1. BNL-Nuclear Physics Seminar Rachid Nouicer 1 Brookhaven National Laboratory Research Affiliate of RIKEN-BNL Research Center New Era of Heavy Flavor Measurements at RHIC: Silicon Vertex Tracker (VTX) Construction and Performance Results From Run-11 BNL Nuclear Physics Seminar, November 29 th, 2011 Run-11 AuAu 200 GeV VTX

2. BNL-Nuclear Physics Seminar Rachid Nouicer 2 Outline of the Talk Motivation: why heavy flavor physics is so appealing VTX technology choices and construction phases VTX commissioning with p+p at 500 GeV and performance results Au+Au at 19.6, 200 and 27 GeV Reconstruction analysis results using VTX and central spectrometers (DC, PC, RICH, EMCal...) in Run-11 - Primary vertex, beam size, DCA… Detector successes, challenges and lessons learned Summary

3. BNL-Nuclear Physics Seminar Rachid Nouicer 3 Motivation: why heavy flavor physics is so appealing The physics goal of HF is to identify and study the properties of QCD matter created in HIC HF hadrons carry quarks with large masses, and this provides particularly good probe of medium produced - mc ~ 1.3 GeV, mb ~ 4.8 GeV >> T c, Λ QCD  less affected than light quarks HF quarks are produced early in the collisions (large Q 2 ) They travel through the created medium interacting with its constituents - Possibly a more direct connection to transport properties of the medium - Radiative energy loss should play a dominant role Three ways to see open heavy flavor: D- and B-mesons via hadronic decays (at mid-rapidity) D- and B-mesons via single electrons (at mid-rapidity) D- and B-mesons via single muons (at forward rapidity )

4. BNL-Nuclear Physics Seminar Rachid Nouicer 4 One of the most surprising results from RHIC Motivation: why heavy flavor physics is so appealing R. Nouicer arXiv:0901.0910 [nucl-ex] Heavy flavor suppression is as large as for light quarks No dependence of energy loss on flavor Do we understand the energy loss mechanism? Where is Beauty contribution?

5. BNL-Nuclear Physics Seminar Rachid Nouicer 5 One of the most surprising results from RHIC Heavy flavor suppression is as large as for light quarks No dependence of energy loss on flavor Do we understand the energy loss mechanism? Where is Beauty contribution? Motivation: why heavy flavor physics is so appealing R. Nouicer arXiv:0901.0910 [nucl-ex]

6. BNL-Nuclear Physics Seminar Rachid Nouicer 6 Motivation: Theoretical Calculations for HF To be published by Ralf F. Rapp et al. Realistic hydro (fit to multistrange and bulk particles) with heavy-quark diffusion in the QGP, hadronization via resonance recombination/fragmentation, followed by hadronic diffusion. There is no tuning of the HQ physics. Ralf F. Rapp, private communication Nuclear modification factor B+D-mesons via single electrons (NPE) Elliptic flow B+D-mesons via single electrons (NPE) Ralf F. Rapp

7. BNL-Nuclear Physics Seminar Rachid Nouicer 7 Motivation: Theoretical Predictions for HF Nuclear modification factor Elliptic Flow D- and B-mesons via single electrons (at mid-rapidity) Ralf F. Rapp, private communication Ralf F. Rapp

8. BNL-Nuclear Physics Seminar Rachid Nouicer 8 Motivation: Theoretical Predictions for HF D-mesons via hadronic decays B-mesons via hadronic decays Ralf F. Rapp, private communication Ralf F. Rapp

9. BNL-Nuclear Physics Seminar Rachid Nouicer 9  Pioneering High Energy Nuclear Interaction eXperiment  2 central spectrometers  2 forward spectrometers  3 global detectors - Luminosity Monitoring (BBCN,BBCS) - Centrality (BBC vs ZDC) - Local polarimetery (ZDC & SMD) West South North East Photon, hadron, electron |  |<0.35,  =   detection 1.2<|  |<2.4, 2  in  PHENIX Detector: Present

10. BNL-Nuclear Physics Seminar Rachid Nouicer 10  Present PHENIX: Access signal from heavy quarks via single electron measurement PHENIX: PRL 88, (2002) 192303  Precision of the measurement limited by systematic uncertainty because,  Huge background contribution  0 and  Dalitz decay  conversion (  -> e + e - )  Cannot separate charm and beauty contributions independently  Lifetime (c  ) of mesons with charm and beauty D ± = 312  m, D 0 = 123  m B ± = 501  m, B 0 = 464  m  Secondary vertex identification is required to suppress background for non-photonic electrons, and will make it possible to distinguish if an electron originates from charm or beauty. Heavy-Quark Probes at PHENIX

11. BNL-Nuclear Physics Seminar Rachid Nouicer 11 - Heavy flavor (c and b quarks) are produced in the early stages of heavy ion collision - Experimentally easy to observe Semi-leptonic decays VTX e-e- e+e+ Expected DCA resolution  ~ 40  m Au+Au 200 GeV pions in 3 <p T <4 GeV/c Life time (c  ) D 0 : 123 mm B 0 : 464 mm DCA p p D B e e Barrel 1 Barrel 2 Barrel 3 Barrel 4 Barrel 1 Barrel 2 Barrel 3 Barrel 4 Pixel Stripixel Technology Choices: VTX Concept

12. BNL-Nuclear Physics Seminar Rachid Nouicer 12 VTXLayerR1R2R3R4 Geometrical dimensions R (cm)2.55101414 Dz (cm)21.8 31.838.2 Area (cm 2 )28056019603400 Channel countSensor size R  z (cm 2 ) 1.28  1.36 (256 × 32 pixels) 3.43 × 6.36 (384 × 2 strips) Channel size 50  425 mm 2 80 mm  3 cm (effective 80  1000 mm 2 ) Sensors/ladder 4  4 56 Ladders1020181826 Sensors16032090156 Readout chips16032010801872 Readout channels1,310,7202,621,440138,240239,616 Radiation length (X/X0) Sensor0.22%0.67 % Readout0.16%0.64 % Bus0.28% Ladder & cooling0.78% Total1.44%2.1 % Pixel Stripixel LayerradiusDetectorOccupancy in Central Au+Au collision Layer 12.5 cmPixel0.53 % Layer 25.0 cmPixel0.16% Layer 310.0 cmStrip4.5 % (x-strip)4.7 % (u-strip) Layer 414.0 cmStrip2.5 % (x-strip)2.7 % (u-strip) Technology Choices: Barrel VTX Parameters  plane Pixel Stripixel

13. BNL-Nuclear Physics Seminar Rachid Nouicer 13 Technology Choices: Silicon Pixel Barrels 1 & 2 ALICE1LHCb readout chip: Pixel: 50 µm (  ) x 425 µm (Z). Channels: 256 x 32. Output: binary, read-out in 25.6  s@10MHz. Radiation Hardness: ~ 30 Mrad Sensor module: 4 ALICE1LHCb readout chips. Bump-bonded (VTT) to silicon sensor. Thickness: 200  m Thickness: r/o chips 150 µm Half-ladder (2 sensor modules + bus) 1.36 cm x 10.9 cm. Thickness bus: < 240 µm. SPIRO module Control/read-out a half ladder Send the data to FEM FEM (interface to PHENIX DAQ) Read/control two SPIROs Interface to PHENIX DAQ Active area  r  1.28 cm = 50mm x 256  z 1.36 cm = 425mm x 32 Solder bump ~20  m

14. BNL-Nuclear Physics Seminar Rachid Nouicer 14 Sensor module consists of 4 ALICE Pixel readout chips bump-bonded to silicon sensor Sensor Half stave is mounted on the support structure Thermo plate + cooling Pixel BUS to bring data out and send control signal into the readout chip is mounted on the half stave Each detector module is built of two half staves, read out on the barrel ends Half stave Pixel BUS Data One readout unit, half stave, made from two sensor modules Full stave 22cm 1.4cm ALICE LHCB1 chip SensorSensor Module Bus Glue Stave Readout chip Sensor Technology Choices: Silicon Pixel Barrels 1 & 2

15. BNL-Nuclear Physics Seminar Rachid Nouicer 15 Status: Pixel Stave Bus Glued Support & Cooling : Stave  Prototype stave has been delivered by HYTEC recently: Technology Choices: Silicon Pixel Barrels 1 & 2

16. BNL-Nuclear Physics Seminar Rachid Nouicer 16 Innovative design by BNL Instr. Div. : Z. Li et al., NIM A518, 738 (2004); R. Nouicer et al., NIM B261, 1067 (2007); R. Nouicer et al., Journal of Instrumentation, 4, P04011 (2009) DC-Coupled silicon sensor Sensor single-sided 2-dimensional position sensitivity by charge sharing “New technology: unique to PHENIX” Technology Choices: Silicon Stripixel Barrels 3 & 4

17. BNL-Nuclear Physics Seminar Rachid Nouicer 17  Sensors produced by HPK with thickness of 625 μm  Point-symmetric structure of readout lines wrt the center of the sensor  Readout pads in longer edges for ladder structure design  No dead space in the middle  Sensor size : 3.4×6.4 cm 2  Pixel array : 80×1000 μm 2 pitch  # readout strip ox-strip : 128×3×2 ou-strip : 128×3×2 oTotal : 1536 channels/sensor  Current per strip: 0.12 nA  Note: Stripixel sensor technology, including the mask design and processing technology has transferred from BNL to HPK. Technology Choices: Silicon Stripixel Barrels 3 & 4

18. BNL-Nuclear Physics Seminar Rachid Nouicer 18  Current per strip: 0.12 nA  Note: Stripixel sensor technology, including the mask design and processing technology has transferred from BNL to HPK. Technology Choices: Silicon Stripixel Barrels 3 & 4  Sensors produced by HPK with thickness of 625 μm  Point-symmetric structure of readout lines wrt the center of the sensor  Readout pads in longer edges for ladder structure design  No dead space in the middle  Sensor size : 3.4×6.4 cm 2  Pixel array : 80×1000 μm 2 pitch  # readout strip ox-strip : 128×3×2 ou-strip : 128×3×2 oTotal : 1536 channels/sensor

19. BNL-Nuclear Physics Seminar Rachid Nouicer 19 Ladder Design Bottom view Silicon sensor SVX4 chips ROC (readout card, ORNL) Top view Silicon Module ADC distributions corrected event-by-event pedestal subtraction Pedestal  = 9.2 Ladder Technology Choices: Silicon Stripixel Barrels 3 & 4

20. BNL-Nuclear Physics Seminar Rachid Nouicer 20 Response to Proton to Beam at 120 GeV (FNAL, 2008) Pixel detector Stripixel detector - Tracking efficiency ~ 99% S/N = 10.3 Residual Distribution (row)

21. BNL-Nuclear Physics Seminar Rachid Nouicer 21 Stripixel Ladders Mass Production at BNL Laser scan of the stave (flatness) Dow Corning glue: 100 [um]Placing modules on stave

22. BNL-Nuclear Physics Seminar Rachid Nouicer 22 EAST: Layer 4 (Stripixel): 12 ladders EAST: Layer 3 (Stripixel): 8 ladders Stripixel Barrels Assembly and Testing at the Lab. WEST: Layer 4 (Stripixel): 12 ladders WEST: Layer 3 (Stripixel): 8 ladders

23. BNL-Nuclear Physics Seminar Rachid Nouicer 23 Layer 1 (PIXEL): 5x2 ladders 23 Layer 2 (PIXEL): 10x2 ladders Spiro Board Pixel Barrels Assembly and Testing at the Lab.

24. BNL-Nuclear Physics Seminar Rachid Nouicer 24 VTX Silicon Vertex Tracker Layer 2 (Pixel): 10 x 2 = 20 Layer 1 (Pixel): 5 x 2 = 10 Layer 4 (Stripixel): 12 x 2 = 24 Layer 3 (Stripixel): 8 x 2 = 16 Full VTX (east + west) Installed at PHENIX-IR on December 1 st, 2010 Layer 1 Layer 2 Layer 3 Layer 4

25. BNL-Nuclear Physics Seminar Rachid Nouicer 25 VTX Survey at the VTX-Lab. Side view of VTX Final VTX Survey Ladder survey Front view of VTX

26. BNL-Nuclear Physics Seminar Rachid Nouicer 26 Full VTX after cablingVTX group and PHENIX technicians West VTX installed on Nov 17 th East VTX installed on Dec. 1 VTX Commissioning at PHENIX-IR VTX Moved to PHENIX-IR

27. BNL-Nuclear Physics Seminar Rachid Nouicer 27 Operation During Run-11 Interlock and cooling systems Slow control Readout DAQ All these systems have been implemented and tested successfully during Run-11 and there are no major plan for modifications. We will only focus to make different systems more robust.  These systems are ready to be used in Run-12

28. BNL-Nuclear Physics Seminar Rachid Nouicer 28 VTX Slow Control and Interlock Systems Cooling systems Stripixel LV Voltage Pixel LV Voltage Bias Voltage

29. BNL-Nuclear Physics Seminar Rachid Nouicer 29 Stripixel: Readout Chain DCMII: Zero-Suppression Detector at the IR Stripixel DIB in the rack room Stripixel ladders at IR p+p at 500 GeV Data Transfer DIB to DCM2 Optical cables 75 meters at DIB stage Pedestal Correction: VTX-Stripixel: Run-11: p+p at 500 GeV M1M2 M3 M4 M5 M6

30. BNL-Nuclear Physics Seminar Rachid Nouicer 30 VTX Performance Results During RHIC Run-11: (VTX+Central Spectrometers): - p+p at 500 GeV: 62M (BBC narrow) - Au+Au at 19.56 GeV: 5M (BBC narrow) - Au+Au at 200 GeV: 6B (BBC narrow) - Au+Au at 19.56 GeV: M (BBC narrow) VTX

31. BNL-Nuclear Physics Seminar Rachid Nouicer 31 Raw hits data from p+p at 500 GeV Beam Data in Stripixel Pedestal correction and zero suppression are working properly Stripixel: Performance Results

32. BNL-Nuclear Physics Seminar Rachid Nouicer 32 X 100 Pedestal distribution: RMS Clear MIP peak is seen in the cluster ADC distribution Pedestal width is 5.3 (per stripixel) S/N = 55/5.16 = 10.7 (at FNAL beam test S/N = 10.3) S/N in Stripixel Detector Stripixel: Performance Results

33. BNL-Nuclear Physics Seminar Rachid Nouicer 33 p+p at 500 GeV Multiplicity Distribution (uncorrected) Acceptance of hits distribution (can be used to build reaction plan)    These basic measurements (multiplicity, flow…) with the VTX are the first step towards a new era of heavy flavor discoveries Stripixel: Performance Results

34. BNL-Nuclear Physics Seminar Rachid Nouicer 34 VTX at RHIC Run-11: Display of Single Event 3) VTX RUN-11: Au+Au at 200 GeV 4) VTX RUN-11: Au+Au at 27 GeV 1) VTX RUN-11: p+p at 500 GeV 2) VTX RUN-11: Au+Au at 19.6 GeV

35. BNL-Nuclear Physics Seminar Rachid Nouicer 35 Track Reconstruction Method 35 B3 B2 B1 B0 VTX DC+PC RICH TOF EMCal VTX Central Arm 2 DC-Track 1 We have two complementary methods 1.Standalone Tracking method  Only VTX is used  Large detector coverage  Worse momentum resolution  Two algorithms are proposed and studied to get confident result. 2.DC based tracking with VTX Cluster (DCTVC)  DC track is used as a guide and associated with VTX Clusters  Coverage is limited to Central Arm  Better momentum resolution VTX p resolution(sim) DC p resolution

36. BNL-Nuclear Physics Seminar Rachid Nouicer 36 Standalone Tracking: Primary Vertex Pixel Primary Vertex in Z Stripixel Primary Vertex in Z Primary Vertex for a Single Event: Peak Position ± 10 bin width is 500 um and 1000 um for pixel and stripixel, respectively. Each bin width corresponds to each pixel size. For DCA measurement, the position of the primary vertex need to be determine event-by-event Run-11 data: Au+Au at 200 GeV

37. BNL-Nuclear Physics Seminar Rachid Nouicer 37 Standalone Tracking: Beam Size Run-11 data: Au+Au at 200 GeV Beam size=104.6 um is consistent with the expected value from beam condition. Measurement of DCA from beam fixed center required measurement of beam size  y = 104.6 um  x = 133.6 um Beam size

38. BNL-Nuclear Physics Seminar Rachid Nouicer 38 Standalone Tracking: VTX Internal Alignment Minimum should be at zero - Stripixel ladders are aligned to the pixel ladders. - The particle has a finite momentum, then particle trajectory bends in B-field. - The residual value between the cluster position and the straight line projection is calculated. If particle has infinite momentum, the residual value should be zero. - We adjust the stripixel position. Pixel B0 Pixel B1 dproj θ B Stripixel Pixel ladders Stripixel ladder

39. BNL-Nuclear Physics Seminar Rachid Nouicer 39 DCA width is: East σ ~ 137 μm West σ ~ 142 μm (Used tracks with p T > 1GeV) Layer 0 Layer 1 Beam Center DCA Standalone Tracking: DCA w.r.t Beam Center Measured DCA width = Beam spot size  (DCA) + Alignment can improve the DCA resolution East σ(DCA) = 88 μm West σ(DCA) = 96 μm DCA distribution

40. BNL-Nuclear Physics Seminar Rachid Nouicer 40 DC Based Tracking with VTX Cluster (DCTVC) DC+PC Rich TOF EMCal

41. BNL-Nuclear Physics Seminar Rachid Nouicer 41 Run-11 data: Au+Au at 200 GeV DC Based Tracking with VTX Cluster (DCTVC) Residual distribution (  ) in VTX barrels - Black: data - Red: Gaussian fit - Blue: Polynomial fit - Pink: Gaus. + Pol. barrel 0 barrel 1 barrel 2 barrel 3

42. BNL-Nuclear Physics Seminar Rachid Nouicer 42 Run-11 data: Au+Au at 200 GeV DC Based Tracking with VTX Cluster (DCTVC) Response of the EMCal Detector h+h+ e+e+ h-h- e-e- E/p distribution with enabling Rich detector “n 0 ” e ± peak should be around 1 but is around 0.8 (full calibration not done yet)

43. BNL-Nuclear Physics Seminar Rachid Nouicer 43 LDTB 6 out of 40 LDTBs didn't work well during RUN11 when triggered at high rate. With digital oscilloscope, voltage oscillations for 3.3 VD and 2.5 VD regulator, may be also some short period voltage drop. Summer repairs: all the stripixel ladders are running properly after replacing the six Tantalum capacitors by Ceramic capacitors on all the LDTB boards; these capacitors stabilize the regulators outputs to the transceivers and FPGA chips. Stripixel: Summer Repairs

44. BNL-Nuclear Physics Seminar Rachid Nouicer 44 Standalone Test of Troubled Ladders SAMTEC SAMTEC connector Popped up GND PIN Cross section of SPIRO board Cold soldering GND pin EXTENDER LADDER GND In RUN11 many pixel ladders couldn't read-out due to GND/Power PIN connection of read-out boards (SPIRO): GND PIN issue in Samtec connector Pixel: Summer Repairs - All boards had been sent to BEST (a company that specialized in PCB rework). - All fixed boards had been delivered and worked correctly. Pixel Issue 1

45. BNL-Nuclear Physics Seminar Rachid Nouicer 45 11/20/2015 rachid.nouicer@bnl.gov Present Status of VTX: Picture Taken on November 22 nd, 2011 FVTX has been built and integrated with VTX FVTX VTX

46. BNL-Nuclear Physics Seminar Rachid Nouicer 46 11/20/2015 rachid.nouicer@bnl.gov VTX and FVTX ready to be moved to PHENIX-IR east west Present Status of VTX: Picture Taken on November 22 nd, 2011

47. BNL-Nuclear Physics Seminar Rachid Nouicer 47 Summary Construction, installation and commissioning of VTX detector, as well as sub-systems (interlock, cooling, slow control), were completed successfully. First look on data from p+p and Au+Au from Run-11 show excellent performance results and indicate that the detector is working properly. Now, our efforts are shifted to operation, data analysis and physics related to the VTX: Excellent progress made in software VTX standalone tracking and global tracking: first look on primary vertex, beam size, DCA… Stay tuned! VTX is moving towards new measurements of heavy flavors leading PHENIX to a new era of discoveries. Plan: PHENIX/VTX first results will be shown at QM-2012

48. BNL-Nuclear Physics Seminar Rachid Nouicer 48 11/20/2015 rachid.nouicer@bnl.gov Thanks to: VTX team PHENIX Collaboration and technical support Special thanks to: Yasuyuki Akiba, Ryoji Akimoto, Hidemitsu Asano, Maki Kurosawa, Maya Simomura, Takashi Hachiya, Mikhail Stepanov and Paul Stankus

49. BNL-Nuclear Physics Seminar Rachid Nouicer 49 11/20/2015 rachid.nouicer@bnl.gov Auxiliary Slides

50. BNL-Nuclear Physics Seminar Rachid Nouicer 50 Detection efficiency Energy deposit in expected CH in layer 2 from the tracking using layer 1 and 3. 50 Layer #All countCount in ADC < 40 Efficiency (%) 21697999.5±0.2 By tracking (x) By tracking (u) Layer #All countCount in ADC < 40 Efficiency (%) 215591898.9±0.3 50 Proton Beam layer 1 layer 2 layer 3 Results satisfy performance demand  Preparing for mass production 50 Sum of ADC in expected CHs (x) in layer2 Sum of ADC in expected CHs (u) in layer2 Hit : >40

51. BNL-Nuclear Physics Seminar Rachid Nouicer 51 First Step: Tests Pulse Test Pulse: we observed test pulse from detector trough DIBs, DCMs to the DAQ: conclusion readout chain is working properly

52. BNL-Nuclear Physics Seminar Rachid Nouicer 52 Status of Ladders Mass Production (started on June 3, 2010) The ladders assembly, testing and survey achieved at BNL using VTX manpower Assembly/Survey machine Clean room for ladder assembly Bench test: ladder/silicon modules Assembly fixtures

53. BNL-Nuclear Physics Seminar Rachid Nouicer 53 Standalone Tracking: Primary Vertex Pixel Primary Vertex in Z Z(VTX) (cm) Z(BBC) (cm) Pixel Primary Vertex in Z Primary Vertex Single Event: BBCz vs Pixel detector BBCz vs Stripixel detector Peak Position ± 10 bin Bin width is 500 um and 1000 um for pixel and stripixel, respectively. Each bin width corresponds to each pixel size. Excellent correlation between VTX primary vertex and BBC vertex.