AGATA Advanced Gamma-Ray Tracking Array

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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
• RD programme started in 1998
• Compact 4? germanium array
• Total Cost 60 M
• INFN contribution 2025
• Construction period 2004-2008-2018
• Experimental Physics program starts in 2008

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New challenges in Nuclear Structure

• Shell structure in nuclei
• Structure of doubly magic nuclei
• Changes in the (effective) interactions

• Proton drip line and NZ 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

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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
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AGATA(Advanced Gamma Tracking Array)

• Main features
• Efficiency 40 (Mg1) 25 (Mg30)
• todays arrays 10 (gain 4) 5 (gain 1000)
• Peak/Total 65 (Mg1) 50 (Mg30)
• today 55 40
• Angular Resolution 1º ?
• FWHM (1 MeV, v/c50) 6 keV !!!
• today 40 keV
• Rates 3 MHz (Mg1) 300 kHz (Mg30)
• 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
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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
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AGATA will look like this
4p ball built out of 12 modules of 5
triple-clusters Fist module of 5 triple clusters
? DEMONSTRATOR Commissioning 2007, Experiments
start in 2008
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Agata detectors
Crystals
Cryostats
Capsules
Single for tests and scanning
0.8 mm Al walls 0.4 mm spacing permanent vacuum
high-purity Ge 1.5 kg 36-pixels cathode
Triple for AGATA clusters
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The Phases of AGATA
2007
Peak efficiency 3 8 _at_ Mg 1 2 4 _at_ 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
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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 NZ (100Sn), n-drip line
nuclei,
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The Phases of AGATA
Magnetic Spectrometer
Also used as partial arrays in different
labs Coupled to spectrometer, beam tracker, LCP
arrays Spectroscopy at the NZ (100Sn), n-drip
line nuclei,
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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
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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
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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
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Physics with AGATA

• Coulomb excitation
• at barrier energies at intermediate energies
• ( 102 pps, b lt 0.1) ( 100 pps, b ? 0.1 -
  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
• (gt 103-4 pps, b ? 0.1 - 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

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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 AGATA and
  recommends that the RD phase be pursued with
  vigour.

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