L. Greiner1SLAC Test Beam 03/17/2011 STAR LBNL Leo Greiner, Eric Anderssen, Howard Matis, Thorsten Stezelberger, Joe Silber, Xiangming Sun, Michal Szelezniak, Chinh Vu, Howard Wieman UTA Jo Schambach IPHC Strasburg Marc Winter CMOS group STAR Pixel Detector A MAPS based vertex detector for STAR Short description of the detector and why we need test beam

L. Greiner2SLAC Test Beam 03/17/2011 STAR Vertex Detector Motivation Direct Topological reconstruction of Charm Detect charm decays with small c , including D 0  K  Method: Resolve displaced vertices ( microns)

L. Greiner3SLAC Test Beam 03/17/2011 STAR 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: TPCSSDISTPXL ~1mm~300µm~250µm vertex <30µm

L. Greiner4SLAC Test Beam 03/17/2011 STAR PXL Detector Mechanical Design Mechanical support with kinematic mounts (insertion side) Cabling and cooling infrastructure Insertion from one side 2 layers 5 sectors / half (10 sectors total) 4 ladders/sector Aluminum conductor Ladder Flex Cable Ladder with 10 MAPS sensors (~ 2×2 cm each) carbon fiber sector tubes (~ 200um thick) 20 cm

L. Greiner5SLAC Test Beam 03/17/2011 STAR Detector Characteristics Pointing resolution(12  19GeV/p  c)  m LayersLayer 1 at 2.5 cm radius Layer 2 at 8 cm radius Pixel size20.7  m X 20.7  m Hit resolution6  m Position stability6  m rms (20  m envelope) Radiation length per layerX/X 0 = 0.37% Number of pixels356 M Integration time (affects pileup)  s Radiation requirement20 to 90 kRad 2*10 11 to MeV n eq/cm 2 Rapid detector replacement < 8 Hours 356 M pixels on ~0.16 m 2 of Silicon

L. Greiner6SLAC Test Beam 03/17/2011 STAR Test Beam use 2011 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. MAPS sensor characteristics: Column parallel RDO with in-chip CDS, discriminators and zero-suppression.

L. Greiner7SLAC Test Beam 03/17/2011 STAR Parameters required for Beam Tests Beam parametersValueComments Particle TypeMIP EnergyMIP Rep RateNA Charge per pulseLow / diffuse 1k / spill Energy SpreadNAMIPs Bunch length rmsNA Beam spot size, x-yMinimum 3cm x 3cm Others (emittance, …) LogisticsRequirements 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 Utilization 1 shift – setup 3 shifts data taking Desired Calendar DatesSpring/summer 2011, 2012, 2013

L. Greiner8SLAC Test Beam 03/17/2011 STAR Beam Test Packages Beam Telescope Sector and detector apparatus with air cooling housing and blower

L. Greiner9SLAC Test Beam 03/17/2011 STAR backup

L. Greiner10SLAC Test Beam 03/17/2011 STAR 2 m (42 AWG TP) 6 m (24 AWG TP) 100 m (fiber optic) Highly parallel system 4 ladders per sector 1 Mass Termination Board (MTB) per sector 1 sector per RDO board 10 RDO boards in the PXL system RDO motherboard w/ Xilinx Virtex-5 FPGA RDO PC with DDL link to RDO board Mass Termination Board + latch-up protected power daughter-card PXL Detector Basic Unit (RDO) Clk, config, data, power Clk, config, data PXL built events

L. Greiner11SLAC Test Beam 03/17/2011 STAR Monolithic Active Pixel Sensors 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 pitch)‏ 100% fill-factor Fast readout Proven thinning to 50 micron MAPS pixel cross-section (not to scale)‏

L. Greiner12SLAC Test Beam 03/17/2011 STAR Mimosa-26 Efficiency vs. threshold

L. Greiner13SLAC Test Beam 03/17/2011 STAR Mimosa-26HR eff vs. fake hit rate

L. Greiner14SLAC Test Beam 03/17/2011 STAR RDO System Design – Physical Layout 1-2 m Low mass twisted pair 6 m - twisted pair Sensors / Ladders / Sectors (interaction point) LU Protected Regulators, Mass cable termination RDO Boards DAQ PCs (Low Rad Area) DAQ Room Power Supplies Platform 30 m 100 m - Fiber optic 30 m Control PCs 30 m

L. Greiner15SLAC Test Beam 03/17/2011 STAR PXL RDO Architecture (1 sector) Ladder x 4 FPGA LU prot. power MTB x 1 Power Supplies Control PCs Trigger DAQ RDO PCs SIUADCUSBi/o RDO board x 1 Sensor testing Probe testing SRAM Black – cfg, ctl, clk. path Blue – data path Red – power / gnd path Green – testing path fiber Unified Development Platform