Getting ready for MagAO 2014B — spare Clio solid nitrogen pump

We’ve had a few meetings lately to prepare for our upcoming 2014B run in Oct–Dec. This will be our second regular science run, and our operations are becoming more smooth and efficient, so we are going to have a more streamlined personnel plan. It will also be our longest run yet (37 nights!).

We are laying in for spares and planning improvements in our operations. One spare Phil has gotten for Clio is a spare pump for pumping on the liquid nitrogen chamber in the dewar to bring the temperature of the detector from 77 K (liquid nitrogen) down to 55 K (solid nitrogen) by lowering the pressure. This spare pump is coming to us from the LBT where it used to be a vacuum pump, and while it is no longer strong enough to deliver a true vacuum, it is strong enough to lower the pressure to solidify the nitrogen in the dewar. It is a Leybold Oerlikon EcoDry M 30 Dry Piston Vacuum Pump.

New Clio pump technical info, from Phil:

The current Clio pump is specified to reach an ultimate vacuum of 5 Torr (7 mbar). This allows the solid N2 vessel to be at 50-51 K. We typically regulate ~5 K above this or 55 K. The new EcoDry pump has an achieved lab pressure of 0.11 Torr. This will put the solid vessel at ~42 K. This suggest we could regulate as low as 47 K on the detector.

Therefore, on this next run, we will explore new setpoints and the effect on detector performance. Thanks Phil!

Here are Laird and Kim (CAAO Project Specialist) working on shipping the spare Clio pump to LCO. It weighs ~130 lbs and is 50 cm long x 30 high x 30 cm wide, and uses 120 V AC. It will be quite at home in the pump room.

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