Mitglied der Helmholtz-Gemeinschaft Andrey Sokolov IKP FZ Jülich, Germany The Central Tracker of the PANDA Detector The X International Conference on Instrumentation for Colliding Beam Physics Novosibirsk, Russia

2 Outline Overview of FAIR project Layout of PANDA detector PANDA Central Tracker:  Micro-Vertex Detector  Straw Tube Tracker Conclusions and Outlook Andrey Sokolov

Andrey Sokolov3

4 Facility for Antiproton and Ion Research Andrey Sokolov4 GSI, Darmstadt - heavy ion physics; - nuclear structure; - atomic and plasma physics; - cancer therapy. FAIR: New facility - heavy ion physics; - higher intensities & energies; - antiproton physics.

5 FAIR Andrey Sokolov5 Key Technical Features Cooled beams; Rapidly cycling superconducting magnets; Parallel Operation. Storage and Cooler Rings Radioactive beams; e - – A (or p -A) collider; stored and cooled antiprotons GeV/c; Future: Polarized antiprotons (?). Primary Beams 238U 28+ : Age; 238U 92+ : up to 35 AGeV Protons : 2 x GeV; up to 90 GeV; times present intensity. Secondary Beams Broad range of radioactive beams; up to AGeV; intensity up to x over present; Antiprotons GeV. SIS 100/300 HESRSuper FRS RESR CR NESR FLAIR UNILAC SIS 18 FRS ESR Existing New

6 High Energy Storage Ring Andrey Sokolov6 PANDA Parameters of HESR Injection of p at 3.7 GeV; Beam momentum GeV/c; Storage ring for internal target operation; Luminosity up to L~ 2x10 32 cm -2 s -1 ; Beam cooling (stochastic & electron); Energy resolution down to 4· E CM

7 The Physics Overview Charmonium and open charm spectroscopy;Charmonium and open charm spectroscopy; Charmed hybrids and glueballs:Charmed hybrids and glueballs: - Many narrow states are predicted; Interaction of charmed particles with nuclei:Interaction of charmed particles with nuclei: - Meson mass modification in the nuclear matter; Hypernuclei:Hypernuclei: - Double hypernuclei production via Ξ-baryon capture; Many further options:Many further options: - Wide angle compton scattering; - Baryon-Antibaryon production; - CP-Violation (Λ,D) Andrey Sokolov7

8 Antiproton ANnihilations at DArmstadt: PANDA Andrey Sokolov8 Detector requirements: nearly 4π solid angle for PWA; high rate capability: 2x10 7 interactions/s; efficient event selection; good momentum resolution ≈ 1%; vertex info for D, K 0, Σ, Λ; good PID (γ, e, μ, π, Κ, p); photon detection 1 MeV – 10 GeV.

9 PANDA Detector Andrey Sokolov9

10 PANDA Detector Andrey Sokolov10 Target Spectrometer: Superconducting solenoid for high p t tracks. Pellet or Cluster Jet Target Forward Spectrometer Dipole magnet for forward tracks

11 PANDA Detector: PID Andrey Sokolov11 Barrel DIRC (G.Shepers) Endcap DIRC Barrel TOF Forward TOF Forward RICH Muon Detectors

12 PANDA Detector: Calorimeters Andrey Sokolov12 PWO Calorimeters, (P.Semenov) Forward Shashlyk EMC Hadron Calorimeter

13 PANDA Detector: Tracking Andrey Sokolov13 Micro vertex Detector Tracker GEM Detectors Drift Chambers P ANDA Central Tracker

14 Micro-Vertex Detector: Challenges Provide an information about secondary vertices from charm and strange particles decays: c  123μm for D 0, c  8.71cm for  0  high precision and large sensitive volume; Broad momentum range of the outgoing particles: low material budget to minimize multiple scattering; Asymmetric particle flux due to the fixed target nature of experiment: specific detector layout; Continuous beam operation: triggerless operational mode; High event rate (up to 10 7 evt/s); Particle identification Andrey Sokolov14

15 Micro-Vertex Detector Andrey Sokolov15 Beam Beam pipe Target pipe

16 Micro-Vertex Detector Andrey Sokolov16 4 Barrel Layers

17 Micro-Vertex Detector Andrey Sokolov17 6 Forward Disks

18 Micro-Vertex Detector: Pixel Part Andrey Sokolov18   Hybrid pixels 100x100 µm 2 ;   120 modules;   Maximum rate up to 10 Mhits/s/module;   ~10 M channels;   ToT;   0.15 m 2 ;   ~1% X 0 per layer.

Andrey Sokolov19 Micro-Vertex Detector: Pixel Part Front-End chip: ATLAS front end chip as a starting point; Custom pixel front-end chip – TOPIX (TOrino PIXel) in 0.13µm CMOS:  TOPIX1 – only analogue part (2005);  TOPIX2 – preamp + buffers (2007). Maximum hit rate up to 2 MHits/s  data rate 200Mbit/s; Thickness ~ 200µm.Sensor: Epitaxial silicon sensors:Epitaxial silicon sensors:  50  50µm, 75µm, 100µm under testingin Torino. INFN Torino

20 MVD: Strip Part Andrey Sokolov20 ~400 modules;~400 modules; ~0.5m 2 active area;~0.5m 2 active area; ~ readout channels.~ readout channels.

21 MVD: Strip Part Andrey Sokolov21 Microstrip readout: 128-channel ASIC for strips; Prototype n-XYTER chip for DETNI (GSI);   Fast timing shaper/amplifier with comparator (1ns time resolution);   Slow channel for analog r/o with peak detector;   Token ring readout of hit channels. Next iteration with lower power consumption; Self-triggering operation mode. Sensor: Silicon double side strip sensor with pitch 100µm.

22 MVD: Spatial resolution Andrey Sokolov22

23 MVD: Particle Identification Andrey Sokolov23

Andrey Sokolov24 MVD Support Structure It’s planned to build the support structure out of the 2mm Carbon foam.

Andrey Sokolov25 STT Assembling and Installation

Andrey Sokolov26 Tracker: TPC Option Multi-GEM stack for amplification and ion backflow suppression; Gas: Ne/CO 2 (+CH 4 /CF 4 ); 100k pads of 2 x 2 mm 2 ; 50-70µs drift, 700 events overlap.Simulations: p/p ~ 1%; dE/dx resolution ~ 6%. Challenges: space charge build-up; continuous sampling; Field homogeneity better 2%; ∫B r /B z dz < 2mm.

Andrey Sokolov27 Straw Tubes Tracker ~4100 straws; 30µm Al-mylar tube, Ø=10mm, l=1.5m; R in = 16cm, R out = 42cm; Gas filling Ar/10%CO 2 ; Light detector with X/X 0 ~ %. Axial layers:  r  < 150µm, A   ~ 99%; Skewed layers: Skewed layers:  z ~ 3mm, A    ~ 90-95% ; Momentum resolution:  pt / p t ~ 1.2 %  pt / p t ~ 1.2 %

Andrey Sokolov28 STT Layout Self-supporting straw layers at ~1 bar overpressure. 1.5m  10mm

29 PANDA Detector Andrey Sokolov29 Straw Tube Tracker

Andrey Sokolov30 COSY-TOF Straw Tube Tracker 3120 straw tubes in 15 planar double layers ; Aligned at  = 0°, 60°, 300° for 3d-reconstruction; Gas: Ar/CO 2 (10%), p=1.2bar; Active volume: 1m 2 x 30cm; Resolution:  r  100 µm; Efficiency:   99%; Radiation length: X/X 0 1.3%; Lowest detector weight ~ 15kg   total stretching force ~ 3200 kg! Operates in vacuum. 1m

Andrey Sokolov31 COSY-TOF STT: Cosmic Ray Test è Spatial resolution  ~ 100µm limited ionisation clusters near tube wall  Radial efficiency  ~ 98%

Andrey Sokolov32 STT Particle Flux Density Recoil protons from the target produce a charge load up to 0.4C/cm/year.

Andrey Sokolov33 STT Aging Beam Test 32 straws in doble layer;32 straws in doble layer; 3 gas mixtures:3 gas mixtures:   Ar+10%CO 2 ;   Ar+30%CO 2 ;   Ar+30%C 2 H 6. Proton beam:Proton beam:   3GeV/c;   up to 810 6 protons/s;   beam spot  ~4cm. Gas gain.5-110 5.Gas gain.5-110 5. Accumulated charge up to 1.2Q/cm (~3 years of PANDA operation).Accumulated charge up to 1.2Q/cm (~3 years of PANDA operation).

Andrey Sokolov34 STT Aging Test Maximum gain drop less than 10%!

Andrey Sokolov35 Conclusions FAIR project has been officially started. PANDA will be a versatile detector for charm physics. The design and prototyping of MVD is on the good way:  Two prototypes of the front end pixel chip are released.  The prototope for the strip front end chip is under construction. The MVD design comprises the good spatial resolution with PID capabilities. The straw tubes is suggested as option for PANDA tracker. Due to the new technique STT will have very low material budget combining with the good spatial resolution and efficiency. The beam test shows sufficient radiation hardness of STT.

Andrey Sokolov36 Outlook TOPIX3 prototype should be ready by the end of this year; Half-cylinder full length STT prototype should be finished in the next year; The PANDA TDR will be ready in the beginning 2010; PANDA commissioning in 2015.

Andrey Sokolov37 The PANDA Collaboration U Basel IHEP Beijing U Bochum U Bonn U & INFN Brescia U & INFN Catania Cracow JU,TU, IFJ PAN 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 Moscow, ITEP & MPEI 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 More than 420 physicists from 55 institutions in 17 countries