agata agata advanced gamma-ray tracking array next-generation spectrometer based on -ray tracking...
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AGATAAGATAAdvanced Gamma-Ray Tracking Array
Next-generation spectrometer based on -ray tracking
Radioactive and stable beams, high recoil velocities
Bulk crystals operated in position sensitive modeVery high efficiency and spectrum qualityCollaboration of 12 European countries
R&D programme started in ~1998Compact 4 germanium array
Total Cost 60 M€INFN contribution 20÷25 %
Construction period 2004-2008-2018Experimental Physics program starts in 2008
Neutron rich heavy nuclei (N/Z → 2)• Large neutron skins (r-r→ 1fm)• New coherent excitation modes• Shell quenching
132+xSn
Nuclei at the neutron drip line (Z→25)• Very large proton-neutron asymmetries• Resonant excitation modes• Neutron Decay
Nuclear shapes• Exotic shapes and isomers • Coexistence and transitions
Shell structure in nuclei• Structure of doubly magic nuclei • Changes in the (effective) interactions
48Ni100Sn
78Ni
Proton drip line and N=Z nuclei• Spectroscopy beyond the drip line• Proton-neutron pairing• Isospin symmetry
Transfermium nucleiShape coexistence
New challenges in Nuclear Structure
Experimental conditions and
challenges• Low intensity• High backgrounds• Large Doppler broadening• High counting rates• High -ray multiplicities
High efficiencyHigh sensitivityHigh throughputAncillary detectors
FAIRSPIRAL2SPESEURISOLREX-ISOLDEMAFFHigh Int. Stable
Need instrumentation
AGATAAGATA(Advanced Gamma Tracking Array)
Main featuresEfficiency: 40% (M=1) 25% (M=30)today’s arrays ~10% (gain ~4) 5% (gain ~1000)
Peak/Total: 65% (M=1) 50% (M=30)today ~55% 40%
Angular Resolution: ~1º FWHM (1 MeV, v/c=50%) ~ 6 keV !!!today ~40 keV
Rates: 3 MHz (M=1) 300 kHz (M=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: SofiaDenmark: Copenhagen
Finland:Finland: JyväskyläFrance: GANIL, Lyon, Orsay, Saclay, StrasbourgGermany: Berlin, Bonn, GSI, Darmstadt, Köln, MünchenHungary: DebrecenItaly: Padova, Milano, LNL, Firenze, Camerino, Napoli,
GenovaPoland: Krakow, Swierk, WarsawRomania: BucharestSweden: Lund, Stockholm, UppsalaTurkey: Ankara, IstanbulUK: Daresbury, Brighton, Keele, Liverpool,
Manchester, Paisley, Surrey, YorkBold, main financial contribution to the AGATA Demonstrator
AGATA will look like this
4 ball built out of 12 modules of 5 triple-clusters
Fist module of 5 triple clusters DEMONSTRATORCommissioning 2007, Experiments start in 2008
Single: for tests and scanning
0.8 mm Al walls0.4 mm spacingpermanent vacuum
Agata detectors
Triple: for AGATA clusters
high-purity Ge~ 1.5 kg36-pixels cathode
Crystals Capsules Cryostats
5 Clusters5 ClustersDemonstratorDemonstrator
The Phases of AGATA
LNL PRISMA CLARAGANIL VAMOS EXOGAMGSI FRS RISINGJYFL RITU JUROBALL
2007
Main issue is Doppler correction capability coupling to beam and recoil tracking devicesImprove resolution at higher recoil velocity
Extend spectroscopy to more exotic nuclei
Peak efficiency3 – 8 % @ M = 1
2 – 4 % @ M = 30
Replace/Complement
15 Clusters 15 Clusters 11
The Phases of AGATA2010
The first “real” tracking arrayUsed at SPIRAL2, FAIR-HISPEC, High Intensity StableCoupled to spectrometer, beam tracker, LCP arrays …Spectroscopy at the N=Z (100Sn), n-drip line nuclei, …
0
5
10
15
20
25
30
35
40
45
50
1 2
Effi
cie
ncy
(%
)
Solid Angle (%)
Efficiency M = 1
Efficiency M = 10
Efficiency M = 20
Efficiency M = 30
= 0 = 0.5
The Phases of AGATA
Also used as partial arrays in different labsCoupled to spectrometer, beam tracker, LCP arraysSpectroscopy at the N=Z (100Sn), n-drip line nuclei, …
30 Clusters 30 Clusters 22
Magneti
c Spect
rom
ete
r
The Phases of AGATA45 Clusters45 Clusters
33
Efficient as a 120-ball (~20 % at high -multiplicity)Ideal instrument for FAIR / EURISOLAlso used as partial arrays in different labsHigher performance by coupling with ancillaries
An
cilla
ry
60 Clusters60 Clusters44
The Phases of AGATA
Full ball, ideal to study extreme deformationsand the most exotic nuclear speciesMost of the time used as partial arraysMaximum performance by coupling to ancillaries
• Demonstrator (5 clusters) ready in 2007
• Next phase (1) discussed in 2005-2006• New MoU and bids for funds in 2007• Construction start in 2008
– 1 ready in 2010 (12 M€)
– 2 ready in 2012 (15 M€)– 3 ready in 2015 (15 M€)– 4 ready in 2018 (15 M€)
• Total cost 60 M€(includes 20 % contingency)(excludes tax and man-power)
Status and Evolution
Estimated dates. Actual dates depend on funding profile and production capability of detectors
Physics with AGATACoulomb excitation
at barrier energies at intermediate energies(~ 102 pps, < 0.1) (~ 100 pps, 0.1 - 0.3)Evolution of shell structure GDR Collective excitations Spin-flip transitionsNuclear astrophysics First excited levels
Transfer reactions,Nucleon knock-out & Coulomb break-up(> 103-4 pps, 0.1 - 0.3)Single particle energiesAngular momentum contributionsSpectroscopic factors
Fragmentation and fusion studies (106 – 1012 pps, 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 4-array of highly segmented Ge detectors for -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 R&D phase be pursued with vigour.
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