A Fast and Compact Electromagnetic Calorimeter for the Detector at GSI Bernd Lewandowski Ruhr-Universität Bochum SCINT 2003 Valencia 11. 9. 2003

A Fast and Compact Electromagnetic Calorimeter for the

Detector at GSI

Bernd LewandowskiBernd LewandowskiRuhr-Universität BochumRuhr-Universität Bochum

SCINT 2003SCINT 2003ValenciaValencia

11. 9. 200311. 9. 2003

11. 9. 200311. 9. 2003 Bernd Lewandowski - Ruhr-Universität Bochum - SCINT 2003Bernd Lewandowski - Ruhr-Universität Bochum - SCINT 2003 22

WhatWhat isis PANDA? PANDA?

AntiProtonANnihilations

at DArmstadt


Where is Darmstadt?Where is Darmstadt?

GSI


The GSI Future FacilityThe GSI Future Facility

Panda

Existing GSI Facilities


Antiproton Physics ProgramAntiproton Physics Program

Charmonium (cc ) spectroscopy: precision measurements of mass, width, decay branches of all charmonium states, especially for extracting information on qq models of mesons.




Search for gluonic excitations (charmed hybrids, glueballs) in the charmonium mass range (3 – 5 GeV/c2).





Search for modifications of meson properties in the nuclear medium,and their possible relationship to the partial restoration of chiral symmetry for light quarks.

pionic atoms

KAOS/FOPI

HESR

π

K

D

vacuum nuclear mediumρρ

π+

π-

K-

K+

D+

D-

25 MeV

100 MeV

50 MeV





Search for modifications of meson properties in the nuclear medium,and their possible relationship to the partial restoration of chiral symmetry for light quarks.

D

50 MeVD

D+

vacuumvacuumnuclear mediumnuclear medium

π

K

25 MeV

100 MeV

K+

K

π

π

Precision -ray spectroscopy of single and double hypernuclei for Extracting information on their structure and on the hyperon-nucleon and hyperon-hyperon interaction.


-3 GeV/c

KKTrigger

_

secondary target

p

-(dss) p(uud) → (uds) (uds)


The Antiproton FacilityThe Antiproton Facility


The Antiproton FacilityThe Antiproton Facility

• Antiproton production similar to CERN, • HESR = High Energy Storage Ring

– Production rate 107/sec

– Pbeam = 1.5 - 15 GeV/c

– Nstored = 5 x 1010 p

• Gas-Jet (or Cluster) Target• High luminosity mode

– Luminosity = 2 x 1032 cm-2s-1

p/p ~ 10-4 (stochastic cooling)

• High resolution mode p/p ~ 10-5 (electron cooling < 8 GeV/c)– Luminosity = 1031 cm-2s-1


Proposed Detector (Overview)Proposed Detector (Overview)

• High Rates– Total ~ 55 mb– 107 interactions/s

• Vertexing– (p,KS,,…)

• Charged particle ID– (e±,±,π±,p,…)

• Magnetic tracking• Elm. Calorimetry

– (,π0,)• Forward capabilities

– (leading particles)• Sophisticated Trigger(s)


Electromagnetic CalorimeterElectromagnetic Calorimeter

Detector material PbWO4

Photo sensors Avalanche Photo Diodes

Crystal size 35 x 35 x 150 mm3 (i.e 1.5 x 1.5 RM2 x 17 X0)

Energy resolution 1.54 % / E[GeV] + 0.3 % (PMT)

Time resolution 130 ps (PMT)

Total number of crystals 7150


Requirements for the EMCRequirements for the EMC

• Nearly 4π solid angle (PWA)

• High rate capability: 107 interactions/s

• High resolution: 1.54 % / E[GeV] + 0.3 %

• Compact design: inside Solenoid

• Operation in magnetic field: 2T


Lessons from LEAR (CB)Lessons from LEAR (CB)

• Final states with 10+ photons

• Merged π0 are easy to handle– “moderate” angular resolution sufficient

• Low thresholds– Emin≤20 MeV

Crystal BarrelCrystal Barrel


Property CsI(Tl) CeF3 PbWO4 BGO

Density [g/cm3] 4.53 6.16 8.28 7.13

Rad. length [cm] 1.85 1.68 0.89 1.12

Molière rad [cm] 3.8 2.63 2.19 2.33

dE/dx [MeV/cm] 5.6 7.9 13.0 9.2

Decay time [ns] 1000 10-30 5-15 60-300

Max. emission [nm]

565 310-340 420-440 480

Rel. lightyield 0.40 0.10 0.01 0.15

Available Inorganic ScintillatorsAvailable Inorganic Scintillators


PWOPWO

• Fast Scintillator

• Allows a very compact design

• Low cost material

• But: light yield too low for detection

of low energy photons

• Improvement of light yield• Cooling (LY changes with temperature)


PWO ImprovementPWO Improvement

photon response: E = 45 -770 MeV@MAMI

0 50 100 150 2000

500

1000

1500

2000

co

un

ts [

a.u

.]

energy [a.u.]

E=45.4 MeV

0 50 100 150 200 250 300 350 400 4500

200

400

600

800

1000

cou

nts

[a.u

.]

energy [a.u.]

E=105.6 MeV

/E=5.3%/E=7.4%cou

nts

energy / a.u.

PMTreadout

further significant increase of light output achievable by:

• improvement of growing technology PWO II(exploiting large experience with CMS/ECAL production)

• optimum co-doping

1 410 90

. %. %

E E[GeV]

ps130~t

CMS/ECAL

R. Novotny et al.,II. Phys. Inst. GI

Bogoroditsk TCP


PWO ImprovementPWO Improvement

M.Korzhik et al., RINC, MinskA.Hofstaetter et al., I. Phys. Inst. GI

crystal imperfections:

• cation vacancies (Pb)• anion vacancies (O)• insite oxygen• excess of doping ions

results based on EPR:• Frenkel defects reduced ( factor >3)• Pt identified - impact on quenching?• oxygen based defects reduced

• Frenkel defects reduced ( factor >3)• Pt identified - impact on quenching?• oxygen based defects reduced

0

500

1000

1500

2000

0 100 200 300 400 500 600

channel

coun

ts

Cs-137662 keV

0

500

1000

1500

2000

0 100 200 300 400 500 600

channel

coun

ts

Cs-137662 keV 137Cs: L.Y.: 43 phe/MeV

„2 times CMS-standard“@ T = 20°C


PWO light yeild

0

10

20

30

40

50

60

70

80

90

-7 -6 -5 -4 -3 -2 -1 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15

T, Celsium degree

LY,

ph

e/M

eV

PWO light yeild

0

10

20

30

40

50

60

70

80

90

-7 -6 -5 -4 -3 -2 -1 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15

T, Celsium degree

LY,

ph

e/M

eV

PWO CoolingPWO Cooling

line shape: @T=200C1= 6.5ns (97%)2=30.4ns ( 3%)

PWO

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1

0 20 40 60 80 100 120 140 160 180 200

Time, ns

Lig

ht

frac

tio

n,

arb

. u

nit

s

T= -6C

T= -2C

T= 9C

T= 14C

PWO

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1

0 20 40 60 80 100 120 140 160 180 200

Time, ns

Lig

ht

frac

tio

n,

arb

. u

nit

s

T= -6C

T= -2C

T= 9C

T= 14C

fraction of light yield collected in different integration gates at various temperatures

change of light yield collectedwithin 100ns as a function oftemperature

R. Novotny et al.,II. Phys. Inst. GI


PWO FuturePWO Future

Ongoing developements in PWO productionwill increase the light yield. Light yield improvement of PWO scintillation crystals for the

PANDA detectorA. Borisevich, V. Dormenev, A. Hofstaetter, V. Ligoun,M. Kozhik, B. K. Meyer, R. Novotny

Combined with cooling andmaximum coverage of readout side by

photosensor can make PWOthe scintillator of choice for the PANDA EMC.


PhotosensorPhotosensor

5 mmAPD Hamamatsu S8664-55• „Photodiode with internal amplification“• operates in B-Field• High quantum efficiency• Active area 5x5mm2

• Large experience with CMS/ECAL Extremely reliable and robust• but: gain, dark current are temp. dependend T < 1°C

Others to be investigated:• Large Area APDs of other manufacturers• Channel Plate Multipliers• Vacuum Triodes, …


APD readout: CsI(Tl)APD readout: CsI(Tl)

137Cs @ T = 0 °C

ADC channel

Ent

ries

662 keV

ADC channel

662 keV

E Ε 16% E Ε 29%

Ent

ries

50 mm60

mm

50 mm

60 m

m

APD (Hamamatsu) readoutactive area: (5 x 5) mm2

PMT ( R1635 ) readoutactive area: Ø 10 mm


APD Quantum EfficiencyAPD Quantum Efficiency

CeF3

BGO

PWO

CsI(Tl)



Density [g/cm3] 4.53 6.16 8.28 7.13

Rad. length [cm] 1.85 1.68 0.89 1.12

Molière rad [cm] 3.8 2.63 2.19 2.33

dE/dx [MeV/cm] 5.6 7.9 13.0 9.2

Decay time [ns] 1000 10-30 5-15 60-300

Max. emission [nm]

565 310-340 420-440 480

Rel. lightyield 0.40 0.10 0.01 0.15

Available Inorganic ScintillatorsAvailable Inorganic Scintillators


Density [g/cm3] 4.53 6.16 8.28 7.13

Rad. length [cm] 1.85 1.68 0.89 1.12

Molière rad [cm] 3.8 2.63 2.19 2.33

dE/dx [MeV/cm] 5.6 7.9 13.0 9.2

Decay time [ns] 1000 10-30 5-15 60-300

Max. emission [nm]

565 310-340 420-440 480

Rel. lightyield 0.40 0.10 0.01 0.15


Density [g/cm3] 4.53 6.16 8.28 7.13

Rad. length [cm] 1.85 1.68 0.89 1.12

Molière rad [cm] 3.8 2.63 2.19 2.33

dE/dx [MeV/cm] 5.6 7.9 13.0 9.2

Decay time [ns] 1000 10-30 5-15 60-300

Max. emission [nm]

565 310-340 420-440 480

Rel. lightyield 0.40 0.10 0.01 0.15

We‘ll come back to this in a minute.


BGOBGO

First tests with

L3 crystals:

APD readout

Temp controlled environmentT=1°Ccontrolled humidity 30% rel.


APD readout: BGOAPD readout: BGO

14%1275keV)ΕE (

APD

ADC channel

22Na511 keV

1275 keV

22.5%1275keV)ΕE (

ADC channel

22Na

511 keV

1275 keV

PMT R1635

25%511keV)ΕE (

25 mm

25 m

m

25 mm

25 m

mEnt

ries

Ent

ries

T=0°C


BGO time resolutionBGO time resolution

PANDA:• 107 events/s 10 ns time resolution• MC: max. single crystal rate: ~200·103/s

BGO timing test:• L3 BGO crystal• Hamamatsu APD• BABAR preamp (250 ns shaping)• Digital Scope• Record a sample of cosmics signals (~15 MeV)

Make a simple MC test


point of time measurement

Linear fit


BGO

Landau fit + DC offset• Use Landau func. to simulate pulses

• Typical: N/S=0.5%

Vary S/N and FADC sampling freq.

• Linear fit of rising edge• Determine time when fit reaches half the signal amplitude



σt [ns]ΔTSamples [ns]N/S [%]σv [V]

4.6501.00.02

9.7502.00.03

2.51000.50.01

5.51001.00.02

10.21002.00.03

41.9505.00.04

2.4500.50.01

46.52005.00.04

12.32002.00.03

6.22001.00.02

2.82000.50.01

39.81005.00.04

5 samples on rising edge

3 sampleson rising edge

10 sampleson rising edge

}}}


BGOBGO

• BGO has sufficient light yield

• Timing can be handled by adequate electronics

We will perform furtherinvestigations with BGO

as an option for the Panda Emc


Summary & OutlookSummary & OutlookR&D tasksR&D tasks

• Improvement of PWO light yieldImprovement of PWO light yield• Detailed time resolution studies for BGODetailed time resolution studies for BGO• Tests of APD readoutTests of APD readout

and radiation damageand radiation damage– Planned this year: Planned this year:

testbeam @ KVI, MAMItestbeam @ KVI, MAMI

• Development of largeDevelopment of large

area APDs (100mmarea APDs (100mm22))

by Hamatsuby Hamatsu• Tests of otherTests of other

PhotosensorsPhotosensors


Panda CollaborationPanda Collaboration

At present a group of 150 physicists

from 40 institutions of 9 Countries.

Bochum, Bonn, Catania, Cracow, Dresden, Dubna I + II, Edinburg, Erlangen, Ferrara, Frascati, Genova, Giessen, Glasgow, KVI

Groningen, FZ Jülich I + II, Los Alamos, Mainz, Milano, TU München, Münster, Northwestern,

BINP Novosibirsk, Pavia, Silesia, Stockolm, Torino I + II, Torino Politecnico,Trieste, TSL

Uppsala, Tübingen, Uppsala, SINS Warsaw, AAS Wien

Bochum, Bonn, Catania, Cracow, Dresden, Dubna I + II, Edinburg, Erlangen, Ferrara, Frascati, Genova, Giessen, Glasgow, KVI

Groningen, FZ Jülich I + II, Los Alamos, Mainz, Milano, TU München, Münster, Northwestern,

BINP Novosibirsk, Pavia, Silesia, Stockolm, Torino I + II, Torino Politecnico,Trieste, TSL

Uppsala, Tübingen, Uppsala, SINS Warsaw, AAS Wien

http://www.gsi.de/hesr/panda

Spokesperson: Ulrich Wiedner - UppsalaDeputy: Paola Gianotti - LNF

Austria - Germany – Italy – Netherlands – Poland – Russia – Sweden – U.K. – U.S.


Appendix


TargetTarget

An internal cluster-jet/pellet target is under study: 1016 atoms/cm2 for D=20-40 m

Pellet target layoutPellet target layout

Cluster-jet target layoutCluster-jet target layout


Vertexing: Micro Vertex DetectorVertexing: Micro Vertex Detector

7.2 mio. barrel pixels50 x 300 μm

2 mio. forward pixels100 x 150 μm

beam pipepelle

t/cl

ust

er

pip

e

Readout: ASICs (ATLAS/CMS) 0.37% X0

or pixel one side – readout other side (TESLA)


Tracking: Straw Tube TrackerTracking: Straw Tube Tracker

Number of double layersSkew angle of dbl layers 1 and 15 Skew angle of dbl layers 2-14

150o

2o-3o

Straw tube wall thicknessWire thicknessGas

LengthDiameter of tubes in double layers 1-5, 6-10, and 11-15Number of straw tubes

26 mm20 mm90%He10%C4H10 150 cm4 mm6 mm8 mm8734

Transverse resolution sx,y

Longitudinal resolution sz

150 mm 1 mm


Tracking: Forward MDCTracking: Forward MDC

• 6 layers of sense wires in• 3 double layers (y,u,v)• not stretched radially

(mass)• realized at HADES

– high counting rates – position resolution 70μm

HADES@GSI


PID: DIRC (Cherenkov)PID: DIRC (Cherenkov)

less space than aero gel costs of calorimeterno problems with field

BaBar@SLAC


PID: Forward RICHPID: Forward RICH

Aerogel n=1.02

Multi pad gasDetector

Mismatch photons CsI photon conversion

LHCbLHCb

proximity focusing mirrors


APD Hamamatsu S8664-55APD Hamamatsu S8664-55

5 mm


CeFCeF33

0 200 400 600 800 10000

500

1000

1500

2000

2500

3000

3500E = 55 M eV

7 6 9 M eV

480 M eV

227 M eV

G E A N TG E A N T

ex p er im en tex p er im en t

en e rg y / M eV

coun

ts/a

.u.

0 200 400 600 800 10000

500

1000

1500

2000

2500

3000

3500E = 55 M eV

7 6 9 M eV

480 M eV

227 M eV

G E A N TG E A N T

ex p er im en tex p er im en t

en e rg y / M eV

coun

ts/a

.u. %70.2

]GeV[E

%17.2

E

limited resolution for photons due to:

• imperfection of crystals• insufficient size

in spite of high luminescence yield

85 MeV p + C @ KVI

proton energy / MeV

cou

nts

10 20 30 40 50 60 70 80 90 1000

50

100

150

200

10 20 30 40 50 60 70 80 90 1000

400

800

1200

10 20 30 40 50 60 70 80 90 1000

50

100

150

10 20 30 40 50 60 70 80 90 1000

40

80

2 x 2 x 15 cm3

2 x 2 x 14 cm3

1.5 x 1.5 x 1.5 cm3

CeF3

TAPS geometry 25 cm

BaF2

PbWO4

PbWO4:Mo

high energy photon detectionlow energy proton detection

@MZ

good resolution for protons due to:

• high light output• localized energy deposition

general applicability proven !

R. Novotny et al., II. Phys. Inst. GIin collaboration with Korth-Kristalle GmbH


CeFCeF33

• CeF3 needs further R&D to improve resolution for photons

• Rel. long X0

compact design not possible (compared to PWO)

• Constraints from targetmay limit the available space for the EMC CeF3 is not an option for the barrel part


BGO: event ratesBGO: event rates

• Max. occupancy of one crystal due to bkgr simulations:

2% · 107 events/s = 2·105 s-1

• Use digital tail cancelation in the feature extraction

• conservative scaling of the rise time

– CsI: 100 ns / 940 ns– BGO: 12 ns / 200 ns

• Rate we can handle: ( 2·trise· 10 )-1 = 2.5·105 events/s


Why Antiprotons?Why Antiprotons?

•high resolution spectroscopy with p-beams in formation experiments: E Ebeam

•high yields in pp of gluonic excitations– glueballs, hybrids

•event tagging by pair wise associated production,– (particle, anti-particle) e.g. ppbar

•large √s at low momentum transfer– important for in-medium "implantation" of hadrons:– study of in-medium effects


TimelineTimeline

•since 1996 Discussion about GSI futureInternational workshops, reviews, accelerator R&D

•May 1999 Letter of Intend for an antiproton facility (40 authors) Studies for detector concept

•Jan. 2001 Detector simulation with GEANT4•Nov. 2001 Conceptual Design Report

of an „International Accelerator Facility forBeams of Ions and Antiprotons”

•Nov. 2001 Review by an international review committee of the „Deutscher Wissenschaftsrat“

•April 2002 International p-Workshop at GSI•July 2002 Positive Votum by the „Deutscher Wissenschaftsrat“•Feb. 5, 2003 Positive Decision by the „bmb+f”


Resonance ScanResonance Scan

ECM

Measured Rate

Beam Profile

Resonance Cross

Section

small and well controlled beam momentum spread

p/p is extremely important

Documents

A Fast and Compact Electromagnetic Calorimeter for the Detector at GSI Bernd Lewandowski Ruhr-Universität Bochum SCINT 2003 Valencia 11. 9. 2003