[Tom Roocke, Oli]

Summary: The 6 QOSEMs and their signal chain for the BBSS are operational with the final sat amp, CER wiring, CDS mapping, in vac DB25 extension cables. All that remains to test before SUS installation is the duopus cables, which are in C&B currently.

In continuation from yesterday, we are testing out the QOSEM signal chain prior to installation of the BBSS. Yesterday we verified the sat amp was still functional and the readouts were showing up in CDS appropriately. See LHO:90072. Today we checked both the DB25 to DB25 extension cables, and the QOSEMs. To come is testing of the duopus cables, which are still in C&B.

DB25 Extension Testing:
Using a known functional Duopus cable (S2600215), and inair DB25, we tested the three DB25 extension cables by reading for the QOSEM coil resistance and diode drops at the in air DB25, where it connects to the sat amp. See the signal continuity test section in T2600170 for more information on this. All 3 cables are functional.

S2001548: DB25 working
S2100358: DB25 working
S2100410: DB25 working

QOSEM CDS Readout Testing:

Using a known functional Duopus Cable (S2600215), DB25 Extension (S2100410) and in air DB25, we checked for the open sum voltage in the CDS readout. This is the voltage seen on the sum channel of the QPD with no lens installed. Seeing a nonzero voltage here indicates that the QOSEM LED, QPD and signal chain are functional, but will be far lower than the operational sum level when the lens flag is appropriately focusing light onto the QPD. We tested the open sum voltage for all 6 QOSEMs designated for the BBSS. All QOSEMs and there signal chain are functional.

S2600008: working with open sum of 13910
S2600009: working with open sum of 14755
S2600010: working with open sum of 15550
S2600011: working with open sum of 15470
S2600012: working with open sum of 15348
S2600013: working with Open Sum of 14380