The DIRC projects of thePANDA experiment at FAIR
Klaus Föhl on behalf of the
Cherenkov Group
Darmstadt Dubna Edinburgh Erlangen Ferrara Giessen Glasgow Krakow Wien
RICH2007Trieste, ItalyOctober 2007
Work supportedby EU FP6 grant
contract number 515837DIRACsecondary-Beams
Antiprotons
Nuclei Far From StabilityCompressed Nuclear MatterHigh Energy Density in Bulk
HESR Hadron spectroscopy - Charmonium spectroscopy - Gluonic excitations (hybrids, glueballs)
Charmed hadrons in nuclear matterDouble -Hypernuclei
A View of PANDAAntiProton ANnihilations at DArmstadt
p
TargetSpectrometer
ForwardSpectrometer
A View of PANDAAntiProton ANnihilations at DArmstadt
• High Rates– 2 107 interaction/s
• Vertexing– KS
0, Y, D, …
• Charged particle ID– e±, μ±, π±, K, p,…
• Magnetic tracking• EM. Calorimetry
– γ,π0,η• Forward capabilities
– leading particles• Sophisticated Triggers
Particle ID & Kinematicspp KK T=5,10,15 GeV/c
pp DD D K T=6.6 GeV/c
pp i.e. open charm production
K K K
K evenor K
--
--
+ ++ ++ +
+ ++ +
-
- +
+
distinguish and K (K and p) ...
D
PANDA Target Spectrometer
Endcap Barrel
Barrel
Target Spectrometer
two areas – two detector geometries
PANDA: 4 detector desire to keep EMC small hence we suggest DIRCs
FS
End
- c
ap
Acceptance forpp h @ 15 GeV
...shipping coal to Newcastle...
...talking about DIRC at RICH...
DIRC Principles
n=1.47
Kp
fused silica10mm 0.4eV
solid DIRC
=1
<1
K p
15 deg
lower p threshold
Time-of-Propagation for C
Detector of InternallyReflectedCherenkov light n
=1
<1
Barrel DIRC
2-dimensionalimaging type
2D + t or (2+1)D design
Barrel-DIRC
BaBar-like
Poster Carsten Schwarz: The Barrel DIRC of the PANDA experiment
“only” 7000 PMT(BaBar 11000 PMT)
kaon efficiency 98%Simulations pp →J/ψ Φ √s = 4.4 GeV/c2
π misidentificationas kaon 1-2%
PANDA barrel DIRCscaled BaBar version suits PANDA
• R&D towards smaller photon detector needs optical elements instead of pinhole focus
– mirrors– lenses
quartz bar
mirrors
focal planedetector two lenses for flat focal plane
SiO2
air
OilH2Oair
PANDA barrel DIRC
close to threshold:small variations in n(λ)cause large δΘ
cos(Θ)=1 / βn(λ)
Y
Time of Propagation (TOP) measurement better 0.5nsallows to correct dispersion for high and low momenta→x,y,t→3D-DIRC
β=0.69
β=0.72
fused silica
PANDA barrel DIRC
x
y
PANDA Target SpectrometerTwo different readout designs:
(1+1)D designEndcap Disc DIRC
Time-of-Propagation Focussing Lightguide
2D + t design
1-dimensionalimaging type
Poster Peter Schönmeier: The Endcap DIRC of the PANDA experiment
dispersive prismcomponent
Focussing – Solution:
narrow bandsin wavelength
Dispersion Corrections
relevant for ToP
ToP – Solution:
different directionsfor different colours for a given time t different horizontal
distances for different photon coloursToP
reflectsomephotonsseveraldifferentpath lengths
mirr
ors
mirrors give different path lengths self timing design
small wavelength bandsminimise dispersion effect+optimised photocathodes
dichroic mirrors as colour filtersallows two wavelength bandshigher photon statistics
single photon resolution t~30-50ps required
colour filters
Time-of-Propagation design
20mm fused silicaradiator disc
mirrors allow longer path lengths better relative time resolution
larger text
Time-of-Propagation design0 reflections1 reflection2 reflections3 reflections
[deg]
time-
of-p
ropa
gatio
n [n
s]
50 events
Time-of-Propagation
particle angle 15 degt=50psE x QE=(0.18+0.2)eVdisc with black hole
Focussing Lightguide
* *
• * discrete lightguide no.• * angle in (r-z) plane • LiF for dispersion correction• photon extraction into lightguide lifts up-down direction ambiguity• focussing inside lightguide
radiatoredge
fused silica (SiO2)radiator 10-15mm
photosensorstrips
SiO2
LiF
lightguides
*
*
two boundary surfaces makechromatic dispersion correctionangle-independent in first order
1-dim aspheric surfacenot-perfectfocussing ascurvature iscompromise(but good enough)
total internal reflectionangle independent of
light never leaves dense optical medium good for phase space
Focal Plane(dispersive direction)1-dimensional readout
Focussing & Chromatic Correction
light is onlygoing upwards
no mirror coating
Focussing Lightguide
simulation example with 2 fit analysisdisc 10mm thick, 0.4eVshort lightguide 125mm, focal plane 48mm
0 [deg] 360
targetvertex
Research & Development
• Polishing Effectiveness
• Radiator Tests
• Radiation Hardness
• Photon Detectors
5.46 nmfull vertical scale
30m x 30 mAFM
Friday Matthias Hoek: Radiation Hardness Study on Fused Silica
Thursday Albert Lehmann: Performance Studies of Microchannel Plate PMTs in High Magnetic Fields
magnetic field (up to B=2T), photon rate (MHz/pixel),light cumulative dose, radiation dose
Summary
• High antiproton rates require novel detectors for PID
• We propose DIRCs for the PANDA Target Spectrometer TS
FS
• Several designs with innovative solutions– Barrel DIRC with optical elements– Endcap DIRC – Time-of-Propagation – Endcap DIRC – Focussing Lightguide
• R&D in progress
Panda Participating Institutes more than 300 physicists (48 institutes) from 15 countries
U BaselIHEP BeijingU BochumU BonnU & INFN BresciaU & INFN CataniaU CracowGSI DarmstadtTU DresdenJINR Dubna (LIT,LPP,VBLHE)U EdinburghU ErlangenNWU EvanstonU & INFN FerraraU FrankfurtLNF-INFN Frascati
U & INFN GenovaU GlasgowU GießenKVI GroningenU Helsinki IKP Jülich I + IIU KatowiceIMP LanzhouU MainzU & Politecnico & INFN MilanoU MinskTU MünchenU MünsterBINP NovosibirskLAL Orsay
U PaviaIHEP ProtvinoPNPI GatchinaU of SilesiaU StockholmKTH StockholmU & INFN TorinoPolitechnico di TorinoU Oriente, TorinoU & INFN TriesteU TübingenU & TSL UppsalaU ValenciaIMEP ViennaSINS WarsawU Warsaw
