The deep underground MACRO detector is currently operating at the
Laboratori Nazionali del Gran Sasso
in Abruzzo, Italy. MACRO has a
geometrical acceptance of nearly 10000 m^2 at an average depth
of 3.8 kilometers of water equivalent under the mountainous overburden
of the Gran Sasso d'Italia. We use this large area detector to research
several topics. The specialty of MACRO is the search for magnetic
monopoles: particles with bare north or south magnetic charge. These
particles are a natural consequence of Grand Unified Theories, which
also predict that the monopole will be very massive: perhaps 10^16
GeV. Such particles can only be produced by the intense energies
available during the big bang. MACRO operates like a giant
Time-Of-Flight counter to detect the unique signature of a slow moving
but penetrating massive particle. MACRO is equipped with tanks of liquid
scintillator, planes of streamer tubes and plates of track etch material
to hopefully record a convincing signature from a single candidate
event. MACRO's high resolution tracking and timing are also used to
perform high statistics measurements of cosmic ray muons; in particular
the scintillator timing is used to distinguish upward going muons
produced by neutrino interactions in the rock. This is an opportunity to
investigate the possible flavor oscillation of massive neutrino's as
suggested by the atmospheric neutrino puzzle, as well as possible
astrophysical point sources of neutrinos. The large area and fine grain
of the tracking affords unique measurements of large multiplicity muon
showers- from these we hope to infer information about the nature of the
primary particles in the high energy range of the cosmic ray
spectrum. The large mass of liquid scintillator (~ 600 tons) is
also instrumented to identify a burst of low energy pulses as might be
caused by the flux of neutrinos from a supernova within our galaxy.
ETK