Cyndia Yu from Stanford working on the helium sorption
fridge of the Keck Array. It's a system that condenses and evaporates helium 3 and helium 4. The sorption fridge connects to the helium pulse tube system, which achieves temperatures around 4 Kelvin (-452 F). With the fridge
on top of that 4K stage temperatures at the focal plane can achieve ~0.3K (-459 deg F.)
