021 |
Anchal, Paco, Gautam | Update | IOO | Restored MC |
We found that megatron is unable to properly run scripts/MC/WFS/mcwfsoff and scripts/MC/WFS/mcwfson scripts. It fails cdsutils commands due to a library conflict. This meant that WFS loops were not turned off when IMC would get unlocked and they would keep integrating noise into offsets. The mcwfsoff script is also supposed to clear up WFS loop offsets, but that wasn't happening either. The mcwfson script was also not bringing back WFS loops on.
Gautam fixed these scripts temprorarily for running on megatron by using ezcawrite and ezcaswitch commands instead of cdsutils commands. Now these scripts are running normally. This could be the reason for wildly fluctuating WFS offsets that we have seen in teh past few months.
gautam: the problem here is that megatron is running Ubuntu18 - I'm not sure if there is any dedicated CDS group packaging for Ubuntu, and so we're using some shared install of the cdsutils (hosted on the shared chiara NFS drive), which is complaining about missing linked lib files. Depending on people's mood, it may be worth biting the bullet and make Megatron run Debian10, for which the CDS group maintains packages.
Quote: |
MC was unlocked and struggling to recover this morning due to misguided WFS offsets. In order to recover from this kind of issue, we
- Cleared the bogus WFS offsets
- Used the MC alignment sliders to change MC1 YAW from -0.9860 to -0.8750 until we saw the lowest order mode transmission on the video monitor.
- With MC Trans sum at around ~ 500 counts, we lowered the C1:IOO-WFS_TRIGGER_THRESH_ON from 5000 to 500, and the C1:IOO-WFS_TRIGGER_MON from 3.0 to 0.0 seconds and let the WFS integrators work out some nonzero angular control offsets.
- Then, the MC Trans sum increased to about 2000 counts but started oscillating slowly, so we restored the delayed loop trigger from 0.0 to 3.0 seconds and saw the MC Trans sum reach its nominal value of ~ 14000 counts over a few minutes.
The MC is now restored and the plan is to let it run for a few hours so the offsets converge; then run the WFS relief script.
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16241
|
Thu Jul 8 11:20:38 2021 |
Anchal, Paco, Gautam | Summary | LSC | PRFPMI locking attempts |
Last night Gautam walked us through the algorithm used to lock PRFPMI. We tried it several times with the PSL HEPA filter off between 10:00 pm July 7th to 1:00 am July 8th. None of our attempts were successful. In between, we tried to do the locking with old IMC settings as well, but it did not change the result for us. In most attempts, the arms would start to resonate with PRMI with about 200 times the power than without power recycling while the arms are still controlled by ALS beatnote. The handover of lock controls "CARM+DARM locked to ALS beatnote" to "Main laser + IMC locked to the CARM+DARM" would always fail. More specifically, we were seeing that as soon as we hand over the DC control of CARM from ALS beatnote to IR by feeding back to MC2, the lock would inevitably fail before the rest of the high-frequency control can be transferred over.
Nonetheless, Paco and I got a good demo of how to do PRFPMI locking if the need appears. With more practice and attempts, we should be able to achieve the lock at some point in the future. The issues in handover could be due to any of the following:
- Although it seems like ALS beatnote fed control of arms keep them within the CARM IR linewidth as we see the IR resonating, there still could be some excess noise that needs to be dealt with.
- Gautam conjectures, that the presence of high power in the arms connects the ITMs and the ETMs with an optical spring changing the transfer function of the pendula. This in turn changes the phase margin and possibly makes the CARM loop in IR PRFPMI unstable.
- We should also investigate the loop transfer functions near the handover point for the ALS beatnote loop and the IR CARM loop and calculate the crossover frequency and gain/phase margins there.
More insights or suggestions are welcome.
Note; An earthquake came around lunch time and tripped all watchdogs. Most suspensions were recovered without issues, but ITMX appeared to be stuck. We tried the shaking procedure, but after this we couldn't restore the XARM lock. From alignment, we tried optimizing the TRX but we only got up to ~0.5 and ASS wouldn't work as usual. In the end the issue was that we had forgotten to enable the LL coil output so after we did this, we managed to recover the XARM. |
16112
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Mon May 3 17:28:58 2021 |
Anchal, Paco, Rana | Update | LSC | IMC WFS noise contribution in arm cavity length noise |
Rana came and helped us figure us where to inject the noise. Following are the characteristics of the test we did:
- Inject normal noise at C1:IOO-MC1_PIT_EXC using AWGGUI.
- Excitation amplitude of 54321 in band 12-37Hz with Cheby1 8th order bandpass filter with same limits.
- Look at power spectrum of C1:IOO-MC_F_DQ, C1:IOO-WFS1-PIT_OUT_DQ and the C1:IOO-MC1_PIT_EXC itself.
- Increased the gain of the noise excitation until we see some effect in MC_F.
- Diaggui also showed coherence plot in the bottom, which let's us have an estimate of how much we need to go further.
Attachment 1 shows a screenshot with awggui and diaggui screens displaying the signal in both angular and longitudinal channels.
Attachment 2 shows the analogous screenshot for MC2.
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Attachment 1: excitationoftheMCanglessothatwecanseesomethingdotpng.png
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Attachment 2: excitationoftheMCanglessothatwecanseesomethingdotpngbutthistimeitsMC2.png
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16190
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Mon Jun 7 15:37:01 2021 |
Anchal, Paco, Yehonathan | Summary | Cameras | Mon 7 in Control Room Died |
We found Mon7 in control room dead today afternoon. It's front power on green light is not lighting up. All other monitors are working as normal.
This monitor was used for looking at IMC camera analog feed. It is one of the most important monitors for us, so we should replace it with a different monitor.
Yehonathan and Paco disconnected the monitor and brought it down. We put it under the back table if anyone wants to fix it. Paco has ordered a BNC to VGA/HDMI converter to put in any normal monitor up there. It will happen this Wednesday. Meanwhile, I have changed the MON4 assignment from POP to Quad2 to be used for IMC. |
10130
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Sat Jul 5 04:18:45 2014 |
Andres | Update | 40m Xend Table upgrade | Adding Two Lenses After the Second Steering Mirror in Order Two Increase the Gouy Phase Difference Between the Sterring Mirrors |
I had been working on the Xend table optical layout update. Since the two steering mirrors in the Xend green are too close to each, there is a very small Gouy Phase different between these two mirrors. It was suggested to place two lenses so that we can increase the Gouy Phase. I have been working with Nick on this problem, and we had found a solution by using a la mode. We had written an a la mode code that optimize the Gouy Phase and the Mode Matching at the same time. After trying different lenses, we found the following results: a mode matching of 0.9939 as it is show in the first attachment below, and we found a Gouy Phase different between the two mirrors of about 60 degrees. I took photos of the Xend Table. The first photo is the Xend table as we had it right now. In the second photo, I moved the 2nd lens, and I placed the two more lenses that we need it, with more or lenses the correct position where they will be placed. The three old lenses will be replaced by three lenses of different focal length as it can be seen in the first attachment below. The first lens and third lens will stay in the same position where the old first lens and old third lens are, and the second lens will be moved by about half of an inch. We might have one or two of the lenses that we need, but we will have to order the rest of the lenses that need. My plan is to verify the lenses that we already have. Then, I need to let Nick know with lenses we need to order. Hopefully, we will be able to update the table by the end of this week if everything turn out fine. |
Attachment 1: OverlapAndComponentsOfTheSolution.png
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Attachment 2: CloseLookToTheGouyPhaseBetweenMirr1AndMirr2.jpg
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Attachment 3: EntireRangeOfBeamPath.jpg
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Attachment 4: XendTableWithTwoNeedLensesAdding.JPG
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Attachment 5: SchematicOfSolutionForTheLensesGouyPhase.jpeg
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Attachment 6: XendGreenModeMatchingAndGouyPhaseOptimization.m
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clear all
% In this code we are using a la mode to optimatize the mode matching and
% to optimatize the Gouy phase between mirror 1 and mirror 2. All the units
% are in meter
w0=2.943*1e-5; % The Waist of the laser measured before the faraday
z0_laser=-0.039; % position measured where the waist is located
lamb= 532*10^-9; % wavelength of green light in mm
lFaraday=.0638; % Length of the faraday
... 148 more lines ...
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Attachment 7: BeforeIncludingLensesORMovingLenses.JPG
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10191
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Sun Jul 13 17:06:35 2014 |
Andres | Update | 40m Xend Table upgrade | Xarm Table Upgrade Calculation and Diagrams of possible new table layout |
Current Mode Matching and Gouy Phase Between Steering Mirrors
We found in 40m elog ID 3330 ( http://nodus.ligo.caltech.edu:8080/40m/3330) a documentation done by Kiwamu, where he measured the waist of the green. The waist of the green is about 35µm. Using a la mode, I was able to calculate the current mode matching, and the Gouy phase between the steering mirrors. In a la mode, I used the optical distances,which is just the distance measured times its index of refraction. I contacted someone from ThorLabs (which is the company that bought Optics For Research), and that person told that the Faraday IO-5-532-LP has a Terbium Gallium Garnet crystal of a length of 7mm and its index of refraction is 1.95. The current mode matching is 0.9343, and the current Gouy phase between steering mirrors is 0.2023 degrees. On Monday, Nick and I are planning to measure the actual mode matching. The attached below is the current X-arm optical layout.
Calculation For the New Optical Layout
Since the current Gouy phase between the steering mirror is essentially zero, we need to find a way how to increase the Gouy Phase. We tried to add two more lenses after the second steering mirror, and we found that increasing the Gouy phase result in a dramatically decrease in mode matching. For instance, a Gouy phase of about 50 degrees results in a mode matching of about .2, which is awful. We removed the first lens after the faraday, and we added two more mirrors and two more lenses after the second steering mirror. I modified the photo that I took and I place where the new lenses and new mirrors should go as shown in the second pictures attached below. Using a la mode, we found the following solution:
label z (m) type parameters
----- ----- ---- ----------
lens 1 0.0800 lens focalLength: 0.1000
First mirror 0.1550 flat mirror none:
Second mirror 0.2800 flat mirror none:
lens 2 0.4275 lens focalLength: Inf
lens 3 0.6549 lens focalLength: 0.3000
lens 4 0.8968 lens focalLength: -0.250
Third mirror 1.0675 flat mirror none:
Fourth mirror 1.4183 flat mirror none:
lens 5 1.6384 lens focalLength: -0.100
Fifth mirror 1.7351 flat mirror none:
Sixth mirror 2.0859 flat mirror none:
lens 6 2.1621 lens focalLength: 0.6000
ETM 2.7407 lens focalLength: -129.7
ITM 40.5307 flat mirror none:
The mode matching is 0.9786. The different Gouy phase different between Third Mirror and Fourth Mirror is 69.59 degrees, Gouy Phase between Fourth and Fifth 18.80 degrees, Gouy phase between Fifth and Sixth mirrors is 1.28 degrees, Gouy phase between Third and Fifth 88.38 degrees, and the Gouy phase between Fourth and Sixth is 20.08 degrees. Bellow attached the a la Mode code and the Plots.
Plan for this week
I don't think we have the lenses that we need for this new setup. Mostly, we will need to order the lenses on Monday. As I mention, Nick and I are going to measure the actual mode matching on Monday. If everything look good, then we will move on and do the Upgrade.
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Attachment 1: CurrentOpticalLayout.png
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Attachment 2: NewSetUp.PNG
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Attachment 3: AlaModeSolutionplots.png
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Attachment 4: EntireScaleRangeAlaModeSolution.png
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Attachment 5: NewXarmOptimizationFromFaraday.m
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close all
clear all
% In this code we are using a la mode to optimatize the mode matching and
% to optimatize the Gouy phase between mirror 1 and mirror 2. All the units
% are in meter
w0=(50*1e-6)/sqrt(2); % The Waist of the laser measured after SHG
z0_laser=-0.0083; % position measured where the waist is located
lamb= 532*10^-9; % wavelength of green light in mm
lFaraday=.0638; % Length of the faraday
... 209 more lines ...
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10195
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Mon Jul 14 16:19:41 2014 |
Andres | Update | 40m Xend Table upgrade | Took the measurement for the Mode Matching |
Nick and I measured the reflected power of the green light in locked and unlocked. I'm working on the calculation of the mode matching. Tonight, I'll be posted my calculation I'm still working on it.
JCD: Andres forgot to mention that they closed the PSL shutter, so that they could look at the green light that is reflected off the harmonic separator toward the IR trans path. Also, the Xarm (and the Yarm) were aligned to IR using the ASS, and then ASX was used to align the green beam to the cavity. |
10207
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Tue Jul 15 22:23:51 2014 |
Andres | Update | 40m Xend Table upgrade | Scan the Xarm for the mode matching |
Nick and I with the help of Jenne scan the green light when the cavity is unlocked. Nick placed a Beam dump on the IR so that we can just scan the green, but it was removed as soon as we finished with the measurement. I'm working on the calculation, and i'll be posted solution tonight. |
10226
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Thu Jul 17 02:57:32 2014 |
Andres | Update | 40m Xend Table upgrade | FInish Calculation on Current X-arm mode Matching |
Data and Calculation for the Xarm Current Mode Matching
Two days ago, Nick, Jenne, and I took a measurement for the Green Transmission for the X-arm. I took the data and I analyzed it. The first figure attached below is the raw data plotted. I used the function findpeaks in Matlab, and I found all the peaks. Then, by taking close look at the plot, I chose two peaks as shown in the second figure attached below. I took the ratio of the TEM00 and the High order mode, and I average them. This gave me a Mode Matching of 0.9215, which this value is pretty close to the value that I predicted by using a la Mode in http://nodus.ligo.caltech.edu:8080/40m/10191, which is 0.9343. Nick and I measured the reflected power when the cavity is unlocked and when the cavity is locked, so we measured the PreflUnLocked=52+1µW and PreflOnLocked=16+2µW and the backgroundNoise=0.761µW. Using this information we calculated Prefl/Pin=0.297. Now, since Prefl/Pin=|Eref/Ein|2, we looked at the electric fields component by using the reflectivity of the mirror we calculated 0.67. The number doesn't agree, but this is because we didn't take into account the losses when making this calculation. I'm working in the calculation that will include the losses.
Today, Nick and I ordered the lenses and the mirrors. I'm working in putting together a representation of how much improvement the new design will give us in comparison to the current setup.
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Attachment 1: RawDataForTheModeGreenScan.png
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Attachment 2: ResultForModeMatching.png
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Attachment 3: DataAndCalculationOfModeMismatch.zip
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10237
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Fri Jul 18 16:52:56 2014 |
Andres | Update | 40m Xend Table upgrade | FInish Calculation on Current X-arm mode Matching |
Quote: |
Data and Calculation for the Xarm Current Mode Matching
Two days ago, Nick, Jenne, and I took a measurement for the Green Transmission for the X-arm. I took the data and I analyzed it. The first figure attached below is the raw data plotted. I used the function findpeaks in Matlab, and I found all the peaks. Then, by taking close look at the plot, I chose two peaks as shown in the second figure attached below. I took the ratio of the TEM00 and the High order mode, and I average them. This gave me a Mode Matching of 0.9215, which this value is pretty close to the value that I predicted by using a la Mode in http://nodus.ligo.caltech.edu:8080/40m/10191, which is 0.9343. Nick and I measured the reflected power when the cavity is unlocked and when the cavity is locked, so we measured the PreflUnLocked=52+1µW and PreflOnLocked=16+2µW and the backgroundNoise=0.761µW. Using this information we calculated Prefl/Pin=0.297. Now, since Prefl/Pin=|Eref/Ein|2, we looked at the electric fields component by using the reflectivity of the mirror we calculated 0.67. The number doesn't agree, but this is because we didn't take into account the losses when making this calculation. I'm working in the calculation that will include the losses.
Today, Nick and I ordered the lenses and the mirrors. I'm working in putting together a representation of how much improvement the new design will give us in comparison to the current setup.
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We want to be able to graphically see how much better it is the new optical table setup in comparison to the current optical table setup. In other words, we want to be able to see how displacement of the beam and how much angle change can be obtained at the ETM from changing the mirrors angles independently. Depending on the spread of the mirrors' vectors we can observe whether the Gouy phase is good. In the plot below, the dotted lines correspond to the current set up, and we can see that the lines are not spread from each other, which essentially mean that changing the angles of the two mirrors just contribute to small change in angle and in the displacement of the beam at the ETM, and therefore the Gouy phase is not good. Now on the other hand. The other solid lines correspond to the new setup mirrors. We can observe that the spread of the line of mirror 1 and mirror 4 is almost 90 degrees, which just implies that there is a good Gouy phase different between these two mirrors. For the angles chosen in the plot, I looked at how much the PZT yaw the mirrors from the elog http://nodus.ligo.caltech.edu:8080/40m/8912. In this elog, they give a plot in mrad/v for the pitch and yaw, so I took the range that the PZT can yaw the mirrors, and I converted into mdegrees/v and then I plotted as shown below. I plot for the current setup and for the new setup in the same plot. The matlab code is also attached below. |
Attachment 1: OldAndNewSetupPlotsOfDisplacementAndAngleAtTheETM.png
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Attachment 2: OldSetUpDisplacementAndNewSetup.m.zip
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Tue Jul 29 20:14:08 2014 |
Andres | Update | 40m Xend Table upgrade | Xarm Green steering mirror upgrade |
Xarm Green Steering Mirror Upgrade
Nick and I did the upgrade for the green steering mirror today. We locked in the TEM00 mode.
We placed the shutter and everything. We move the OL, but we placed it back. Tonight, I'll be doing a more complete elog with more details. |
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Wed Jul 30 10:16:54 2014 |
Andres | Update | 40m Xend Table upgrade | Green Steering Mirror Upgrade completed |
Green Steering Mirror Update
Yesterday, Nick and I completed the green steering mirrors upgrade. I attached the file that contained the procedure that we plan before we did the upgrade. We placed an iris at the input of the OL and we place another iris before the harmonic separator. We did not use the beam scanner because someone was using it, so what we did was to assume that the cavity is well align and place the iris so that we can recover the alignment. We used the measuring tape to approximate as close as we could the position where the lenses were supposed to go. I did a measurement of the derivative of the waist size in terms of the position of the lens and the derivative of the waist Position in terms of the lenses position at the optimum solution that a la mode give us. Because of this plot, we decide to mount lens 3 and lens 5 into translational stages. After mounting each lenses and mirrors we worked on the alignment of the beam into the cavity. We were able to align the green into the cavity and we were able to locked the cavity to the TEM00 mode. We started to work on the optimization of the mode matching. However, the maximum mode matching that we got was around 0.6, which we need to work a little bit more on the tuning of the mode matching. We leave the iris mounted on the table. I took a picture of the table, and I attached below. For the OL, we just make sure that the output where somehow hitting the QPD, but we didn't really I aligned it. We need to work a little bit more on the alignment of the OL and the tuning of the mirror to maximize the green mode matching. |
Attachment 1: XarmUpgrade.pdf
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Attachment 2: dWaistSize_dlensVsdWaistPosition_dlens.png
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Attachment 3: XarmNewOpticalSetup.PNG
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Wed Aug 13 10:50:04 2014 |
Andres | Update | IMC | Calculation for the input mode cleaner |
Calculation for the input mode cleaner
I have been working on the calculation for the input mode cleaner. I have come out with a new optical setup that will allow us increase the Gouy phase different between the WFS to 90 degrees. I use a la mode to calculate it. The a la mode solution :
label z (m) type parameters
----- ----- ---- ----------
MC1 0 flat mirror none:
MC3 0.1753 flat mirror none:
MC2 13.4587 curved mirror ROC: 17.8700
Lens1 29.6300 lens focalLength: 1.7183
BS2 29.9475 flat mirror none:
First Mirror 30.0237 flat mirror none:
WFS1 30.2269 flat mirror none:
Second Mirror 30.2650 flat mirror none:
Third Mirror 30.5698 flat mirror none:
Lens2 30.9885 lens focalLength: 1
Fourth Mirror 31.0778 flat mirror none:
Lens3 31.4604 lens focalLength: 0.1000
Fifth Mirror 31.5350 flat mirror none:
Sixth Mirror 31.9414 flat mirror none:
WFS2 31.9922 flat mirror none:
I attached a pictures how the new setup is supposed to look like. |
Attachment 1: ModeCleanerSetup0.PNG
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Attachment 2: alaModeModeCleanersolution.png
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Thu Aug 14 15:10:47 2014 |
Andres | Update | IMC | Calculation for the input mode cleaner |
Quote: |
Can you please give us some more details on how this design was decided upon? What were the design considerations?
It would be nice to have a shorter path length for WFS2. What is the desired spot size on the WFS? How sensitive are they going to be to IMC input alignment? Are we still going to be recentering the WFS all the time?
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I did the calculation, and I reduced the beam Path. In my calculation, I restricted the waist size at the WFSs to be between 1mm-2mm also the other parameter is that the Gouy Phase different between the WFSs have to be 90 degrees. I also try to minimize the amount of mirrors used. I found the Gouy phase to be 89.0622 degrees between the WFSs and the following table shows the solution that I got from a la mode:
label z (m) type parameters
----- ----- ---- ----------
MC1 0 flat mirror none:
MC3 0.1753 flat mirror none:
MC2 13.4587 curved mirror ROC: 17.8700 (m)
Lens1 28.8172 lens focalLength: 1.7183(m)
BS2 29.9475 flat mirror none:
First Mirror 30.0237 flat mirror none:
Lens3 30.1253 lens focalLength: -0.100 (m)
Lens2 30.1635 lens focalLength: 0.1250(m)
WFS1 30.2269 flat mirror none:
Second Mirror 30.2650 flat mirror none:
Third Mirror 30.5698 flat mirror none:
Lens4 30.8113 lens focalLength: -0.075 (m)
WFS2 31.0778 flat mirror none:
In the first image attached below is the a la mode solution that show the waist size in the first WFS, and I used that solution to calculate the solution of the waist size for the second WFS, which is shown in figure 2. I photoshop a picture to illustrate how the new setup it supposed to look like. |
Attachment 1: SolutionForTheModeCleanerSetup00.png
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Attachment 2: SolutionForTheModeCleanerSetup11.png
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Attachment 3: PossibleSetupForModeCleaner.PNG
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Attachment 4: alaModeSolution.zip
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Tue Aug 19 21:40:44 2014 |
Andres | Update | IMC | New Optical Setup for the IMC |
IMC Calculation and Setup
I have been working in the calculation for improving the Gouy Phase separation between the WFSs. I tried different possible setup, but the three big constrains in choosing a good optical table setup are to have a Waist size that range from 1mm-2mm, the Gouy Phase between the WFSs have to be greater than 75 degrees and there has to be a steering mirror before each WFS. I will be showing the best calculation because that calculation complies with Rana request of having both WFSs facing west and having the shortest beam path. I approximate the distances by measuring with a tape the distance where the current optics are located and by looking at the picture that I took I approximated the distance where the lenses will be placed. I'm using a la mode for calculating the gouy phase different. I attached a picture of the current optical table setup that we have. Using a la mode, I found that the current gouy phase that we have is 49.6750 degrees.
Now, for the new setup, a run a la mode and found a Gouy phase of 89.3728 degrees. I have to create a two independent beam path: one for the WFS1 and another one for WFS2. The reason for this is that a la mode place everything in one dimension so and since the WFS1 will have a divergence lens in order to increase the waist size, and since that lens should not be interacting with the waist size in the WFS2. We need two beam path for each WFS. A la mode give us the following solution:
For the beam path of the WFS1
label z (m) type parameters
----- ----- ---- ----------
MC1 0 flat mirror none:
MC3 0.1753 flat mirror none:
MC2 13.4587 curved mirror ROC: 17.8700 (m)
Lens1 29.3705 lens focalLength: 1.0201 (m)
BS2 29.9475 flat mirror none:
First Mirror 30.0237 flat mirror none:
Lens3 30.2000 lens focalLength: -0.100 (m)
WFS1 30.4809 flat mirror none:
For the beam path of the WFS2
label z (m) type parameters
----- ----- ---- ----------
MC1 0 flat mirror none:
MC3 0.1753 flat mirror none:
MC2 13.4587 curved mirror ROC: 17.8700 (m)
Lens1 29.3705 lens focalLength: 1.0201 (m)
BS2 29.9475 flat mirror none:
Second Mirror 30.2650 flat mirror none:
Lens2 30.4809 lens focalLength: -0.075 (m)
Third Mirror 30.5698 flat mirror none:
WFS2 30.6968 flat mirror none:
I attached bellow how the new setup should look like in the second picture and also I include and attachment of the a la mode code.
I used Mist to be able to see the read out that we get in the WFSs that take the Mode Cleaner Reflection and the QPD that take the transmitted from MC2. In the following, plots I'm misaligned the each mirrors: MC1, MC2 and MC3. The misalignment are in Yaw and Pitch. I'm dividing the WFSs reading by the total power reflect power, and I'm dividing the QPD for the MC2 transmission by the total transmitted power. In my Mist model, I have a laser of 1W and my EOM is modulated at 30MHz instead of 29.5MHz and the modulation depth was calculating by measuring the applied voltage using and Spectrum analyzer. I using Kiwamu measurement of modulation depth efficiency vs the applied voltage, https://dcc.ligo.org/DocDB/0010/G1000297/001/G1000297-v1.pdf, I got a modulation depth of 0.6 mrad. I put this modulation depth and I got the following plots: The fourth and fifth attachment are for the current optical setup that we have. The sixth and seventh attachment is for the new optical setup. The eighth attachment is showing the mode cleaner cavity resonating. The last attachment contains the plots of WFS1 vs WFS2, MC2_QPD vs WFS1, MC2_QPD vs WFS3 for each mirror misaligned. The last two attachment are the MIST code for the calculation.
We have all the lenses that we need. I checked it last Friday and if everything is good we will be ready to do the new upgrade this coming Friday. For increasing the power, I check and we have different BS so we can just switch from the current setup the BS. Can you let me know if this setup look good or if I need to chance the setup? I would really love to do this upgrade before I leave.
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Attachment 1: ModeCleanerSetup.PNG
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Attachment 2: NewOpticalTableSetupForTheModeCleaner.PNG
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Attachment 3: ReduceWFSPathWorkingOn.m.zip
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Attachment 4: MIST_WFSsAndQPDReadingForYaw.png
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Attachment 5: MIST_WFSsAndQPDReadingForPitch.png
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Attachment 6: MIST_WFSsAndQPDReadingForYawNewSetup.png
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Attachment 7: MIST_WFSsAndQPDReadingForPitchNewSetup.png
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Attachment 8: MISTResonanceCavityReflectionAndTransmissionNewSetup.png
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Attachment 9: 2Dplots.zip
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Attachment 10: ModeCleanerCurrentOpticalTableMIST.zip
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Attachment 11: ModeCleanerNewSetupMIST.zip
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Fri Aug 22 18:05:02 2014 |
Andres | Update | IMC | Upgrade of the IMC WFSs for the reflection |
Upgrade of IMC Reflection Optical Setup
Nick and I upgrade the IMC. We move both WFSs and placed them facing west. When aligning the beam into the WFS, we make sure that the beam were hitting the center of the mirrors and then we placed the lenses in their corresponding position. We used the beam scanner to measure the waist and the waist in the second WFS was bigger than 1mm, and the second WFS was a little bit below than 1mm. We center the beam in the WFSs and in the PD. We did haven't measure whether we have a good Gouy Phase. Below I attached the picture of how the new setup look like.
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Attachment 1: ModeCleanerUpgrade.PNG
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Wed Jun 25 14:52:22 2014 |
Andres Medina | Update | elog | Placing a lens between the steering mirrors and another lens between the second steering mirror and the cavity |
I was asked to calculate the lenses that we need in order to obtained a Gouy phase close to 90 degrees between the two mirrors that are in the Xend green. Yesterday, I measured the distances between the mirrors, and the distance between the mirror relative to the cavity as illustrate in the image attached below. I looked in to the 40m elog and Manasa did the last update on the length of the cavity. She measured 37.7 + 0.05m. The waist size of the beam that was measured by Annalisa in ID 8637 after the Faraday was w0=2.943e-5m @ -0.039m. I calculated the waist size inside the cavity, and I found a waist of w0=2.2 mm. My plan this week is to keep working in the calculation and finish all the calculation this week so that next week I can go inside and place the lenses. |
Attachment 1: SchematicForXendGreenGoingToTheCavity.pdf
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75
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Wed Nov 7 02:14:08 2007 |
Andrey | Bureaucracy | IOO | More information about MC2 ringdown |
As Tobin wrote two hours ago, we (Andrey, Tobin, Robert) made a series of ringdown measurements for MC2
in the spirit of the measurement described by Rana -> see
entry from Mon Oct 29 23:47:29 2007, rana, Other, IOO, MC Ringdowns.
I attach here some pictures that we saw on the screen of the scope, but I need to admit that I am not experienced enough to present a nice fit to these data, although I attach fits that I am able to do today.
I definitely learned a lot of new Matlab functions from Tobin - thanks to him!, but I need to learn two more things:
Firstly, I do not know how to delete "flat" region (regions before the ringdown starts) in Matlab ->
I needed to delete the entries for times before the ringdown ("negative times") by hand in the text-file, which is extremely non-elegant method;
Secondly, I tried to approximate the ringdown curve by a function ydata=a*exp(b*xdata) but I am not exactly sure if this equation of the fitting curve is a good fit or if a better equation can be used.
It seems, in this situation it is better for me to ask more experienced "comrades" on November 7th.
P.S. It seems I really like the type of message "Bureaucracy" - I put it for every message. As Alain noted, maybe that is because some things are very bureacratized in the former USSR / Russia. By the way, when I was young, November 7th was one of two most important holidays in the USSR - I liked that holiday because I really liked military parades on the red square. I attach a couple of pictures. November 7 is the anniversary of the Revolution of 1917. |
Attachment 1: image-attempt_1.png
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Attachment 2: image-attempt_2.png
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Attachment 3: image-attempt_3.png
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Attachment 4: image-attempt_4.png
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Attachment 5: image-attempt_5.png
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Attachment 6: Fit-1st_attempt.jpg
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Attachment 7: Fit-5th_attempt.jpg
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Attachment 8: 7_Nov_1941-parad-na-krasnoy-ploschadi.jpg
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Attachment 9: parad1984-moskva.jpg
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Wed Nov 28 12:43:53 2007 |
Andrey | Bureaucracy | | Here was the PDF-file of my presentation |
I was making a report with powerpoint presentation during that Wednesday's 40-m meeting.
Here was the pdf-file, but LATER IN THE EVENING I CREATED A WIKI-40M-page describing the algorithm, and now the pdf-file is ON THAT WIKI-40M PAGE.
NOTE ADDED AFTER THE PRESENTATION: I double checked, I am indeed taking the root-mean-square of a difference, as we discussed during my talk.
My slide #17 "Calculation of differential length" was wrong, but now I corrected it. |
135
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Wed Nov 28 19:02:41 2007 |
Andrey | Bureaucracy | WIKI-40M Update | New WIKI-40M page describing Matlab Suspension Modeling |
I created the WIKI-40m page with some details about my today's talk on the 40-m lab meeting.
The address is:
http://lhocds.ligo-wa.caltech.edu:8000/40m/Modeling_of_suspensions
(or you can go to the main page, http://lhocds.ligo-wa.caltech.edu:8000/40m/ , and click on the link "Modeling of suspensions").
The WIKI-40m page describes my transfer functions and contains the pdf-file of my presentation. |
151
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Fri Nov 30 20:17:26 2007 |
Andrey | Configuration | PEM | Accelerometers and alum.plates for them |
All 6 accelerometers which were located near the ITMX are turned off and disconnected from the power cords.
Actually these accelerometers are now in the office area on the electronics bench (to the left from Steve Vass' place).
I made today 4 new aluminum mounting plates for the accelerometers (I drilled holes and made threads in them). On Monday I will buy short screws and install accelerometers on these new mounting plates. These mounting plates will be screwed directly into the metallic frame which is firmly cemented to the ground. Before yesterday accelerometers were mounted on top of blue stack towers, not on the ground directly, so we hope that new measurements of the ground noise will be more realistic.
The 4 mounting plates are on the same desk -> on the electronics bench (to the left from Steve Vass' place). Please do not displace them.
Attached is a drawing of the aluminum mountain plate. |
Attachment 1: Scheme_Aluminum_Piece-inches.pdf
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168
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Wed Dec 5 18:08:36 2007 |
Andrey | Update | ASC | Optical Lever laser for ETMX is installed |
A new laser with \lambda=633nm has been intalled and the mirror adjusted so that the signal hits the center of the photodetector.
Output power level of that laser is 3.45 +- 0.05 mW.
Only about 0.29mW hits the photodetector.
Cable clips have been used to firmly fix the power supply cable for the laser.
See attached photopicture of the ETMX - "oplev" - optical - table. |
Attachment 1: DSC_0199.JPG
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172
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Wed Dec 5 23:19:03 2007 |
Andrey | Configuration | PEM | Accelerometers are turned on |
All accelerometers have been turned on, as Alan asked during Wednesday meeting.
Typical power spectra and coherence plots are attached below.
"East" in the name means that the previous location of accelerometrs was to the east from "Beamsplitter" (the location for "east" accelerometers was not changed, actually, it is still near ITMX), while "west" means that previously accelerometers were to the west from the BS, but now their new location is near the ETMX.
I will change the names of the channels tomorrow (Thursday) when someone (Tobin?) will show to me how to do it.
P.S. (addition made on Dec. 19th, 2007, by Andrey) I intended to change the names of accelerometers the next day, Thursday Dec. 06,
but I did not do it that day (did not understand how to do it), then I fell ill, and eventually
I changed the names of accelerometers on December 19th, see entry to ELOG #204) |
Attachment 1: Power_Sp_and_Coh_XY-EAST.pdf
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Attachment 2: Coherence-ZX_East.pdf
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Attachment 3: Coherence-ZY_East.pdf
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Attachment 4: Power_Sp_WEST.pdf
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Attachment 5: Coherence-ZX_West.pdf
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Attachment 6: Coherence-XY_West.pdf
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Attachment 7: Coherence-YZ_West.pdf
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Thu Dec 6 15:22:42 2007 |
Andrey | Summary | Electronics | Pictures of the inside of He-Ne laser |
Steve gave me an old "dead" He-Ne laser that long time ago was used for ETMX optical lever.
I dismantled it (cutting the metallic enclosure with a metallic saw), and these are two pictures of what is inside. |
Attachment 1: DSC_0226.JPG
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Attachment 2: DSC_0228.JPG
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Thu Dec 6 19:19:47 2007 |
Andrey | Configuration | SUS | Suspension damping Gain was restored |
Suspension damping gain was disabled for some reason (all the indicators in the most right part of the screen C1SUS_ETMX.adl were red), it is now restored. |
191
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Thu Dec 13 23:56:02 2007 |
Andrey | Configuration | Computer Scripts / Programs | Overnight measurements |
After my disease (fever, vomitting, nose problem, overall weakness) I returned to LIGO today for the first time after the weekend, and I am running the script for the XARM-measurements over this night.
So, suspension dumping gains should undergo changes in the interval from 1 to 10 in both ITMX and ETMX.
XARM has been of course locked.
I started running the script for the first time at about 10PM, but I realized after an hour and a half that my step of gain increase 0.2 was too shallow, too small to execute my program during one night. Therefore, I needed to terminate the program, change my program so that it increases the gain with increment 0.5, not 0.2, and started it again around midnight.
Going home.
P.S. The red pump that I borrowed from the lab (Steve's pump?) is back at its previous place. The tire-worker tells me that I absolutely need to change all four tires for almost 500 dollars. I regret a lot about that huge money loss. |
194
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Mon Dec 17 23:42:08 2007 |
Andrey | Configuration | Computer Scripts / Programs | Overnight measurements in X-arm |
I am making overnight measurements this night (from Monday to Tuesday) in XARM.
The X-arm is now locked, and the values for suspension damping gain will be changed in the interval from 1 to 7 with the step 0.5 in both ITMX and ETMX.
This is the second, repeated measurement. The results of the first measurement from Saturday to Sunday night will be reported in the separate ELOG entry (sorry, I did not make an ELOG entry on Saturday evening about running the program overnight).
The very first attempt to run the script in the night from Thursday to Friday was not successful. |
195
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Tue Dec 18 00:51:39 2007 |
Andrey | Update | Computer Scripts / Programs | Results of Saturday overnight measurements |
As I indicated in the previous e-log entry (#194), I made overnight measurements in XARM in the night from Saturday to Sunday.
Root-mean-square values of the peaks in calibrated spectra were calculated, and I plotted them as functions of suspension gains in ITMX and ETMX "position" degrees of freedom.
More specifically, Q_ITMX means the value in the channel "C1:SUS-ITMX_SUSPOS_GAIN", while Q_ETMX means the value in the channel "C1:SUS-ETMX_SUSPOS_GAIN".
Root-mean-square values (RMS) were calculated during that night in three intervals:
1) around 0.8 HZ in the interval (0.6 Hz <-> 1.0 Hz);
2) around 3.0 Hz in the interval (2.0 Hz <-> 3.6 Hz);
3) in the broad interval from 0.6Hz to 3.6Hz.
I plotted three results for RMS in the abovementioned three intervals in three different ways:
1) view from the top in the axes (Q_{ITMX}+Q_{ETMX})/2 and (Q_{ITMX}-Q_{ETMX}) -> first three graphs (attachments 1 -3);
2) view from the side in the same sum- and difference-axes -> next three graphs (attachments 4-6);
3) view from the side in Q_{ITMX} and Q_{ETMX} axes -> next three graphs (attachments 7-9), above accelerometer spectra (attachments 10-11).
Also, I compared the ground noise level by comparing spectra of accelerometer signals at different times during that night. As a reminder, before my disease I installed one accelerometer near ITMX and another accelerometer near ETMX (see entries 161 and 172 in ELOG). The plots of ratios of accelerometer signals at different times (pairs of times that were used: 12AM and 3AM, 12AM and 6AM, 12AM and 9AM) are given below, see attachments 10-11.
Tomorrow I will try to compare the results with the second measurements that are being taken tonight. |
Attachment 1: RMS_08Hz_top_view.png
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Attachment 2: RMS_3Hz_top_view.png
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Attachment 3: RMS_broad_top_view.png
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Attachment 4: RMS_08Hz_Qsum-Qdiff-axes.png
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Attachment 5: RMS_3Hz_Qsum-Qdiff-axes.png
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Attachment 6: RMS_broad_Qsum-Qdiff-axes.png
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Attachment 7: RMS_08Hz_Qaxes.png
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Attachment 8: RMS_3Hz_Qaxes.png
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Attachment 9: RMS_broad_Qaxes.png
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Attachment 10: Accel_ITMX.png
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Attachment 11: Accel_ETMX.png
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Tue Dec 18 23:27:36 2007 |
Andrey | Configuration | Computer Scripts / Programs | New overnight measurements (this night from Tue to Wed) |
I am making overnight measurements in XARM tonight.
This is the third night of measurements in XARM, but tonight I am scanning the narrower region between values of damping gain 1.00 and 4.50 with the smaller step 0.25. (for comparison, during two previous measurements the region was between 1.0 and 7.0 with the step 0.5).
I have relocked the XARM before the start of the measurements.
I started running the program at 9.30PM, and it should collect all the data by 9.00AM wednesday morning.
Below are explanations why I chose these different parameters for the interval and step:
I am going to put the results of previous night measurements into the next ELOG entry, and it we be pretty obvious from those graphs that results in XARM from the two previous (different) nights agree well with each other, and the approximate positions of minima and areas of "big growth" of the surfaces are pretty obvious from those graphs. It is clear that RMS are too big for the values of the damping gain bigger than 4.0, and that minima are somewhere near the values of 2.0. But those graphs were too rough to locate a somewhat precise value for the minima. Therefore, I am studying tonight the interval of gains between 1.00 and 4.50 with a smaller step.
A short note how I estimate time that is necessary to collect the experimental data.
there are 15 experimental points for each ETMX and ITMX suspension gains in the interval between 1.00 and 4.50 with the step 0.25. They are: 1.00, 1.25, 1.50, 1.75, 2.00, ..., 3.75, 4.00, 4.25, 4.50. As I am changing both ETMX and ITMX gains, I have an array of 15*15=225 elements.
It takes 3 minutes for each point to collect the data (I wrote the program that way). Therefore, the total time it takes to run the program is: 225*3=675 minutes, or 675/60=11.25 hours, almost 11 and a half hours. |
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Tue Dec 18 23:41:00 2007 |
Andrey | Summary | Computer Scripts / Programs | Results of Mon/Tue overnight measurements (entry #194) |
Here I inform our community about the results of the measurements of RMS values in XARM during the previous night from Monday to Tuesday (I announced those measurements in ELOG entry #194).
All the plots in today's report seem to agree well with the analogous plots from the night from Saturday to Sunday (those results are given in ELOG entry # 195).
All the intervals in which RMS have been calculated are the same as in yesterday's ELOG entry #195.
I plotted three results for RMS in the abovementioned three intervals in three different ways:
1) view from the top in the axes (Q_{ITMX}+Q_{ETMX})/2 and (Q_{ITMX}-Q_{ETMX}) -> first three graphs (attachments 1 -3);
2) view from the side in the same sum- and difference-axes -> next three graphs (attachments 4-6);
3) view from the side in Q_{ITMX} and Q_{ETMX} axes -> next three graphs (attachments 7-9, also attch. 12), above accelerometer spectra (attachments 10-11).
Also, I compared the ground noise level by comparing spectra of accelerometer signals at different times during that night. As a reminder, before my disease I installed one accelerometer near ITMX and another accelerometer near ETMX (see entries 161 and 172 in ELOG). The plots of ratios of accelerometer signals at different times (pairs of times that were used: 11PM and 2AM, 11PM and 5AM, 11PM and 8AM) are given below, see attachments 10-11. The program was running from 11PM on Monday till 9AM on Tuesday.
As I explained in the previous ELOG entry # 198, tonight I am taking experimental data in the narrowere interval from 1.00 to 4.50 with a smaller step 0.25. |
Attachment 1: RMS_08HZ_Top_View.png
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Attachment 2: RMS_3HZ_Top_View.png
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Attachment 3: RMS_broad_Top_View.png
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Attachment 4: RMS_08HZ_Side_View.png
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Attachment 5: RMS_3HZ_Side_View.png
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Attachment 6: RMS_broad_Side_View.png
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Attachment 7: RMS_08HZ_Q_E_Q_I_Axes.png
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Attachment 8: RMS_3HZ_Q_E_Q_I_Axes.png
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Attachment 9: RMS_broad_Q_E_Q_I_Axes.png
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Attachment 10: Accelerometer_ITMX.png
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Attachment 11: Accelerometer_ETMX.png
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Attachment 12: RMS_broad_Q_E_Q_I_Axes.png
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201
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Wed Dec 19 15:51:00 2007 |
Andrey | Update | Computer Scripts / Programs | Daytime measurements in XARM and their results |
I was making measurements in XARM for three different nights. All the results agree with each other (I will put the results from the last night soon).
Steve Vass recommended to me to compare those results with the daytime data, in order to see if there is a real necessity to run the scripts overnight or if daytime results will yield similar results.
XARM has been locked, and I am taking measurements today from 3.30PM till 11.30PM.
I will be changing the suspension damping gains in ETMX and ITMX "position" degrees of freedom in the interval from 1.0 to 3.75 with the step 0.25.
BELOW: RESULTS OF MEASUREMENTS WERE ADDED ON THURSDAY, DEC. 20.
All the meaning of the attachments 1-3, 4-6, 7-9, 10-11 is the same as in previous ELOG entries # 195, # 199, # 202, see in those entries which graph corresponds to which coordinate axes orientation. |
Attachment 1: RMS-08Hz-Top_View.png
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Attachment 2: RMS-3Hz-Top_View.png
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Attachment 3: RMS-broadband-Top_View.png
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Attachment 4: RMS-08Hz-Side-View.png
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Attachment 5: RMS-3Hz-Side_View.png
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Attachment 6: RMS-broadband-Side_View.png
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Attachment 7: RMS-08Hz-Q_I-Q_E-Axes.png
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Attachment 8: RMS-3Hz-Side_View.png
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Attachment 9: RMS-broadband-Side_View.png
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Attachment 10: Accelerometer_ETMX.png
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Attachment 11: Accelerometer_ITMX.png
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202
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Wed Dec 19 16:07:37 2007 |
Andrey | Summary | Computer Scripts / Programs | Results of overnight measurements Tue/Wed night (entry #198) |
As indicated in ELOG entry 198, I was making overnight measurements during last night from Tuesday to Wednesday.
I was changing the suspension damping gain in ETMX and ITMX in "position" degree of freedom between values of 1.00 and 4.50 with the step 0.25.
Results for RMS of peaks (A) at 0.8Hz, (B) at about 3.0Hz and (C) in the range from 0.6Hz to 3.7Hz ("RMS in a broad interval") are given below:
I plotted three results for RMS in the abovementioned three intervals in three different ways:
1) view from the top in the axes (Q_{ITMX}+Q_{ETMX})/2 and (Q_{ITMX}-Q_{ETMX}) -> first three graphs (attachments 1 -3);
2) view from the side in the same sum- and difference-axes -> next three graphs (attachments 4-6);
3) view from the side in Q_{ITMX} and Q_{ETMX} axes -> next three graphs (attachments 7-9)
Attachments 10 and 11 show ratios of accelerometer signals at different times of the night/morning.
A little discussion about these graphs:
1) The areas of minima and of rapid growth are the same for all the measurements during all three nights.
2) Tonight there was a strange spike for the values of Q_{ETMX}=2.5 and Q_{ITMX}=4.0. I interpret that as an error of experiment.
3) On all the plots from all three nights there is a wide area of minimum on the plots for RMS at 0.8Hz and for "RMS in the broad interval",
and the graph for "RMS at 3Hz" indicates a clearer minimum in a localized area for Q_{ITMX}=2+-1, Q_{ETMX}=2+-1. Note that this area 2+-1
is included into the wide region of minimum for "RMS at 0.8Hz" and "RMS in a broad range".
Therefore, my guess at this stage is that we can choose the optimized value of suspension damping gains for both Q_{ITMX} and Q_{ETMX} somewhere
around 2+-1. I would like to make another overnight measurement (tonight) in that narrowed region with a small step to have more certainty.
By the way, I realized that I was a little bit careless and at some plots Q_I stands for {Q_ITMX}, and Q_E stands for Q_{ETMX}.
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Attachment 1: RMS_08Hz_Top_view.png
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Attachment 2: RMS_3Hz_Top_view.png
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Attachment 3: RMS_broad_Top_view.png
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Attachment 4: RMS_08Hz_Side_view.png
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Attachment 5: RMS_3Hz_Side_view.png
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Attachment 6: RMS_broadband_Side_view.png
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Attachment 7: RMS_08Hz_Q_I-Q_E-axes.png
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Attachment 8: RMS_3Hz_Q_I-Q_E-axes.png
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Attachment 9: RMS_broadband_Q_I-Q_E-axes.png
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Attachment 10: Accelerom_ETMX.png
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Attachment 11: Accelerom_ITMX.png
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204
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Wed Dec 19 20:28:27 2007 |
Andrey | DAQ | PEM | Names for all 6 accelerometers have been changed |
I eventually changed the names for all 6 accelerometers (see my ELOG entry # 172 from Dec. 05 about my intent to do that).
I removed the word "BS" from their names,
and I changed the word combination "ACC_BS_EAST" in the old name for "ACC_ITMX" in the new name;
as well "ACC_BS_WEST" is now replaced by "ACC_ETMX".
(the reasoning behind such a change should become clear from my ELOG entry #172).
New accelerometer names are:
(note: there are no spaces (nowhere!) in the names of accelerometers, but ELOG replaces ": P" written without a space by a strange symbol )
C1 : PEM - ACC _ ETMX _ X ;
C1 : PEM - ACC _ ETMX _ Y ;
C1 : PEM - ACC _ ETMX _ Z ;
C1 : PEM - ACC _ ITMX _ X ;
C1 : PEM - ACC _ ITMX _ Y ;
C1 : PEM - ACC _ ITMX _ Z .
One can find them in "C1 : PEM - ACC" in Dataviewer.
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205
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Thu Dec 20 02:04:09 2007 |
Andrey | Update | Computer Scripts / Programs | New overnight measurements in XARM and their results |
I ran in the daytime/evening time my program, changing the damping gains in suspension "position" degree of freedom for ETMX and ITMX
in the interval from 1.00 to 3.75 with the step 0.25 (see entry # 201).
Now I am running overnight (from 2AM till 9AM) the program changing the gains in the interval from 1.3 to 3.5 with the step 0.20,
12 X 12 = 144 experimental points. I started so late because I fell asleep after my Wednesday evening dinner, then woke up half an hour ago and hurried to the lab.
BELOW: RESULTS OF MEASUREMENTS WERE ADDED ON THURSDAY EVENING, DEC. 20.
All the meaning of the attachments 1-3, 4-6, 7-9, 10-11 is the same as in previous ELOG entries # 195, # 199, # 202, see in those entries which graph corresponds to which coordinate axes orientation. |
Attachment 1: RMS-08Hz-Top-View.png
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Attachment 2: RMS-3Hz-Top-View.png
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Attachment 3: RMS-broadband-Top-View.png
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Attachment 4: RMS-08Hz-Side_View.png
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Attachment 5: RMS-3Hz-Side_View.png
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Attachment 6: RMS-broadband-Side_View.png
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Attachment 7: RMS-08Hz-Q_I-Q_E-Axes.png
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Attachment 8: RMS-3Hz-Q_I-Q_E-Axes.png
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Attachment 9: RMS-broadband-Q_I-Q_E-Axes.png
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Attachment 10: Accelerometer-ETMX.png
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Attachment 11: Accelerometer-ITMX.png
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208
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Thu Dec 20 21:57:34 2007 |
Andrey | Update | Computer Scripts / Programs | Measurements in XARM today |
Today at 2PM I started a program, it should change the suspension gains in the interval from 1.0 to 3.8 with the step 0.2. Estimated running time is till 3.30AM coming night.
Results will be reported on Friday.
BELOW: ADDITION MADE ON FRIDAY EVENING.
Due to some unforeseen circumstances, I was unable to add results on Friday. I have so far accelerometer spectra only, which I add to this ELOG entry.
I have files with the measurement results, and I will process them after Christmas and add to this ELOG entry. I might not be in the lab on Dec. 24 and 25. |
Attachment 1: Accelerom_ETMX.png
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Attachment 2: Accelerom_ITMX.png
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209
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Thu Dec 20 21:58:28 2007 |
Andrey | Summary | Computer Scripts / Programs | Results for 2 previous XARM measurements have been added |
I attached results (plots) of yesterday's daytime and overnight measurements to the initial reports about those measurements.
These are ELOG entries # 201 and # 205. |
251
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Mon Jan 21 23:30:03 2008 |
Andrey | Update | Computer Scripts / Programs | Matlab Program for Q-factor measurements (XARM -> ITMX and ETMX) |
Finally I overcame difficulties with adapting Sonia's Matlab programs for XARM (Sonia's program was for MC),
and now there exists a Matlab program that makes a fit of a ringdown curve and calculates Q-factor for a mirror ITMX.
Specifically, this program allows to measure ringdown, fit it and calculate Q-factor for the ITMX-mirror for a specific value of
"C1:SUS-ITMX_SUSPOS_GAIN".
Attached is a plot of a ringdown curve and its fit for the value 4.0 in channel "C1:SUS-ITMX_SUSPOS_GAIN".
Calculations yield the result Q=3.7+-0.2 for the value 4.0 in channel "C1:SUS-ITMX_SUSPOS_GAIN".
As Robert started 10 minutes ago the long procedure of the whole interferometer locking,
I cannot disturb the interferometer now, so I will measure Q-factors for various combinations of suspension damping gain on Tuesday.
I will also easily modify the program for measuring Q-factors of ETMX-mirror and make measurements with ETMX on Tuesday.
The Matlab scripts are in directory /cvs/cds/caltech/users/rodionov/Q-Factors/ |
Attachment 1: Example-ITMX_POS_40.png
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256
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Wed Jan 23 12:31:36 2008 |
Andrey | Summary | SUS | Dissapointing Results of XARM optimization (PDF-file) |
I attach a PDF-file which summarizes briefly the results of measurements/calculations of Q-factors for ITMX mass as a function of suspension damping gain,
and this file contains the results of measurements of RMS peaks on the values of suspension gains of ITMX and ETMX (see ELOG entries from December 2007, specifically #202, #199, #194)),
but now those dependences are plotted in Q-ITMX and Q_ETMX axes.
Unfortunately, there are no clear narrow areas of minimum in those dependences (that explains the sad title of this ELOG entry).
The attached pdf-file can be shown as a short presentation for a wall during our Wednesday meeting. |
Attachment 1: Sad_Results_XARM.pdf
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260
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Thu Jan 24 20:03:40 2008 |
Andrey | Configuration | SUS | Changes to Dataviewer channels (XARM) |
1) Good news. I added a chanel "C1:SUS-ETMX_POS" to Dataviewer.
I followed the instructions from WIKI-40:
modify the file "C1SUS_EX.ini" in /cvs/cds/caltech/chans/daq,
then telnet to fb40m,
then "click the appropriate blue button on the DAQ MEDM screen".
So, I can now read a signal from the channel "C1:SUS-ETMX_POS" in Dataviewer,
and this allows me to measure Q-factors of ETMX this evening (make similar work for what I did on Tuesday for ITMX).
2) BAD NEWS. While "clicking the appropriate blue button" on the DAQ MEDM screen,
namely CODAQ_DETAIL,adl screen, I obviously clicked some blue button that I should not have clicked,
and as a result the signal in Dataviewer from the channel "C1:SUS-ITMX_POS" has disappeared (it is now a straight line).
Description of what has happened and of my wrong actions:
I had two channels opened in Dataviewer simultaneously (both "C1:SUS-ETMX_POS" and "C1:SUS-ITMX_POS"),
and after clicking some blue button on CODAQ_DETAIL,adl screen, the signal from "C1:SUS-ITMX_POS" became
a straight line, while signal from "C1:SUS_ETMX_POS" continued to be a random noise.
I was scared that I made worse for the channels and for Dataviewer, and I started clicking random blue buttons chaotically hoping that it will restore the signal from "C1:SUS-ITMX_POS". Random clicking on arbitrary blue buttons did not return the signal.
As the channel "C1:SUS-ETMX_POS" works normally, I will be measuring Q-factors of ETMX tonight,
but it is obvious that someone else (Rana, Robert,Steve?) needs to restore the correct settings for "C1:SUS-ITMX_POS".
Moreover, as I was clicking chaotically all the blue buttons on CODAQ_DETAIL,adl screen, someone else (Rana, Robert, Steve?) will need to check somehow that I did not destroy signals from some other channels.
I apologize for the negative consequences of my channel adding,
but Rana asked me in the very beginning in September to let others know if I spoil something, so that others would be aware of it and could fix the problem.
Again, I apologize and hope that the problem is not very serious. |
261
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Thu Jan 24 22:10:49 2008 |
Andrey | Configuration | Computer Scripts / Programs | Problem with channels - help of Rana, Robert or Steve is needed |
I definitely spoiled something (changes some settings) by chaotically clicking those blue buttons (see my previous entry # 260).
Unfortunately, I cannot use standard library of functions for reading from channels from mDV directory.
Although I see the curve of a noise in the Dataviewer from the channel "Ch1:SUS_ETMX_POS", when I try to read data from the channel using the program "get_data" from MDV directory, I get the error message
"Warning: No data available for [numbers representing "gps_start_time" and "gps_end_time"].
In new_readframedata at 136
In new_fetch_shourov at 71
In get_data at 98"
I checked, both gps-times are in the past from now, so as far I understand, nothing is recorded into the channels.
Of course, I added two hours ago to the directory "mDV", that is I used addpath(pwd) in that directory.
And I also cannot run the program that I used on Tuesday evening which takes data from "C1:SUS_ITMX_POS" (no data from that channel), which worked perfectly on Tuesday.
I again apologize for clicking the wrong blue button (see my explanation in my previous message #260). I ask someone who knows how to return normal working of channels (normal interaction of computer and channel memory) to do that.
Before that I cannot take data. I do not know how to restore the initial settings which existed before I started adding the channel to Dataviewer.
Andrey. |
262
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Thu Jan 24 22:52:18 2008 |
Andrey | Bureaucracy | General | Ants around a dirty glass (David - please read!) |
Dear coleagues,
there are rains outside these days, so ants tend to go inside our premises.
David was drinking some beverage from a glass earlier today (at 2PM) and left a dirty glass near the computer.
There are dozens, if not hundreds, of ants inside of that glass now.
Of course, I am washing this glass.
A. |
273
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Sat Jan 26 02:34:34 2008 |
Andrey | Update | Computer Scripts / Programs | Overnight Measuremts in XARM |
I am running the program for measuring RMS of peaks in XARM tonight. I just started it, and it will run for about 9 hours until noon on Saturday. Please do not disturb the interferometer. Now the XARM is locked, it should stay locked over the night.
Andrey. |
281
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Mon Jan 28 17:16:54 2008 |
Andrey | Configuration | Computers | Matlab libraries DO NOT WORK properly sometimes |
Working in Matlab, I encountered at two different times today the license distribution problem:
??? License checkout failed.
License Manager Error -4
Maximum number of users for Curve_Fitting_Toolbox reached.
Try again later.
To see a list of current users use the lmstat utility or contact your License Administrator.
Troubleshoot this issue by visiting:
http://www.mathworks.com/support/lme4a |
286
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Wed Jan 30 13:09:55 2008 |
Andrey | Update | SUS | New results for XARM (pdf) |
See attachments: pdf-presentation with plots in "true" axes Q_ETMX and Q_ITMX, and seismic backgound measurement.
Results that were shown a week ago turned out to be not sad at all! |
Attachment 1: New_Results_XARM.pdf
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Attachment 2: Accel-Seismic_10AM.pdf
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