| ID |
Date |
Author |
Type |
Category |
Subject |
Text |
 |
|
14241
|
Wed Oct 10 12:38:27 2018 |
yuki | Configuration | LSC | All hardware was installed | I connected DAC - AIboard - PZTdriver -
PZT mirrors and made sure the PZT mirrors
were moving when changing the signal |
|
|
14285
|
Wed Nov 7 23:07:11 2018 |
gautam | Update | LSC | DRMI locking recovered | I had some
success today. I hope that the tweaks I made
will allow working with the DRMI during the |
|
|
14288
|
Sat Nov 10 17:32:33 2018 |
gautam | Update | LSC | Nulling MICH->PRCL and MICH->SRCL | With the DRMI locked, I drove a line in
MICH using the sensing matrix infrastructure.
Then I looked at the error points of MICH, |
|
|
14292
|
Tue Nov 13 18:09:24 2018 |
gautam | Update | LSC | Investigation of SRCL-->MICH coupling | Summary:
I've been looking into the
cross-coupling from the SRCL loop control |
|
|
14298
|
Fri Nov 16 00:47:43 2018 |
gautam | Update | LSC | More DRMI characterization | Summary:
More DRMI characterization
was done.
I was working on trying |
|
|
14313
|
Wed Nov 21 09:59:26 2018 |
gautam | Update | LSC | LSC feedforward block diagram | Attachment
#1 is a block diagram depicting
the pathway by which the vertex DOF control |
|
|
14326
|
Fri Nov 30 19:37:47 2018 |
gautam | Update | LSC | LSC feedforward block diagram | I wanted to set up an RTCDS model to understand
this problem better. Attachment #1 is the
simulink diagram of the signal flow. The |
|
|
14339
|
Mon Dec 10 15:53:16 2018 |
gautam | Update | LSC | Swept-sine measurement with DTT | Disclaimer:
This is almost certainly some user error |
|
|
14445
|
Fri Feb 8 20:48:52 2019 |
gautam | Update | LSC | IFO recovery | Several housekeeping tasks were carried
out today in preparation for the Y-arm loss
measurement. |
|
|
14446
|
Mon Feb 11 15:41:49 2019 |
gautam | Update | LSC | TRY 60 Hz solved - but clipping persists | Rich came by the 40m to photocopy some
pages from Hobbs, and saw me working on the
60 Hz hunting. As I suspected, the problem |
|
|
14447
|
Mon Feb 11 16:38:34 2019 |
gautam | Update | LSC | ETMY OL calibration updated | Since we changed the HeNe, I updated the
calibration factors, and accepted the changes
in the SDF. |
|
|
14459
|
Fri Feb 15 18:42:57 2019 |
gautam | Update | LSC | TRY 60 Hz solved | A more permanent fix than a crocodile clip was
implemented. Should probably look to do this
for the X end unit as well. |
|
|
14704
|
Wed Jun 26 21:01:26 2019 |
gautam | Update | LSC | POX and POY locking | Now that the IMC is remaining locked for
extended periods of time, the next problem
to attack is the ASS dither alignment system. |
|
|
14705
|
Thu Jun 27 14:28:12 2019 |
gautam | Update | LSC | POX and POY locking | After a more systematic alignment effort,
I was able to get the spots better centered
on the optics (judged by eye from the analog |
|
|
14720
|
Tue Jul 2 17:34:54 2019 |
gautam | Update | LSC | Irides opened up on EY table | In preparation for the ASS debugging, I decided |
|
|
14738
|
Tue Jul 9 18:06:05 2019 |
gautam | Update | LSC | Y-arm ASS in a workable state | The Y-arm ASS was tuned to be in a workable
state. Basically, I followed Koji's recipe. |
|
|
14904
|
Fri Sep 20 18:28:34 2019 |
gautam | Update | LSC | Y arm locking attempt | I tried to lock the Y arm cavity length
to the PSL frequency using POY11_I as an
error signal. Even though I think the cavity |
|
|
14910
|
Sun Sep 29 15:58:19 2019 |
gautam | Update | LSC | POX locking attempt | Summary:
There is no visible PDH error signal
on the POX11 channels. As a result, I am |
|
|
14915
|
Mon Sep 30 14:16:43 2019 |
gautam | Update | LSC | POX PD checkout - solved | I confirmed that there is light incident
on the POX photodiode. So the problem must
lie downstream in the demod / whitening / |
|
|
14920
|
Tue Oct 1 21:19:51 2019 |
gautam | Update | LSC | PRMI locked on carrier | Summary:
The |
|
|
14924
|
Wed Oct 2 11:52:16 2019 |
gautam | Update | LSC | PRMI Oplev loop checkout | I measured the OLTF of both the PRM Oplev
loops. Nothing odd sticks out as odd to me
in this measurement - there seems to be ~40 |
|
|
14926
|
Wed Oct 2 23:15:02 2019 |
gautam | Update | LSC | FPMI locking | Summary:
I was able to lock the FPMI. The
lock was quite stable. However, |
|
|
14928
|
Thu Oct 3 11:01:18 2019 |
rana | Update | LSC | (PR)FPMI locking | wonder if its possible to do variable finesse
locking
Gabriele mentioned that Virgo used |
|
|
14933
|
Thu Oct 3 19:40:18 2019 |
gautam | Update | LSC | POX/POY imbalance | Summary:
There is an imbalance between
the POX and POY detector outputs reported |
|
|
14954
|
Tue Oct 8 18:35:09 2019 |
gautam | Update | LSC | Locking prep | In preparation for some locking work tonight,
I did the following at the POP in air table
with the PRMI locked on carrier: |
|
|
14960
|
Wed Oct 9 18:15:26 2019 |
gautam | Update | LSC | PRMI 3f locking | After making sure the beams were hitting
the 3f photodiodes on the "AP"
table, I was able to lock the PRMI with the |
|
|
14961
|
Wed Oct 9 22:02:58 2019 |
gautam | Update | LSC | REFL55 whitening issue | This
problem has re-surfaced. Is this indicative
of some problem with the on-board VGA? Even |
|
|
14962
|
Thu Oct 10 01:12:56 2019 |
gautam | Update | LSC | Locking studies | Summary:
ALS control of arms in
the CARM/DARM basis seems pretty robust - |
|
|
14963
|
Thu Oct 10 22:11:53 2019 |
gautam | Update | LSC | Trans QPD checkout |
I removed the flip-mount that was
installed on the EY in-air table for the
mode-spectroscopy project (see |
|
|
14973
|
Wed Oct 16 11:42:17 2019 |
gautam | Update | LSC | Poor separation of PRCL/MICH in 3f signals | Summary:
There is poor separation
of the PRCL and MICH length error signals |
|
|
14974
|
Thu Oct 17 11:19:28 2019 |
gautam | Update | LSC | Locking activity last night |
Tuning the MICH-->PRM
output matrix element
Locked
the PRMI with the carrier field resonant |
|
|
14983
|
Tue Oct 22 00:52:27 2019 |
gautam | Update | LSC | Locking updates |
Transition of arms from POX/POY
to CARM/DARM was much smoother today - a
change was made at the EX PDH setup, see |
|
|
14996
|
Tue Oct 29 01:24:45 2019 |
gautam | Update | LSC | More locking updates | Summary:
The two arm lengths can
be controlled reliably in the CARM/DARM basis |
|
|
14997
|
Tue Oct 29 15:13:19 2019 |
gautam | Update | LSC | More locking updates | I looked at some signals for a 10 second
period when the PRMI was locked with at some
CARM offset, just before the PRMI lost lock, |
|
|
14998
|
Tue Oct 29 17:40:48 2019 |
gautam | Update | LSC | More locking updates | I set up a photodiode (PDA10CF) in the
IFO REFL beampath and the Agilent NA is sitting
on the east side of the PSL enclosure. This |
|
|
14999
|
Wed Oct 30 01:27:00 2019 |
gautam | Update | LSC | More locking updates | Tried a bunch of things tonight.
Modified the "ELP300"
filter module in the MICH filter bank - this |
|
|
15000
|
Wed Oct 30 11:53:41 2019 |
gautam | Update | LSC | MICH loop shape tuning | I changed the shape of the low pass filter
to reduce high frequency sensor noise injection
into the MICH control signal. The loop stability |
|
|
15001
|
Wed Oct 30 17:08:40 2019 |
gautam | Update | LSC | POP22 investigation | The POP beam coming out of the vacuum chamber
is split by a 50/50 BS and half is diverted
to the POP22/POP110/POPDC photodiode (Thorlabs |
|
|
15009
|
Mon Nov 4 15:29:47 2019 |
gautam | Update | LSC | POP signal path | There are many versions of the POP22 signal
path I found on the elog, e.g. this
thread. But what I saw at the LSC rack |
|
|
15010
|
Mon Nov 4 16:06:58 2019 |
gautam | Update | LSC | POP optical path | I did some re-alignment of the POP beam
on the IX in air table. Here are the details:
|
|
|
15012
|
Tue Nov 5 11:52:27 2019 |
gautam | Update | LSC | Locking notes | Summary:
I am still unable to achieve arm
powers greater than TRX/TRY ~10 while keeping |
|
|
15014
|
Wed Nov 6 02:08:48 2019 |
gautam | Update | LSC | Locking updates | Summary:
There seems to be stronger-than-expected
coupling between CARM and the 3f sensors. |
|
|
15015
|
Wed Nov 6 17:05:45 2019 |
gautam | Update | LSC | CARM calibration | Summary:
A coarse calibration of the CARM
error point (when on ALS control) is |
|
|
15016
|
Wed Nov 6 17:45:34 2019 |
gautam | Update | LSC | ~ | Here is a comparison of the response of
various DoFs in our various RFPD sensors
for two different CARM offsets. Even in the |
|
|
15026
|
Thu Nov 14 23:56:18 2019 |
rana | Update | LSC | off the bad Violin filters | We turned off many excessive violin mode
bandstop filters in the LSC.
Due to some feedforward work by |
|
|
15028
|
Fri Nov 15 11:58:12 2019 |
gautam | Update | LSC | off the bad Violin filters | The clue was that the loop X arm POX loop looked
to have low (<3dB)) gain margin around
600 Hz (and again at 700 Hz). |
|
|
15029
|
Fri Nov 15 12:08:04 2019 |
gautam | Update | LSC | POPDC whitening board | The DC port of the Bias-Tee is routed to
(a modified
version of) the iLIGO whitening board. |
|
|
15034
|
Mon Nov 18 21:04:38 2019 |
gautam | Update | LSC | Locking - some ideas | Some ideas Koji suggested:
Try approaching the CARM
offset zero point "from the other side" |
|
|
15037
|
Wed Nov 20 01:07:18 2019 |
gautam | Update | LSC | Locking - progress | Summary:
CARM offset was reduced
to 0 with the PRMI locked.
TRY |
|
|
15038
|
Wed Nov 20 12:14:17 2019 |
gautam | Update | LSC | Locking - progress | I took a look at the TRX/TRY RIN reported
in the single arm POX/POY lock, and compared
the performance of the two available PDs |
|