With help from CherylV, JoeG, VolkerQ, OlliP, PeterK et al., we completed the installation of the H1 PSL ISS 2nd loop PD array in HAM2 yesterday afternoon.

This array was fabricated and aligned by OlliP, PeterK, RichA, and CalumT at CIT, then shipped to LHO and set up in the H2 laser area enclosure for further testing of sensitivity to pointing fluctuations and final alignment.

An updated method for quantifying the pointing sensitivity and executing the final alignment was developed and is documented in T1300925 which will be posted to the DCC shortly.  Also, the performance of this array is captured in the test report, E1300863, which should also be posted to the DCC shortly.

The installation went relatively smoothly after recovering from compiling issues after the update of the RCG code on Tuesday (thanks to Arnaud and Jeff for help with the suspensions).  The DC voltage levels seem to indicate that the PD positioning was somewhat compromised compared with what was achieved in the H2 Laser Area Enclosure before transporting, installing and connecting cables.  I suspect that the forces involved in connecting the cables and the weight of the cables is responsible for movement of some of the PDs.

All eight array PDs and the QPD checked out electrically and with laser or flashlight light.

The measured DC levels after installation and alignment (viewed from the back - terminal side of PDs) were:
Upper Left:   415 mV
Upper Middle Left: 475 mV
Upper Middle Right: 470 mV
Upper Right: 365 mV
Lower Left: 395 mV
Lower Middle Left: 67 mV
Lower Middle Right: 565 mV
Lower Right: 554 mV

Pre-installation measurements are summarized in the attached plots.