Physics & Astronomy
Colloquium
It is an observational fact that cosmic rays have been observed
in excess of 1020 eV, many orders of magnitude above the
energies
that even the most powerful man made particle accelerators are
capable of producing here on earth. Nearly a century after their
discovery, the sources of these high energy particles remain enigmatic:
protons and photons do not reveal their sources, since protons are bent
in magnetic fields, and both photons and protons will interact with the
cosmic
microwave background. Neutrinos may have the potential to
shed light on this mystery,
since they are only weakly interacting and travel unimpeded from their
source.
This very advantage, however, makes them exceedingly difficult to
detect. This fact, along with the steeply falling spectrum at
higher
energies, suggests that an exceptionally large detector volume is
required
for the observation of astrophysical neutrinos.
An effort is now underway by the "IceCube" collaboration to
instrument one cubic
kilometer of the clear ice beneath the South Pole as an optical Cherenkov
neutrino
observatory. The design, construction and first physics results
from
the IceCube detector will be presented, and the physics potential of the
completed detector array will be discussed.
It is also theorized that the interactions of highest energy
neutrinos in the ice will result in the emission of
coherent rf signals. The cold South Polar ice has been found to be
rf
transparent on a kilometer scale, which may make an even larger, more
sparsely instrumented array feasible in the not too distant future.
The efforts to develop a next generation neutrino observatory based on
radio antennas will also be reviewed.
3:30 PM, Friday, October 27, 2006
Room 155, Chem-Phys Building
Dr. Kara Hoffman
Department of Physics
University of Maryland, College Park
``Imaging the heavens with neutrinos''
Refreshments will be served in CP 179 at 3:15 PM