Figure 1 shows the simplified noise budget when the beam is on WE center. To match the measured noise I had to increase the amplitude of the 1/f^4 noise, and increase the 1/f^{2/3} noise level by 40%. The difference in DARM optical gain is automatically taken into account by the noise budget.

Figure 2 shows the simplifed noise budget when the beam is offset by 6mm in Y on WE. To match the measured noise I had to increase the amplitude of the 1/f^4 noise further, which is understandable as angular noise couplings are higher with a beam off-centered on the mirror. The 1/f^{2/3} noise level in mW is the same, and the only things that changes it is the increase in optical gain when the beam is miscentered on WE.

Figure 3 shows for illustration the same data as figure 1 (beam on WE center) using the noise parameters from Feb/Mar 2025.

Figure 4 shows a sanity check a simplified noise budget from March with the same parameters as figure 3.

/users/mwas/detchar/toySensitivity_20250429/toySensitivity.m