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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