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Message ID: 15047     Entry time: Mon Nov 25 22:10:26 2019
Author: shruti 
Type: Update 
Category: NoiseBudget 
Subject: Diagnostics  

This is to help troubleshoot the excess noise measured earlier.

The following channels were measured at GPS times 1258586880 s and 1258597457 s, corresponding to low and high Power Recycling Gain (PRG) respectively.

Excess noise was seen between 25-110 Hz in the high PRG case when compared to the low PRG case in the following channels:


C1:LSC-CARM-IN1_DQ (shown in Attachment 1 where the reference is low PRG)






Surprisingly, it was also seen to a smaller extent in (refer Attachment 3)



A different type of noise spectrum, attributed to known electronic effects, was observed for

C1:SUS-ITMY_SENSOR_{LL,UL}    (refer Attachment 2)


These did not show any significant change in the noise spectrum:

C1:LSC-DARM-IN1_DQ (shown in Attachment 1 where the reference is low PRG)




C1:SUS-ITMY_SENSOR_{LR,UR}  (refer Attachment 2)


Broadband noise in:



Attachment 1: LSC.pdf  42 kB  | Show | Show all
Attachment 2: ITMY.pdf  74 kB  | Show | Show all
Attachment 3: ITMX_L.pdf  41 kB  | Show | Show all
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