1. The PANDA Detector at FAIR
Lars Schmitt, GSI Darmstadt
VCI '07, Vienna, February 22nd 2007
The Facility
PANDA Physics
Spectrometer Overview
Tracking in PANDA
Particle Identification
Calorimetry in PANDA
Conclusion & Outlook

2. Facilitiy for Antiproton and Ion Research
GSI, Darmstadt
German National Lab for Heavy Ion Research
Highlights:
- Heavy ion physics
- Nuclear physics
- Atomic and plasma physics
- Cancer research
FAIR: New facility
RIB
Heavy ions
higher intensities & energies
Antiprotons
The Facility
L. Schmitt, VCI '07

3. Storage and Cooler Rings Key Technical Features
Layout of FAIR
Primary Beams
238U28+ : AGeV;
238U92+: 1010/s @ up to 35 AGeV
Protons : 2 30 GeV;
up to 90 GeV
times present intensity
SIS 100/300
SIS
UNILAC
FRS
Secondary Beams
Broad range of radioactive beams
up to AGeV
intensity up to x over present
Antiprotons GeV
ESR
HESR
Existing
New
Super
FRS
Storage and Cooler Rings
Radioactive beams
e-– A (or Antiproton-A) collider
1011 stored and cooled antiprotons GeV/c
Future: Polarized antiprotons (?) CR
RESR
FLAIR
NESR
Cooled beams
Rapidly cycling superconducting magnets
Parallel Operation
Key Technical Features
The Facility
L. Schmitt, VCI '07

4. HESR – Storage Ring for Antiprotons
Injection of p at 3.7 GeV
Slow synchrotron ( GeV/c)
Storage ring for internal target operation
Luminosity up to L~ 2x1032 cm-2s-1
Beam cooling (stochastic & electron)
ECM
Resonance Scan
PANDA
The Facility
L. Schmitt, VCI '07

5. Stronq coupling constant vs R
PANDA Physics
Structure & Dynamics of Hadrons in the transition regime of QCD
Why don’t we observe free quarks?
Charmonium spectroscopy
→ Quark confinement
How are color neutral states formed?
Hadrons (qqq or qq)
Gluonic excitations
Multi-quark systems
→ QCD predictions
How do hadrons obtain mass?
p-A interactions
Meson properties in nuclear medium
→ Restoration of chiral symmetry
What is the structure of the nucleon?
Hard scattering processes & soft fragmentation
→ From partons to hadrons
Stronq coupling constant vs R
perturbative
strong
QCD
PANDA Physics

6. Hadron Spectroscopy Spectroscopy with antiprotons χc1
pp machine allows ΔE ~ 100 keV vs.
ΔE ~ 10 MeV in e+e−
obtain m and Γ with high precision
e+e− directly produces only JPC = 1−− (γ)
pp accesses all states
Charm spectroscopy
Charmonium: Positronium of QCD
Charm hybrids
c-states narrow, understood
Little interference between ccg and
cc-states
Mass 4–4.5 GeV, c c g narrow,
~ σ( p p → c c)
Charm meson spectroscopy
3500
3520 MeV
3510
Crystal Ball ev./2 MeV
100
ECM
CBall
E835
χc1
1000
E 835 ev./pb
PANDA Physics

7. Nuclear Physics in PANDA
Charm in the Medium
Mesons in nuclear matter
Masses change in nuclei
D-mass lower
Enhanced charmonium states due to lower D D threshold
J/ψ absorption in nuclei
Hypernuclei
3rd dimension in nuclear chart
Study interactions of nucleons in the nuclear potential
PANDA: Double Hypernuclei
Production via Ξ- capture
Λ Λ interaction in nucleus
PANDA Physics

8. Electromagnetic Processes
Electromagnetic formfactors
Discrepancy between timelike and spacelike region
Measure pp→e+e-
Generalized Parton Distributions
Wide angle Compton scattering
Hard exclusive meson production
Transverse nucleon spin
Drell Yan Process
(full PWA or polarized beam/target) p p
Vector
meson
GPDs
GPDs p p p
e,µ p
e,µ
PANDA Physics

9. Detector Requirements
Physics benchmarks:
Hybrid charmonium e.g. 7 photons, PWA
Charmonium decays e.g. J/Ψ→ e+e- and µ+µ-, or with π0 & γ
Charm mesons Weak decays in K0S and K±
Hypernuclei Hyperon cascades
Wide angle Compton scattering High energy photons
Proton formfactors Efficient e± identification
Detector requirements:
nearly 4 solid angle for PWA
high rate capability: 2x107 s-1 interactions
efficient event selection
momentum resolution ~1%
vertex info for D, K0S,  (c = 317 m for D±)
good PID (, e, , , K, p)
photon detection 1 MeV – 10 GeV
Spectrometer Overview

10. PANDA Spectrometer
Spectrometer Overview

11. PANDA Spectrometer Pellet or cluster jet target
Dipole magnet for forward tracks
Solenoid magnet for high p t tracks:
Superconducting coil & iron return yoke
Spectrometer Overview

12. Forward Drift Chambers
PANDA Spectrometer
Silicon Microvertex
Central Tracker
Forward Drift Chambers
Spectrometer Overview

13. PANDA Spectrometer Muon Detectors Forward RICH Barrel DIRC Barrel TOF
Endcap DIRC
Forward TOF
Spectrometer Overview

14. PANDA Spectrometer PWO Calorimeters Forward Shashlyk EMC
Hadron Calorimeter
Spectrometer Overview

15. Data Acquisition and Trigger
Self-triggering readout
Components
Time distribution system
Intelligent frontends
Powerful compute nodes
Configurable high speed network
Data Flow
Data reduction
First selection at high rate
Further selections at lower rates, but with more detectors
Data logging after online reconstruction
Programmable Physics Machine
Spectrometer Overview

16. Silicon Micro Vertex Detector
Layout of MVD
General structure:
4 Barrels & 6 disks
Inner layers pixels
Outer layers strips
(forward mixed)
Pixel part:
Hybrid pixels 100 x100 µm2
140 modules
13 M channels
0.15 m2
Strip part:
Double sided silicon
400 modules
70k channels
0.5 m2
Beam pipe
Barrels
Target pipe
Disks
Tracking in PANDA

17. Silicon Micro Vertex Detector
Readout of MVD
Self-triggering electronics
Pixel readout:
Custom pixel chip TOPIX:
ASIC in 0.13µm CMOS
First prototype:
Preamp & discriminator
Analog output
Microstrip readout:
128-channel ASIC for strips
Prototype n-XYTER chip for DETNI
Fast timing shaper/amplifier with comparator
Slow channel for analog r/o with peak detector
Token ring readout of hit channels
Next iteration with lower power consumption
Tracking in PANDA

18. Central Tracker – STT Option
5340 straws in layers
Al-mylar film tube: 10.0  0.03  1500 mm (ØdL)
rin/rout: 160 / 420 mm, V = 610 l
Self-supporting straw layers at
~1 bar overpressure (Ar/CO2)
Straw pitch: 10 mm
15 kg straw weight
Axial layers:
r ~ 150µm, A   ~ 98%
Skewed layers:
z ~ 2.9 mm, A   ~ 90-95%
Radiation length:
X/X0 ~ %
pt / pt ~ 1.2 %
Tracking in PANDA

19. Central Tracker – STT Option
5340 straws in layers
Al-mylar film tube: 10.0  0.03  1500 mm (ØdL)
rin/rout: 160 / 420 mm, V = 610 l
Self-supporting straw layers at
~1 bar overpressure (Ar/CO2)
Straw pitch: 10 mm
15 kg straw weight
Axial layers:
r ~ 150µm, A   ~ 98%
Skewed layers:
z ~ 2.9 mm, A   ~ 90-95%
Radiation length:
X/X0 ~ %
pt / pt ~ 1.2 %
Tracking in PANDA

20. Central Tracker – STT Option
5340 straws in layers
Al-mylar film tube: 10.0  0.03  1500 mm (ØdL)
rin/rout: 160 / 420 mm, V = 610 l
Self-supporting straw layers at
~1 bar overpressure (Ar/CO2)
Straw pitch: 10 mm
15 kg straw weight
Axial layers:
r ~ 150µm, A   ~ 98%
Skewed layers:
z ~ 2.9 mm, A   ~ 90-95%
Radiation length:
X/X0 ~ %
pt / pt ~ 1.2 %
Tracking in PANDA

21. Central Tracker – TPC Option
General layout: GEM-TPC
2 half cylinders
Drift field E || B
Gas: Ne/CO2 (+CH4/CF4)
Multi-GEM stack for amplification
and ion backflow suppression
100 k pads of 2 x 2 mm2
50-70 µs drift, 500 events overlap
Simulations:
p/p ~ 1%
dE/dx resolution ~ 6%
Challenges:
space charge build-up
continuous sampling
Tracking in PANDA

22. Central Tracker – TPC Option
General layout: GEM-TPC
2 half cylinders
Drift field E || B
Gas: Ne/CO2 (+CH4/CF4)
Multi-GEM stack for amplification
and ion backflow suppression
100 k pads of 2 x 2 mm2
50-70 µs drift, 500 events overlap
Simulations:
p/p ~ 1%
dE/dx resolution ~ 6%
Challenges:
space charge build-up
continuous sampling
Tracking in PANDA

23. Particle Identification
PANDA PID Requirements:
Particle identification essential for PANDA
Momentum range 200 MeV/c – 10 GeV/c
Different process for PID needed
PID Processes:
Cherenkov radiation: above 1 GeV
Radiators: quartz, aerogel, C4F10
Energy loss: below 1 GeV
Best accuracy with TPC
Time of flight
Problem: no start detector
Electromagnetic showers: EMC for e and γ
dE/dX by TPC
Forward ToF
More details on PID in PANDA: see Poster B41 by Björn Seitz in Session B
Particle Identification

24. DIRC Concept Detection of Internally Reflected Cherenkov light
Different Cherenkov angles give different reflection angles
PANDA DIRC similar to BaBar
96 Fused silica bars, 2.6m length
Water tank & 7000 PMTs
Alternative readout: (x,y,t), mirrors
Schwiening
Schwiening
Particle Identification

25. PANDA Endcap DIRC Setup of Endcap Cherenkov DIRC principle
Disc shaped fused silica radiator
2.1 m diameter
Measure coordinate and time
Dispersion correction through dichroic filters or second coordinate
Sato
Particle Identification

26. Electromagnetic Calorimeters
Backward Endcap
800 Crystals
Worse resolution due to
service lines of trackers
Needed for hermeticity
Barrel Calorimeter
11000 PWO Crystals
LA APD readout
σ(E)/E~1.5%/√E + const.
Forward Endcap
4000 PWO crystals
High occupancy in center
Readout LA APD or
vacuum triodes
Forward Shashlyk
(after dipole magnet)
350 channels
Readout via PMTs
σ(E)/E~4%/√E + const.
Alternative Designs:
Spiral Shashlyk
Segmented composite
Shashlyk-Sandwich for
for (e/h/µ)
Calorimetry in PANDA

27. PANDA PWO Design Benefits of PWO Challenges
High density → compact detector
Hermetic coverage and fine granularity
Fast scintillator
Good resolution
Challenges
Radiation damage of crystals
Temperature stabilization to 0.1oC
In PANDA: Low energy photons (few MeV)
Increase PWO light yield
Operation at -25oC
Higher output crystals PWO-II from BCTP
Large area APDs
Crystal Design
Tapered PWO crystals
Length 200mm, front face 20x20 mm2
Offers from Bogoroditsk, Shanghai, Apatiti
Carbon fibre alveoles as housing
Calorimetry in PANDA

28. Conclusion & Outlook will be a versatile QCD experiment:
Large acceptance and double spectrometer
Tracking and vertexing capabilities
Particle identification and calorimetry
Flexible data acquisition & trigger
Novel techniques in detector and readout design
Technical Design until 2009
Commissioning in 2014

29. The PANDA Collaboration
More than 350 physicists from 48 institutions in 15 countries
U Basel
IHEP Beijing
U Bochum
U Bonn
U & INFN Brescia
U & INFN Catania
U Cracow
GSI Darmstadt
TU Dresden
JINR Dubna
(LIT,LPP,VBLHE)
U Edinburgh
U Erlangen
NWU Evanston
U & INFN Ferrara
U Frankfurt
LNF-INFN Frascati
U & INFN Genova
U Glasgow
U Gießen
KVI Groningen
U Helsinki
IKP Jülich I + II
U Katowice
IMP Lanzhou
U Mainz
U & Politecnico & INFN
Milano
U Minsk
TU München
U Münster
BINP Novosibirsk
LAL Orsay
U Pavia
IHEP Protvino
PNPI Gatchina
U of Silesia
U Stockholm
KTH Stockholm
U & INFN Torino
Politechnico di Torino
U Oriente, Torino
U & INFN Trieste
U Tübingen
U & TSL Uppsala
U Valencia
SMI Vienna
SINS Warsaw
U Warsaw