Reports until 05:18, Monday 29 January 2018
H1 PSL (PSL)
peter.king@LIGO.ORG - posted 05:18, Monday 29 January 2018 - last comment - 10:19, Monday 29 January 2018(40305)
Laser trip
Came in this morning to find the oscillator off.  The front end was still running.  Looks like the watchdog kicked in
some ime around 5:30 pm Saturday.

    The power decay from head 1 is the reason for the decay in laser output power.  I upped the current of the 3 other
diode boxes by 0.5 A.

    Laser restarted without any major hiccups.  Other stuff came on-line pretty quickly.  Witnessed a couple of
occasions where the injection locking was lost.
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jason.oberling@LIGO.ORG - 10:19, Monday 29 January 2018 (40309)

In an attempt to stabilize HPO DB1, I adjusted the operating temperatures of the 7 individual pump diodes in DB1.  The changes are summarized below:

  Operating Temperature (°C)
Old New
D1 24.0 24.5
D2 24.0 24.5
D3 22.5 21.5
D4 24.0 23.5
D5 24.0 23.0
D6 24.0 24.5
D7 24.0 24.5

This took the output power of the HPO from 138.9 W to 140.4 W, an increase of 1.5 W simply from temperature tweaks.  We will continue to monitor.