Friday, 22 November 2013

New neutrino observatory a mile below Antarctic ice is on line.

You never heard of the Ice Cube Neutrino Observatory?  The Super-K and Sudbury SNO neutrino observatories were pioneers but this one far below Antarctic ice has already found a couple dozen events coming from around the cosmos and is building a directional data base.

ICNO design.
Despite trillions of neutrinos streaming through you this moment, they rarely bump into anything in thousands of years.  Their behaviour can thus conserve information about events from the earliest days of the universe.

The ICNO is "among the most ambitious scientific projects ever attempted". The picture illustrates the structure well:    86 cores were drilled 1 1/2 to 2 1/2 km into the ice with 60 sensors per string and 6 of those strings dedicated to extra depth.  The ice is clear as glass at those depths and when once in a while a neutrino (one of three types) happens to interact with a bit of ice matter, the by product includes a speck of light called Cerenkov radiation.  Beautiful.

"Bert" - at 1.04 petaelectronvolts is the highest
energy neutrino ever detected.
Science Daily News reporting on ICNO.
I admire the modular design.  After the first few strings were in place, data collection had already begun.  Redundancy is built into the experiment.

View down one shaft, insulated at the top.
The Sudbury experiment used a sphere of heavy water about a mile down an isolated mineshaft and was looking for solar neutrinos.  The Japanese experiment used a larger sphere with more detectors but with pure regular water, collecting from more sources.

Notes: Information and view down the bore hole are from spaceref site

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