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AGATA - Advanced GAmma Tracking Array

Scope

AGATA, the first complete 4pi gamma-ray spectrometer solely built from Germanium (Ge) detectors, is based on the novel technique of gamma-ray tracking. AGATA will be an instrument of major importance for nuclear structure studies at the very limits of nuclear stability, capable of measuring gamma radiation in a very large energy range (from a few tens of keV up to 10 MeV and more), with the largest possible efficiency and with a very good spectral response. AGATA will be several orders of magnitude more powerful than all current and near-future gamma-ray spectrometers. Key parameters are

(i) a photo-peak efficiency of about 50% at 1 MeV,
(ii) a position resolution of < 5 mm and
(iii) a trigger rate of up to 1 MHz.

AGATA design characteristics
Multiplicity 1 Multiplicity 30
Efficiency AGATA 43% 28%
Today's Arrays ~10% ~5%
Peak to Total AGATA 58% 49%
Today's Arrays ~55% ~40%
Rates AGATA 3 MHz 300 kHz
Today's Arrays 1 MHz 20 kHz
Angular Resolution
FWHM (1 MeV, v/c = 50%)
Angular Resolution Energy Resolution
AGATA ~1° ~6 keV
Today's Arrays ~40 keV

Science

AGATA will allow the pursuit of a very rich physics programme in many existing and future European Research Infrastructures producing either radioactive or high-intensity stable ion beams. For SPIRAL II and FAIR/NUSTAR AGATA will be one of the most important experimental facilities. Exotic beams allow approaching and mapping the drip-line regions in order to answer the open questions in nuclear structure physics about the nuclear interaction and dynamics, and the occurrence of new symmetries.

High-resolution gamma-spectroscopic studies will open up unique possibilities for a very rich physics program to be addressed. The investigation of exotic nuclei will be aiming at essentially all nuclear degrees of freedom, such as

(i) proton-rich nuclei at and beyond the proton drip line,
(ii) the extension of the N=Z line of self-conjugate nuclei,
(iii) neutron-rich nuclei towards the drip line in medium heavy elements and
(iv) the heaviest elements towards new super-heavy elements.

The internal degrees freedom of nuclei will be exploited by investigating, e.g.,
(i) ultra-high spin states produced in extremely cold reactions,
(ii) meta-stable states at high spins and at very large deformation,
(iii) multi-phonon giant resonances as well as other high-temperature phenomena, such as quantum chaos.

Only AGATA will be capable of disentangling the structure of exotic nuclei produced with extremely small cross section in an overwhelming background of less exotic nuclei and possibly under the constraint of severe Doppler effects.

More than 350 scientists from 44 European institutes constitute the AGATA collaboration and will use the instrument at several European host laboratories for complementary physics research programmes.

Concept

A programme to develop a new generation of position-sensitive high-purity Germanium (HPGe) detectors has been started in the 5th EU Framework Programme. Within a TMR network project a proof of concept for gamma-ray tracking has been achieved. As a result, a technical proposal for AGATA has been produced in 2001 and an MoU has been signed in 2002 by signatories of 12 European countries for planning, developing and funding the AGATA demonstrator, comprising a sub-set of five detector units with full tracking capability and all associated equipment. This phase of the project is supported within the 6th EU Framework Programme as a JRA within the I3 EURONS. Click here to see the final Technical Design Report.

Already in 2005 tests with the first detector unit showed outstanding qualities and encouraged the collaboration to revisit the timing of the construction phase. Therefore a LoI for constructing the full AGATA array has been signed in 2005 which will be followed by a MoU by 2007. It is planned to realize a sub-array by 2010 and the full array by 2015.

A physics programme with the demonstrator for the time period 2008 to 2010 has been approved by the AGATA Steering Committee with campaigns planned at LNL Legnaro, Ganil Caen, GSI Darmstadt and ILL Grenoble. The AGATA infrastructure has an intended lifetime of about 10 years and is considered to be further employed for other applications thereafter.

Impact

The European nuclear spectroscopy community has demonstrated with the worldwide unique development such as EUROBALL and the currently operating EXOGAM, MINIBALL and RISING instruments that such experimental facility for basic research delivers important novel scientific and technical methods with a large impact for society and a broad potential use in industry.

The AGATA facility will contribute not only to basic research, but also to radiation tracking and imaging with a wide range of important applications including nuclear counter terrorism, medical imaging and materials inspection. Moreover, AGATA will provide excellent conditions for education of students in many disciplines and the training of young scientists.