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Ghost particles PDF Print E-mail
Written by Daniel Marin   
Tuesday, 08 July 2008

Most of the matter in our Universe does not emit light. This dark matter may consist of exotic particles not yet discovered, such as Weakly Interacting Massive Particles (WIMPs) or axions. Their discovery is very important for understanding what the Universe is made of. But they are very dificult to observe. An innumerable number of neutrinos go through the Earth every second but they are also very elusive. They can travel extremely long distances as they interact very weakly with matter, bringing information from the past and from the interior of cosmic bodies. This advantage also becomes a handicap, since the probability of interacting with our detectors is also extremely small. Very large detectors are then needed to increase our chance of detection. Going underground and using special shielding are essential to avoid any spurious signal that would spoil the possibility of observing those particles. Underground laboratories are the cleanest environments in the world from this point of view.


 BOREXINO: a scintillation detector to study neutrinos from the Sun.
• © Borexino collaboration LNGS/INFN •

 DAMA: a dark matter experiment using highly
radiopure scintillators.
• © DAMA /LIBRA Collaboration •
 EDELWEISS: a hybrid detector to search for
dark matter.
• © JJ. Bigot/ CEA/Dapnia •
 XENON10: a dark matter experiment using xenon
as detector.
• © XENON Collaboration

The experiments for underground physics are placed in an environment with the least amount of radiation in the world. Cosmic rays are absorbed by the Earth, but also extremely low radioactivity techniques are applied, such as archaeological lead to shield the detectors.

Last Updated ( Tuesday, 01 June 2010 )
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