STAR

1. STAR STAR Upgrade Plans and R&D Open Meeting on RHIC Planning, December 4, 2003 R. Majka for STAR

2. Physics Questions • What are the gross properties of the partonic matter? • Is it equilibrated? • Does it behave collectively? • What are its early temperature and pressure? • What is its gluon density? • Are symmetries restored/broken in the partonic matter? • Spontaneous CP violation • Chiral symmetry and UA(1) restoration • What are the properties of the hadronic medium after hadronization • What are the gluon densities in normal nuclear matter • What are the contributions to the nucleon spin?

3. Upgrade Goals • Keep (expand) STAR’s large coverage • Enhanced (higher momentum) PID – barrel TOF • Micro vertex detector and inner tracking for enhanced heavy quark ID • Improved momentum resolution for forward (1<|h|<2) region - inner and end cap tracking, • High rate readout and DAQ – present large samples to high level trigger, also record very large samples • Enhanced Forward instrumentation - |h|>2 (Hadron calorimetry) • High rate tracking capability • High Luminosity, Large pp polarization – RHIC development and upgrades

4. Upgrade • Physics Bullets • Determine degree of thermalization and collectivity in partonic matter formed in RHIC collisions • Test QCD (for variety of parton types) and determine the fate of its fundamental symmetries in bulk partonic matter • Map the contributions of gluons and sea antiquarks of different flavor to the spin of the proton • Probe the large gluon densities at low momentum fraction in heavy nuclei TOF Barrel Pixel Vertex DAQ/FEE upgrade } RHIC-II } Inner/ endcap tracking Forward hadron calorimeter

5. TOF: Correlations, Fluctuations, Partonic Collectivity, Open Charn, Vector meson (->e+e-), lepton, di-lepton spectra, away-side jet fragmentation, exotica searches, LL helicity correlations, Microvertex: Heavy quark production with identification via slightly displaced vertices; D yields & flow to test degree of thermalization & partonic collectivity; c- and b-quark energy loss in partonic matter. DAQ/FEE: Acquisition of very large data samples for precision and rare process studies: e.g., b-quark jet quenching; CP violation search via  spin correlations opposite a high-pT hadron;  HBT. Inner/Forward Tracking Upgrade: W± production and charge sign discrimination in polarized pp collisions, especially in endcap region, for kinematically clean distinction of flavor-dependence of sea antiquark vs. valence quark polarizations in proton. Forward Hadron Calorimeter: Jet reconstruction at high pseudorapidity: CGC monojet search in d(p) + A; isolation of fragmentation effects in largesingle-spin transverse asymmetries inpp  0 production. Robust Tracking in High Luminosity RHIC II era: High luminosity studies of  - and heavy-quark tagged jets;  HBT.

6. STAR Detector

7. Ongoing Improvements of STAR Capability

8. STAR Barrel TOF • MRPC modules to cover outer barrel of STAR TPC • Dt < 100 ps • Large coverage –p<f<p, -1<h<1, R≈2.1 m • More than double momentum range of PID (95% of charged particles in acceptance) • 3800 modules with 23,000 readout channels • Fast detector – maintains (improves) trigger capability of existing CTB scintilators.

9. Multigap Resistive Plate Chamber MRPC Technology developed at CERN Read out pad size： 3.15cm×6.3cm gap：6×0.22mm 95% C2H2F4 5% Iso-butane 3800 modules, 23,000 readout chan. to cover TPC barrel

10. Examples of Benefit of TOF Open Charm and Resonances in central Au-Au collisions FOM (figure of merit) = reduction in required data set by using TOF PID TOF PID also reduces systematic errors from correlated back-ground due to misidentified particles Certain measurements are impossible without TOF – unlike particle correlations (X-p), scale dependent correlation studies (velocity vs momentum correlations), exotic searches…

11. TOF R&D • Accomplished in FY03 • For RHIC run 3, one full tray installed in STAR • 28 MRPC modules • 72 chan. of readout using final FEE components on prototype boards connected to CAMAC digitizers • Signals split to form TOF trigger

12. TOF R&D Accomplished in FY03 • SF6 is NOT required in the gas mix • HV was on for the entire run – no failures • Noise rate ~200Hz from OR of 72 chan. • TPC track matching done (software developed) • Calibrations (t-zero, slewing, TDC nonlinearity, …) are all performed (software developed) • 85 ps MRPC timing resolution demonstrated for a small system in the RHIC/STAR environment • 95%MRPC efficiency demonstrated in the RHIC/STAR environment • PID capability demonstrated (software developed) • Electron tagging demonstrated • Physics publication submitted

13. From TOF Triggered Data in d-Au Collisions p/K separation p=1.6GeV/c, p/(K+p) p=3GeV/c

14. Electron tag from combining TPC dE/dx and TOF TPC dE/dx for all tracks TPC dE/dx for tracks with TOF b ~ 1

15. TOF + TPC electron Tag • Works well at low energy – complements calorimeter • Gives access to vector meson (r, w, f, J/y) e+e- decays • In medium modification, ‘onia studies • Thermal dileptons • Single electron spectrum • D meson yield, flow Simulations show inner mvertex tracker can suppress g conversions Do decay electrons follow Do flow!

16. MRPC TOF has run successfully in STAR and produced publishable physics results. Nucl-ex/0309012, Sept. 2003 Submitted to PRL

17. TOF R&D in 2004 • For the upcoming run (Run 4): • TOF Tray rebuilt with prototypes of “final” FEE boards • A few channels of HPTDC digitizers • Address integration volume issues (space, cooling) • Gain experience with final FEE configuration (24 channel boards, sealing top of trays • Gain experience with HPTDC • Gain running experience with Au-Au collisions • Continue software development and physics analysis

18. TOF R&D in 2004 (cont.) • For Run 5: • Build a significant amount of full electronics chain (up to four trays) • Build significant number of MRPC modules (up to 4 trays) • Operational experience with full electronics chain • Check electronics design for production • Experience with module production lines • Finalize module production and QA procedure • Extended physics capability

19. Proposal for construction is submitted: • Construction funding in FY05 • Construction FY05 – FY07 • 30 Trays (25% coverage) in FY06 • Partial (and increasing) coverage (and physics capability) available during construction phase.

20. Highresolution inner vertex detector, better than 10 m resolution, with better than 20m point-back accuracy at the primary vertex. CMOS Active Pixel Sensor (APS) technology – can be very thin, allows some readout to be on same chip as detector. Develop high speed APS technology for second generation silicon replacement (LEPSI/IReS, and LBNL+UC Irvine) Required Areas of development: • APS detector technology • Mechanical support and cabling for thinned silicon • Thin beam pipe development • Calibration and position determination • Data stream interfacing Micro-Vertex Detector

21. Features of First Generation Design: • 2 layers • Inner radius ~1.8 cm • Active length 20 cm • Readout speed 20 ms (generation 1) • Number of pixels 130 M • Goals and Milestones: • Choose MIMOSTAR fabrication process, End 03 • Thinned MIMOSA-5 chips to LEPSI/IReS, Feb. 04 • Design of LEPSI/IReS MIMOSTAR chip, May 04 • Tested MIMOSA-5 to LBNL, June 04 • Submit fabrication MIMOSTAR, 2 proto, Sept 04 • First ladder prototype, start Oct. 04 • Tests of 2 MIMOSTAR prototypes, Jan 05 • Final MIMOSTAR prototype design, Mar 05 • Submit fab final MIMOSTAR prototype, Apr 05 • Production tests of final MIMOSTAR proto type on wafer, July 05 • Send MIMOSTAR for thinning, Aug 05 • Test thinned and diced MIMOSTAR prototype chips, Sept 05 • Mount MIMOSTAR chips on final ladder prototype • Proposal in 2004

22. aluminum kapton cable (100 m) silicon chips (50 m) 21.6 mm 254 mm carbon composite (75 m) Young’s modulus 3-4 times steel Mechanical and integration issues are being addressed: Thin stiff ladder concept Two Layers of APS Existing Silicon Integration volume and rapid insertion/removal being studied using modern 3-D modeling tools.

23. STAR DAQ upgrade – DAQ1000 • GOAL: increase STAR’s rate capability to equivalent of 1 kHz min-bias Au+Au  ~820 MB/s instantaneous (~300 MB/s time-averaged?) • IMPLEMENTATION: (1) replace TPC FEE with version based on ALICE ALTRO chip; (2) replace TPC DAQ system with one based on storage of only cluster information extracted in fast hardware; (3) upgrade EMC Level 2 Receiver Boards and use for other new subsystems as well. • MILESTONES: • FY04 Run: deploy Fast Cluster Finder algorithm ( DAQ100) and cluster storage only in software as proof-of-principle; handle clustered event building with 4 Linux-based EVB work stations • FY04 R&D: implement a Row Computing Slice (RCS) incorporating FCF in hardware (FPGA, DSP, …); design generic new DAQ Receiver Board; prototype ALTRO-based FEE • FY05 Run: implement new Receiver Board for BEMC/EEMC Level 2 triggering • FY05 R&D: design ALTRO  DAQ interconnect; prototype DAQ fiber interconnect & network system

24. Improved Tracking for h>1 All hits TPC hits only > 7 hits/track “Fast” Detector hits only GEM in front of TPC + 3-layer Si strip barrel + GEM plane in front of EEMC 18%, wrong sign Pt, GeV/c, reconstructed • Inner (Si strip) + forward (GEM) tracking detector concept should eliminate incorrect sign reconstructions for W daughters in endcap region! • Simulated events illuminate endcap region ~ uniformly, assume modest fast detector spatial resolutions of 100 m (GEM) and 50 m (Si) Primary Vertex position, Z, cm Pt, GeV/c, simulated

25. GEM =GasElectron Multiplier A micropattern structure produced in 50mm thick copper clad kapton using lithographic techniques. 55mm holes on ~140mm centers Gain up to ~103 for single foil 3M Foil (J. Collar) Photo – Bo Yu, BNL CERN Foil (F. Sauli) Photo – G. Jesse

26. Inner Tracking + Forward Tracking • November 7-8, Meeting at MIT to begin to address issues related to integrating requirements and design for tracking upgrades • New working group formed to: • Decide on optimal sequence/staging/integration of upgrades and replacement of existing STAR subsystems, navigating highly coupled issues: • APS needs fast inner tracker consistent with FEE/DAQ upgrade. • W± sign discrimination in endcap region requires inner tracker coverage beyond  = 1 • Endcap tracker needs space freed by TPC FEE upgrade • Present SVT + FTPC introduce intricate mechanical problems for APS insertion/removal • Mapping onto physics priorities, funding, RHIC run plan • Produce an integrated design addressing these issues

27. detectors beam beam pipe Forward Physics • Forward Hadron Calorimetry (~2.4<h<4.0, 0<f<2p) • Simulations and Design • Forward jets – probing gluon saturation, mono-jets • Is the asymmetry for pions produced in transversely polarized proton scattering due to spin dependent fragmentation? Roman Pots (h~6.5) Access to a variety of diffractive phenomena in p-p scattering

28. Goals for FY04 TOF: Proposal submittedconstruct 4 prototype MRPC TOF trays with ~ final on-board time digitization electronics for installation in STAR for RHIC run 5; design Level 2 Receiver Board for TOF + other sub-systems. Vertex: design and begin fabrication of prototype MIMOSTAR chips; advance mechanical design and begin fabrication of first prototype APS ladder. Develop proposal FEE/DAQ build/test several prototype FEE boards utilizing ALTRO chip. Implement Fast TPC Cluster Finder algorithm in hardware; contribute to design of new Receiver Board. GEM: (Joint R&D with PHENIX) prepare prototype GEM pad detector and readout electronics for installation within STAR for RHIC run 5, to test operation and backgrounds in RHIC collision environment. Build prototype compact TPC module Inner + Endcap tracking: Develop integrated design.

29. STAR Future Physics and Planned Upgrades SystemR&DConstr/CostBenefit to STAR Barrel MRPC ‘ 04  ‘05 ‘ 05  ‘06 PID information for ~ 95% TOF $260k $4.3M of kaons and protons in acc; + $2.5M in- kind extended pT for resonances;  v2; D’s; ebe correlations; anti-nuclei; inclusive electrons Inner vtx ‘04  ‘06 ‘ 06  ‘07 D’s , flavor- tagged jets (Forward Tracker) $ 965K $4M (TBD) (Charge sign for W± ) DAQ Upgrade ‘04  ‘06 ‘ 06  ‘08 1 kz  L3; D’s;  & D, $1.77M $5M v2, cp, D thermalization FEE Upgrade ‘04  ‘05 ‘ 05  ‘06 1 kz  L3; D’s; , D, $250k $2.5M v2, cp, D thermalization Forward Hadron before next d-Au forward jets, mono-jets, Calorimeter TBD collins fragmentation GEM DeV ‘ 04  ‘06 ‘08 - ‘10 Compact, fast TPC;robust $900k ? tracking for high Q2 physics at 40 x L GEM pad chambers for forward/inner tracking