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Entry  Thu Jul 9 17:12:52 2020, gautam, Update, BHD, In-air BHD OMCchamber.pdfAP_Table_20180328.pdf
    Reply  Tue Jul 14 15:29:25 2020, gautam, Update, BHD, In-air BHD - DCPD amplifier noise DCPDamp.pdf
    Reply  Wed Jul 15 19:11:40 2020, gautam, Update, BHD, In-air BHD - alignment into OMC 
       Reply  Thu Jul 16 01:12:22 2020, gautam, Update, BHD, In-air BHD - preparing the LO path IMG_8626.JPGIMG_8627.JPGIMG_8628.JPGIMG_8629.JPG
          Reply  Sun Jul 19 15:40:15 2020, gautam, Update, BHD, In-air BHD - CDS and wiring summary wiringDiagram.pdf
             Reply  Wed Jul 29 11:57:59 2020, rana, Update, BHD, In-air BHD - CDS and wiring summary 
          Reply  Mon Jul 20 17:55:15 2020, gautam, Update, BHD, In-air BHD - preparing the LO path 
             Reply  Tue Jul 21 00:30:24 2020, gautam, Update, BHD, In-air BHD - LO RIN LO_RIN.pdf
Message ID: 15497     Entry time: Tue Jul 21 00:30:24 2020     In reply to: 15495
Author: gautam 
Type: Update 
Category: BHD 
Subject: In-air BHD - LO RIN 

Attachment #1 shows the RIN of the local oscillator beam delivered to the AP table via fiber. I used a PDA520 to make this measurement, while the electronics for the DCPDs are pending. I don't really have an explanation for the difference between the locked IFO trace vs the not locked trace - we don't have an ISS running (but this first test suggests we should) and the beam is picked off before any cavities etc, so this is a reflection of the state of the FSS servo at the times of measurement?


Tried locking CARM using the hybrid REFL (for AO path) and POX 11 (for MCL path) scheme a bunch of times today, but I had no luck. When the CARM offset is zeroed, the PRMI lock is lost almost immediately. Maybe this is indicative of some excess noise in the POX data stream relative to the REFL signal? The one thing I haven't tried is to take the IFO all the way to the locked state, and then transition the MCL actuation from CM_SLOW to POX11_I.


An SR785 is sitting on the North side of the AP table in the walkway - I will clear it tomorrow.

Attachment 1: LO_RIN.pdf  142 kB  Uploaded Tue Jul 21 01:30:29 2020  | Hide | Hide all
LO_RIN.pdf
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