A week or two ago, Physicist Jon Kaufman gave me a brief tour of the Bicep2 Microwave Telescope, operating here at the South Pole. Aa I reported earlier, the telescope operates at a very very low temperature – only a few millikelvin above absolute zero. In this particular telescope, to get down to that temperature, liquid helium is used in a series of nested cryostats – each reducing the temperature further. In order to maintain the cold temperature needed, liquid helium must periodically be added from an outside source. A few photos of Jon performing a recent refill of liquid helium:
That grey puff coming out of the tip of the filling hose is actually liquid helium. Strangely, as we were working around the telescope as it was off-gassing lots and lots of helium, we could breathe in deeply near the vent hose (warmer, gaseous helium) and our voices would get high – just like sucking on a party balloon.