Status of the Micro Vertex Status of the Micro Vertex Detector of the CBM ExperimentDetector of the CBM Experiment

N. Bialas1, N. Chon-Sen2, G. Claus2, C. Colledani2, R. De Masi2, M. Deveaux1, D. Doering1, M. Domachowski1, A. Dorokhov2,

C. Dritsa1;2;3, W. Dulinski2, H. Düring2, J. C. Fontaine2, I. Fröhlich1, T. Galatyuk1, M. Goffe2, A. Himmi2, C. Hu2, K. Jaaskelainen2,

M. Koziel2, J. Michel2, F. Morel2, C. Müntz1, S. Ottersbach1, F. Rami2,P. Scharrer11, C. Schrader1, S. Seddiki1;2, M. Specht2, J. Stroth1, T. Tischler1,

C.Trageser1, I. Valin2, F. M. Wagner4, B. Wiedemann2, and M. Winter2

1Institut für Kernphysik, Goethe Universität Frankfurt am Main — 2Institut Pluridisciplinaire Hubert Curien (IPHC), Strasbourg/France — 3GSI, Helmholtzzentrum für Schwerionenforschung GmbH, Darmstadt —

4Forschungsneutronenquelle Heinz-Maier-Leibnitz (FRM II), Technische Universität München

M. Deveaux, 15th CBM collaboration meeting , 14th April 2010, GSI 2

Sensors for the MVD

CBM

wish list

MAPS*

(2003)

MAPS*

(2009)

MIMOSA-26

Binary, 0

Single point res. ~ 5 µm 1.5 µm 1 µm 4 µm

Material budget < 0.3% X0 ~ 0.1% X0 ~ 0.05% X0 ~ 0.05% X0

Rad. hard. non-io. >1013 neq 1012 neq/cm² >3x1013 neq few 1012 neq

Rad. hard. io > 3 Mrad 200 krad > 1 Mrad > 300 krad

Time resolution < 30 µs ~ 1 ms ~ 25 µs 110 µs

Optimized for one parameter Current compromise

Monolithic Active Pixel Sensors(MAPS, also CMOS-Sensors)

• Invented by industry (digital camera)• Modified for charged particle detection since 1999 by IPHC Strasbourg • Also foreseen for ILC, STAR… => Sharing of R&D costs.

M. Deveaux, 15th CBM collaboration meeting , 14th April 2010, GSI 3

Chapter 1

Sensor R&D

M. Deveaux, 15th CBM collaboration meeting , 14th April 2010, GSI 4

Radiation hardness studies

Undepleted MAPS

Depleted MAPS

Radiation tolerance of MAPS as function of pixel pitch

Sensor ok if det. eff > 95%

M. Deveaux, 15th CBM collaboration meeting , 14th April 2010, GSI 5

Sensor R&D: MIMOSA-26

Analog pixel outputs for tests

JTAG slow control On-chipvoltagegenerators

1152 discriminators

zero suppr. logic

Output memories

3 mm

Suited for up to 9 hits/line => ~ 1% occupancy

21.2 x 10.6 mm²18.6 µm pixel pitch

M. Deveaux, 15th CBM collaboration meeting , 14th April 2010, GSI 6

First analysis resultsFirst analysis results

6

Mimosa26 Spectrum

Mimosa26 Noise

First tests successfully performed at T= -20°C and .

Prelim

inary

D. D

oering

M. Deveaux, 15th CBM collaboration meeting , 14th April 2010, GSI 7

Comparison standard and depleted sensor

7

0 50 100 150 200 250 300 350 400 450 500 550 600 6500

100

200

300

400

500

600

unirradiated

6 1012 neq/cm²

Ent

ries

in h

isto

gram

Charge collected [ADC]

Depleted sensor 400 Epitaxial layer: 15µm

Fe-554 pixel clusterT=-20°C

Fe-55 4 pixel cluster T=-20°CShift afterirradiation No shift

Very uniform charge collectionproperties but: Strong radiationeffect.

Sensor not uniform (as partiallydepleted): Reduced radiation effect.

D. D

oering

M. Deveaux, 15th CBM collaboration meeting , 14th April 2010, GSI 8

Sensors for the MVD

CBM

wish list

MAPS*

(2003)

MAPS*

(2009)

MIMOSA-26

Binary, 0

Single point res. ~ 5 µm 1.5 µm 1 µm 4 µm

Material budget < 0.3% X0 ~ 0.1% X0 ~ 0.05% X0 ~ 0.05% X0

Rad. hard. non-io. >1013 neq 1012 neq/cm² >3x1013 neq few 1012 neq

Rad. hard. io > 3 Mrad 200 krad > 1 Mrad > 300 krad

Time resolution < 30 µs ~ 1 ms ~ 25 µs 110 µs

Optimized for one parameter Current compromise

Monolithic Active Pixel Sensors(MAPS, also CMOS-Sensors)

• Invented by industry (digital camera)• Modified for charged particle detection since 1999 by IPHC Strasbourg • Also foreseen for ILC, STAR… => Sharing of R&D costs.

M. Deveaux, 15th CBM collaboration meeting , 14th April 2010, GSI 9

Annealing studies with combined radiation irradiated MAPSAnnealing studies with combined radiation irradiated MAPS

9

Temperature profile

T[°C]

Time

20°C

80°C

Neutronradiation

1 year

X-rayradiation

Measurementsat T=20°C (280h)

Heating at T=80°C (73h)

Measurements and storage at T=20°C (191h)

2h transport

D. D

oering

M. Deveaux, 15th CBM collaboration meeting , 14th April 2010, GSI 10

Annealing studies

0 40 80 120 160 200 240 280 320 3600

50

100

150

200

250

300

350

400

450

irradiated with 200 krad X-ray

1013 neq

/cm²

xRay + neutrons no radiationLe

akag

e cu

rren

t [f

A]

Net anneal time [h]

T=20°C T=80°C

-70%

Annealing dims ionizing radiation substantiallyNo trace of reverse annealing (yet) => Recover detector on the fly(?)

D. D

oering

M. Deveaux, 15th CBM collaboration meeting , 14th April 2010, GSI 11

Chapter 3: Data rates and performances

1 fake hit / hit in the MVD

Measurement of the dark rate of irradiated MIMOSA-18

hits/pixel/readout

M. D

omachow

ski

To be used as input for the MVD-Digitizer

M. Deveaux, 15th CBM collaboration meeting , 14th April 2010, GSI 12

Chapter 2:

System integration (1)

M. Deveaux, 15th CBM collaboration meeting , 14th April 2010, GSI 13

Design of a ladder for the MVD

CBM-AcceptanceLow material

5 cm

M. Deveaux, 15th CBM collaboration meeting , 14th April 2010, GSI 14

Steps of a system integration: The MVD-Demonstrator

Idea

Thermal simulation

CAD-Design

Construction

Power: ~ 1W /cm²

M. Deveaux, 15th CBM collaboration meeting , 14th April 2010, GSI 15

Achievements:

System design validatedGood noise: 21 e- ENCSpatial res.: < 6µm

Steps of a system integration: The MVD-Demonstrator

Construction

Beamtest @ CERN-SPS(Nov 2009)

signal (a.u.)

Shadow of trigger scintillator

Prelim

inary

Demonstrator project

accomplished

S. A

mar-Y

oucef

M. Deveaux, 15th CBM collaboration meeting , 14th April 2010, GSI 16

Towards the MVD: HP-2 ULISI

Build an ultra thin ladder. Partners: IPHC, IKF, IMEC

Chip on polyamide: Technology demonstrator by IMEC, Belgium

Build a “prototype” with:• Fast digital sensors• FEE/DAQ for multiple sensors• “Close to real detector” performance

M. Deveaux, 15th CBM collaboration meeting , 14th April 2010, GSI 17

Towards the MVD: HP-2 ULISI

Diamond 200-300 µm

~ 60(1) -150(2) µm Si

< 200 µm Si

~ 60(1) -150(2) µm Si

~ 320(1)-500(2) µm Si

Polyamide SensorMetal lines

Build an ultra thin ladder.Partners: IPHC, IKF, IMEC

(1) first MVD station(2) last MVD station

Project kick off: Dec. 2009First Prototype: Apr. 2010First results: End 2010

M. Deveaux, 15th CBM collaboration meeting , 14th April 2010, GSI 18

Chapter 2:

Simulation

.

.

.

.

.

.

.

M. Deveaux, 15th CBM collaboration meeting , 14th April 2010, GSI 19

Open charm simulation with delta-electrons and pile-up

• Thickness of sensors - Geometry used– Pixel pitch : 18.4 × 18.4 µm2 (From MIMOSA 26)

• Time resolution = 30 µs (MIMOSIS-2)

Station Z [cm]Thickness

[µm]Rinner [mm] Router [mm]

1 5 300 5.5 25

2 10 500 5.5 50

Collision rate(interactions/s)

Collisions/year(mbias)

D0 →π+K-

(generated) *

No pile up 3 ·10 4 1.5·1011 68 000

Pile up 5 1.5 ·10 5 7.5·1011 340 000

C. D

ritsa

M. Deveaux, 15th CBM collaboration meeting , 14th April 2010, GSI 20

Analogue readout: PV sigma

Pile UpSignal Efficiency

(PV>3)

Background rejection

(PV>3)

0 30.0 % 99.4 %

5 29.8 % 98.0 %

10 30.8 % 92.2 %

C. D

ritsa

M. Deveaux, 15th CBM collaboration meeting , 14th April 2010, GSI 21

Hit merging and track reconstruction

1: High P track

2: Low P track

MVD STS

• The high P track will be reconstructed first and will “own” the hit.• The track parameters will be slightly modified.• Hit sharing is not implemented in the MVD: The low momentum

track does not “find” the hit. There is a probability to pick up a wrong neighbouring hit (?)

C. D

ritsa

M. Deveaux, 15th CBM collaboration meeting , 14th April 2010, GSI 22

Open Charm reconstruction

No pile-upC

. Dritsa

M. Deveaux, 15th CBM collaboration meeting , 14th April 2010, GSI 23

~ 2500 D0

~ 700 D0

Significance

Operating with pile-up seems mandatory but:• Hardware has to be optimized – review detector position and geometry• Pattern recognition should be studied – reduce background

C. D

ritsa

M. Deveaux, 15th CBM collaboration meeting , 14th April 2010, GSI 24

Chapter 3:

FEE and DAQ

M. Deveaux, 15th CBM collaboration meeting , 14th April 2010, GSI 25

Data rates for 1.5 x 105 coll/s

Data rate of the sensors was simulated accounting for:

pile-up, delta electrons, clustering,fake hits rates , data protocols....

S. S

eddi

ki

No multiplexers in vacuum vessel (cooling, radiation dose) => more than 200 differential links ( > 10 GB/s compressed data)

100 GB/s for 3D-Sensors

S. S

eddiki

M. Deveaux, 15th CBM collaboration meeting , 14th April 2010, GSI 26

DAQ-system for the MVD

Slow control:JTAG

Time stampingSensor Control

Data concentrationFPGA based:• Cluster finding (?)• Fake rejection (?)• Pattern recognition (?)

PC interface:4x 3.8 Gbit/s•GPU based data processing•Interface to FLES

All hardware components shown are available (HADES TRBNet)Prototype MVD-DAQ: • Compact radiation hard and vacuum compatible FEE-boards• System validation (Firmware, Data concentration algorithms)• Speed up TRBNet (So far designed for 200 MB/s with 2 Gbit/s links)

C. S

chrader

M. Deveaux, 15th CBM collaboration meeting , 14th April 2010, GSI 27

Summary and Conclusion

The MVD – demonstrator project was successfully completed.• Readout chain shows good noise performance in beam• Spatial resolution obtained in beam test fits CBM-requirements

The feasibility of open charm reconstruction with pile-up 5 and delta electrons was demonstrated => 1.5 x 105 coll/s with MIMOSIS-2.

• Relatively high background => Improve hit finder, MVD-tracking.• High occupancy: Review mag. field, detector position

Radiation hardness tests are progressing: • Test of MIMOSA-26 HR show first promising results • Annealing tests suggest that ionizing radiation damage can be partially recovered in installed detector.

Outlook: Build prototype with “close to real detector”-performance• Study silicon in polyamide technology => would match material budget goals• Study realistic FEE-DAQ based on Hades TRBNet

M. Deveaux, 15th CBM collaboration meeting , 14th April 2010, GSI 28

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