The advanced gamma ray tracking array AGATA

Abstract

New accelerator facilities for radioactive-ion beams and high-intensity stable beams will start operation in a few years. Although these beams will provide interesting opportunities for exploring unknown territories of the nuclear landscape, the experimental conditions will be very challenging and, indeed, the nuclear structure community has realized that a new generation of powerful arrays for γ-ray spectroscopy has to be built in order to cope with them. As a result of years of experience with Compton suppressed germanium arrays and of intensive R&D work targeted to extend their limits, it is now clear that the next 4π γ-ray spectrometers will be built fully from germanium detectors and will be based on the technique of γ-ray tracking. The "Advanced GAmma Tracking Array" (AGATA), proposed in Europe, will be an instrument of major importance for nuclear structure studies at the very limits of nuclear stability. It will be built out of 120/180 highly segmented Ge crystals operated in position sensitive mode by means of digital data techniques and pulse shape analysis of the segment signals. AGATA will be able to measure γ radiation in a large energy range (from ∼ 10 keV to ∼ 10 MeV), with the largest possible photopeak effi ciency (25 % at Mγ = 30) and with a good spectral response. In particular, its very good Doppler correction and background rejection capabilities will allow to perform "standard" γ-ray spectroscopy experiments using fragmentation beams with sources moving at velocities up to β ∼ 0.5.

Characterisation of a symmetric AGATA detector using the imaging scanning technique

“…To explore unknown territories of the nuclear chart with the future beam facilities, it is required to develop improved gamma detector arrays for gamma-ray spectroscopy. A great deal of instrumentation and developmental work is going on for two major projects in this direction, AGATA [9][10][11] in Europe and GRETA [12] in the USA. These arrays are based on electrically segmented large volume HPGe detectors and digital electronics.…”