  The Cryogenic Apparatus for Precision Tests of Argon Interactions with
Neutrino (CAP- TAIN) program is designed to make measurements of scientific
importance to long-baseline neutrino physics and physics topics that will be
explored by large underground detectors. The CAPTAIN detector is a liquid argon
TPC deployed in a portable and evacuable cryostat. Five tons of liquid argon
are instrumented with a 2,000 channel liquid argon TPC and a photon detection
system. Subsequent to the commissioning phase, the detector will collect data
in a high-energy neutron beamline that is part of the Los Alamos Neutron
Science Center to measure cross-sections of spallation products that are
backgrounds to measurements of neutrinos from a supernova burst, cross-sections
of events that mimic the electron neutrino appearance signal in long-baseline
neutrino physics and neutron signatures to constrain neutrino energy
reconstruction in LBNE's long-baseline program. Subsequent to the neutron
running, the CAPTAIN detector will be moved to a neutrino source. Two
possibilities are an on-axis run in the NuMI beamline at FNAL and a run in the
neutrino source produced by the SNS. An on-axis run at NuMI produces more than
one million events of interest in a two or three year run at neutrino energies
between 1 and 10 GeV - complementary to the MicroBooNE experiment, which will
measure similar interactions at a lower energy range - 0.5 to 2 GeV. At the SNS
the neutrinos result from the decays stopped positively charged pions and muons
yielding a broad spectrum up to 50 MeV. If located close to the spallation
target, CAPTAIN can detect several thousand events per year in the same
neutrino energy regime where neutrinos from a supernova burst are. Measurements
at the SNS yield a first measurement of the cross- section of neutrinos on
argon in this important energy regime.
