 Mon Jan 23 22:51:17 2023, yuta, Summary, BHD, 60 Hz harmonics side lobe investigations 
|
[Paco, Yehonathan, Yuta]
Since we have installed BH44, we are seeing side lobes of 60 Hz + harmonics in AS55, REFL55, BH55, BH44, preventing us from locking FPMI BHD (40m/17405). |
|
Tue Jan 24 21:29:31 2023, yuta, Summary, BHD, Electronics diagram around BH44 and BH55
|
1) Turning the whitening filter before the ADC on/off didn't changed the relative height of 60 Hz peak compared with the noise floor. When the
whitening filter was turned on, increase of the dark noise measured at C1:LSC-****_(I|Q)_IN1 was roughly consistent by eye with the whitening filter
transfer function (gain of 1 at DC, ~15 Hz zero x2, ~150 Hz pole x2), which suggests the 60 Hz pickup is before the whitening filter. |
|
Wed Jan 25 11:35:20 2023, yuta, Summary, BHD, REFL55 visually inspected, BH44 Kapton taped
|
Following was done to investigate 60 Hz noise issue, but no significant change in the FPMI noise observed.
|
|
Wed Jan 25 18:01:21 2023, yuta, Summary, BHD, BH44 setup isolated, but 60 Hz noise stays the same
|
[Paco, Anchal, Yuta]
Isolating BH44 setup from the rest didn't help reducing the 60 Hz noise. |
|
Thu Jan 26 16:07:05 2023, yuta, Summary, PSL, PMC aligned, now PMC transmission is 0.7
|
PMC aligned (Attachment #1).
Over the past month, PMC transmission is actually slowly growing from 0.68 to 0.70 (Attachment #2), since it suddenly dropped from
0.72 on Dec 27 (40m/17390). |
|
Fri Jan 27 19:35:31 2023, yuta, Summary, BHD, 60 Hz noise investigations around IMC 6x
|
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. |
|
Fri Jan 27 21:22:57 2023, yuta, Summary, BHD, V beam dump installed for BH44 RF PD
|
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. |
|
Fri Feb 3 17:39:38 2023, yuta, Summary, BHD, 60 Hz noise investigations around IMC, part 2
|
[Paco, Yuta]
We estimated the frequency noise of IMC output beam at 60 Hz using different methods to see if they are consistent. |
|
Tue Feb 7 20:10:05 2023, yuta, Summary, BHD, 60 Hz noise investigations around IMC, part 3
|
[Anchal, Yuta]
We have measured OLTF of IMC loop, and revisited IMC error point calibration again. |
|
Thu Feb 9 10:05:37 2023, yuta, Update, CDS, c1sus2 all FE models crashed spontaneously again
|
I just noticed that c1sus2 crashed again. Following 40m/17335,
I fixed it by running
|
|
Thu Feb 9 10:19:22 2023, yuta, Summary, BHD, 60 Hz noise investigations around IMC, part 4, using ALS BEAT
|
[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. |
|
Thu Feb 9 17:33:34 2023, yuta, Summary, BHD, 60 Hz noise investigations around IMC, part 6, TTFSS
|
[Anchal, Yuta]
Measurements yesterday (40m/17458) suggested that 60 Hz noise is injected after MC_F |
|
Mon Feb 13 11:54:54 2023, yuta, Summary, BHD, 60 Hz frequency noise is coming from MC1 coils
|
[JC, Yuta]
We have found that MC1 coils are causing 60 Hz noise. |
|
Tue Feb 14 10:49:04 2023, yuta, Summary, BHD, MC1 electronics diagram and cable diconnection tests
|
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. |
 Thu Feb 16 14:44:06 2023, yuta, Update, BHD, FPMI BHD with BH55 recovered
|
FPMI BHD with LO phase locked using BH55 is recovered after 60 Hz frequency noise saga.
Attachment #1 shows the calibrated FPMI spectrum with RF(AS55_Q) readout and BHD, compared with those taken on January 13 (40m/17400,
before BH44 installation). |
|
Wed Feb 22 17:32:16 2023, yuta, Update, BHD, BH55 and BH44 both amplified
|
Since we need more signal for both BH55 and BH44 to compare LO phase locking scheme, BH55 and BH44 RF outputs are now amplified with ZFL-1000LN+ and
ZFL-500HLN+ respectively (see Attachment #1).
The amplifiers each draw ~0.1 A current of 15V DC power supply, and Sorensen power supply now reads 6.9 |
|
Thu Feb 23 14:55:49 2023, yuta, Update, BHD, BH55 and BH44 orthogonality checks
|
Ideally, BH55 and BH44 should give orthogonal signals to lock LO phase (40m/17302).
This was checked with various interferometer configurations.
BH55 and BH44 are indeed orthogonal in ITM single bounce and MICH, but was not |
|
Mon Mar 13 19:53:36 2023, yuta, Update, BHD, FPMI BHD sensing matrix measurement with individual lines
|
FPMI BHD sensing matrix was measured by an updated method with updated RF demodulation phases for REFL55 and AS55.
Now audio demodulation phase for CARM components is 90 deg to make the sign correct.
Also, oscillators are turned on one by one to reduce contamination between DoFs (especially between MICH and CARM). |
|
Tue Mar 14 18:44:39 2023, yuta, Update, BHD, LO phase noise measurements in ITMX single bounce, MICH and FPMI
|
[Anchal, Yuta]
We have measured LO phase noise in ITMX single bounce, simple MICH and FPMI configurations with LO phase locked with BH55 or BH44. |
|
Mon Mar 20 20:27:30 2023, yuta, Update, BHD, LO phase noise contribution in MICH BHD
|
[Paco, Yuta]
MICH was locked with balanced homodyne readout with LO phase locked using BH55_Q and BH44_Q.
It turned out that BH44_Q gives better LO phase in MICH configuration (in FPMI, BH55_Q is better; |
|
Thu Mar 23 19:15:39 2023, yuta, Summary, LSC, PRMI locked using REFL55
|
[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. |
|
Fri Mar 24 12:54:51 2023, yuta, Summary, LSC, Actuator calibration of PRM using PRY
|
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 |
|
Fri Mar 24 15:05:41 2023, yuta, Summary, LSC, PRMI sensing matrix and RF demodulation phase tuning
|
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. |
|
Sun Mar 26 19:13:48 2023, yuta, Summary, LSC, PRMI sensing matrix and RF demodulation phase tuning
|
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 !!" |
|
Wed Apr 12 21:32:22 2023, yuta, Summary, LSC, PRMI BHD power measurements
|
[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. |
|
Tue Apr 18 19:29:43 2023, yuta, Update, BHD, LO phase noise measurements in ITMX single bounce, MICH and FPMI
|
[Anchal, Yuta]
We have repeated LO phase noise measurement done in elog 40m/17511. |
|
Wed Apr 19 15:12:01 2023, yuta, Summary, SUS, Coil dewhitening check for PRM
|
[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: |
|
Fri Apr 28 20:17:37 2023, yuta, Summary, ASC, IFO alignment in bad shape
|
[Mayank, Paco, Yuta]
IFO alignment is not good. |
|
Wed May 3 15:06:44 2023, yuta, Summary, LSC, POP attenuation and PRMI PRG estimate
|
[Paco, Yuta]
Measured |
|
Wed Jun 7 17:05:36 2023, yuta, Summary, LSC, RF FPMI recovered after c1sus DAC card replacement
|
[Paco, Yuta]
RF FPMI is recovered after c1sus DAC-0 card replacement |
|
Thu Jun 8 10:31:46 2023, yuta, Update, CDS, c1sus2 all FE models crashed spontaneously again and IMC/vertex optics damping stopped
|
[Mayank, Yuta]
We noticed that c1sus2 crashed again |
|
Fri Jun 9 17:39:48 2023, yuta, Update, LSC, High bandwidth YARM test
|
[Paco, Mayank, Yuta]
CARM Common Mode Board works for YARM locking
|
|
Fri Jul 7 17:29:16 2023, yuta, Summary, ASC, IFO alignment is in a strange state
|
IFO alignment is in a strange state.
BHD is not fringing, and misalignment script is not working properly
IFO alignment status |
|
Mon Jul 10 15:22:25 2023, yuta, Summary, ASC, IFO alignment is in a strange state
|
"gain_offset" for ETMY coil outputs has been turned on
As mentioned in elog #17671,
the "gain_offset" of gain(0.48) for ETMY coil outputs had been turned off for some reason.
I have turned on all of the "gain_offset" for ETMY coils and have changed the alignment offsets for ETMY to compensate the effect |
|
Thu Jul 13 14:47:38 2023, yuta, Bureaucracy, General, Things we need to fix
|
ETMX damping loops are not good. ETMX is moving by ~10 urad (if oplev is correctly calibrated), and beam spot moves by ~0.5 beam spot on ETMX
when Xarm is locked. TRX fluctuates by ~10%. Simply tuning gains did not solve.
ETMX does not come back after putting some offset to misalign
and remove the offset to align. Hysterisis makes me hysteric.
Xend acromag is removed, and we cannot access Xend shutter and ETMX slow channels.
XARM |
|
Thu Jul 13 17:20:53 2023, yuta, Update, LSC, PRMI 1f not locking stably
|
PRMI carrier on 1f now locks for ~1min but not more. Below is the configuration.
The configuration is the same as basically the same as 40m/17578, except for PRCL gain.
Maybe the RF demodulation phases changed? |
|
Mon Jul 31 15:46:03 2023, yuta, Update, SUS, Strange behavior of ITMX and ITMY probably due to DAC issue
|
I did the same test we did in 40m/17616 to see if DACs are working fine for ITMX and ITMY.
I used awggui to excite all the coil outputs of the optic with 0.1 Hz with an amplitude of 3000 counts, and checked VMons.
Found that ITMX, ITMY, PRM and BS face coil DAC outputs cannot drive positive voltages. In |
|
Thu Aug 10 19:52:47 2023, yuta, Summary, ALS, simultaneous hold and release of the arm (aka two arm ALS)
|
I just wanted to take the same time series data I took back in 2012 (40m/6874).
ALS noise look much better than 2012, but MICH contrast during both arms hold on IR resonance with ALS looks pretty bad compared with 2012, which
indicate unbalance of the arms. |
|
Tue Aug 15 09:56:52 2023, yuta, Update, IOO, PMC aligned, c1sus2 crashed
|
[JC,
Yuta]
|
|
Wed Aug 16 18:33:40 2023, yuta, Update, LSC, PRMI 1f/3f switching in both carrier/sideband resonant configurations
|
[JC, Yuta]
Transitioning from 1f to 3f in both PRMI carrier and sideband is now smooth
once you have PRMI nicely aligned (key is to tweak TT1 and TT2). |
|
Wed Sep 27 14:01:11 2023, yuta, Update, SUS, Whitening/dewhitening check at Yend
|
[Paco, Yuta]
We checked whitening and dewhitening situations in all the suspensions, and fixed them for ETMY. |
|
Wed Sep 27 21:11:36 2023, yuta, Update, SUS, Checking suspension damping loop polarity conventions
|
[Paco, Yuta]
We checked the polarity of suspension damping loops if they follow the conventions we agreed in 40m/16898. |
|
Thu Sep 28 11:30:13 2023, yuta, Update, SUS, Checking suspension damping loop polarity conventions
|
To further homogenize the suspensions, we did the following changes.
- Turned on DECIMATION in PR2 URCOIL
- Changed +/- 13 in SDCOIL_GAIN of SR2,LO1,LO2,AS1,AS4 to +/-1 and increased SUSSIDE_GAIN accordingly |
|
Fri Sep 21 09:59:09 2018, yuki, Configuration, ASC, Y end table upgrade plan
|
[Yuki, Gautam]
Attachments #1 is the current setup of AUX Y Green locking and it has to be improved because:
current efficiency of mode matching is about 50%
current setup doesn't separate the degrees of freedom of TEM01 with |
|
Sun Sep 23 17:38:48 2018, yuki, Update, ASC, Alignment of AUX Y end green beam was recovered
|
[ Yuki, Koji, Gautam ]
An alignment of AUX Y end green beam was bad. With Koji and Gautam's advice, it was recovered on Friday. The maximum value of TRY was
about 0.5. |
|
Sun Sep 23 19:32:23 2018, yuki, Configuration, ASC, Y end table upgrade plan
|
[ Yuki, Gautam ]
The setup I designed before has abrupt gouy phase shift between two steering mirrors which makes alignment much sensitive. So I designed a new
one (Attached #1, #2 and #3). It improves the slope of gouy phase and the difference between steering mirrors is about 100 deg. To install this, we need |
|
Mon Sep 24 11:09:05 2018, yuki, Configuration, ASC, Y end table upgrade plan
|
[ Yuki, Steve ]
With Steve's help, we checked a new lens can be set soon after dichroic mirror.
Quote:
|
|
Tue Sep 25 18:08:50 2018, yuki, Configuration, ASC, Y end table upgrade plan
|
[ Yuki, Gautam ]
We want to remotely control steeing PZT mirrors so its driver is needed. We already have a PZT driver board (D980323-C) and the
output voltage is expected to be verified to be in the range 0-100 V DC for input voltages in the range -10 to 10 V DC. |
|
Thu Sep 27 14:02:55 2018, yuki, Configuration, ASC, PZT driver board verification
|
[ Yuki, Gautam ]
I fixed the input terminal that had been off, and made sure PZT driver board performs as we expect.
At first I ran a simulation of the PZT driver circuit using LTspice (Attached #1 and #2). It shows that when the bias is |
|
Sun Sep 30 20:14:51 2018, yuki, Configuration, ASC, QPD calibration
|
[ Yuki, Gautam, Steve ]
Results:
I calibrated a QPD (D1600079, V1009) and made sure it performes well. The calibration constants are as follows: |