Detector STAR STAR Pixel Detector A MAPS based by dffhrtcv3



                           STAR Pixel Detector

             A MAPS based vertex detector for STAR

              Short description of the detector and why we need test beam

                                                                  Leo Greiner, Eric Anderssen, Howard Matis,
                                                                 Thorsten Stezelberger, Joe Silber, Xiangming
                                                                      Sun, Michal Szelezniak, Chinh Vu,
                                                                               Howard Wieman

                                                                               Jo Schambach

                                                                              IPHC Strasburg
                                                                          Marc Winter CMOS group

L. Greiner                           SLAC Test Beam 03/17/2011                                          1
                Vertex Detector Motivation

         Direct Topological
      reconstruction of Charm
     Detect charm decays with            Method: Resolve displaced
     small c, including D0  K         vertices (100-150 microns)

L. Greiner                  SLAC Test Beam 03/17/2011                 2
                    Inner Detector Upgrades

                                                               TPC – Time Projection Chamber
                                                               (main tracking detector in STAR)

                                                               HFT – Heavy Flavor Tracker
                                                                SSD – Silicon Strip Detector
                                                                        r = 22 cm
                                                                  IST – Inner Silicon Tracker
                                                                        r = 14 cm
                                                                  PXL – Pixel Detector
                                                                        r = 2.5, 8 cm

  We track inward from the TPC with graded resolution:
             ~1mm         ~300µm           ~250µm              <30µm
       TPC          SSD             IST                PXL                 vertex

L. Greiner                         SLAC Test Beam 03/17/2011                                     3
                       PXL Detector Mechanical Design
                                                                                   Cabling and cooling
   Mechanical support with kinematic
   mounts (insertion side)

  carbon fiber sector tubes (~ 200um

                                                                 Insertion from one side
                                                                 2 layers
                                                                 5 sectors / half (10 sectors total)
                                                                 4 ladders/sector

                                                              Ladder with 10 MAPS sensors
                                                              (~ 2×2 cm each)
                                       buffers/    MAPS
                                                   4-layer kapton cable with aluminium traces
                                                  Aluminum conductor Ladder Flex Cable

                                                                             20 cm

L. Greiner                                   SLAC Test Beam 03/17/2011                                   4
                                  Detector Characteristics
                 Pointing resolution           (12  19GeV/pc) m
                 Layers                        Layer 1 at 2.5 cm radius
                                               Layer 2 at 8 cm radius
                 Pixel size                    20.7 m X 20.7 m
                 Hit resolution                6 m
                 Position stability            6 m rms (20 m envelope)
                 Radiation length per layer    X/X0 = 0.37%
                 Number of pixels              356 M
                 Integration time (affects
                 pileup)                       185.6 s
                 Radiation requirement         20 to 90 kRad
                                               2*1011 to 1012 1MeV n eq/cm2
                 Rapid detector                < 8 Hours

             356 M pixels on ~0.16 m2 of Silicon

L. Greiner                               SLAC Test Beam 03/17/2011            5
                           Test Beam use
                      MAPS sensor characteristics:
 Column parallel RDO with in-chip CDS, discriminators and zero-suppression.

   • Characterize pre-production prototype sensors in a
     beam telescope configuration to check efficiency and
     resolution as a function of bias and discriminator settings
     for MIPS.
   • Prototype sector and detector tests. Test tracking with
     MIPs through 4 layers of detector. Track stability with
     cooling air flowing.
   • Production sector and detector tests. As above.

L. Greiner                     SLAC Test Beam 03/17/2011                 6
               Parameters required for Beam Tests
         Beam parameters                   Value                  Comments
         Particle Type                      MIP
         Energy                             MIP
         Rep Rate                            NA
         Charge per pulse         Low / diffuse 1k / spill
         Energy Spread                       NA                      MIPs
         Bunch length rms                    NA
         Beam spot size, x-y      Minimum 3cm x 3cm
         Others (emittance, …)

     Logistics                           Requirements
     Space requirements (H x W x L)      2011 – 3’ x 3’ x 1’ for telescope
                                         2012/2013 – 2’ x 6’ x 2’ + blower
     Duration of Test and Shift          1 shift – setup
     Utilization                         3 shifts data taking
     Desired Calendar Dates              Spring/summer 2011, 2012, 2013
L. Greiner                            SLAC Test Beam 03/17/2011              7
             Beam Test Packages

                             Beam Telescope

                           Sector and detector
                           apparatus with air cooling
                           housing and blower

L. Greiner      SLAC Test Beam 03/17/2011               8


L. Greiner   SLAC Test Beam 03/17/2011   9
                                    PXL Detector Basic Unit (RDO)
     6 m (24 AWG TP)
                                                                                     2 m (42 AWG TP)

                Clk, config, data
                                                                                   Clk, config, data, power
                                         Mass Termination Board + latch-up
                                         protected power daughter-card

                                         100 m (fiber optic)

                                         PXL built events
                                                                             RDO PC with DDL link to RDO board

  RDO motherboard               Highly parallel system
  w/ Xilinx Virtex-5 FPGA

                                    4 ladders per sector
                                    1 Mass Termination Board (MTB) per sector
                                    1 sector per RDO board
                                    10 RDO boards in the PXL system

L. Greiner                                          SLAC Test Beam 03/17/2011                                    10
                         Monolithic Active Pixel Sensors
     MAPS pixel cross-section (not to scale)‫‏‬

      •      Standard commercial CMOS technology
      •      Room temperature operation
      •      Sensor and signal processing are integrated in the same silicon wafer
      •      Signal is created in the low-doped epitaxial layer (typically ~10-15 μm) → MIP
             signal is limited to <1000 electrons
      •      Charge collection is mainly through thermal diffusion (~100 ns), reflective
             boundaries at p-well and substrate → cluster size is about ~10 pixels (20-30 μm
      •      100% fill-factor
      •      Fast readout
      •      Proven thinning to 50 micron

L. Greiner                                  SLAC Test Beam 03/17/2011                          11
             Mimosa-26 Efficiency vs. threshold

L. Greiner             SLAC Test Beam 03/17/2011   12
             Mimosa-26HR eff vs. fake hit rate

L. Greiner             SLAC Test Beam 03/17/2011   13
                RDO System Design – Physical Layout

                                                   Sensors / Ladders / Sectors
                                                       (interaction point)
                                   1-2 m
                             Low mass twisted pair

                              LU Protected Regulators,
   Platform        30 m       Mass cable termination

    Power                                 6 m - twisted pair
    Supplies      30 m

                                RDO Boards             100 m - Fiber optic
      Control     30 m                                                  DAQ Room
       PCs                                                               DAQ PCs
                             (Low Rad Area)

L. Greiner                 SLAC Test Beam 03/17/2011                           14
                              PXL RDO Architecture (1 sector)
                                                            Ladder x 4

                                            RDO board x 1
                                                                             fiber       DAQ
                                                     FPGA         SIU
                                                                                       RDO PCs
             LU prot. power

                                                                  ADC      Unified Development Platform
                                                                  USB                Sensor testing
                                          SRAM                    i/o
                                                                                     Probe testing

                                                                               Black – cfg, ctl, clk. path
                                                                               Blue – data path
                                Power            Control                       Red – power / gnd path
       MTB x 1                 Supplies           PCs
                                                                 Trigger       Green – testing path

L. Greiner                                  SLAC Test Beam 03/17/2011                                 15

To top