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DEPFET detectors for future colliders . Activities at IFIC, Valencia. Terceras Jornadas sobre la Participación Española en los Futuros Aceleradores Lineales de Partículas Universitat de Barcelona. Carlos Mariñas, IFIC, CSIC-UVEG. Outlook.
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DEPFET detectorsforfuturecolliders. Activities at IFIC, Valencia Terceras Jornadas sobre la Participación Española en los Futuros Aceleradores Lineales de Partículas Universitat de Barcelona Carlos Mariñas, IFIC, CSIC-UVEG C. Mariñas, IFIC, CSIC-UVEG
Outlook C. Mariñas, IFIC, CSIC-UVEG
Vertexingin futurecollidersrequiresexcellentvertexreconstruction and efficient heavy quark flavourtaggingusinglowmomentumtracks • Thisrequirementsimposeunprecedentedconstraintsonthe detector: • Highgranularity • Fastread-out • Low material budget • Lowpowerconsumption • DEPFET • Measurementsmadeonrealistic DEPFET prototypeshavedemonstratedthatthe concept isone of the principal candidatestomeetthesechallengingrequirements Vertexing in futurecolliders C. Mariñas, IFIC, CSIC-UVEG
Each pixel is a p-channel FET on a completelydepletedbulk • A deep n-implantcreates a potentialminimumforelectronsunderthegate (internalgate) • Signalelectronsaccumulate in theinternalgate and modulatethe transistor current (400pA/e-) • Accumulatedcharge can be removed by a clearcontact • Fullydepleted • Largesignal • Fastsignalcollection • Lowcapacitance, internalamplification • Lownoise • Transistor ON onlyduringreadout • Lowpower • Complete clear • No resetnoise Features DEPFET principle C. Mariñas, IFIC, CSIC-UVEG
Faradaycage • PC for data acquisition • Stack of powersupplies • Laser • Motorstages XYZ • Complete systemfor air and liquidcooling • Cooling blocks • Aluminiumcoils • Pulse generator IntroducingtheValencia’s set up C. Mariñas, IFIC, CSIC-UVEG
Full electricaloptimization of matrices: Thisimpliesscansover a widerange of theoperatingvoltagestoachievethebestsignal-to-noise ratio. • Clear High/Low • Gate ON/OFF • Back • Bulk • Cleargate • Source • Calibration of thesystemusingradioactivesources • Gain of thesystem • ENC • Laser scans: Chargecollectionuniformity Matrixcharacterization C. Mariñas, IFIC, CSIC-UVEG
Alreadytested at IFIC C. Mariñas, IFIC, CSIC-UVEG
Blk D1 G1 Clg Cl S Cl G2 Clg D2 Innerstructure Set-up • Betterunderstanding of new structures • Differentgeometries (L-gate) • Implants • Directaccesstothesystem’sparameters • Complete clear • Chargecollection • Noise DEPFET Single-pixel (underconstruction) C. Mariñas, IFIC, CSIC-UVEG
Test Beam C. Mariñas, IFIC, CSIC-UVEG
Full electricalcharacterization of one DUT • Participate in theassembly and allignment of thetelescope • Parallel set-up in control room • Analysis of data • Test BeamCoordinators 2008 and 2009 (M.Vos) x z y BEAM 120 GeV ∏ Test Beam: Our role C. Mariñas, IFIC, CSIC-UVEG
Voltagescans: Cross-checkoptimalsettings • VBiastothewafer 150-220V • VEdge • VClearHigh • Angular scan: Resolution vs. Clustersize • -5, -4, -3, -2, -1.5, -1, -0.5, 0, 0.5, 1, 1.5, 2, 3, 4, 5, 6, 9, 12, 18, 36 • Beamenergyscan: Separation “multi-scattering-intrinsicresolution” • 20, 40, 60, 80, 120 GeV • Largestatistics • Chargecollectionuniformity • 3 Mevents in nominal conditions 3.5 TB of data 20 Millionevents Test Beam: Measurements C. Mariñas, IFIC, CSIC-UVEG
Seedsignal Entries stotal=2,5mm Preliminary Preliminary Residual (sMSÅsTelÅsInt, mm) Preliminary T.B. Data analysis Distance (mm) BeamEnergy (GeV) C. Mariñas, IFIC, CSIC-UVEG
Thermalsimulation First DEPFET thermalmock-up Thermalstudies: Simulation and measurements C. Mariñas, IFIC, CSIC-UVEG
Thermalmeasurements • Influence of conduction • T of cooling blocks • Bumpbonding • Influence of convection • Air speed • Air temperature • Study of new materials Temperature (ºC) Air speed (m/s) New materials Temperature (ºC) DT normalized (K/mm2) Power (W) Power (W) C. Mariñas, IFIC, CSIC-UVEG
Thermalsimulation • Modelimplemented in SolidWorksforfuturemechanicalstudies • ANSYS studiescalibratedwith real data C. Mariñas, IFIC, CSIC-UVEG
Switchingmechanismisintroduced Influence of air and liquidcoolingstudies A couple of movies… C. Mariñas, IFIC, CSIC-UVEG
Vertexing in FutureColliders • Veryhardconditions • Radiation (10MRad forSuperBelle) • Background • Reduced material budget • Unprecedentedgranularity • Powerconsumption and heatdissipation • Improvement of thedetector’s performance isneeded • New generation of pixel detectors try to cope withthisrequirements • DEPFET: One of themostpromisingtechnologiesforvertexing and tracking Conclusions C. Mariñas, IFIC, CSIC-UVEG
Matrixcharacterization • 2 differentgenerationscharacterized • Full electricaloptimization • Calibration • Chargecollectionuniformity • Workingon Single Pixel set-up • Test Beam • Optimization of DUT • Instalation and alignment of thetelescope • Data analysis • Thermalstudies • DEPFET thermalmock-up • Study of new materialsforbettercooling • Influence of air/liquidcooling • Simulation Conclusions: DEPFET in Valencia C. Mariñas, IFIC, CSIC-UVEG
Backupslides C. Mariñas, IFIC, CSIC-UVEG
Supportstructures: • FEA models of mechanicalproperties • Natural frequencies • Rigidity • Stability • Deformations • Validationwithmock-up • Module: • Simulationsusing FEA: (FiniteElementAnalysis) • Mechanicaleffects: Strenght of module • Thermaleffects: Cooling • Validationwithprototypes Mechanics C. Mariñas, IFIC, CSIC-UVEG
Discarded • Material • Granularity DEPFET CompetitorsforSuperBelle C. Mariñas, IFIC, CSIC-UVEG
Competitorsfor ILC C. Mariñas, IFIC, CSIC-UVEG
Double pixel structure C. Mariñas, IFIC, CSIC-UVEG
ADU 310.4 209.9 22 30 E (keV) • Ba-133 (30keV g-ray) → 310.4 ADC Units • Cd-109 (22keV g-ray) → 209.9 ADC Units FIT Slope=Gain b=12.5 ADC/keV y=a+bx Noise Gain Energytocreate e-h Gain and noise C. Mariñas, IFIC, CSIC-UVEG
S/N for a MIP 1.- ATLAS supposition: 1 MIP→22300 pairs e-h in 285μm of Si 2.- Our DEPFET has 450μm of Si 3.- The scale factor between Ba-133 30keV g and a MIP is: 4.- The S/N of 30keV Ba-133 grayscaledto a MIP: C. Mariñas, IFIC, CSIC-UVEG
Noise in current 1.- ADC dynamic range: 2 V – 14 bits -> 2.- trans-impedance amplifier gain = 1 V / 50 mA 3.- 15 ADC counts of noise C. Mariñas, IFIC, CSIC-UVEG
A-GATE B-CLEAR • Switchers A (Gate) and B (Clear) for CLG CURO Introducing the device C. Mariñas, IFIC, CSIC-UVEG
VClear-High VClear-High VClear-Low VClear-Low Amp/mV Time/ms VCleargate-High VCleargate-Low Clocked-Cleargate Common-Cleargate CLG vs CCG VCommon-Cleargate C. Mariñas, IFIC, CSIC-UVEG
Noise peak #Entries Signal peak Incomplete clear Background Effect on spectrum Leackage Current ADU C. Mariñas, IFIC, CSIC-UVEG
-3.2V 7V 1.8V 1.3V AD8129 OUT IN R10 +IN Iin -IN 6mV R50 150pF -5V 5V 14V REF R50 R10 FB AD8015 39kΩ >2V -7V -8.2V Vsubstr 2kΩ 18kΩ Amplifiers C. Mariñas, IFIC, CSIC-UVEG
10V C. Mariñas, IFIC, CSIC-UVEG
Double pixel cell 33 x 47 µm2 Double pixel structure Actual size of two pixels C. Mariñas, IFIC, CSIC-UVEG
GND Pulsers Sequencer PC VGATE 55Fe Shaper ADC Light VDRAIN C. Mariñas, IFIC, CSIC-UVEG
Correlated Double Sampling Scheme CDS C. Mariñas, IFIC, CSIC-UVEG