Attached are trends of the various flow sensors in the PSL.  Comparison of the timestamps shows that the high power oscillator
tripped because of a flow rate problem with the AMP circuit.  The problem does not lie within the 4 laser heads, leaving either
the front end power amplifier, or the 4 crystal chambers.

    Unfortunately checking the 4 crystal chambers requires dismantling the laser.  The vortex flow sensor in the AMP circuit
is relatively new.  The other object in that circuit is the power amplifier module.  An inspection mirror might be able to
afford a view of the plumbing underneath the housing.

    One can see that the flow rate in the AMP circuit drops before the output of the front end laser drops, and that the output
power of the front end laser drops before the high power oscillator.  I think the sequence of events is the following:
 1. flow rate problem in the AMP circuit trips the flow watch dog of the front end laser
 2. the switching off of the front end laser breaks the injection locking of the high power oscillator
 3. the loss of injection locking results in a power drop in the high power oscillator which then trips the power watch dog
 4. the power watch dog switches the high power oscillator off