John SimpsonNuclear Physics GroupDaresbury Laboratory

The AGATA project

NUSTAR ’05 University of Surrey January 2005

John SimpsonNuclear Physics GroupDaresbury Laboratory

AGATA the ultimate gamma-ray spectrometer!

Next generation spectrometer based on gamma-ray trackingBased on years of worldwide R&DNo suppression shields 4 germanium arrayVery high efficiency and spectrum quality Stable, radioactive beams, low-high velocities

AGATA The Advanced Gamma Ray Tracking Array

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

FAIRSPIRAL2SPESREX-ISOLDEMAFFEURISOLHI-SIB

Need instrumentation

AGATAAGATA(Advanced GAmma Tracking Array)

4 -array for Nuclear Physics Experiments at European accelerators providing radioactive and high-intensity stable

beams

Main features of AGATA

Efficiency: 40% (M =1) 25% (M =30)today’s arrays ~10% (gain ~4) 5% (gain ~1000)

Peak/Total: 55% (M=1) 45%

(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 Ge crystals in 60 triple-clusters • Digital electronics and sophisticated Pulse Shape Analysis algorithms allow• Operation of Ge detectors in position sensitive mode -ray tracking

Exogam, Miniball, SeGa: optimized for Doppler correction at low -multiplicitiy up to 20%

Tracking Arrays based onPosition Sensitive Ge Detectors

Large Gamma Arrays based onCompton Suppressed Spectrometers

40 — 20 % ( M=1 — M=30)

10 — 5 % ( M=1 — M=30)

GAMMASPHEREEUROBALL GRETAAGATA

Idea of Idea of -ray tracking-ray tracking

Tracking requires:Good position determination fromDigital pulse processing

Previous/current projects:

EU Vth Framework TMR `Development of –ray tracking detectors’ (6 EU countries)

Miniball and Exogam (European collaborations)

Mars, Italy

UK Instrumentation grant ‘Digital Pulse Processing and –ray tracking’ (Liverpool, Surrey, Daresbury)

GRETA, USA

Proved that position resolution can be achieved, tracking algorithms developed, Highly segmented detectors developed

Next step

Build a sub array of few highly segmented detectors, prove tracking in real situationsScale up to full array, fund full array

AGATA Europe (10 (12) countries, 42 (46) laboratories) Research and Development Phase

Funding approved in France, Germany, Italy, UK, other countries bidding.

GRETA U.S.A. Funded for development modules GRETINA U.S.A. Funded for 30 crystals

The AGATA CollaborationMemorandum of Understanding 2003 Research and Development

Bulgaria: Univ. Sofia Denmark: NBI Copenhagen Finland: Univ. Jyvaskyla France: GANIL Caen, IPN Lyon, CSNSM Orsay, IPN Orsay,

CEA-DSM-DAPNIA Saclay, IreS Strasbourg

Germany: HMI Berlin, Univ. Bonn, GSI Darmstadt, TU Darmstadt, FZ Jülich, Univ. zu Köln, LMU München, TU München

 Italy: INFN and Univ. Firenze, INFN and Univ. Genova, INFN Legnaro, INFN and Univ. Napoli,

INFN and Univ. Padova, INFN and Univ. Milano, INFN Perugia and Univ. Camerino Poland: NINP and IFJ Krakow, SINS Swierk, HIL & IEP Warsaw Romania: NIPNE & PU Bucharest Sweden: Chalmers Univ. of Technology Göteborg, Lund Univ.,

Royal Institute of Technology Stockholm, Uppsala Univ. UK: Univ. Brighton, CLRC Daresbury, Univ. Keele, Univ. Liverpool, Univ. Manchester,

Univ. Paisley, Univ. Surrey, Univ. York

 

Turkey

Hungary

The First Step:The AGATA Demonstrator

Objective of the final R&D phase 2003-2008

1 symmetric triple-cluster5 asymmetric triple-clusters

36-fold segmented crystals540 segments555 digital-channels

Eff. 3 – 8 % @ M = 1

Eff. 2 – 4 % @ M = 30

Full ACQwith on line PSA and -ray trackingTest Sites:GANIL, GSI, Jyväskylä, Köln, LNLCost ~ 7 M €

The AGATA RESEARCH and DEVELOPMENT PHASE

•Develop 36 fold segmented encapsulated detector of right shape

•Develop cryostat for groups “clusters” of these detectors

•Develop digital electronics (700 channels)

•Finalise signal algorithms for energy, position and time

•Develop tracking algorithms

•Build demonstration unit to prove tracking in real situations

•Write technical proposal for full array

Ingredients ofIngredients of --TrackingTracking

Pulse Shape Analysisto decompose

recorded waves

Highly segmented

HPGe detectors

·

·

··

Identified interaction

points(x,y,z,E,t)i

Reconstruction of tracks

e.g. by evaluation of permutations

of interaction points

Digital electronicsto record and

process segment signals

1

2 3

4

reconstructed -rays

AGATA Detectors

3 encapsulated crystals111 preamplifiers with cold FET~230 vacuum feedthroughs

LN2 dewar, 3 litre, cooling power ~8

watts

Hexaconical Ge crystals90 mm long80 mm max diameter36 segmentsAl encapsulation

0.6 mm spacing0.8 mm thickness

37 vacuum feedthroughs

AGATA Prototypes•Symmetric detectors

–3 ordered, Italy, Germany

–3 delivered

–Acceptance tests in Koln

–2 work very well

–3rd under test First results very good:

36 outer contacts 0.9-1.1keV at 60keV and 1.9-2.1keV at 1.3MeV Core1.2keV at 60keV and 2.1keV at 1.3MeV

Cross talk less than 10-3

AGATA Prototypes

Asymmetric detectors for the 180 geometry

–8 ordered in 2004

–4 to be ordered in 2005

–delivery starts end 2005

Full scan of first in Liverpool

Assembly of triple cryostat (CTT)

Cluster ready by March 2005

First triple cryostat in Cologne

AGATA Design and Construction

GRETINA

The 4 180 detector Configuration

180 hexagonal crystals 3 shapes60 triple-clusters all equalInner radius (Ge) 25 cmAmount of germanium 374 kgSolid angle coverage 78 %Singles rate ~50 kHz6480 segments

Efficiency: 39% (M=1) 25% (M=30)Peak/Total: 53% (M=1) 46% (M=30)

Ge crystals size:length 90 mmdiameter 80 mm

http://agata.pd.infn.it/documents/simulations/comparison.html

Segment level processing: energy, timeDetector level processing: trigger, time, PSAGlobal level processing: event building, tracking, software trigger, data storage

Scanning with collimated source to characterise rise time responses

Detector characterisation

Detector scanned with collimated source

First AGATA detector being scanned in Liverpool Liverpool System

• Parker linear positioning table• Pacific scientific stepper motors• 0.3mCi 137Cs• 2mm steps collimator• Singles/coincidence 8 NaI system• GRT4 cards

Preliminary resultsCore response to 662keV

Scanning in progress

• PSA– Apply and test Genetic Algorithm on measured

data with the AGATA prototypes– Develop new and specialised algorithms– Implement for on-line analysis– Gamma-neutron differentiation

• Detector characterisation– Crystal scanning for pulse-shape data base

construction– Simulation of charge carrier transport– Test neutron damage on PSA efficiency

• γ-tracking– Optimise and couple the different

tracking algorithms for improved AGATA performance

– Determine the impact on AGATA performance of the use of additional detectors

– Determine the AGATA response to simulated physics events

Timescale

Five year research and development phase of AGATAStart January 2003 ---end December 2007

•First three symmetric capsules expected mid 2004 •Test individual as 3-unit module by Easter 2005•Start ordering asymmetric capsules in 2004 •First asymmetric cluster end 2005•Test first crystals/ modules with “existing electronics”•Electronics and DA required mid 2006•Time for R&D, GUI, algorithms PSA, tracking…•Test sub array 2007

• Demonstrator ready in 2007

• Next phases discussed in 2005-2006

• New MoU and bids for funds in 2007• Start construction in 2008• Rate of construction depends on

production capability• Stages of physics exploitation,

facility development

Status and Evolution

The Phases of AGATA-180

5 Clusters5 Clusters113355 Clusters55 Clusters44 Array Array

The Phases of AGATA-180

5 Clusters5 ClustersDemonstratorDemonstrator

The Phases of AGATA

GSI FRS RISINGLNL PRISMA CLARAGANIL VAMOS EXOGAMJYFL RITU JUROGAM

12007

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 AGATA 2

The first “real” tracking arrayUsed at FAIR-HISPEC, SPIRAL2, SPES, HI-SIBCoupled 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 345 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

60 Clusters60 Clusters44

The Phases of AGATA 4

Full ball, ideal to study extreme deformationsand the most exotic nuclear speciesMost of the time used as partial arraysMaximum performance by coupling to ancillaries

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.

Tracking Arrays based onPosition Sensitive Ge Detectors

40 — 20 % ( M=1 — M=30)

GRETAAGATA

AGATANew physics

Reveal the inner secrets of the atomic

nucleus

AGATA web AGATA web pagepage

http://www-w2k.gsi.de/agata/http://www-w2k.gsi.de/agata/

The Second AGATA The Second AGATA WeekWeek

21-2521-25thth February 2005 February 2005

GSIGSI

All welcomeAll welcome

The Management