Did some characterisation measurements of the first loop power stabilisation.  All measurements
were taken with the reference level set to -2.00.

    SCRN0001.jpg shows the free running and stabilised power noise as measured with an out of
loop photodiode.  A large peak appears around 70 kHz to 100 kHz when the integrator is engaged
(SCRN0002.jpg).  These measurements were taken with the offset slider set to 10.00.  Clearly
there are a number of peaks that should not be there.  Not sure what they are caused by at the
moment but they may have something to do with the pre-modecleaner.

    SCRN0003.jpg shows the free running and suppressed power noise for lower frequencies when
the gain slider is at 15 dB.  Increasing the gain slider to 18 dB causes the loop to rail.  This
is partly alleviated by reducing the offset to 8.00.

    SCRN0004.jpg and SCRN0005.jpg show the open loop transfer function with the integrator on
and off, when the gain slider is set to 13 dB and an offset of 8.00.

    In addition, it seems that the number of 60 Hz related peaks in the power noise spectrum has
been reduced by the replacement of the AOM driver power cord (alog 42939).

    pn.png shows the power noise from 100 kHz down to 10 Hz.

    The power stabilisation works.  Need to track down the source of the peaks in the spectrum.