Reports until 10:31, Tuesday 28 February 2017
H1 PSL
jason.oberling@LIGO.ORG - posted 10:31, Tuesday 28 February 2017 (34456)
PSL Maintenance (WP 6501)

As per LHO WP 6501, this morning I temperature tuned the HPO pump diodes after last Saturday's pump diode current increase.  I began by turning the ISS OFF and then proceeded to tune the HPO pump diodes' operating temperature.  The old and new pump diode operating temperatures for the 7 diodes in each diode box are listed in Table 1 below. 

Table 1: Summary of Old and New HPO Diode Box Operating Temperatures
  Diode Box 1 (°C) Diode Box 2 (°C) Diode Box 3 (°C) Diode Box 4 (°C)
Old New Old New Old New Old New
D1 25.5 25.0 20.0 20.0 22.0 22.0 24.5 24.0
D2 26.0 25.5 19.5 19.5 26.0 26.0 22.0 21.5
D3 28.0 27.5 20.5 20.5 26.0 26.0 23.5 23.0
D4 24.5 24.0 18.5 18.5 23.0 23.0 22.0 21.5
D5 26.5 26.0 18.5 18.5 27.0 27.0 24.0 23.5
D6 26.0 25.5 19.0 19.0 21.5 21.5 24.0 23.5
D7 23.5 23.0 19.5 19.5 22.5 22.5 24.0 23.5

 In addition, I increased the current to DB1 by a further 0.2A to bring it closer to the other diode boxes; this diode box is starting to decay more rapidly than the others, so is likely to need replacement first.  A summary of the old and new HPO diode box operating currents is shown in Table 2 below.  The PSL HPO is now outputting ~169.0 W.

Table 2: Summary of Old and New HPO Diode Box Operating Currents
  Operating Current (A)
Old (pre-2/25/2017) New (2/28/2017)
DB1 51.0 51.7
DB2 51.0 51.5
DB3 51.0 51.5
DB4 51.0 51.5

Following that, with the ISS still OFF, I then proceeded to tweak the beam alignnment into the PMC; only small tweaks were necessary to to maximize the transmitted power.  With the ISS turned back ON, the PMC transmitted power is now 65.0 W and the PMC reflected power is now 14.0 W.  This closes WP 6501.