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Reports until 17:25, Tuesday 03 May 2016
H1 PSL (PSL)
peter.king@LIGO.ORG - posted 17:25, Tuesday 03 May 2016 - last comment - 17:46, Wednesday 04 May 2016(26972)
HPO status
The attenuated output from the front end, or seed, laser was admitted into the high
power oscillator ring.  No signs of clipping on the intermediate optics was observed.
However the overlap between the beam promptly reflected from the oscillator's output
coupler and the beam that traversed the ring was slightly off - the interference
fringes were clearly left of centre.  This was corrected for.  The mis-alignment of
the output coupler was most likely caused by the drag wipe cleaning the previous day.

    Each laser head was powered up with 5A of pump current.  No bright spots were
observed on the optics that would indicate some kind of point damage.  Each head was
powered up to 50A and again, no point damage spots were observed.

    The oscillator was then fully powered up, starting at 40A-45A per head.  The
laser power was noticeably down.  The beam from the oscillator, shown in
FirstTurnOn1.png, was ugly but stable.  My interpretation of this was that there
was no point damage on the optics but that the resonator was severely mis-aligned.
The exact reason for why the resonator would have become mis-aligned is not clear
to me.

    Adjusting the output coupler did improve the beam shape but not the output
power.  A more thorough alignment process will be embarked on tomorrow.
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peter.king@LIGO.ORG - 17:46, Wednesday 04 May 2016 (27017)
Forgot to add this picture yesterday, which was after adjusting the output coupler.
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