AD vanced MO nolithic S ensors for THE MICRO VERTEX DETECTOR OF CBM Joachim Stroth Goethe University Frankfurt / GSI 56 th Winter Meeting on Nuclear Physics, Bormio, January 23 rd , 2018
THE CBM EXPERIMENT Joachim Stroth | 56th Winter Meeting on Nuclear Physics | Bormio (Italy) 2
The Compressed Baryonic Matter Program at FAIR Quark-gluon plasma STAR BES LHC SPS STAR FXT SIS100 AGS Hadrons SIS18 Nuclei CBM/HADES
Transition Ring Time of Flight Silicon Radiation Imaging Dipol Detector HADES Tracking Detector Cherenkov Magnet System p+p, p+A Micro A+A (low mult.) Vertex Detector Muon Projectile Detector Spectator DAQ/FLES HPC cluster Detector
The CBM strategy 10 5 - 10 7 Au+Au reactions/sec o determination of displaced o vertices (σ » 50 µ m) identification of leptons o and hadrons fast and radiation hard o detectors and FEE free-streaming o readout electronics high speed o data acquisition and online event selection 4-D event o reconstruction
MAPS BASED MVD Joachim Stroth | 56th Winter Meeting on Nuclear Physics | Bormio (Italy) 6
The Micro Vertex Detector Monolithic Active Pixel Sensor Commercial CMOS process (180 nm TOWER-JAZZ) Thinned down to about 50 !" . m u u c a V Integrated on CVD diamond and TPG. Lateral heat evacuation Beam and stability Placed inside vacuum 7
MIMOSIS Principle of Operation es used for ASIC production Organisation ludes full chain upstream Cluster Finding circuitry o Pixel dimension: 26.88 !" x 30.24 !" o Full signal processing micro-circuitry integrated on chip (low noise !) o Verymodestmaterialbudget: ∼ 0.05%X0 o Binary charge encoding often sufficient for O( !" ) position resolution o Data driven read-out (320 Mbit/s)
Applications of MAPS running STAR HFT ALICE ITS upgrade ILC 2008 2014 2016 2018 2020 2024 2022 running running EUDet NA61 SAVD CBM - MVD Telescope
CBM-MVD Sensor Requirements ALPIDE MIMOSIS Factor (demonstrated) (MVD design goal) Ion. Rad. Tolerance 0.3 Mrad > 3 Mrad 10 Non. Io. Tolerance 10 13 n eq /cm² > 3x10 13 n eq /cm² 3 Heavy ion tolerance N/A 1 kHz / cm² -- Time resolution ~10 µs 5 µs 2 Data rate (internal) ~0.8 Gbps 20 Gbps 25 Data rate (external) 0.8 Gbps 2.5 Gbps 3 Data reduction Trigger Elastic buffer -- GBTx compatible No Yes --
INTEGRATION
Detector Configuration Geometry ↔ Multiple Scattering ! "# = 10/()* / mrad + -/.)* / 0 Station 0 Station 1 Station 2 Station 3 Target 5 10 15 20 cm Approximate formular for the two nearest stations
Prototyping (double-sided integration) Lateral heat evacuation on thin sheets to heat o sink Double sided integration to avoid inactive o region Signal transport through ultra-thin flex prints o 13
Cooling Performance IR picture Vacuum vessel Heat-up curve Setup: MVD geometry & thermal o heaters, vacuum IR: Thermal relaxation times & o temperature differences 280 W total heat dissipation o Σ 279 W keep in mind…
RADIATION HARDNESS Joachim Stroth | 56th Winter Meeting on Nuclear Physics | Bormio (Italy) 15
Occupancy Two running scenarios. Substantial load due to # -electrons in case of Au+Au 1230 pixel/ !! "
Established knowledge on radiation tolerance 2006 AMS-0.35µm (10 W cm) 15 10 CBM Radiation hardness [n eq /cm²] Requirements 14 10 T«0°C 13 10 MIMOSA-18 „standard“ 12 MIMOSA-15 (2006) 10 MIMOSA-9 MIMOSA-9 11 10 0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 Pitch eff [µm] 17
Established knowledge on radiation tolerance 2013 AMS-0.35µm (10 W cm) 15 10 AMS-0.35µm (~1k W cm) CBM Radiation hardness [n eq /cm²] Requirements MIMOSA-18AHR (2011) 14 10 T«0°C 13 10 MIMOSA-18 High resistivity MIMOSA-29 (2013) epitaxial layer 12 MIMOSA-15 (2006) 10 MIMOSA-9 MIMOSA-9 11 10 0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 Pitch eff [µm]
Established knowledge on radiation tolerance 2015 AMS-0.35µm (10 W cm) 15 10 AMS-0.35µm (~1k W cm) TOWER-0.18µm (>1k W cm) CBM Radiation hardness [n eq /cm²] Requirements High-res & MIMOSA-18AHR (2011) 14 10 smaller feature MIMOSA-34 (2015) size T«0°C 13 CBM 10 Req. MIMOSA-18 Spatial resolution [µm] 5 - 10 MIMOSA-29 (2013) Material budget [X 0 ] < 0,05% 12 MIMOSA-15 (2006) 10 Readout speed [kfps] > 30 MIMOSA-9 Non-Ionizing rad. hardness[n eq /cm²] >3*10 13 Ionizing radiation hardness [krad] > 3 000 MIMOSA-9 Operation in vacuum & magnetic field 11 10 0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 Pitch eff [µm]
Apply voltage to the collecting diode Seed CCE, Fe55, Pipper-2, P1, 10 13 n eq /cm 2 , 22x22µm², t read = 12.8 µs, T = -60° C 6000 5 V Reference chip: 10 #$ & '( /*+² 10 V 5000 20 V 30 V 40 V Entries (1/2 ADU) 4000 Note: A sensor irradiated to 10 #$ & '( /*+² is considered as: 3000 • Obviously destroyed (2003) • Worth testing (2007) 2000 • Working reasonably (2010) • “Mostly not irradiated” (2017) 1000 0 50 100 150 200 250 300 Charge collected (ADU) Sensor seems fully depleted after 5-10 V. No charge sharing => Need ~17µm x 17µm pixel pitch to obtain CBM resolution.
PERFORMANCE
Alternative Ξ " Reconstruction conventional M 3 1.6 <= y < 1.8 1.6 <= y < 1.8 π - Entries MC Signal, Slope = -4.7 Entries MC Signal, Slope = -4.7 4 Side Bands, Slope = -4.8 10 4 Side Bands, Slope = -5.0 10 Multi differential, Slope = -5.1 Multi differential, Slope = -5.1 Σ - n 2 10 2 10 6 2 × 10 n = 5.1 MeV/c σ Entries 0.2 S/B = 3.27 0.1 1 1 0 2 4 0 2 4 0.7 0.8 0.9 1 m [GeV/c] 2 m [GeV/c] m n [GeV/c ] t inv t Ξ " → Λ ()**)+, + & " Ξ " → Λ + & " → ' + & " + & "
Thank You for Your Attention 3/2017
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