40m QIL Cryo_Lab CTN SUS_Lab TCS_Lab OMC_Lab CRIME_Lab FEA ENG_Labs OptContFac Mariner WBEEShop
  40m Log  Not logged in ELOG logo
Entry  Sun Feb 16 17:40:11 2014, Koji, Update, LSC, Friday Night ALS 
    Reply  Tue Feb 18 18:52:08 2014, Jenne, Update, LSC, ALS not locking with LSC  ALSX_POXvsBeatnote.pdfALSY_POYvsBeatnote.pdfBeatNoteSpectra_ArmsLockedWithIR_28Feb2014.pdfALSvsLSC_LockingFilters.pdf
       Reply  Tue Feb 18 20:31:29 2014, Koji, Update, LSC, ALS not locking with LSC  
          Reply  Tue Feb 18 23:27:14 2014, Jenne, Update, LSC, ALS not locking with LSC  ALSX_POXvsBeatnote_withEXCtfs.pdf
Message ID: 9641     Entry time: Sun Feb 16 17:40:11 2014     Reply to this: 9646
Author: Koji 
Type: Update 
Category: LSC 
Subject: Friday Night ALS 

I wanted to try common/differential ALS Friday evening. I tried ALS using the LSC servo but this was not successfull.
The usual ALS servo in the ALS model works without problem. So this might be coming from the shape of the servo filter.
The ALS one has 1:1000 filter but the LSC one has 10:3000. Or is there any problem in the signal transfer between
ALS and LSC???


- MC:
Slow offset -0.302V

- IR:
TRX=1.18 / TRY=1.14, XARM Servo gain = 0.25 / YARM Servo gain = 0.10

- Green Xarm:
GTRX without PSL green 0.562 / with PSL green 0.652 -> improved upto 0.78 by ASX and tweaking of PZTs
Beat note found at SLOW OFFSET +15525
Set the beat note as +SLOW OFFSET gives +BEAT FREQ

- Green Yarm:
GTRY without PSL green 0.717 / with PSL green 1.340
Beat note found at SLOW OFFSET -10415
Set the beat note as +SLOW OFFSET gives -BEAT FREQ

- BEAT X -10dBm on the RF analyzer@42.5MHz / Phase tracker Qout = 2300 => Phase tracking loop gain 80 (Theoretical UGF = 2300/180*Pi*80 = 3.2kHz)
- BEAT Y -22dBm on the RF analyzer@69.0MHz / Phase tracker Qout = 400 => Phase tracking loop gain 300 (Theoretical UGF = 2.1kHz)

Transfer function between ALSX/Y and POX/Y11I @560Hz excitation of ETMX
POX11I/ALSX = 54.7dB (~0deg)
POY11I/ALSY = 64.5dB (~180deg)

POX11I calibration:

ALSX[cnt]*19230[Hz/cnt] = POX11I[cnt]/10^(54.7/20)*19230[Hz/cnt]
= 35.4 [Hz/cnt] POX11I [cnt] (Hz in green frequency)

35.4 [Hz/cnt]/(2.99792458e8/532e-9 [Hz]) * 37.8 [m] = 2.37e-12 [m/cnt] => 4.2e11 [cnt/m] (c.f. Ayaka's number in ELOG #7738 6.7e11 cnt/m)

POY11I calibration:

ALSY[cnt]*19230[Hz/cnt] = POY11I[cnt]/10^(64.5/20)*19230[Hz/cnt]
= 11.5 [Hz/cnt] POX11I [cnt] (Hz in green frequency)

11.5 [Hz/cnt]/(2.99792458e8/532e-9 [Hz]) * 37.8 [m] = 7.71e-13 [m/cnt] => 1.3e12 [cnt/m] (c.f. Ayaka's number in ELOG #7738 9.5e11 cnt/m)

ELOG V3.1.3-