Gamma Ray Astrophysics at Notre Dame, GRAND > Homepage

The G.R.A.N.D (Gamma Ray Astrophysics at Notre Dame) project is an extensive air shower array which studies the gamma rays in two energy bands depending on the trigger selected: trigger 1, from 30 to 300 GeV (GeV is giga, or billion, electron volts); and trigger 2, from 100 to 100 000 TeV (TeV is teva, or trillion eV).

The original goal of this array is to study stellar point sources of gamma rays. This study requires: good angular resolution, good particle identification, and sufficient running time to gather statistics. This project has pioneered the use of tracking detectors (proportional wire chambers, PWCs) in cosmic ray research; tracking detectors have the advantage of providing superior angular resolution and simultaneous particle identification. These PWC tracking detectors also allow the array to be used for added studies including our newest goal: to measure the atomic composition of cosmic rays in the energy region from 100 to 100,000 TeV.