C. Schwarz Physics with Antiprotons - Detector - • Detector requirements • Overview of the detector concept • Detector components • Trigger • Costs
Jan 10, 2016
C. Schwarz
Physics with Antiprotons - Detector -
• Detector requirements
• Overview of the detector concept
• Detector components
• Trigger
• Costs
C. Schwarz
Detector requirements (simulations)
• Energy release of charmed hadrons high → large ptrans → large angles
• High cm-velocity (fixed target) → high energies → small angles
Formation of Ψ’ and decay in muons
Ψ’→μ+μ-
Ψ’→J/Ψ + X ↓ μ+μ-
electrons similar→ calorimeter for large angles.
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Detector requirements (PID)
• Forward angles need π/K separation up to 3 GeV/c: Cherenkov n=1.02
• Backward: higher value of n.
p+p → ΦΦ→ 4K s½ =3.6 GeV
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Overview of detector concept
internal target
forward spectrometertarget spectrometer
Heavy charmed mesons decay inlight products with large pt.Solenoid is important.
top view
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Overview of detector conceptside view
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C. Schwarz
Central tracking: Microvertex Detector 7.2 mio. barrel pixels
50 x 300 μm
2 mio. forward pixels100 x 150 μm
beam pipe
pelle
t pi
pe
Space resol.: σz=80μm, σ r-φ=15μmTrack resol. : σL=60-300 μm σT =12μm
Readout: ASICs (ATLAS/CMS) 0.37% X0
or pixel one side – readout other side (TESLA)
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Central tracking:
Straw tubesWASA@Celsius
15 skewed double layers to remove left-right ambiguity
Ø 4-8 mm
skew angle: 5-15o APUD@HESR
p+p → φ φ →K+ K- K+ K-
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Mini Drift Chambers• 6 layers of sense wires in 3 double
layers (y,u,v)
• not stretched radially (mass)
• realized at HADES• expected counting rates
• position resolution 70μm
HADES@GSI
APUD@HESR
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Particle identification• PID from
• 00<Θ<50 hadronic calorimeter
• 50<Θ<220 Aerogel Cherenkov Counters
• 220<Θ<1400 DIRC (BABAR@SLAC)
DIRC thickness: 0.19 X0
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Cherenkov opening angle: Internal reflection → different vel. thresholds
p + p → J/Ψ+φ @ 8.5AGeV/cε=80%
PID: DIRC
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Calorimeter
PbWO4
Length = 17 X0
APD readout (in field)σ(E) = 1.54% / E½ + 0.3%
pp J/Ψ + η γγ
140o
5o
22o
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e±/π± sep.
electron/pion separation 10-3
2 4 6 8 p (GeV/c)0
Ed
ep (
GeV
/c)
2
4
6
8
10
e+/-
π+
2 4 6 8 p (GeV/c)0
10-3
π+ probability
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Trigger• Front end and DAQ structure
• pipelining
• 3-level trigger
• Ex.: HADES/LHCb
• LVL-1: <106 events/s• J/ψ large pT (e, μ)
• neutral K, hyperons: multiplicity jump in MVD
• D-meson: vertex
• LVL-2: <104 events/s• Pattern recognition
• EMC: em. shower photon reconstruction
• Minv from EMC or muons
• LVL-3: <103 event/s• global kin. conditions
HADES@GSI
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Pellet target
• Frozen hydrogen pellets 20-40μm
• Δx=±1 mm (±0.04o)
• 60 m/s
• 70000 pellets/sec.
• 1014-1016 atoms/cm2 (avg.)
1 mm
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CostsSolenoid 2.5 M€
Calorimeter (target spectrometer) 12.5 M€
Tracking (pixel detector, straw tubes) 3.0 M€
Cherenkov 3.5 M€
Hypernuclei (read out electronics,micro tracker) 2.0 M€
Varia (e.g. refurbishing of forward detector parts) 1.9 M€
Trigger 1.5 M€
Infrastructure 2.0 M€
Contingency 2.0 M€
Sum 30.9 M€