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Advanced Gamma Tracking Array AGATA . Dino Bazzacco INFN Padova On behalf of the AGATA Collaboration. AGATA. 180 hexagonal crystals 3 shapes 60 triple-clusters all equal Inner radius ( Ge ) 23.5 cm Amount of germanium 362 kg Solid angle coverage 82 %

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Advanced gamma tracking array agata

Advanced Gamma Tracking Array AGATA

Dino Bazzacco

INFN Padova

On behalf of the AGATA Collaboration


Agata

AGATA

180 hexagonal crystals3 shapes

60 triple-clusters all equal

Inner radius (Ge) 23.5 cm

Amount of germanium 362 kg

Solid angle coverage 82 %

36-fold segmentation 6480 segments

Singles rate ~50 kHz

Efficiency: 43% (Mg=1) 28% (Mg=30)

Peak/Total:58% (Mg=1) 49% (Mg=30)

6660 high-resolution digital electronics channels

Detectors operated in position-sensitive mode 

Digital EDAQ + Pulse Shape Analysis + g-ray Tracking

Coupling to ancillary detectors for added selectivity


Agata1

Conventional array

Segmented detectors

g-ray tracking

Energy (keV)

AGATA

v/c = 50%

Using the detectors in position-sensitive modewill provide very high efficiency and excellent energy resolution , making AGATA ideal for spectroscopic studies of weak channels

Effective energy resolution maintained at “extreme” v/c


Reconstruction of 0 1 10 mev gammas

Mg = 30

Reconstruction of 0.1÷10 MeV gammas

MC simulation of a high-multiplicity event

Efficiency depends on position resolution

Position resolution (FWHM, mm)


Pulse shape analysis concept

Pulse Shape Analysis concept

A3

A4

A5

B3

B4

B5

C3

C4

C5

CORE

measured

791 keV deposited in segment B4


Pulse shape analysis concept1

Pulse Shape Analysis concept

A3

A4

A5

B3

B4

B5

(10,10,46)

C3

C4

C5

y

B4

C4

CORE

measuredcalculated

D4

x

A4

F4

E4

791 keV deposited in segment B4

z = 46 mm


Pulse shape analysis concept2

Pulse Shape Analysis concept

A3

A4

A5

B3

B4

B5

(10,15,46)

C3

C4

C5

y

B4

C4

CORE

measuredcalculated

D4

x

A4

F4

E4

791 keV deposited in segment B4

z = 46 mm


Pulse shape analysis concept3

Pulse Shape Analysis concept

A3

A4

A5

B3

B4

B5

(10,20,46)

C3

C4

C5

y

B4

C4

CORE

measuredcalculated

D4

x

A4

F4

E4

791 keV deposited in segment B4

z = 46 mm


Pulse shape analysis concept4

Pulse Shape Analysis concept

A3

A4

A5

B3

B4

B5

(10,25,46)

C3

C4

C5

y

B4

C4

CORE

measuredcalculated

D4

x

A4

F4

E4

791 keV deposited in segment B4

z = 46 mm


Pulse shape analysis concept5

Pulse Shape Analysis concept

A3

A4

A5

B3

B4

B5

(10,30,46)

C3

C4

C5

y

B4

C4

CORE

measuredcalculated

D4

x

A4

F4

E4

791 keV deposited in segment B4

z = 46 mm


Pulse shape analysis concept6

Pulse Shape Analysis concept

A3

A4

A5

Result of Grid SearchAlgorithm

B3

B4

B5

(10,25,46)

C3

C4

C5

y

B4

C4

CORE

measuredcalculated

D4

x

A4

F4

E4

791 keV deposited in segment B4

z = 46 mm


Examples of signal decomposition

Examples of signal decomposition

Eg = 1172 keV net-charge in A1

A B C D E F CC

Eg = 1332 keV net-charge in C3, E1, E3


Status after more than 10 years of r d

Status after more than 10 years of R&D

  • Germanium detectors

  • Pulse Shape Analysis

  • Gamma-ray Tracking

  • AGATA Demonstrator

  • Electronics and DAQ

  • Problems encountered

  • Performance

  • Experiments

  • Evolution


Agata crystals

AGATA Crystals

80 mm

90 mm

Manufactured by

Canberra France

Volume ~370 cc Weight ~2 kg

(the 3 shapes are volume-equalized to 1%)

6x6 segmented cathode


Advanced gamma tracking array agata

Asymmetric AGATA Triple Cryostat

- integration of 111 high resolution

spectroscopy channels

- cold FET technology for all signals

Challenges:

- mechanical precision

- heat development, LN2 consumption

- microphony, noise, high frequencies

Manufactured by CTT

Energy resolution at 1332 keV

Core: 2.4 keV Segments: 2.1 keV

A. Wiens et al. NIM A 618 (2010) 223–233

D. Lersch et al. NIM A 640(2011) 133-138


The agata demonstrator objective of the r d phase 2003 2009 used for physics at lnl in 2010 2011

The AGATA Demonstrator Objective of the R&D phase 2003-2009Used for Physics at LNL in 2010-2011

5 asymmetric triple-clusters

15 36-fold segmented crystals540 segments555 high-resolution digital-channels

Eff. 3 – 8 % @ Mg = 1Eff. 2 – 4 % @ Mg = 30

Real time operation

Pulse Shape Analysisg-ray Tracking

Hosting sites

LNL  2009-2011

GSI 2012-2013GANIL 2014

S. Akkoyun et al. NIM A 668 (2012) 26–58

A. Gadea et al. NIM A 654 (2011) 88-96


Agata demonstrator prisma infrastructure at completed mid 2009 all clusters in place may 2011

AGATA Demonstrator + PRISMAinfrastructure at completed mid 2009, all clusters in place May 2011


Agata structure of electronics and daq

AGATA: Structure of Electronics and DAQ

Fast 1st Level Trigger

Clock

100 MHz

T-Stamp

PSA farm

Other detectors

Control,

Storage…

TRACKING

DIGITIZER

PREAMPL.

Other Detectors

GL Trigger

Digital preamplifier concept

200MB/s/seg.

Detector

Level

GTS

GTS

Core +

36 segments

Processing

Processing

High throughput pre-processing

For one crystal:

2 ATCA carriers 1 GTS + 7 processing mezzanines

100MB/s/detector

Processing

LAN

Global Level

DAQ-NARVALRUN- & SLOW-Control

EVENT BUILDER

Other detectors:interface to GTS, merge time-stamped data into event builder, prompt local trigger from digitisers


Gts the system coordinator all detectors operated on the same 100 mhz clock

GTS : the system coordinatorAll detectors operated on the same 100 MHz clock

Downwards 100 MHz clock + 48 bit Timestamp (updated every 16 clock cycles)

Upwardstrigger requests, consisting of address (8 bit) and timestamp (16 bit)max request rate 10 MHz total, 1 MHz/detector

Downwardsvalidations/rejections, consisting of request + event number (24 bit)


Some important issues

Some important issues

  • Cross talk among the channels of one crystal

  • Need to run at very high counting rates

  • Neutron damage and degradation of energy resolution of the segments

  • Annealing of crystals to restore the original energy resolution is a delicate procedure


Crosstalk

Sum of segment Energies vs fold

Energy [keV]

Segment sum energies projected on fold

2-folds : centroid of Core and Segment-sum

…all 1260 possible 2-fold combinations

Crosstalk

  • Crosstalk is present in any segmented detector

  • Creates strong energy shifts proportional to fold

  • Tracking needs segment energies !


Cross talk correction results

Cross talk correction: Results


High counting rate

High counting rate

  • The detection efficiency of AGATA is, so far, provided by a small number of crystals. Experiments want to collect big statistics and push for running at high singles counting rates.

  • Thanks to digital signal processing, we can work in conditions impossible with conventional electronics.

  • Under these «extreme» conditions, the performance of the detectors is still acceptable.

  • A limit exists, due to pileup of the signals which exhaust the dynamical range of the FADC. Counteract this by reducing the gain of the preamplifiers but then energy resolution worse also at low counting rate.


Singles rates and shaping time

Singles rates and shaping time

6 different rates x 4 trapezoid risetimesx 6 BLR lengths

Two independent sources of dead-time: pile-up rejector and GTS

60Co - fixed

137Cs – 6 positions

Francesco Recchia, Padova


Neutron damage shape of the 1332 kev line

Neutron damage: shape of the 1332 keV line

Blue: April 2010  FWHM(core)~2.3 keV FWHM(segments) ~2.0 keV

Red: July 2010  FWHM(core) ~2.4 keV FWHM(segments) ~3 keV

Damage after 3 high counting-rate experiments (3 weeks of beam at 30-80 kHz singles)

Worsening seen in most of the detectors; more severe on the forward crystals;

segments are the most affected, cores almost unchanged (as expected for n-type HPGe)


Crystal c002

Crystal C002

 corrected

April 2010

July 2010

CCr=15mm

SGr=15mm

CCr=15mm

SGr=15mm

The 1332 keV peak as a function of crystall depth (z) for interactions at r = 15mm

The charge loss due to neutron damage is proportional to the path length to the electrodes. The position is provided by the PSA (which is barely affected by the amplitude loss).

Knowing the path, the charge trapping can be modeled and corrected away (Bart Bruyneel, IKP Köln)


Energy resolution at the end of the lnl campaign before and after charge trapping correction

Energy resolution at the end of the LNL campaignBeforeand After charge-trapping correction

Core

Sum of 15 spectra

FWHM 3.2 keV  2.8 keV

FWTM 7.2 keV  5.6 keV

Segments

Sum of 15*36=540 spectra

FWHM 5.5 keV  2.9 keV

FWTM 15.5 keV  6.8 keV

Eg (keV)

Undamaged detectors: FWHM ~2.5 keV, FWTM ~4.8 keV


Performance of the agata demonstrator

Performance of the AGATA Demonstrator

Just a few examples


Doppler correction capability small v c 220 mev 56 fe 197 au atc1 dante july 2009

Doppler Correction Capability, “small” v/c220 MeV 56Fe  197Au (ATC1 + DANTE, July 2009)

56Fe 2+ 0+

846.8 keV

Au recoils also seen by Dante

56Fe 4+ 2+

1238.3 keV

4.8 keV FWHM

Original

Corrected

Doppler correction using PSA (AGS) and trackingFWHM = 3.5 keV

(3.2 keV using only single hits)

v/c 8%

E(2+) = 846.8 keV

Doppler correction using center of hit segments

FWHM = 7 keV

Detector FWHM = 2.2 keV

Doppler correction usingcenter of crystals

FWHM ~20 keV

Eg (keV)


Doppler correction capability large v c inelastic scattering 17 o @ 20 mev u on 208 pb

Doppler Correction Capability, “large” v/cinelastic scattering 17O @ 20 MeV/u on 208Pb

16O

Charged particles detected in TRACE

No Doppler Corr.

Crystal Centers

SegmentCenters

PSA+Tracking

F

O

N

v/c 20%

C

dE (MeV)

B

Be

Li

a

TKE (MeV)

Fabio Crespi, Milano


Gg capabilities 135 mev 32 s 110 pd 6 agata crystals only

gg capabilities 135 MeV 32S  110Pd (6 AGATA crystals only)

The performance of AGATA using g-ray tracking is comparableto conventional arrays with a much larger number of crystals

138Sm

6 gates on:347keV,545keV,686keV,775keV,552keV,357keV

871 keV 22+ - 20+


Imaging of e g 1332 kev gamma rays agata used as a big compton camera

Imaging of Eg=1332 keV gamma raysAGATA used as a big Compton Camera

Far Field Backprojection

All 9 detectors

One detector

Near Field Backprojection

All 9 detectors

One detector

Source at 51 cm Dx ~Dy ~2 mm Dz ~2 cm

Francesco Recchia


The experimental campaign at lnl

neutrons

protons

The Experimental Campaign at LNL

Octupole-deformedRa and Th nuclei

Neutron-rich nuclei in the vicinity of 208Pb

n-rich Th and U

Isospin Mixingin 80Zr

Pygmy and GQR states

Neutron drip-line

g.s. rotationin Dy, Er, Yb

High-lying statesin 124Sn and 140Ce

Shape transition in 196Os

Molecular structure of 21Ne

n-rich nuclei

Order-to-chaos transition in 174W

Proton drip-line

Lifetimeof 136Te

N=84 isotone140Ba

Coulexof 42Ca

N=51 nuclei

Neutron-rich nuclei populated by fission

20exp.148 days

Lifetimes of the n-rich Cr isotopes

Lifetimes in n-rich Ni, Cu and Zn isotopes

Lifetimes near the island of inversion

Lifetime of the 6.792MeV state in 15O


From the demonstrator to agata 1 plans for the next few years

From the Demonstrator to AGATA 1πPlans for the next few years

LNL: 2010-20115 TC

Total Eff. ~6%

GSI: 2012-2013≥ 5 TC + 5 DC

Total Eff.~10%

GANIL: 2014-201515 TC

Total Eff. ~15%

AGATA D.+PRISMA

AGATA + FRS

AGATA+VAMOS


Status of agata at gsi

Status of AGATA at GSI

  • Mechanics & detector support infrastructure

  • 7 crystals (2 DC, 1 TC) used in the 3rd commissioning test (May 23-28). more detectors added in the next few months.

  • Electronics and DAQ ready for 15 crystals

  • Second batch of electronics modules under test to instrument the up 25 crystals.

  • Coupling to FRS, LYCCA, HECTOR done.

First experiments Q4 2012


The agata collaboration

The AGATA Collaboration

Bulgaria: Sofia

Finland:Jyväskylä

France: GANIL, Grenoble, Lyon, Orsay, Saclay, Strasbourg

Germany:Darmstadt, GSI, Köln, München

Italy:Firenze, LNL, Milano, Padova

Poland: Krakow, Warsaw

Romania: Bucharest

Spain:Valencia, Madrid, Salamanca

Sweden:Göteborg, Lund, Stockholm, Uppsala

Turkey:Ankara, Istanbul

UK:Brighton, Daresbury, Edinburgh, Liverpool, Manchester, Paisley, Surrey, York


First implementations of the g ray tracking array concept

First implementations of theg-ray tracking array concept

AGATA Demonstrator

GRETINA

15 crystals in 5 Triple Clusters

Commissioned in 2009 at LNL (with 3 TC)

Experiments at LNL in 2010-2011

Being reinstalled and expanded at GSI

28 crystals in 7 Quadruple Clusters

Engineering runs started early 2011 at LBNL

Experiments at LBNL in 2011

Being reinstalled at NSCL


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