  Project GRAND is an extensive air shower array of proportional wire chambers.
It has 64 stations in a 100m x 100m area; each station has eight planes of
proportional wire chambers with a 50 mm steel absorber plate above the bottom
two planes. This arrangement of planes, each 1.25 square meters of area, allow
an angular measurement for each track to 0.25 degrees in each of two
projections. The steel absorber plate allows a measurement of the identity of
each muon track to 96% accuracy. Two data-taking triggers allow data to be
simultaneously taken for a) extensive air showers (multiple coincidence station
hits) at about 1 Hz and b) single muons (single tracks of identified muons) at
2000 Hz. Eight on-line computers pre-analyze the single track data and store
the results on magnetic tape in compacted form with a minimum of computer
dead-time. One additional computer reads data from the shower triggers and
records this raw data on a separate magnetic tape with no pre-analysis.
