Project GRAND
Prof. John Poirier
Email: poirier (at) nd (dot) edu
Project GRAND (Gamma Ray Astrophysics at Notre Dame) is a cosmic ray detector array which simultaneously studies cosmic rays in two energy bands depending on the trigger: single track triggers study the energy region from 10 to 300 GeV (GeV is Giga, or billion electron Volts); and multiple track triggers study 100 to 100 000 TeV (TeV is Teva, or trillion eV).  GRAND studies stellar point sources of gamma rays which requires: good angular resolution, good particle identification, and a large area for sufficient statistics.  The project pioneered the use of proportional wire chambers (pwc-s) in cosmic ray research.  Pwc-s are tracking detectors which have the advantage of providing superior angular resolution and, with a steel plate in each detector station, provide particle identification of muons and electrons.  Since each detector is a track-by-track detector of identified muons with their angle measured, it is an ideal detector to study secondary muons arising from the highest energy protons which our sun is capable of accelerating (our current focus).  GRAND, as a muon detector, has: the world's best muon angular resolution (+/- 1/4-deg), the largest detector area (a total of 82 sq-m), and an ideal geographical location relative to the rest of the solar muon detectors of the world (it is the only one in North America). Collectively, this network of muon detectors allows 24/7 observation of the sun's flaring activity.  This coming summer's project will build on the ongoing work at ND where students analyze current and archived data as well as gain experience with the detector itself.