40m
QIL
Cryo_Lab
CTN
SUS_Lab
TCS_Lab
OMC_Lab
CRIME_Lab
FEA
ENG_Labs
OptContFac
Mariner
WBEEShop
|
40m Log |
Not logged in |
 |
|
Tue Jul 25 02:03:59 2017, gautam, Update, Optical Levers, Optical lever tuning thoughts
|
Fri Jul 28 15:36:32 2017, gautam, Update, Optical Levers, Optical lever tuning thoughts  
|
Tue Aug 1 16:05:01 2017, gautam, Update, Optical Levers, Optical lever tuning - cost function construction   
|
Thu Nov 16 13:57:01 2017, gautam, Update, Optical Levers, Optical lever noise 
|
Thu Nov 16 15:43:01 2017, rana, Update, Optical Levers, Optical lever noise
|
Tue Nov 21 11:37:29 2017, gautam, Update, Optical Levers, BS OL calibration updated  
|
Tue Nov 21 16:28:23 2017, gautam, Update, Optical Levers, BS OL calibration updated
|
Tue Nov 21 23:04:12 2017, gautam, Update, Optical Levers, Oplev "noise budget"
|
Wed Nov 22 05:41:32 2017, rana, Update, Optical Levers, Oplev "noise budget"
|
Wed Nov 22 15:29:23 2017, gautam, Update, Optical Levers, Oplev "noise budget"
|
Wed Nov 22 16:40:00 2017, Koji, Update, Optical Levers, Oplev "noise budget"
|
Wed Nov 22 19:20:01 2017, rana, Update, Optical Levers, Oplev "noise budget"
|
Wed Nov 22 23:56:14 2017, gautam, Update, Optical Levers, Oplev "noise budget"
|
Thu Nov 23 18:03:52 2017, gautam, Update, Optical Levers, Oplev "noise budget" 
|
|
Message ID: 13437
Entry time: Tue Nov 21 11:37:29 2017
In reply to: 13433
Reply to this: 13439
|
Author: |
gautam |
Type: |
Update |
Category: |
Optical Levers |
Subject: |
BS OL calibration updated |
|
|
I calibrated the BS oplev PIT and YAW error signals as follows:
- Locked X-arm, ran dither alignment servos to maximize transmission.
- Applied an offset to the ASC PIT/YAW filter banks. Set the ramp time to something long, I used 60 seconds.
- Monitored the X arm transmission while the offset was being ramped, and also the oplev error signal with its current calibration factor.
- Fit the data, oplev error signal vs arm transmission, with a gaussian, and extracted the scaling factor (i.e. the number which the current Oplev error signals have to be multiplied by for the error signal to correspond to urad of angular misalignment as per the overlap of the beam axis to the cavity axis.
- Fits are shown in Attachment #1 and #2.
- I haven't done any error analysis yet, but the open loop OL spectra for the BS now line up better with the other optics, see Attachment #3 (although their calibration factors may need to be updated as well...). Need to double check against OSEM readout during the sweep.
- New numbers have been SDF-ed.
The numbers are:
BS Pitch 15 / 130 (old/new) urad/counts
BS Yaw 14 / 170 (old/new) urad/counts
Quote: |
I bet the calibration is out of date; probably we replaced the OL laser for the BS and didn't fix the cal numbers. You can use the fringe contrast of the simple Michelson to calibrate the OLs for the ITMs and BS.
|
|
|
|
|
|
|
|