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AGATA A dvanced Ga mma-Ray T racking A rray. Next-generation spectrometer based on g -ray tracking Radioactive and stable beams, high recoil velocities Bulk crystals operated in position sensitive mode Very high efficiency and spectrum quality Collaboration of 12 European countries
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AGATAAdvanced Gamma-Ray Tracking Array Next-generation spectrometer based on g-ray tracking Radioactive and stable beams, high recoil velocities Bulk crystals operated in position sensitive mode Very high efficiency and spectrum quality Collaboration of 12 European countries R&D programme started in ~1998 Compact 4 germanium array Total Cost 60 M€ INFN contribution 20÷25 % Construction period 2004-2008-2018 Experimental Physics program starts in 2008
Shape coexistence Transfermium nuclei 100Sn 48Ni 132+xSn 78Ni New challenges in Nuclear Structure • Shell structure in nuclei • Structure of doubly magic nuclei • Changes in the (effective) interactions • Proton drip line and N=Z nuclei • Spectroscopy beyond the drip line • Proton-neutron pairing • Isospin symmetry • Nuclear shapes • Exotic shapes and isomers • Coexistence and transitions • Neutron rich heavy nuclei (N/Z → 2) • Large neutron skins (rn-rp→ 1fm) • New coherent excitation modes • Shell quenching • Nuclei at the neutron drip line (Z→25) • Very large proton-neutron asymmetries • Resonant excitation modes • Neutron Decay
Experimental conditions and challenges FAIR SPIRAL2 SPES EURISOL REX-ISOLDE MAFF High Int. Stable • Low intensity • High backgrounds • Large Doppler broadening • High counting rates • High g-ray multiplicities High efficiency High sensitivity High throughput Ancillary detectors Need instrumentation
AGATA(Advanced Gamma Tracking Array) Main features Efficiency: 40% (Mg=1) 25% (Mg=30) today’s arrays ~10% (gain ~4) 5% (gain ~1000) Peak/Total: 65% (Mg=1) 50% (Mg=30) today ~55% 40% Angular Resolution: ~1º FWHM (1 MeV, v/c=50%) ~ 6 keV !!! today ~40 keV Rates: 3 MHz (Mg=1) 300 kHz (Mg=30) today 1 MHz 20 kHz 180 large-volume, 36-fold segmented, encapsulated HPGe crystals 3 shapes, 60 all equal triple-clusters solid angle coverage 80 % 6660 high-resolution digital electronics channels Sophisticated Pulse Shape Analysis Position sensitive operation mode Gamma-ray tracking
The AGATA Collaboration Bulgaria: Sofia Denmark: Copenhagen Finland: Jyväskylä France: GANIL, Lyon, Orsay, Saclay, Strasbourg Germany: Berlin, Bonn, GSI, Darmstadt, Köln, München Hungary: Debrecen Italy: Padova, Milano, LNL, Firenze, Camerino, Napoli, Genova Poland: Krakow, Swierk, Warsaw Romania: Bucharest Sweden: Lund, Stockholm, Uppsala Turkey: Ankara, Istanbul UK: Daresbury, Brighton, Keele, Liverpool, Manchester, Paisley, Surrey, York Bold, main financial contribution to the AGATA Demonstrator
AGATA will look like this 4p ball built out of 12 modules of 5 triple-clusters Fist module of5 triple clusters DEMONSTRATOR Commissioning 2007, Experiments start in 2008
Agata detectors Crystals Cryostats Capsules Single: for tests and scanning high-purity Ge ~ 1.5 kg 36-pixels cathode 0.8 mm Al walls 0.4 mm spacing permanent vacuum Triple: for AGATA clusters
5 ClustersDemonstrator The Phases of AGATA 2007 Peak efficiency 3 – 8 % @ Mg = 1 2 – 4 % @ Mg = 30 Replace/Complement Main issue is Doppler correction capability coupling to beam and recoil tracking devices LNL PRISMA CLARA GANIL VAMOS EXOGAM GSI FRS RISING JYFL RITU JUROBALL Improve resolution at higher recoil velocity Extend spectroscopy to more exotic nuclei
15 Clusters 1p b = 0 b = 0.5 The Phases of AGATA 2010 The first “real” tracking array Used at SPIRAL2, FAIR-HISPEC, High Intensity Stable Coupled to spectrometer, beam tracker, LCP arrays … Spectroscopy at the N=Z (100Sn), n-drip line nuclei, …
30 Clusters 2p The Phases of AGATA Magnetic Spectrometer Also used as partial arrays in different labs Coupled to spectrometer, beam tracker, LCP arrays Spectroscopy at the N=Z (100Sn), n-drip line nuclei, …
45 Clusters3p The Phases of AGATA Ancillary Efficient as a 120-ball (~20 % at high g-multiplicity) Ideal instrument for FAIR / EURISOL Also used as partial arrays in different labs Higher performance by coupling with ancillaries
60 Clusters4p The Phases of AGATA Full ball, ideal to study extreme deformationsand the most exotic nuclear species Most of the time used as partial arrays Maximum performance by coupling to ancillaries
Status and Evolution • Demonstrator (5 clusters) ready in 2007 • Next phase (1p) discussed in 2005-2006 • New MoU and bids for funds in 2007 • Construction start in 2008 • 1p ready in 2010 (12 M€) • 2p ready in 2012 (15 M€) • 3p ready in 2015 (15 M€) • 4p ready in 2018 (15 M€) • Total cost 60 M€ (includes 20 % contingency) (excludes tax and man-power) Estimated dates. Actual dates depend on funding profile and production capability of detectors
Physics with AGATA Coulomb excitation at barrier energies at intermediate energies (~ 102 pps, b<0.1) (~ 100 pps, b0.1 - 0.3) Evolution of shell structure GDR Collective excitations Spin-flip transitions Nuclear astrophysics First excited levels Transfer reactions, Nucleon knock-out & Coulomb break-up (> 103-4 pps, b0.1 - 0.3) Single particle energies Angular momentum contributions Spectroscopic factors Fragmentation and fusion studies (106 – 1012 pps,b 0.05- 0.3) First excited states in nuclei close to the drip lines Neutron rich nuclei at (very) high spins Structure of the heaviest nuclei close to the “line of stability”
Long Range Plan 2004Recommendations and priorities … In order to exploit present and future facilities fully and most efficiently, advanced instrumentation and detection equipment will be required to carry on the various programmes. The project AGATA, for a 4p-array of highly segmented Ge detectors for g-ray detection and tracking, will benefit research programmes in the various facilities in Europe. NuPECC gives full support for the construction of AGATAand recommends that the R&D phase be pursued with vigour. page 25