Post on 26-Dec-2015
David L. Winterfor the PHENIX Collaboration
PHENIX Silicon Detector Upgrades
RHIC & AGS Annual Users' MeetingWorkshop 3
RHIC Future: New Physics Through Upgrades27 May 2008
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Outline
Motivation
Design
Schedule and Status
Summary
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Physics goalsImprove vertex resolutionImprove p resolutionImprove high-pT trackingMeasure reaction planeSuppress background
Enabling:Separate measurement of production and flow of charm and beautyStudy of production and suppression of quarkoniaStudy of q, g contribution to proton spin
Using signals:b B , ec D , eJ/’ +-, e+e-
Hadrons
e-
e+
+
-
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Signals and Backgrounds
The problem(s):Backgrounds (, K , e) dominate the signal
Cannot easily distinguish single leptons from those produced from charm, bottom
Central arms: electronsForward arms: muons
Simulated RHIC-II p+p run
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Separating Signal from Background
Mean , K e decay distance is large
D, B mesons travel some distance before semileptonic decay to or e
Prompt e have 0 DCA
c
D0 125 m B0 464 mD± 317 m B± 496 m
K± 3.7 m ± 7.8 m
Separate D, B decays from prompt leptons and from long-lived decays from , K by measuring the DCA to the primary vertex
e-
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Design SpecificationsNeed sufficient DCA resolution
Central: ~ 50 m
Forward: ~ 100 m
Need low enough occupancy to find tracks in central AuAu events (<few %)
Need enough hits to reconstruct a track ( 3 hits)
Need to match tracks with Central arm detectors: ||= 0.35
Muon system: || = 1.2 - 2.4
Large solid angle coverage
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Detectors
.
Barrel vertex detector (VTX)
Forward vertex detectors (FVTX)
80 cm
40 cm
38 cm
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Barrel Pixels (Layers 1 & 2)2 Pixel buses per ladder
30 ladders in 2 cylindersPixels: 50 x 425 m2 150 m - thick SiliconR = 2.5 and 5.0 cmLength = 22 cmReadout:
1.3 and 2.6M channelsALICE1LHCb chipFull bus readout in ~50 sFast-OR available for Lvl-1 trigger
Rad Len 1.44% total
LadderSPIRO Board
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Barrel Stripixels (Layers 3 & 4)Based on sensor design by BNL InstrumentationEffective pixels: 80 x 1000 m2 650 m - thick SiliconR = 10 and 14 cm44 Total laddersLength = 32 and 38 cm140K and 280K channelsReadout with SVX4 chipRad Len 2.7% total
Single sided, 2D readout
Strip pixel sensor wafer made by HPK
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Endcap Strips (Eight Stations)
4 disks / side 48 wedges/disk75 um strips,2.8-11.2 mm long1664 strips/column1.1M channels totalReadout with FPHX chip
7.5°
HDI
Detector
FPHX Chips
Backplane
Rigid, thermally conductive epoxy
Rigid epoxy
~10 cm
2.8mm
11.2mm
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Endcap Readout: FPHX chip
128 Channels (strips)Signal polarity: positive (holes)Gain at shaper output: 50 mV/fC3-bit ADCNominal peaking time: 60 nsNoise: 110e + 196 e/pFData push architectureOutput 4 hits in 4 beam clocksPower: ~600 uW per channel for maximum input transistor bias current
128 input bond padsin a double row
32 I/O pads in a single row
9 mm
1.2 mmDevelopment by FNAL, Based on FPIX design from BTeV
FPHX placement on wedge
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Mechanical Design
Single integrated VTX-FVTX mechanical structure being designed by HYTECTwo half-cylinder shellsServices routed top/bottom (VTX) and out ends (FVTX)Electronics mounted on “big wheel(s)”New, smaller diameter beam-pipe
FVTXBigWheel
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Construction Schedule
Barrel construction well underwaypixel layers completion in 2009
stripixels completion in 2010 (first ladders)
Forward detector construction started in FY08, installation to be in 2011
2008 2009 2010 2011 2012
VTX
FVTX
R&D Phase Construction Phase Ready for Data
pixels stripixels
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Pixel Ladder Bus
1.5cm bus before assembly
Fine pitch detail of the bus
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Cosmic Ray Telescope
Ladders and SPIRO Boards
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Pixel Bus Cosmic Ray TestsComic Ray telescope with 3 pixel busesBoth external trigger and fast-OR triggerUsed complete readout chain.Last test- Sept. ‘07
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Pixel Source Test
Use source to illuminate sensor module on 1/2-ladder
Self-trigger using readout chip Fast-OR
100K events
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StatusPIXEL Ladders:
Cosmic ray events observed, Sept '07Ladder production to start in 20082 Barrels ready for installation in 2009, Run 10
STRIPIXEL Ladders:Readout-Card Prototyping in progress.First Ladders ready for installation in 2010, Run 11Full detector ready in 2011, Run 12
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Construction Status: FVTX
Mechanical design ~ 80% completeFirst prototype FPHX submission is very soon (June)HDI under developmentDAQ readout electronics have been prototyped
Prototype DAQ Electronics
Thermally conducting silicone
Honeycomb support panel
Wedges front and back
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Performance: VTX
Simulated Au+AuAfter 2<1 cut, DCA distributions of light hadrons and D0 decay are clearly separated
D0 decay
Collision vertex
~ 40 m
Single with 3<pT<4200 thick pixel layers650 thick stripixel layersPassive material is:
1.0% pixel2.75% stripixel
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Performance: FVTX
improved background rejectionImproved mass resolutionSeparate ’
’
100 m
DCA – R component
DCA – component
300 m
DCA metric“Perfect” track finding
Kalman filter fit
Includes VTX hits
With FVTX
Without FVTX
p+p MB Au+AU
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Open Charm, Bottom Signals
Nuclear Modification Factor expected with VTX
• VTX to separately measure RAA of be and ce• Same goal for FVTX (e )
• factor 4-5 suppression!(?!)• perturbative QCD?
Nuclear Modification Factor without VTX
PHENIX: PRL 98, 172301 (2007)
single electrons from heavy flavor decay
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SummaryThe VTX and FVTX detectors have been proposed, approved, and being constructed to address heavy-flavor physics
Large coverage (2 @ 1.2<||<2.4 and nearly 2 @ ||<0.35
Improved tracking and resolution
These projects will enableStudy of heavy-flavor production and flow (charm and bottom separately)
Study of quarkonia production and suppression
Study of contribution to proton spin
Greatly improved background suppression
Construction is underway for both detectorsInner barrels installed by 2009
Outer barrels installed by 2010/2011
Endcaps installed by 2011