Reports until 11:01, Wednesday 06 August 2025
H1 SUS (SEI, SUS)
edgard.bonilla@LIGO.ORG - posted 11:01, Wednesday 06 August 2025 (86222)
OSEM calibration of H1:SUS-PR3

Oli, Ivey, Edgard.

We used Oli's measurements from [LHO: 86204] to do an OSEM calibration for the PR3 M1 OSEMs. Here are the outputs of the calibration script.
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OSEM calibration of H1:SUS-PR3
Stage: M1
2025-08-05_1700 (UTC).

The suggested (calibrated) M1 OSEMINF gains are
(new T1) = 1.770 * (old T1) = 2.055
(new T2) = 1.547 * (old T2) = 1.544
(new T3) = 1.443 * (old T3) = 1.511
(new LF) = 1.590 * (old LF) = 1.862
(new RT) = 1.774 * (old RT) = 2.063
(new SD) = 1.543 * (old SD) = 1.639

To compensate for the OSEM gain changes, we estimate that the H1:SUS-PR3_M1_DAMP loops must be changed by factors of:
L gain = 0.596 * (old L gain)
T gain = 0.648 * (old T gain)
V gain = 0.617 * (old V gain)
R gain = 0.617 * (old R gain)
P gain = 0.670 * (old P gain)
Y gain = 0.596 * (old Y gain)

The calibration will change the apparent alignment of the suspension as seen by the at the M1 OSEMs
NOTE: The actual alignment of the suspension will NOT change as a result of the calibration process

The changes are computed as (osem2eul) * gain * inv(osem2eul).
Using the alignments from 2025-08-05_1700 (UTC) as a reference, the new apparent alingments are:

DOF        Previous value       New value            Apparent change
---------------------------------------------------------------------------------
L          -57.1 um             -33.6 um               +23.5 um
T          -101.3 um            -65.6 um               +35.7 um
V           62.4 um              36.6 um               -25.8 um
R           433.5 urad           225.7 urad          -207.8 urad
P          -631.8 urad          -406.5 urad          +225.2 urad
Y          -166.7 urad          -76.1 urad           +90.5 urad

We have estimated a OSEM calibration of H1 PR3 M1 using HAM2 ST1 drives from 2025-05-21_0000 (UTC).
We fit the response M1_DAMP/HAM2_SUSPOINT between 5 and 15 Hz to get a calibration in [OSEM m]/[GS13 m]

This message was generated automatically by OSEM_calibration_SR3.py on 2025-08-06 01:07:57.985744+00:00 UTC

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EXTRA INFORMATION

The H1:SUS-PR3_M1_OSEMINF gains at the time of measurement were:
(old) T1: 1.161
(old) T2: 0.998
(old) T3: 1.047
(old) LF: 1.171
(old) RT: 1.163
(old) SD: 1.062

The matrix to convert from the old Euler dofs to the (calibrated) new Euler dofs is:

+0.596    -0.0    +0.0    -0.0    +0.0    -0.003
+0.0    +0.648    -0.0    +0.0    +0.0    -0.0
-0.0    +0.0    +0.617    -0.004    +0.001    +0.0
+0.0    +0.0    -0.748    +0.617    -0.007    -0.0
+0.0    +0.0    +0.517    -0.036    +0.67    -0.0
-0.407    +0.0    -0.0    +0.0    -0.0    +0.596

The matrix is used as (M) * (old EUL dof) = (new EUL dof)
The dof ordering is ('L', 'T', 'V', 'R', 'P', 'Y')

Images attached to this report