J. Oberling, P. King

Spent the day chasing water leaks.  We started by swapping the flow sensor for the Laser Head 1 water circuit (this is the one we think caused the laser shutdown on Saturday).  We brought the laser up and left it on over lunch to warm up.  When we got back in we noticed that one of the connections for the recently replaced flow sensor had begun leaking over lunch.  We shut everything down, drained the water circuit, and replaced the teflon tape for the connection.  Upon starting the chillers, the other connection for this flow sensor started leaking.  Shut everything down, drained the water circuit, and this time swapped the flow sensor entirely (We are now out of spare flow sensors.  Luckily Peter has some new ones on order, should arrive later this week.).  We started the chillers again and saw no leaks in the 10'ish minutes we observed the system running.  In the interest of protecting the laser we are leaving it shut down over night with the chillers running.  Maybe this is an abundance of caution, but we'd rather take it slow and be sure than assume it's all OK and end up really causing a problem.  We will assess whether or not we still have a water leak in the morning.

The brief time that we did have the laser up today (right before lunch), we did attempt to injection lock it.  For some reason, the injection locking was very unstable; over the course of ~20 minutes we had roughly 20 relocks.  This is a big change that we can't yet explain; previous to this the injection locking has been robust.  Add this to the list of control loops that aren't working quite right.  Will investigate this first thing tomorrow, provided we don't have another water leak to fix.