THE MICRO VERTEX DETECTOR OF CBM Joachim Stroth Goethe University - - PowerPoint PPT Presentation

THE MICRO VERTEX DETECTOR OF CBM

Joachim Stroth Goethe University Frankfurt / GSI 56th Winter Meeting on Nuclear Physics, Bormio, January 23rd, 2018

ADvanced MOnolithic Sensors for

THE CBM EXPERIMENT

Joachim Stroth | 56th Winter Meeting on Nuclear Physics | Bormio (Italy) 2

The Compressed Baryonic Matter Program at FAIR

LHC

Nuclei Quark-gluon plasma Hadrons

STAR FXT SIS18 SIS100 AGS SPS STAR BES

CBM/HADES

HADES

p+p, p+A A+A (low mult.) Dipol Magnet Micro Vertex Detector Silicon Tracking System Ring Imaging Cherenkov Transition Radiation Detector Time of Flight Detector Projectile Spectator Detector Muon Detector DAQ/FLES HPC cluster

The CBM strategy

• 105 - 107 Au+Au reactions/sec
• determination of displaced

vertices (σ » 50 µm)

• identification of leptons

and hadrons

• fast and radiation hard

detectors and FEE

• free-streaming

readout electronics

• high speed

data acquisition and

• nline event selection
• 4-D event

reconstruction

MAPS BASED MVD

Joachim Stroth | 56th Winter Meeting on Nuclear Physics | Bormio (Italy) 6

The Micro Vertex Detector

7

V a c u u m

Beam

Commercial CMOS process (180 nm TOWER-JAZZ) Thinned down to about 50 !". Integrated on CVD diamond and TPG. Lateral heat evacuation and stability Placed inside vacuum

Monolithic Active Pixel Sensor

MIMOSIS Principle of Operation

es used for ASIC production

• Pixel dimension: 26.88 !" x 30.24 !"
• Full signal processing micro-circuitry

integrated on chip (low noise !)

• Verymodestmaterialbudget:∼0.05%X0
• Binary charge encoding often sufficient for

O(!") position resolution

• Data driven read-out (320 Mbit/s)

Organisation

ludes full chain upstream Cluster Finding circuitry

Applications of MAPS

EUDet Telescope ILC STAR HFT ALICE ITS upgrade 2008 2014 2018 2016 2020 NA61 SAVD CBM - MVD

running running running

2024 2022

CBM-MVD Sensor Requirements

ALPIDE (demonstrated) MIMOSIS (MVD design goal) Factor

• Ion. Rad. Tolerance

0.3 Mrad > 3 Mrad 10

• Non. Io. Tolerance

1013 neq/cm² > 3x1013 neq/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/()* + -/.)* / /0 mrad

Station 0 Station 1 Station 2 Station 3

5 10 15 20 cm Target Approximate formular for the two nearest stations

Prototyping (double-sided integration)

13

• Lateral heat evacuation on thin sheets to heat

sink

• Double sided integration to avoid inactive

region

• Signal transport through ultra-thin flex prints

Cooling Performance

Vacuum vessel IR picture Heat-up curve

• Setup: MVD geometry & thermal

heaters, vacuum

• IR: Thermal relaxation times &

temperature differences

• 280 W total heat dissipation

keep in mind… Σ 279 W

RADIATION HARDNESS

Joachim Stroth | 56th Winter Meeting on Nuclear Physics | Bormio (Italy) 15

Occupancy

1230 pixel/!!" Two running scenarios. Substantial load due to #-electrons in case of Au+Au

CBM Requirements

Established knowledge on radiation tolerance 2006

17

5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80

10

11

10

12

10

13

10

14

10

15

MIMOSA-9 MIMOSA-9 MIMOSA-15 (2006) MIMOSA-18

AMS-0.35µm (10Wcm)

Radiation hardness [neq/cm²] Pitcheff [µm] T«0°C „standard“

CBM Requirements

5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80

10

11

10

12

10

13

10

14

10

15

MIMOSA-29 (2013) MIMOSA-18AHR (2011) MIMOSA-9 MIMOSA-9 MIMOSA-15 (2006) MIMOSA-18

AMS-0.35µm (10Wcm)

Radiation hardness [neq/cm²] Pitcheff [µm] T«0°C

AMS-0.35µm (~1kWcm)

Established knowledge on radiation tolerance 2013

High resistivity epitaxial layer

CBM Requirements

Established knowledge on radiation tolerance 2015

5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80

10

11

10

12

10

13

10

14

10

15

MIMOSA-34 (2015) MIMOSA-29 (2013) MIMOSA-18AHR (2011) MIMOSA-9 MIMOSA-9 MIMOSA-15 (2006) MIMOSA-18

AMS-0.35µm (10Wcm)

Radiation hardness [neq/cm²] Pitcheff [µm] T«0°C

AMS-0.35µm (~1kWcm) TOWER-0.18µm (>1kWcm)

CBM Req. Spatial resolution [µm] 5 - 10 Material budget [X0] < 0,05% Readout speed [kfps] > 30 Non-Ionizing rad. hardness[neq/cm²] >3*1013 Ionizing radiation hardness [krad] > 3 000

Operation in vacuum & magnetic field

High-res & smaller feature size

Apply voltage to the collecting diode

50 100 150 200 250 300 1000 2000 3000 4000 5000 6000

Entries (1/2 ADU) Charge collected (ADU)

5 V 10 V 20 V 30 V 40 V

Seed CCE, Fe55, Pipper-2, P1, 1013 neq/cm2, 22x22µm², tread = 12.8 µs, T = -60° C

Sensor seems fully depleted after 5-10 V. No charge sharing => Need ~17µm x 17µm pixel pitch to obtain CBM resolution. Note: A sensor irradiated to 10#$ &'(/*+² is considered as:

• Obviously destroyed (2003)
• Worth testing (2007)
• Working reasonably (2010)
• “Mostly not irradiated” (2017)

Reference chip: 10#$ &'(/*+²

PERFORMANCE

Alternative Ξ" Reconstruction

[GeV/c]

t

m

2 4

Entries

1

2

10

4

10

1.6 <= y < 1.8 MC Signal, Slope = -4.7 Side Bands, Slope = -4.8 Multi differential, Slope = -5.1

conventional

[GeV/c]

t

m

2 4

Entries

1

2

10

4

10

1.6 <= y < 1.8 MC Signal, Slope = -4.7 Side Bands, Slope = -5.0 Multi differential, Slope = -5.1

M3 Ξ" → Λ + &" → ' + &" + &" Ξ" → Λ()**)+, + &"

]

2

n [GeV/c

inv

m

0.7 0.8 0.9 1

Entries

0.1 0.2

6

10 ×

2

= 5.1 MeV/c σ n S/B = 3.27

n π- Σ-

3/2017

Thank You for Your Attention