ID |
Date |
Author |
Type |
Category |
Subject |
Text |
 |
13890
|
Thu May 24 20:31:03 2018 |
gautam | Configuration | ALS | DFD noises | A
couple of months ago, I took 21 measurements
of the delay line transfer function. As shown |
 |
13955
|
Wed Jun 13 12:21:09 2018 |
gautam | Update | ALS | PDFR laser checkout | I want to use the Fiber Coupled laser from
the PDFR
system to characterize the response of |
|
13957
|
Wed Jun 13 22:07:31 2018 |
gautam | Update | ALS | BeatMouth PDFR measurement | Summary:
Neither |
  |
13973
|
Fri Jun 15 14:22:05 2018 |
gautam | Update | ALS | BeatMouth PDFR measurement | I did the measurement with the BeatMouth
open today. Main changes:
Directly pipe the RF output |
 |
14468
|
Wed Feb 20 23:55:51 2019 |
gautam | Update | ALS | ALS delay line electronics | Summary:
Last year, I worked
on the ALS delay line electronics, thinking |
|
14475
|
Thu Mar 7 01:06:38 2019 |
gautam | Update | ALS | ALS delay line electronics | Summary:
The restoration of the delay-line
electronics is complete. The chassis has |
|
14477
|
Tue Mar 12 22:51:25 2019 |
gautam | Update | ALS | ALS delay line electronics | This
Hanford alog may be of relevance as we
are using the aLIGO AA chassis for the IR |
|
14478
|
Wed Mar 13 01:27:30 2019 |
gautam | Update | ALS | ALS delay line electronics | This test was done, and I determine the
frequency discriminant to be |
 |
14479
|
Thu Mar 14 23:26:47 2019 |
Anjali | Update | ALS | ALS delay line electronics | Attachment #1 shows the schematic of the
test setup. Signal generator (Marconi) was
used to supply the RF input. We observed |
|
14480
|
Sun Mar 17 00:42:20 2019 |
gautam | Update | ALS | NF1611 cannot be shot-noise limited? | Summary:
Per the manual (pg12)
of the NF 1611 photodiode, the "Input |
|
14481
|
Sun Mar 17 13:35:39 2019 |
Anjali | Update | ALS | Power splitter characterization | We characterized the power splitter ( Minicircuit-
ZAPD-2-252-S+). The schematic of the measurement
setup is shown in attachment #1. The network/spectrum/impedance |
   |
14482
|
Sun Mar 17 21:06:17 2019 |
Anjali | Update | ALS | Amplifier characterisation | The goal was to characterise the new amplifier
(AP1053). For a practice, I did the characterisation
of the old amplifier.This test is similar |
   |
14486
|
Mon Mar 18 20:22:28 2019 |
gautam | Update | ALS | ALS stability test | I'm running a test to see how stable
the EX green lock is. For this purpose, I've
left the slow temperature tuning servo on |
|
14498
|
Thu Mar 28 19:40:02 2019 |
gautam | Update | ALS | BeatMouth with NF1611s assembled | Summary:
The parts I was waiting for arrived.
I finished the beat mouth assembly, and did |
   |
14502
|
Fri Mar 29 21:00:06 2019 |
gautam | Update | ALS | BeatMouth with NF1611s installed |
Newfocus 15V current limited supply
was taken from bottom NE corner of the ITMY
Oplev table to power the BeatMouth on the |
 |
14503
|
Sun Mar 31 15:05:53 2019 |
gautam | Update | ALS | Fiber beam-splitters not PM | I looked into this a little more today.
Looking at the beat signal
between the PSL and EX beams from the |
|
14510
|
Wed Apr 3 09:04:01 2019 |
gautam | Update | ALS | Note about new fiber couplers | The new fiber beam splitters we are ordering,
PFC-64-2-50-L-P-7-2-FB-0.3W,
have the slow axis working and fast axis |
|
14513
|
Wed Apr 3 12:32:33 2019 |
Koji | Update | ALS | Note about new fiber couplers | Andrew seems to have an integrated solution
of PBS+HWP in a singe mount. Or, I wonder
if we should use HWP/QWP before the coupler. |
|
14516
|
Fri Apr 5 00:33:58 2019 |
gautam | Update | ALS | Promising IR ALS noise | Summary:
I set up a free-space
beat on theNW side of the PSL table between |
 |
14519
|
Fri Apr 5 11:49:30 2019 |
gautam | Update | ALS | PSL + X green beat recovery | Since we haven't been using it, the
PID control was not enabled on the doubling
oven on the PSL table (it is disabled after |
|
14521
|
Mon Apr 8 00:04:08 2019 |
gautam | Update | ALS | IR ALS noise budget | To start the noise budgeting, I decided
to measure the "DFD noise", which
is really the quadrature sum of the following |
|
14523
|
Mon Apr 8 18:28:25 2019 |
gautam | Update | ALS | EX Green PDH checkout | I worked on characterizing the green PDH
setup at EX, as part of the ALS noise budgeting
process. Summary of my findings: |
 |
14524
|
Mon Apr 8 23:52:09 2019 |
gautam | Update | ALS | EX Green PDH error monitor calibrated | Some time ago, I had done an actuator
calibration of ITMX. This suspension
hasn't been victim to the recent spate |
   |
14525
|
Tue Apr 9 00:16:22 2019 |
rana | Update | ALS | EX Green PDH error monitor calibrated | G=10 or
G=100? |
|
14526
|
Tue Apr 9 00:18:19 2019 |
gautam | Update | ALS | EX Green PDH error monitor calibrated | wrong assumption - i checked the gain just
now, it is G=10, and is running in the "low-noise"
mode, so can only drive 4V. fixed elog, filter. |
|
14527
|
Tue Apr 9 18:44:00 2019 |
gautam | Update | ALS | EX Green PDH discriminant measurement | I decided to use the more direct method,
of disconnecting feedback to the EX laser
PZT, and then looking at the cavity flashes. |
 |
14528
|
Tue Apr 9 19:07:12 2019 |
gautam | Update | ALS | IR ALS noise budget | Updated the noise budget to include the
unsuppressed frequency noise from the EX
laser. It does not explain the noise |
 |
14533
|
Thu Apr 11 01:10:05 2019 |
gautam | Update | ALS | Large 2kHz peak (and harmonics) in ALS X | These weren't present last week. The
peaks are present in the EX PDH error monitor
signal, and so are presumably connected with |
|
14548
|
Wed Apr 17 00:50:17 2019 |
gautam | Update | ALS | Large 2kHz peak (and harmonics) in ALS X no more | I looked into this issue today. Initially,
my thinking was that I'd somehow caused
clipping in the beampath somewhere which |
|
14549
|
Wed Apr 17 11:01:49 2019 |
gautam | Update | ALS | Large 2kHz peak (and harmonics) in ALS X no more | EX green stayed locked to XARM length overnight
without a problem. The spectrogram doesn't
show any alarming time varying features around |
|
14643
|
Wed May 29 18:13:25 2019 |
gautam | Update | ALS | Fiber beam-splitters are now PM | To maintain PM fibers all the way through
to the photodiode, I had ordered some PM |
|
14645
|
Fri May 31 15:55:16 2019 |
gautam | Update | ALS | PSL + X beat restored | Coupling into the fast axis
of the fiber:
The PM couplers I bought require |
|
14740
|
Tue Jul 9 18:42:15 2019 |
gautam | Update | ALS | EX green doubling oven temperature controller power was disconnected | There was no green light even though the
EX NPRO was on. I checked the doubling oven
temperature controller and found that its |
|
14800
|
Mon Jul 22 23:53:16 2019 |
gautam | Update | ALS | IR ALS locking attempt | Summary:
My goal tonight was to lock the
PSL frequency to be resonant in the |
  |
14802
|
Wed Jul 24 00:22:24 2019 |
gautam | Update | ALS | PSL frequency locked to XARM length using ALS | Summary:
I succeeded in locking the PSL
frequency to the XARM cavity length, with |
  |
14811
|
Thu Jul 25 12:25:56 2019 |
gautam | Update | ALS | IR ALSX noise | Summary:
There are some broad peaks
in the ALS out-of-loop noise, centered at |
|
14823
|
Fri Aug 2 11:37:38 2019 |
gautam | Update | ALS | EY IR ALS Assay | Summary:
I'd like to confirm that the
IR ALS scheme will work for locking. The |
 |
14835
|
Tue Aug 6 23:09:20 2019 |
gautam | Update | ALS | EY table work |
Removed power monitoring PD (It
was off anyways)
Installed Steering
mirror and collimator in K6XS mount (fast |
|
14838
|
Fri Aug 9 16:37:39 2019 |
gautam | Update | ALS | More EY table work | Summary:
220 uW / 600 uW (~36 %
mode-matching) of IR light coupled into fiber |
 |
14846
|
Thu Aug 15 18:54:54 2019 |
gautam | Update | ALS | ALS sensing noise due to IMC | Summary:
I came aross an interesting
suggestion by Yutaro that KAGRA's |
|
14847
|
Fri Aug 16 04:24:03 2019 |
rana | Update | ALS | ALS sensing noise due to IMC | What about just use high gain feedback
to MC2 below 20 Hz for the IMC lock? That
would reduce the excess if this theory is |
|
14918
|
Mon Sep 30 18:20:26 2019 |
gautam | Update | ALS | ALS OOL noise - a first look | Attachment #1 shows a
first look at the IR ALS noise after my re-coupling |
|
14938
|
Fri Oct 4 00:32:24 2019 |
gautam | Update | ALS | More locking updates | Summary:
I managed to achieve a few transitions
of control of the XARM length using the ALS |
 |
14943
|
Sat Oct 5 21:26:34 2019 |
gautam | Update | ALS | Y-end green alignment tweaked | Summary:
I improved the alignment of the
green beam into the Y arm cavity. |
 |
14944
|
Sun Oct 6 15:23:27 2019 |
gautam | Update | ALS | Arm control using error signals achieved | Summary:
I |
  |
14979
|
Fri Oct 18 20:21:33 2019 |
shruti | Update | ALS | AM measurement attempt at X end | [Shruti, Rana]
- At the X end, we set up the network
analyzer to begin measurement of the AM transfer |
|
14981
|
Mon Oct 21 12:25:46 2019 |
gautam | Update | ALS | DFD electronics checkout | Summary:
There are no unexpected red-flags
in the performance of the DFD electronics. |
   |
14984
|
Tue Oct 22 15:32:15 2019 |
gautam | Update | ALS | EX uPDH electronics checkout | Summary:
The EX PDH setup had what I thought
was insufficient phase and gain margins. |
|
14986
|
Wed Oct 23 10:23:26 2019 |
rana | Update | ALS | EX uPDH electronics checkout | During our EX AM/PM setups, I don't
think we bumped the PDH gain knob (and I
hope that the knob was locked). Possible |
|
14987
|
Wed Oct 23 11:11:01 2019 |
gautam | Update | ALS | EX uPDH electronics checkout | The closest thing I can think of is here.
|
|