STAR Inner Tracking Upgrades with an emphasis on the Heavy Flavor Tracker presented by Jim Thomas

1. STAR Inner Tracking Upgrades with an emphasis on the Heavy Flavor Tracker presented by Jim Thomas Lawrence Berkeley Laboratory 11 / 08 / 2006

2. Lattice results The Light Quark Program at STAR is Compelling Its hot Spectra Its dense Jets & Rcp and it flows at the partonic scale Vn Now we can make these measurements in the charm sector  and , too!

3. Heavy Flavor Energy Loss … RAA for Charm M. Djordjevic, et. al. nucl-th/0507019 • Heavy Flavor energy loss is uncertain • Gluon densities up to 3500 are insufficient to describe the data • ~ 1000 from light quark data • Beauty dominates single electron spectra above 5 GeV and makes the model worse Current energy loss mechanisms can only account for part of the strong suppression of RAA for electrons

4. Flow: Constituent Quark Number Scaling In the recombination regime, meson and baryon v2 can be obtained from the quark v2 : Does it work in the Charm Sector? A strong test of the theory

5. Elliptic Flow with Charm • D  e +X Single electron spectra from PHENIX show hints of elliptic flow • The HFT will cut out large photonic backgrounds: g e+e- and reduce other large statistical and systematic uncertainties • STAR can make this measurement with 50 M Au+Au events in the HFT • Smoking gun for thermalization at RHIC! M. Kaneta (PHENIX), J. Phys. G: Nucl. Part. Phys. 30, S1217 (2004). Better if we can do direct topological identification of Charm

6. Single Electron Spectra … are not sufficient • Hydro and Pythia are extreme models on opposite ends of the model spectrum • Charm in red, Beauty in Blue … Hydro is the solid line, Pythia is dashed • Single electron spectra are not sufficient to distinguish hard and soft physics below 3 GeV • We will also see this in the RAA measurements • The decayed spectra are shown in black and are nearly indistinguishable • We heard this message many times at QM05 and will hear it again at QM06 S. Batsouli et al., Phys. Lett. B 557 (2003) 26. We need direct topological identification of Charm

7. Direct Topological Identification of Open Charm Goal: Put a high precision detector near the IP to extend the TPC tracks to small radius The STAR Inner Tracking Upgrades will identify the daughters in the decay and do a direct topological reconstruction of the open charm hadrons. No Mixed events, no random background subtraction.

8. The HFT: 2 layers of Si at mid rapidity The Heavy Flavor Tracker • A new detector • 30 mm silicon pixels to yield 10 mm space point resolution • Direct Topological reconstruction of Charm • Detect charm decays with small ct, including D0 K  • New physics • Charm collectivity and flow to test thermalization at RHIC • Charm Energy Loss to test pQCD in a hot and dense medium at RHIC • R&D with HFT + SSD • A proposal has been submitted and a TDR is in preparation

9. 2 or more layers of Si at  = 0 3 or more layers of Si & GEMs at forward  Inner & Forward Tracking Upgrades • The Inner Tracking Upgrade include • HPD (1 layer) • IST (2 layers) • The ITUp will add high quality space points to tracks in the TPC • Si at h = 0 • The FTUp will add high quality space points at forward η • 1 < η < 2 • High Rate tracking for heavy flavor physics and W production

10. 2 options for the location of Triple-GEM detectors (Barrel or Disk configuration) B. Surrow et al., Nucl. Instr. and Meth. B241 (2005) 293. Forward Tracking Upgrade • Polarized pp program at √s = 500 GeV at RHIC at BNL: • Study the proton spin flavor structure of the proton spin • W detection via W e decay • identification of the e charge sign is critical • Employ triple-GEM detectors as part of STAR tracking upgrade • Low dead material, fast time response, precise hit determination, cost effective • Barrel or Disk configuration • With 4 conventional silicon disks in the forward direction e+/e-

11. Surround the Vertex with Si The HFT is a thin detector using 50 m Si to finesse the limitations imposed by MCS Add the HPD, IST, and SSD to form the STAR Inner Tracking Upgrade ( ITUp )

12. Inside the IFC ~ 1 m • Goal: graded resolution from the outside – in • TPC – IST – HPD – HFT • TPC pointing resolution at the SSD is ~ 1 mm • SSD pointing at the IST is ~ 300 mm • IST pointing at the HPD is ~ 150 mm • HPD pointing at the HFT is ~ 100 mm • HFT pointing at the VTX is ~ 50 mm

13. SSD ~ 60 cm • Double sided Si wafers 300 mm thick with 95 mm x 4.2 cm strips • Crossed at 35 mrad – effectively 30 mm x 900 mm • One layer at 23 cm radius • 20 ladders, 67 cm long • air cooled •  < 1.2 • 1 % radiation length @  = 0

14. IST ~ 36 cm • Singled sided Si wafers 300 mm thick with 60 mm x 4.0 cm strips • Si pads ~ 1 mm**2 on the other side of each ladder • Two layers at 17 & 12 cm radius • 27 ladders, 52 cm long • 19 ladders, 40 cm long • air cooled •  < 1.2 • 1.5 % per layer @  = 0

15. HPD ~ 22 cm • ALICE Hybrid Pixels 350 mm thick, with 250 mm in the sensor and 150 mm in the ASIC • 50 mm x 425 mm strips • One layer at 9.1 cm radius • 48 ladders, 28 cm long • C6F14 Evaporative cooling •  < 1.2 • 1.1 % radiation length @  = 0

16. HFT ~ 17 cm • Active Pixel Sensors, thinned to 50 mm thickness • 30 mm x 30 mm pixels • Two layers at 7 & 2.5 cm radius • 24 ladders, 19.2 cm long • 9 ladders, 19.2 cm long • air cooled •  < 1.2 • 0.28 % radiation length @  = 0

17. R&D in Run 7 A Three Layer Telescope with MimoSTAR II Chips. A full system test from pixel to DAQ using an extension of one TPC sector trigger line.

18. Install and run MimoSTAR IV Detector (Full) Install MimoSTAR III Ladder Install MimoSTAR IV Prototype Detector Install UltraSTAR Detector (Full) X X X X X 06 07 08 09 10 Install and test Prototype detector. Reduced diameter BP is required. HFT R&D and Installation Timeline Install MimoSTAR II Telescope Proposed HFT Timeline – the HPD and IST come about 1 year later X marks the installation dates. Running comes after installation.

19. A Rich Physics Program • There is a rich physics program when all of the STAR physics detectors are working together • Flow in the Charm sector • dE/dx in the Charm sector • Recombination and RAA in the Charm sector • Vector Mesons • Charm Angular Correlations • non-photonic electrons • …

20. Working with the rest of STAR … ( )n Combining the power of the STAR TOF barrel to identify electrons with the ability of the TPC and Inner Tracking Upgrades to identify and eliminate conversion electrons means we can execute a vigorous single electron and di-electron program of measurements

21. Summary • The STAR Inner Tracking Upgrade will explore the Charm sector • We will do direct-topological-reconstruction of open Charm • Our measurements will be unique at RHIC • The key measurements include • V2 • Energy Loss • Charm Spectra, RAA & Rcp • Vector mesons • Angular Correlations • The technology is available on an appropriate schedule

22. Supplementary slides

23. Si Pixel Developments in Strasbourg • Mimosa – 1 • 4k array of 20 m pixels with thick epi layer • Mimosa – 4 • Introduce Forward Biased Diode • Mimosa – 5 • 1M array of pixels, 17 m pixels using AMS 0.6 process • 4 msec readout scan rate • Mimosa – 8 • Fast parallel column readout with internal data sparsification • 200 sec readout scan rate • MimoSTAR – 1 128x128 pixels using TSMC 0.25 • MimoSTAR – 2 128x128 pixels using AMS 0.35 • Duct tape these to the STAR Beam Pipe for 07 run • MimoSTAR – 3 320x640 pixels using AMS 0.35 • MimoSTAR – 4 640x640 pixels production run • Ultra – 1 • Ultra – 2

24. Addition Detail

25. Copy the Alice HPD using only one layer

26. HPD Ladders - Sector Layout Kapton cables MCM RDO section active area HPD total ~ 1000 pixel chips, ≈ 107 pixels Image: INFN Padova

27. 11mm SMD component 7 7 7 7 6 6 5 5 4 235µm PIXEL_BUS 3 Aluminium 2 2 1 1 Polyimide PIXEL DETECTOR Glue <350µm (design target) READOUT CHIP 1 ANALOG_GND 25µ 2 ANALOG_ POWER 25µ 3 HORIZONTAL LINES 10µ 4 VERTICAL LINES 5µ 5 DIGITAL_POWER 25µ 6 DIGITAL_GND 25µ 7 RES + CAPA PADS 15µ ? CARBON FIBER SUPPORT COOLING TUBE HPD Ladder Cross-Section 7-layer Aluminum Kapton Flex 200 mm 150 mm M. Morel