Jennie W, Sheila, Jim, Robert

tl;dr: HAM1 motion as measured by table-top L4Cs is at least an order of magnitude below DARM.

I have been using Sheila's power projection code to work on analysing Robert's shaker measurements on HAM1 chamber in October last year. Below is the injection info from Robert. The shaker was on top of one of the chamber HEPI tables.

"A line at 25 Hz was injected by shaking HAM1 for nearly 20 minutes starting at 30/09/2024 18:02:00 (DTT notation). This was one of the injections used to determine which HAM had the vibrational coupling.After determining  that the Coupling was at HAM1, we made A 20-26 Hz  "wide band" injection with a strong resonance peak at about 23 Hz, for about 5 minutes starting at 31/10/2024 18:20:57."

The attached plot shows the projection of HAM1 noise as measured by the table-top L4C in the x direction (beam propagation direction). The DARM noise measurement over this range is shown in blue and the projection in green. DARM was taken from H1:CAL-DELTAL_EXTERNAL_DQ and is not calibrated. This part of the code needs further work so this projection is valid but its absolute value should not be compared to other noise budgets without fixing this error.

The code can be found on my branch of Sheila's code as ham1_coupling.py.

The second image shows the ASDs I used in DTT. The 30th September shaker injection was only done at 25 Hz so I just used the broadband injection between 20 and 26Hz from the 31st of October to make the projection. The quiet time was taken directly after the measurement stopped in the same lock. The top plot is DARM and the bottom is the table-top L4Cs in units of nm/sqrt(Hz) as Jim calibrated them from velocity units these channels are in with three poles at 0Hz and two zeros at 0.707 Hz.

The data is in /ligo/home/jennifer.wright/git/2025/HAM1_Coupling/20250121_HAM1_Coupling_excess_power_proj_bb.xml and the ndscope I used to find the times is in the same folder called HAM1_coupling.yaml.