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