As the other half of Jeff's Side Quest 4 (87102), I took measurements for calculating the absolute calibration of SRM.
Doing this will make the estimator work for SRM easier later on. Like Jeff, I also took two sets of measurements, one with the offsets on (ALIGNED), and one with the offsets off (HEALTH_CHECK). The official measurements that we will be using for getting the OSEM absolute calibration are the ones where the optic is ALIGNED, since that's where it usually is. The set of measurements taken with the alignmet offsets off is to see how much of a difference we see between the two states.
The drive in ISO_{X,Y,Z} correlate with the same optic motion directions as they did when I was taking these same measurements for SR3: ISO_X -> SUS_DAMP_T, ISO_Y -> SUS_DAMP_L, ISO_Z -> SUS_DAMP_V.
These were the settings for the measurements:
- HAM5 in ISI_DAMPED_HEPI_OFFLINE
- SRM in ALIGNED or SRM in HEALTH_CHECK (with damping on)
SRM in ALIGNED (official measurements)
Found in /ligo/svncommon/SusSVN/sus/trunk/HSTS/H1/SRM/Common/Data/
2025-09-23-1830_H1ISIHAM5_ST1_SRM_ALIGNED_WhiteNoise_ISO_X_0p05to40Hz_calibration.xml r12666
2025-09-23-1830_H1ISIHAM5_ST1_SRM_ALIGNED_WhiteNoise_ISO_Y_0p05to40Hz_calibration.xml r12666
2025-09-23-1830_H1ISIHAM5_ST1_SRM_ALIGNED_WhiteNoise_ISO_Z_0p05to40Hz_calibration.xml r12666
In ALIGNED, here are the suspension positions according to the OSEMs (in urads*, see Jeff's explanation):
M1 OPTICALIGN sliders M1 OSEM M2 OSEM M3 OSEM
P +2520 +1071 +790 +837
Y -3809 +40 -479 -397
The alignment slider calibrations for SRM are P = 1.875 [DAC ct/"urad"] and Y = 2.681 [DAC ct/"urad"]
SRM in HEALTH_CHECK with damping on (extra measurements for looking at difference)
Found in /ligo/svncommon/SusSVN/sus/trunk/HSTS/H1/SRM/Common/Data/
2025-09-23-1810_H1ISIHAM5_ST1_SRM_NoOffsets_WhiteNoise_ISO_X_0p05to40Hz_calibration.xml r12666
2025-09-23-1810_H1ISIHAM5_ST1_SRM_NoOffsets_WhiteNoise_ISO_Y_0p05to40Hz_calibration.xml r12666
2025-09-23-1810_H1ISIHAM5_ST1_SRM_NoOffsets_WhiteNoise_ISO_Z_0p05to40Hz_calibration.xml r12666
Comparing the two sets of measurements, you can see that between both L's and both V's, the M1 OSEMs for the ALIGNED cases are closer to each other than the Offsets Off case, but they still need a calibration factor.
