B. Weaver, T. Sadecki, A. Pele, J. Kissel

In hopes of find a smoking gun in a dead OSEM LED or photo-diode, we backed off the H1 SUS ITMX's R0 F2 and F3 OSEMs and gathered a new measurement of their open light current. Sadly, the difference is at most 5-10%, and does not explain the factor of two seen last Friday (LHO aLOG 12522). Thus far we haven't changed the OSEMINF compensation values to match the new reading, because we're not sure if we're gunna swap out the OSEMs yet. Or next step is to drive alignment offsets and compare against other suspensions to see if the coil / actuation side of the OSEM is the culprit. We'll also measure coil resistance. (Remember, the electronics chain has been exonerated with the cable swap test we did on Friday).

For reference:
      Raw   New    New      Former   Former
      ADC   Gain   Offset   Gain     Offset
R0F2 28600  1.049  -14300   1.003    -14958
R0F3 26320  1.140  -13160   1.063    -14114

Obtained using the following matlab script:
/ligo/svncommon/SusSVN/sus/trunk/Common/MatlabTools/
[resultstring gains offsets] = prettyOSEMgains('H1','ITMX');