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Monday, December 6, 2010

Cryo

You wouldn't think we needed cryogenics at the South Pole.  At least I didn't: after all this is one of the coldest places on earth!  In fact, we happen to have one of the most sophisticated cryogenics production and storage facilities in the world.  For the non-techies, cryogenics refers to refrigerated liquids, typically liquid nitrogen and liquid helium.  Liquid Nitrogen has a temperature of -196 C, or -320 F, and liquid Helium reaches down to -269 C, or -452 F.  They are used in a variety of scientific and medical applications.  Here we use them to cool the detectors in our telescopes, so they can reach the highest sensitivity to observe the faintest signals from the skies.

The South Pole telescopes: MAPO on the left, the 10-mt telescope and BICEP on the right.  They are located approximately 0.75 miles from the station in what we call the Dark Sector (Photo courtesy CS).

We produce liquid nitrogen on site by compressing and purifying air, while we receive several tons of liquid helium from the US every year.
Once the liquid Helium arrives on station it is stored into very large containers called dewars in a dedicated hi-tech facility.  From these containers it is transferred into smaller dewars that can be delivered to the various science projects.
I have been cross-trained in the cryogenics operation.  The cross-training turned out to be useful when Nick, the primary cryo operator at South Pole, left the station last week to go fetch the year's supply of Liquid Helium from New Zealand.  I made my first delivery to one of the telescopes yesterday.

In this photo taken two weeks ago in the cryo facility, under Nick's supervision, I am being trained in the transfer of liquid Helium from one of the large dewars on the right (the white tank) into the smaller 250-liter dewar (the silver tank on the ground), which is suitable for transport around the station (Photo courtesy AB).

Yesterday I delivered my first dewar to the BICEP telescope.  We secure the dewar onto a sled and haul it with a snowmobile to its final destination in the last mile of a complex liquid helium transportation system.  The liquid helium was produced in the US and transprted on land, sea, air, and, finally, on ice.

This is a photo of the Galaxy Cluster 1ES 0657-56, first observed with the South Pole Telesope.  Now when I look at these beautiful images I can think that I, too, contributed some (photo source: http://mm04.nasaimages.org)/

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