AGATE: Expanding on the Success of EGRET

Abstract

The Energetic Gamma-Ray Experiment Telescope (EGRET) on the Compton Observatory has increased our understanding of active galactic nuclei, pulsars, diffuse emission, solar flares and gamma ray bursts. In order to continue these advances in high energy gamma-ray astronomy, development of a follow-on telescope to EGRET is in progress. The new experiment, named the Advanced Gamma-Ray Astronomy Telescope Experiment (AGATE), has the same basic components which have made EGRET a successful, low background telescope for 30 MeV to 30 GeV gamma rays; however, the sensitivity has been increased by an order of magnitude, the energy range extended to higher energies, and the angular resolution improved.

The large area, 2m x 2m, of AGATE has lead to the selection of drift chambers for the tracking detector, rather than the spark chambers used in EGRET. Drift chambers have fewer wires and much less deadtime per event. The power per wire is low enough to use many layers in order to reduce the multiple scattering of the electron and positron before the gamma-ray direction can be measured.

A 16 layer prototype of l/2m x l/2m drift chambers has been built. Muon tracks are used to study position resolution, efficiency, and noise. Preliminary work has also begun on the spacecraft requirements.