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Entry  Thu Feb 13 16:35:32 2020, anchal, DailyProgress, BEAT, BN Detector was saturated. Reduced laser powers. 
    Reply  Fri Feb 14 10:59:13 2020, anchal, DailyProgress, BEAT, Beatnote noise lowered in low frequency region 
       Reply  Mon Feb 17 16:08:23 2020, anchal, DailyProgress, BEAT, Beatnote noise lowered in low frequency region with ISS CTN_Noise_Budget_Effect_ISS_ON.pdf
          Reply  Fri Feb 21 16:22:04 2020, anchal, DailyProgress, BEAT, Beatnote noise lowered in low frequency region with ISS CTN_Noise_Budget_Effect_ISS_ON_New.pdf
             Reply  Tue Mar 3 10:02:12 2020, anchal, DailyProgress, BEAT, Lowest ever beatnote spectrum today! CTN_Noise_Budget_March03-2020.pdf
                Reply  Thu Mar 12 11:06:35 2020, anchal, DailyProgress, BEAT, Lowest ever beatnote spectrum today! CTN_Noise_Budget_March11-2020.pdf
                   Reply  Wed Mar 18 12:51:22 2020, anchal, DailyProgress, BEAT, Super beatnote measurement analysis results CTN_Beatnote_SuperMeasurement_March13-16.pdf
                      Reply  Mon Apr 13 16:52:30 2020, anchal, DailyProgress, BEAT, Beatnote measurements back on track CTN_Latest_BN_Spec.pdf
Message ID: 2562     Entry time: Wed Mar 18 12:51:22 2020     In reply to: 2556     Reply to this: 2566
Author: anchal 
Type: DailyProgress 
Category: BEAT 
Subject: Super beatnote measurement analysis results 

On March 13th around 7:30 pm, I started a super measurement of the beatnote spectrum for over 2 days. The script superBNSpec.py took a beatnote spectrum every 15 minutes for a total of 250 measurements. The experiment was stable throughout the weekend with no lock loss or drift of the beatnote frequency. All data with respective experimental configuration files are present in the Data folder. HEPA filters were on during this measurement.


Analysis and Inference:

  • I first plotted time series of how beatnote frequency ASD at 300 Hz varies over the 2 days.
  • Remember, this is a median measurement done using function modPSD which uses modWelch function we wrote a while back (See CTN:2399).
  • Then I plotted the same for a bunch of frequencies from 200 Hz to 1 kHz.
  • It is clear that the time of the day does not have any major or meaningful effect on the beatnote spectrum. It mostly remains the same.
  • Finally, I took the median of the 250 ASD measurements.
  • I also calculated lower and upper bounds using RMS of difference between 250 upper and lower bounds and the median calculated above.
  • All the noise peaks are intact indicating that all noise sources are stationary and REAL (in Will Farr's language).

Data

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