 Fri Jan 27 19:35:31 2023, yuta, Summary, BHD, 60 Hz noise investigations around IMC 6x
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So far different measurements are consistent with the hypothesis that the 60 Hz noise is from PSL frequency noise (40m/17423).
We have done several measurements in REFL55 and POX/POY to show this hypothesis, and all are consistent with
the frequency noise hypothesis. |
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Fri Jan 27 21:22:57 2023, yuta, Summary, BHD, V beam dump installed for BH44 RF PD
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One of these V beam dumps was installed for BH44 RF PD.
The rest is now stored in the box in the shelf along Yarm, together with RF PD mounts. |
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Mon Jan 30 10:59:15 2023, JC, Summary, PSL, PMC aligned, now PMC transmission is 0.7
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PMC hit a drop around mid-day on Saturday and has been going down since. As of now,
C1:PSL-PMC_PMCTRANSPD - 0.664
I will go in and adjust now. |
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Mon Jan 30 18:08:56 2023, Paco, Summary, BHD, c1cal DAQ error 0x2000
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[JC, Paco]
I tried restarting all models this afternoon to see if the DC error 0x2000 on c1cal model cleared (currently no frame data is being written from
c1cal). By running ./restartAllModels.sh on the scripts/cds/ folder, and then BURT restoring, but unfortunately this didn't work. I also tried restarting |
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Tue Jan 31 11:02:16 2023, Anchal, Summary, BHD, c1cal DAQ error 0x2000 fixed
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The 0x2000 error happens when the rtcds model can not acquire the requested number of channels at their data rates. Basically, there is a maximum total
data acquisition that one model can do (which is unknown to me). To fix this, I removed 2048 Hz acquiring of C1:CAL-SENSMAT_<DOF>_<RFPD>_<I/Q>_DEMOD_SIG_IN1.
This would not allow us to do software demodulation of calibration lines ourselves. but C1:CAL-SENSMAT_<DOF>_<RFPD>_<I/Q>_DEMOD_<I/Q>_IN1 |
 Wed Feb 1 16:53:55 2023, Alex, Summary, General, Shadowing Anchal on developing a change for the c1ioo CDS computer
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During my time shadowing Anchal, we discussed the need for digital control systems on the suspension systems for the 40 meter optics. The controls and
diagnostics system (CDS) allows us to develop our own feedback controls and filters for the suspension systems by taking in analog signals from the shadow
sensors. The feedback control system developed in the CDS then utilizes the OSEM actuators to dampen harmonic motion and noise on the suspension lines. |
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Thu Feb 2 19:41:49 2023, Anchal, Summary, PowerShutdown, Recovery from power outage events
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[Anchal, JC, Radhika, Paco]
JC reported that power outage happened twice in 40m today at around 4:17 pm.
We followed instructions from this page mostly to recover today. |
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Fri Feb 3 17:39:38 2023, yuta, Summary, BHD, 60 Hz noise investigations around IMC, part 2
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[Paco, Yuta]
We estimated the frequency noise of IMC output beam at 60 Hz using different methods to see if they are consistent. |
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Fri Feb 3 17:41:26 2023, Paco, Summary, BHD, Systematic line noise hunting around BH44
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[Paco, Yuta]
We devised a plan to systematically hunt for the line noise source assuming it has something to do with BH44 and/or our recent changes in the |
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Sun Feb 5 10:25:49 2023, Anchal, Summary, PowerShutdown, Main laser tripping
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Our main laser has tripped suspiciously twice since the power shutdown. The last time it happened on Thursday Feb 2 night (the day of power outage happened).
Next morning Paco turned the laser back on, I'm not sure if he did anything else other than turning the diode current driver ON. Paco, please add anything
else you did. |
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Sun Feb 5 18:02:46 2023, rana, Summary, BHD, 60 Hz noise investigations around IMC, part 2
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For the loop calculation, don't you have to consider the IMC cavity pole? What about the analog filter on the output of the HV driver for the laser
PZT? |
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Mon Feb 6 07:58:00 2023, JC, Summary, PowerShutdown, Main laser tripping
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I came in today and it seems like the main laser tripped again yesterday around 3:00 pm.
There was a series of earthquakes in Turkey today, but all our suspension seem to be okay. |
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Mon Feb 6 11:50:44 2023, Anchal, Summary, PowerShutdown, Main laser tripping
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[Anchal, JC]
During shimmer test yesterday, the man laser tripped again. This morning, JC and I went to inspect the situation closer. We figured that if we
can take a look inside the controller, we can get the replacement fan part number. Attached are some photos of inside. To open the controller, all you |
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Tue Feb 7 20:10:05 2023, yuta, Summary, BHD, 60 Hz noise investigations around IMC, part 3
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[Anchal, Yuta]
We have measured OLTF of IMC loop, and revisited IMC error point calibration again. |
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Thu Feb 9 10:19:22 2023, yuta, Summary, BHD, 60 Hz noise investigations around IMC, part 4, using ALS BEAT
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[Anchal, Yuta]
Yesterday, we have measured the frequency noise of PSL with IMC locked/unlocked using ALS BEATX/Y to narrow down where the 60 Hz is coming from. |
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Thu Feb 9 17:33:34 2023, yuta, Summary, BHD, 60 Hz noise investigations around IMC, part 6, TTFSS
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[Anchal, Yuta]
Measurements yesterday (40m/17458) suggested that 60 Hz noise is injected after MC_F |
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Mon Feb 13 11:54:54 2023, yuta, Summary, BHD, 60 Hz frequency noise is coming from MC1 coils
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[JC, Yuta]
We have found that MC1 coils are causing 60 Hz noise. |
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Mon Feb 13 17:35:20 2023, Anchal, Summary, BHD, 60 Hz frequency noise is coming from MC1 coils
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[Anchal, Yuta]
We think we have narrowed down the source of 60 Hz noise to one fo the following possibilities:
Ground loop present along the MC1 suspension damping loop
60 Hz DAC noise on inputs of MC1 coil driver
60 |
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Tue Feb 14 10:49:04 2023, yuta, Summary, BHD, MC1 electronics diagram and cable diconnection tests
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Below are summary of electronics around MC1 and cable disconnection tests.
These suggest that the 60 Hz noise is probably from somewhere between DAC and the coil driver.
For now, we can work on IFO with SimDW off. |
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Wed Feb 15 16:16:59 2023, Anchal, Summary, BHD, IMC optics Coil Output Filter corrections
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Overtime the coil output filters on IMC optics have drifted into a bad configuration. Today at the meeting, Rana told us the correct configuration for
these filters. I'll summarize this here and we have changes the filters on all IMC optics, MC1, MC2, and MC3 to match this configurations:
MC1 and MC3
Analog side: |
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Fri Feb 24 13:29:16 2023, Alex, Summary, IMC, Updated angular actuation calibration for IMC mirrors
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Also reply to: 40m/17352
Tomohiro, Anchal, and I did the following to make updates to the calibration constants for pitch and yaw on MC1, MC2 and MC3.
To acquire the data used for fitting a curve respective to the change in counts per change in mirror pitch and yaw, we utilized some code that |
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Fri Feb 24 13:33:22 2023, Tomohiro, Summary, IMC, Updated angular actuation calibration for IMC mirrors
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Alex, Anchal, and I did the following to make updated angular actuation calibration for IMC mirrors. This is the revised version of Anchal's: 40m/16125.
In order to make the calibration formulas, we consider a matrix : connecting displacements
and rotations of the IMC's beam waist to PIT and YAW rotations of every mirror |
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Fri Mar 3 18:47:13 2023, Paco, Summary, BHD, LO phase POS noise coupling - I
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I tried some LO PHASE noise coupling measurements today. With MICH locked using AS55_Q, I control the LO phase using the single RF (BH55_Q) or double
RF (BH44_Q) demodulation error signals. The calibrated error and control points for single RF sideband sensing are shown in Attachment #1.
In either case feedback loop is closed using FM5, FM8 first with a gain of 1.5 and then a "boost" using FM4. The actuation point is LO1 POS and |
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Wed Mar 22 18:38:54 2023, Paco, Summary, BHD, "On why BH55 senses the LO phase, a finesse adventure of loss and residual DARM offsets"
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[Paco, Yehonathan]
I took over the finesse calculations Yehonathan had set up for BHD. The notebook is here
and for this post I focused on simulating what we might expect from our single RF vs dual RF sensors (55 MHz and 44 MHz respectively) in terms of LO phase |
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Thu Mar 23 14:20:29 2023, Koji, Summary, BHD, "On why BH55 senses the LO phase, a finesse adventure of loss and residual DARM offsets"
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This is interesting. With the FPMI, the DARM phase shift is enhanced by the cavity. Therefore, I suppose the effect on the BH55 is also going to be enhanced
(i.e. a much smaller displacement offset causes a similar LO phase rotation).
|
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Thu Mar 23 19:15:39 2023, yuta, Summary, LSC, PRMI locked using REFL55
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[Paco, Yuta]
We locked PRMI in sideband using REFL55_I and REFL55_Q.
Lock is not quite stable probably due to alignment fluctuations, and power recylicing gain is breathing. |
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Fri Mar 24 12:54:51 2023, yuta, Summary, LSC, Actuator calibration of PRM using PRY
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PRM actuator was calibrated using PRY by comparing the actuation ratio between ITMY.
It was measured to be
PRM : -20.10e-9 /f^2 m/counts |
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Fri Mar 24 15:05:41 2023, yuta, Summary, LSC, PRMI sensing matrix and RF demodulation phase tuning
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PRMI sensing matrix was measured under PRMI locked with REFL55_I and Q.
MICH actuator is 0.5*ITMX-0.5*ITMY (to have more pure MICH, according to 40m/15996)
and PRCL actuator is PRM. |
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Sun Mar 26 19:13:48 2023, yuta, Summary, LSC, PRMI sensing matrix and RF demodulation phase tuning
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that is really a lot of high precision for the REFL_11 demod phase...
for this kind of measurement, I wish we had a python code that would plot this measurment relative to our Finesse/PyKat model so we know if this
table is like "Oh, nothing to see here." or "Wow! that's a Nobel prize worthy measurement !!" |
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Mon Mar 27 20:28:57 2023, Paco, Summary, BHD, "On why BH55 senses the LO phase, a finesse adventure of loss and residual DARM offsets"
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Yuta pointed out that the BH55 signal was weirdly never going to zero, so I actually tuned the demod angle and made sure I was reading the right (Q)
quadrature. This doesn't affect our previous qualitative conclusion about DARM offsets, but here's an updated gif which also makes visualization
easier (?). |
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Tue Mar 28 10:58:03 2023, rana, Summary, BHD, "On why BH55 senses the LO phase, a finesse adventure of loss and residual DARM offsets"
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but what about including the DC reflectivity imbalance of the arms? there would be another BH55 term from that field maybe.
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Wed Mar 29 16:36:04 2023, Paco, Summary, BHD, "On why BH55 senses the LO phase, a finesse adventure of loss and residual DARM offsets"
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I repeated the calculations but with FPMI (last case was all MICH). The qualitative behavior
is the same, the BH55 sensing is mostly affected by residual darm offset. If the darm offset is of a couple of nm, the single RF sideband may sense
the LO phase at as much as > 20 deg away from the nominal phase angle. This is not too different from the MICH case; so |
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Thu Mar 30 16:45:09 2023, Paco, Summary, LSC, PRMI gain estimates and expected flashing at BHD and POP ports
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Here are our best estimates for the optic transmission (power) coefficients.
PRM
PR2
PR3
BS
ITMX
ITMY
LO1
LO2
SRM
SR2
AS1
AS2
AS3
AS4
BHD-BS
0.05637
0.022
0.00005
0.5
0.01384
0.01384
0
0
0.09903
0.00005
0
0.1
0
0
0.5
Assuming
our input power to the IFO is 0.95 Watts, and the IMC transmission is 90%, about 855 mW should be incident on the PRM. Furthermore, following our recent |
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Mon Apr 3 12:01:59 2023, Radhika, Summary, LSC, PRMI sensing matrix and RF demodulation phase tuning
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[Paco, Radhika]
We locked PRMI in carrier.
We refereced the old IFOconfigure script (/opt/rtcds/caltech/c1/burt/c1ifoconfigure/C1configurePRM_Carr.sh)
to manually configure the LSC screen for PRMI. The final MICH/PRCL gain values used to achieve lock were flipped in sign: |
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Tue Apr 4 11:03:35 2023, JC, Summary, Electronics, SR560: reworking
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| <p>I purchased some more of these from DigiKey. These parts are currently in the EE shop. These are replacements for the NDP5565 part of the SR560.</p> |
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Tue Apr 4 11:10:19 2023, Anchal, Summary, NeuralNet, Testing neural network controller during day time
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I ran two recently trained neural network controllers today between 10 am and Noon. Each test comprised of four segments:
All loops open
Linear loop closed
Neural Network working alone
Neural Network + Linear Loop
The
latest controller unfortunately failed in both cases, working alone and working together with linear loop. |
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Wed Apr 5 16:44:31 2023, Radhika, Summary, LSC, PRMI sensing matrix and RF demodulation phase tuning
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[Paco, Radhika]
We calibrated the PRM oplev.
1. Disabled PRM damping and oplev loops
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Thu Apr 6 11:49:45 2023, Anchal, Summary, NeuralNet, Testing neural network controller during day time
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I've turned on NN controller for MC WFS PIT loops. One can disable this controller and go back to linear controller by sitemap>IOO>C1IOO_WFS_MASTER>Actions!>Stop
Shimmer . One can start the controller again sitemap>IOO>C1IOO_WFS_MASTER>Actions!>Run Shimmer . |
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Thu Apr 6 21:09:12 2023, Koji, Summary, NeuralNet, Testing neural network controller during day time
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I'm going to get into the PSL enclosure. Also turn on the HEPA for a while during the intrusion.
Work done.
Start of the work: |
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Fri Apr 7 16:28:34 2023, Radhika, Summary, LSC, PRMI sensing matrix and RF demodulation phase tuning
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[Paco, Radhika]
To determine the PRM angle-to-length coupling for PRCL, we want to inject pitch/yaw lines into PRM and find the corresponding peaks in the PRCL
closed-loop control signal (below loop UGF). Below is a summary of PRMI locking efforts. |
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Wed Apr 12 16:11:41 2023, Radhika, Summary, LSC, PRMI sensing matrix and RF demodulation phase tuning
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[Yuta, Radhika]
We copied the coil balancing procedure found in /scripts/SUS/coilStrengthBalancing/AS1/CoilStrengthBalancing.ipynb to a new PRM directory. After
modifying channel names for PRM, we followed the coil balancing procedure: |
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Wed Apr 12 21:32:22 2023, yuta, Summary, LSC, PRMI BHD power measurements
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[Paco, Yuta]
We measured the power around BHD PDs to see if the numbers make sense.
Measured values are 10-20% less than expected values, which sounds good. |
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Tue Apr 18 17:37:58 2023, rana, Summary, ASC, RL controller left for overnight
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Anchal and I turned on another RL policy (ninedwarfs) with Chris's help.
It looks to be performing great, with good low frequency suppression and low noise injection at higher frequencies.
Going to leave it on overnight. It seems to respond well to lockloss of IMC, me whacking the MC2 chamber, walking near the MC2 chamber, kicking |
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Wed Apr 19 15:12:01 2023, yuta, Summary, SUS, Coil dewhitening check for PRM
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[Mayank, Paco, Yohanathan, Yuta]
We checked if coil dewhitening switch is working by measuring transfer function from coil outputs to oplev pitch and yaw.
Method: |
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Wed Apr 19 17:02:48 2023, Yehonathan, Summary, SUS, Coil dewhitening check for BS and ITMX
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[Yehonathan, Paco]
Repeated the coil dewhitening check for BS. Attachment #1 show results. Note however the DW filter shape for BS is more complicated:
zpk([86.7884+i*86.5657, 86.7884-i*86.5657,57.338+i*66.4261, |
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Mon Apr 24 19:11:20 2023, Koji, Summary, BHD, LO/MI(DARM) signal strength comparison between the configurations
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Yuta and I had a discussion last week about the signal strength between the configurations. Here are some naive calculations.
=== Please check the result with a more precise simulation ===
Michelson: Homodyne (HD) phase signal @44MHz is obtained from the combination of LO11xAS55 and LO CAxAS44. SBs at AS |
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Wed Apr 26 11:27:49 2023, Paco, Summary, BHD, LO/MI(DARM) signal strength comparison between the configurations with finesse
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I'm checking Koji + Yuta's not-so-naive calculations using finesse.
Michelson
PRMI carrier
PRMI sideband
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Fri Apr 28 20:17:37 2023, yuta, Summary, ASC, IFO alignment in bad shape
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[Mayank, Paco, Yuta]
IFO alignment is not good. |
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Fri Apr 28 20:56:06 2023, Koji, Summary, ASC, IFO alignment in bad shape
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I suppose ASS Y arm is using PR2/3 to align the beam to the arm.
Can't we have ASS PRM bring the beams to the center (or some defined places) of the PRM and PR2 by moving the TTs?
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Mon May 1 14:45:48 2023, Mayank, Summary, LSC, Attenuated BHD DC Beam
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[Yuta, Mayank]
UPDATE: It turned out that the pair of 0.3 OD ND filters we used were not matched. So we replaced them with new 0.5
OD NENIR05A-C from thorlabs. Now both the photodiodes give similar count. |