overview of gretina status

February 21, 2005 The AGATA Week 1

Overview of GRETINA Status

I-Yang LeeLawrence Berkeley National Laboratory

The AGATA Week, 21-25th February 2005, GSI


Outline

• Physics opportunities

• High lights of recent achievements

• Plan for 2005

• Schedule and cost

• Management structure


Capabilities of a 4 -ray tracking detector

Resolving power: 107 vs. 104

– Cross sections down to ~1 nb• Most exotic nuclei• Heavy elements (e.g. 253,254No)• Drip-line physics• High level densities (e.g. chaos)

Efficiency (high energy) (15% vs. 0.5% at E=15 MeV)

– Shape of GDR– Studies of hypernuclei

Efficiency (slow beams) (48% vs. 8% at E =1.3 MeV)

– Fusion evaporation reactions

Efficiency (fast beams) (48% vs. 0.5% at E =1.3 MeV)

– Fast-beam spectroscopy with low rates -> RIA

Angular resolution (0.2º vs. 8º)– N-rich exotic beams

• Coulomb excitation

– Fragmentation-beam spectroscopy• Halos

• Evolution of shell structure

• Transfer reactions

Count rate per crystal (100 kHz vs. 10 kHz)– More efficient use of available beam

intensity

Linear polarization

Background rejection by direction


Advantages of - ray Tracking

• High position resolution

• High efficiency

• High P/T

• High counting rate

• Background rejection

• Large recoil velocity– Fragmentation– Inverse reaction

• Low beam intensity

• High background rate– Beam decay– Beam impurity

For Radioactive Beam Experiments


Important Features of GRETINA

• Better position Resolution – 2 mm vs. 20 mm– High recoil velocity experiments

• Higher efficiency for high energy gamma rays– Giant resonances studies

• Compactness – ¼ GRETA is comparable or better than Gammasphere– Use with auxiliary detectors, recoil separators etc.

GRETINA = ¼ GRETA


Physics Opportunities with GRETINA

• How does nuclear shell structure and collectivity evolve in exotic n-rich nuclei?

• What is the influence of increasing charge on the dynamics and structure for the heaviest nuclei?

• How do the collective degrees of freedom and shell structure evolve with the excitation energy and angular momentum?

• What are the characteristics of the Giant Dipole Resonances built on superdeformed states and loosely bound nuclei?


Recent Achievements

• Received CD1 approval – start design phase• Developed design concept for mechanical support• Received 3-crystal detector prototype III

– Extensive testing with sources and beam

• Analyzed in-beam test results of prototype II• Set up a data acquisition system• Finalized detector module design• Written requirement documents• MOU’s signed with collaborating institutions• Carried out safety and risk analysis

CD0: Approve mission needCD1: Approve preliminary baseline range CD2: Approve performance baseline rangeCD3: Approve start of construction CD4: Approve start of operation


Concept of Mechanical Support

• Two quarter-spheres• 17 detector mounting

positions• Allow translation and

rotation• Wedge plate for

detector alignment• Tool for detector

installation• Movable among

laboratories (e.g. ANL, LBNL, MSU, ORNL)


Three-crystal Prototype

Tests performed

• Mechanical dimension

• Temperature and LN

holding time

• Energy resolution

• Singles and preliminary

coincidence scan

• In-beam measurements

Tapered hexagon shape Highly segmented 6 6 = 36 Close packing of 3 crystals 111 channels of signal

Received June 4, 2004

8 cm

9 cm

10 deg.


Prototype Test Results

0

200

400

600

800

1000

1200

1400

0 10 20 30 40 50 60 70

Y (mm)

Co

un

ts 6

0k

eV

Am

(0,-50, )

FrontLeftRightBack

Crystal B, noise substracted

20

25

30

35

-90 -60 -30 0 30 60 90

Angle (degrees)

Dri

ft t

ime

(10

nse

c)

T90 - T10

T80 - T20

Crystal A segments 1 and 4

Segment boundary Electron drift velocity

In-beam measurementsSignal shapes

Under analysis


Detector Module Design

Design Choices

• 4 crystals per cryostat

• Warm FETs

Reasons Simpler geometry – 2 types of crystal, one cryostat Easier FET replacement – 1 day vs. 9 days Higher availability – near 100% vs. 85% Lower price – $400k cost difference, with one more crystal


Detector Geometry

• Packing scheme: 12 pentagons, 120 hexagons • Pentagon size: = 5.2%, fit a OD = 1.7” tube• Ge crystals: = 81.1%• Target-to-crystal distance: r = 185 mm

E = 1.3 MeV

46.4

46.8

47.2

47.6

48

48.4

15 17 19 21radius [cm]

Eff

i [%

]

33.5

33.9

34.3

34.7

35.1

35.5

35.9

36.3

36.7

37.1

37.5

14.5

14.9

15.3

15.7

16.1

16.5

16.9

17.3

17.7

18.1

18.5

Theta B

Th

eta

A

Sol id Angle

0.808-0.81

0.806-0.808

0.804-0.806

0.802-0.804

Packing scheme Optimization of shapes Optimization of distance

Geant4 program from Dino Bazzacco and Enrico Farnea


Crystal Shapes

Crystal A Corner angle Taper angle

124.84 9.70 117.71 9.64 117.45 9.33 115.18 9.86 119.98 9.70 124.84 9.59

Crystal B Corner angle Taper angle

118.29 9.72 121.46 9.64 119.41 9.86 123.51 10.15 118.94 10.15 118.39 9.34


Data Acquisition System

Signal digitizer Trigger/timing system Network switch Processing farm Data storage

Signal digitizer prototype

• 100 MHz, 12 bit• Energy

– trapezoidal filter– P/Z correction

• Leading edge time• Constant fraction time• Pulse shape

Data Acquisition System Schematic

Aux. Det. Trigger

Global TriggerModule

SignalDigitizers

Local TriggerModule

NetworkSwitch

Processing Farm

30 Crystals

Data Storage

2.2 MB/s

Aux. Det. Data

66 MB/s

75 dual Processors

Workstations, Servers

6.9 MB/s

2.3 MB/s + Aux. Det. Data


Electronics

• Produced twenty units of the 2nd version of the signal digitizer. Fifteen are in use.

• Added P/Z cancellation algorithm to FPGA.

• Studied the performance of Ge detector preamplifier

• Tested Ge signal cables and connectors

• Completed draft of requirement document

Before P/Z After P/Z


Detector Testing System

Use 15 prototype DSP boards in VME crate to acquire data from all 111 channels of prototype detector

Acquisition rate > 8 Mbytes/sec

Data stored to a redundant disk array (2 Tbytes) over Gigabit network

Three data processing computers

Online histogramming during in-beam test

Offline analysis programs

Setup for detector testing


Computing Requirements

Assumptions– Movable among labs, expandable to more detectors

Performance Requirements– Process 20,000 gamma/sec, store 10 Mbytes/sec

Data Processing Components– Readout, event building, signal decomposition, tracking

Services– Controls, configuration management, online

monitoring, data archiving


Pulse Shapes with n-damage

Pulse shapes from an undamaged detector (solid) and a neutron damaged detector after 1010 n/cm2 (dashed)

Neutrons cause:1) Reduction of

charge collection efficiency

2) Residual charge in neighboring segments


Neutron Damage effects

Degradation in E resolution

occurs for <100 cm, before

correction and for <30 cm, after

correction. But only for <17 cm position

resolution becomes worse than 1

mm.

A measurable effect of neutron

damage on position resolution is

never reached before annealing is

required for energy resolution!


Impurity Concentration

Impurity => Space Charge =>Electric Field => Drift velocity => Pulse shape

• Impurity concentration is not constant in the crystal.

From the manufacturer (z-variation) Vop = 5000 V

Crystal A: = (0.45 _ 1.5 ) x 1010 a/cm3 Vfd = 2500 V

Crystal B: = (0.76 _ 1.2 ) x 1010 a/cm3 Vfd = 2000 V

Crystal C: = (0.83 _ 1.8) x 1010 a/cm3 Vfd = 3750 V

• Impurity concentration from = 0 to = 1.4 x 1010 a/cm3.• Position resolution has been calculated.• The capability of reconstructing the interaction position is not affected, if the impurity concentration is known with accuracy of:

= 0.75 x 1010 atoms/cm3 => 1 mm


Improve Tracking Speed

Optimal permutation sequence– Track energy ordered

interactions (Learning mode)– Arrange permutation by success rate– Track with learned order of permutation (production mode)

0

10

20

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50

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70

0 200 400 600 800 1000

Energy Permutation

Even

ts

1.33 MeV, N=7

1.33 MeV, N = 7

7! = 5040

Permu. Event 3.4% 50% 5.0% 59% 7.0% 64% 8.4% 65%

0

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20

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0 100 200 300 400 500

Permutation

Eve

nts

SuccessOrdered

0

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0 100 200 300 400

Permutation

accu

mu

ltiv

e E

ven

ts

Success ordered

Random

1 2 3 5 6 7 4

1 2 3 7 5 6 4

1 2 3 5 7 6 4

1 3 2 5 6 7 4

1 2 3 6 5 7 4

1 2 4 5 7 6 3

1 2 6 5 7 4 3

1 2 5 4 6 7 3

1 2 6 4 5 7 3

1 2 5 7 4 6 3


Plan for 2005

Receive CD2A/3A approval for detector Receive and approve drawings of the 4-crystal detector

module and award contract Complete design of the Mechanical Support Structure Complete design of the Liquid Nitrogen System Complete analysis of in-beam data of prototype III Finalize Electronics Requirement Document Finish electronics R&D – preamp, trigger etc. Finalize Computing System Requirement Document Continue signal decomposition and tracking algorithm

developments


Schedule (Fiscal Years)

WBS Task Name

1 GRETINA

1.1 Mechanical

1.1.2 Design

1.1.3 Production

1.2 Detector Module

1.2.1 Purchasing

1.2.2 Test/Characterize Module 1

1.2.3 Test/Characterize Rest of Modules

1.3 Electronics

1.3.2 Prototype

1.3.3 Production

1.4 Computing Systems

1.4.2 Prototype

1.4.3 Production

1.5 System Assembly

1.5.1 Prototype

1.5.2 Production

1.6 Project Management

1.7 Environment and Safety

1.12 Level 1 Milestones: Critical Decisions CD1 CD2/3A CD2/3B CD4

Complete test proc. and apparatus Complete test/charac. module

1

Award module contract Exercise option last module

Complete design/draw. support structure

Complete mechanical subsystem

Complete test DSP module

Start production DSP module

Award computer farm contract

Ready for prototype assembly

Ready for final assembly

CD0

3 4 1 2 3 4 1 2 3 4 1 2 3 4 1 2 3 4 1 2 3 4 1 2 3 4 1 2 3 4 1 2 3 42003 2004 2005 2006 2007 2008 2009 2010 2011


GRETINA Cost (Jan. 04)

Item Cost (M$)

• Mechanical 0.91 • Detector 6.95 • Electronics 1.52• Computer 1.15• Assembly 0.18 • Management 2.22• Safety 0.12

Sub total 13.05Contingency 2.85

(22%)Escalation 1.10

Total (TEC) 17.0

Includes overheadDoes not include R&D and scientific efforts

Gretina - MIE Labor & Matl Costs by Year

0

500

1000

1500

2000

2500

3000

3500

4000

4500

5000

$k

Matl

Labor

Matl 280 1669 1717 2996 3272 939 7

Labor 720 831 1283 904 1128 1061 193

FY04 FY05 FY06 FY07 FY08 FY09 FY10


Management Structure


Collaborating Institutions

• Argonne National Laboratory– Trigger system– Calibration and online monitoring software

• Michigan State University– Detector testing

• Oak Ridge National Laboratory– Liquid nitrogen supply system– Data processing software

• Washington University– Target chamber

Role defined by MOU’s


Management Advisory Committee

• Don Geesaman, Argonne National Laboratory

• Konrad Gelbke, Michigan State University

• James Symons, (Chair) Lawrence Berkeley National Laboratory

• Glenn Young, Oak Ridge National Laboratory


Gretina Advisory Committee

• Con Beausang, Yale University• Doug Cline, University of Rochester• Thomas Glasmacher, Michigan State University• C. Kim Lister, Argonne National Laboratory• Augusto Macchiavelli, Lawrence Berkeley Laboratory• David Radford(Chair), Oak Ridge National Laboratory• Mark Riley, Florida State University• Demetrios Sarantites, Washington University• Kai Vetter, Lawrence Livermore National Laboratory


Working Groups

• Physics M. A. Riley

• Detector A. O. Macchiavelli

• Electronics D. C. Radford

• Software M. Cromaz

• Auxiliary Detectors D. G. Sarantites

ANL, LANL, LBNL, LLNL, NRL, ORNL, FSU, Georgia Tech, MSU, Miss. SU, Purdue, U. Mass. Lowell, Rochester, Notre Dame, Vanderbilt, Wash. U., Yale

ANU, CEA Saclay, Cologne, Daresbury, CNEA-UNSAM, CSNSM, Guelph,IFIC Valencia, INFN Podava, INFN Milano, Jyväskylä, Keele, KTH RIT, Liverpool, Lund, Manchester, Paisley, S. Paulo, Surry, TRIUMF, Tsinghua, TU Munich, Toronto, York, Uppsala, Warsaw


Working Group Meetings

• Detector– March 19-20, 2004, ORNL

• Software – June 22-23, 2004, LBNL

• Electronics– July 24-25, 2004, ANL


Summary

• Received CD1 – Started design phase

• No technical show stoppers

• Project on schedule and within cost so far

• Construction starts in 2007

• Completion in 2010


Summary

• Collaboration with AGATA has benefited GRETA/GRETINA

• We would like to continue and expand the collaboration

• Software working group meeting on signal decomposition ~ May 2005

• Postdoc position available at Berkeley

overview of gretina status

Documents

beam measurements

mevfastbeam spectroscopy

detector installationmovable

detector alignmenttool

agata weekprototype

chaos efficiency high

excitation energy

exotic nrich nuclei