Space Station Becomes Dark Matter Hunter 40
CWmike writes "With a new $2 billion device successfully installed Thursday, the International Space Station has become a dark matter hunter. Two robotic arms worked in tandem to lift the 15,251-pound instrument, called the Alpha Magnetic Spectrometer-2, out of space shuttle Endeavour's payload bay and then attached it to the backbone of the space station. The instrument will orbit the Earth, sifting through cosmic particles and providing data that it is hoped will help find the answers to fundamental questions of physics related to antimatter and dark matter."
Re:Isn't that expensive? (Score:5, Informative)
The original plans called for a cryogenic magnet. It is interesting to note that they have gotten to the point where the system estimated lifetime would be 3 years, but swapped it for a permanent magnet version in the end.
I imagine this was quite challenging as loss of cooling/superconductivity would result in an explosion - not a good thing to have. And that loss can simply result from a high-energy cosmic ray striking a tiny superconducting wire. Somehow they found a way around this..
Re:Isn't that expensive? (Score:5, Informative)
What's the advantage of this over one in a mine that justifies the cost
Primary cosmic rays are much simpler animals than secondary cosmic rays. Primary cosmic rays are almost 100% protons, which almost never reach the surface of the Earth because they interact with the atmosphere and create cosmic ray "showers" that are rich and complex, full of muons and gamma rays and prolific in neutron production as well. Even fairly deep underground dealing with these backgrounds is a complicated process.
Having only primary cosmic rays to deal with makes life somewhat easier. There may also be dark matter signals that are too low energy to penetrate the Earth's atmosphere--that is, weak signals in the low-energy cosmic ray background due to dark matter collisions or decays integrated over a very large volume.
The ideal place to do this kind of work is on the Moon: because it has no atmosphere, pions produced by cosmic ray protons will come to a halt before they decay, so there are only low-energy muons produced. Thus, a couple of metres of rock on the Moon will give you shielding as good as a much thicker layer on Earth.