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Entry  Mon Nov 15 18:05:34 2010, tara, DailyProgress, BEAT, coherence <fbeat|RCAV>, <fbeat|ACAV> coherence_before_realign.pngcoherence_after_realign.pngbeat_2010_11_15.png
    Reply  Mon Nov 15 19:22:58 2010, rana, DailyProgress, NoiseBudget, Preparation to suppress intensity noise. 
       Reply  Tue Nov 16 03:36:55 2010, tara, DailyProgress, NoiseBudget, Preparation to suppress intensity noise. RIN.pngcoh.png2010_11_15.matcurrent_mod_TF.pngTF_current.mat
Message ID: 392     Entry time: Mon Nov 15 18:05:34 2010     Reply to this: 393
Author: tara 
Type: DailyProgress 
Category: BEAT 
Subject: coherence <fbeat|RCAV>, <fbeat|ACAV> 

 I realigned the beam to PMC, ACAV, RCAV, optimized gain, and find a significant coherence between ACAV_RCTRASPD and RCAV_TRANSPD.


I haven't re-aligned the beam to each cavities for awhile, and the alignment was quite bad.

PMC_RCTRANSPD: 9.4 - > 10.9 V

RCAV_RCTRANSPD: 1.7 ->2.07 V

ACAV_RCTRANSPD: 0.8 -> 1.3 V

So I need to optimize the gain setup again, see detail below. 

I measured beat signal and coherence before and after realigning. 

For coherence, I see nothing significant except <beat | ACAV>, see fig1, so I did not save the rest of the measurement.

After I realigned the beam, there is a big coherence between ACAV andRCAV see fig 2.

the coherence between PMC and RCAV follow the same trait as that of PMC and ACAV, but slightly less, so I show only PMC and ACAV.

However,  the beat note before and after realigning the beam are still the same, see fig3.


I'll add RIN from  RCAV/ACAV/PMC .




gain setup


PMC: Gain 16

         RF_ADJ 5.7 V


FSS: Common gain 21.5

         FAST gain 21.2

        RF_ADJ  10

These values allow maximum Transmission power and stable lock (I checked this by unlock and lock the cavity and see if the signal is stable after loss lock)

Attachment 1: coherence_before_realign.png  16 kB  Uploaded Mon Nov 15 23:14:39 2010  | Hide | Hide all
Attachment 2: coherence_after_realign.png  21 kB  Uploaded Mon Nov 15 23:14:50 2010  | Hide | Hide all
Attachment 3: beat_2010_11_15.png  31 kB  Uploaded Mon Nov 15 23:50:17 2010  | Hide | Hide all
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