status of the micro vertex detector m. deveaux, goethe university frankfurt for the cbm-mvd...

Status of the Micro Vertex Detector

M. Deveaux, Goethe University Frankfurt for the CBM-MVD collaboration

The CBM-MVD

M. Deveaux 2

CB

M

We are here

How will it look

M. Deveaux 3

Magnet Silicon Tracking System

DAQcards

Vacuum vessel

MVD - planes

4M. Deveaux,

Open charm reconstruction: Concept

Primary Beam: 25 AGeV Au Ions (up to 109/s)

Primaryvertex Secondary

vertex

Short lived particle D0 (ct = ~ 120 µm)

Detector 1Detector2Target

(Gold)

z

Reconstruction concept for open charm

Central Au + Au collision (25 AGeV)

• A good time resolution to distinguish the individual collisions (few 10 µs)

• Very good radiation tolerance (>1013 neq/cm²)

Reconstructing open charm requires: • Excellent secondary vertex resolution (~ 50 µm)=> Excellent spatial resolution (~5 µm)=> Very low material budget (few 0.1 % X0)=> Eventually: Detectors in vacuum

5

Status of the sensors (last meeting 2011)

M. Deveaux

CBMSIS300

MAPS*(2003)

MAPS* (2011)

MIMOSA-26

(2010)

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 1x1013 neq 1013 neq

Rad. hard. io > 3 Mrad 200 krad > 1 Mrad > 500 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, ALICE…

=> Sharing of R&D costs.

A word on simulation

6M. Deveaux

MVD and STS

integration

Global design: How many MVD stations?

M. Deveaux 7

5 cm

Targ

et

MV

D 1

MV

D 2

ST

S 1

ST

S 2

ST

S 3

Vacuumwindow

Tracking, artist view


M. Deveaux 8

5 cm

Targ

et

MV

D 1

MV

D 2

ST

S 1

ST

S 2

ST

S 3

Vacuumwindow



M. Deveaux 9

5 cm

Targ

et

MV

D 1

MV

D 2

ST

S 1

ST

S 2

ST

S 3

Vacuumwindow



M. Deveaux 10

5 cm

Targ

et

MV

D 1

MV

D 2

ST

S 1

ST

S 2

ST

S 3

Vacuumwindow



M. Deveaux 11

5 cm

Targ

et

MV

D 1

MV

D 2

ST

S 1

ST

S 2

ST

S 3

Vacuumwindow



M. Deveaux 12

5 cm

Targ

et

MV

D 1

MV

D 2

ST

S 1

ST

S 2

ST

S 3

Vacuumwindow


L1 “MVD track finding efficiency” vs. MVD design

13

MV

D tr

ack

findi

ng e

ffici

ency

[%]

2 MVD stations

3 MVD stations

4 MVD stations

5 10None pile up

100% = primary tracks, geo-metrically accepted by MVD,> 4 hits in STS

90

50

Tracking efficiency = 83% for standard MVD, drops to <55% at pile up 10

Tracking efficiency is substantially improved by additional stations

Impact for 4th station to be studied in detail

M. Deveaux

C. T

rageser

Background rejection capabilities of the MVD

14

0

50

None 5 10

acce

pted

BG

-tra

cks

/ eve

nt

Bad reconstruction

Some bad hits

Good track finding

Not accepted

Cuts:p >1 GeVpt>0.3 GeVLong (>4 in STS)IP<600µmIP/sIP>6

M. Deveaux

More than 2 MVD stations are needed for BG rejectionExpect good sensitivity for open charm with >3 stations

C. T

rageser

Sensor R&D

M. Deveaux 15

for (Int_t Mimosa=1; true; Mimosa++) {

Build_Next_Prototype (Mimosa);Test_Prototype (Mimosa);Enjoy_Spectacular_Progress_Of(Mimosa);

ImproveDesign(Mimosa);}

0 5 10 15 20 25 30 35 401011

1012

1013

1014

1015

MIMOSA-9

MIMOSA-9

MIMOSA-15 (2006)MIMOSA-18 (2008)

Uncertainty range

Radia

tion tole

rance

[n

eq/c

m²]

Pixel pitch [µm]

Long standing believes vs. technological progress

16

A small pixel pitch is needed to reach the radiation tolerance needed for CBM

CBM goal

M. Deveaux

17M. Deveaux

Sensor R&D: The operation principle

Reset+3.3V+3.3V

Output

SiO2 SiO2 SiO2

N++ N++N+ P+

P-

P+

15µm50µm

18

Sensor R&D: Tolerance to non-ionising radiation

+3.3VOutput

SiO2 SiO2

N++

N+SiO2 SiO2

P++ P++ P++

GND GND

+3.3V

19


+3.3VOutput

SiO2 SiO2

N++

N+SiO2 SiO2

P++ P++ P++

GND GND

+3.3V

Key observation: Signal amplitude is reduced by bulk damage

20


+3.3VOutput

SiO2 SiO2

N++

N+SiO2 SiO2

P++ P++ P++

GND GND

+3.3V

Electric field increases the radiation hardness of the sensorDraw back: Need CMOS-processes with low doping epitaxial layer

E


21


MIMOSA-32:20x40µm² pixel99.5%0 5 10 15 20 25 30 35 40

1011

1012

1013

1014

1015

MIMOSA-9

MIMOSA-9

MIMOSA-15 (2006)MIMOSA-18 (2008)

MIM

OSA-18 AHR (2011)*

Sensor based on high-resistivity EPI layer Sensor based on low-resistivity EPI layer Uncertainty range

Ra

dia

tion

to

lera

nce

[n

eq/c

m²]

Pixel pitch [µm]* Cooled down to -35°C

D. Doering et al. – Mimosa18 AHR

CBM goal

M. Deveaux

22

Status of the sensors (last meeting 2011)

M. Deveaux

CBMSIS300

MAPS*(2003)

MAPS* (2011)

MIMOSA-26

Binary, 0



Rad. hard. non-io. >1013 neq 1012 neq/cm² >1x1013 neq >1013 neq








23

Update on sensor R&D

M. Deveaux

CBMSIS300

MAPS*(2003)

MAPS* (2013)

MIMOSA-26

Binary, 0











Challenge: Find MAPS-compatible 0.18µm CMOS process

• 32 mm² surface

Radiation tolerance of MAPS

24

So far - Radiation tolerance limited by:

• Leakage current – noise• Conduction channels between transistors (?)

DONE

First prototype: MIMOSA-32

• 32 different kinds of pixels• 32 µs readout time

33 mm²

Known solution: • Use 0.18 µm CMOS instead of 0.35µm CMOS

M. Deveaux


25


MIMOSA-32:20x40µm² pixel99.5%0 5 10 15 20 25 30 35 40

1011

1012

1013

1014

1015

MIMOSA-9

MIMOSA-9

MIMOSA-15 (2006)MIMOSA-18 (2008)

MIM

OSA-18 AHR (2011)*


Ra

dia

tion

to

lera

nce

[n

eq/c

m²]


CBM goal

Mimosa-32, 20x40µm² pitch(Beam test @ SPS by IPHC, preliminary)

99.5% detection efficiencyAfter 1013 neq/cm² + 1 MRad !

M. Deveaux


26

MIMOSA-32:20x40µm² pixel99.5%0 5 10 15 20 25 30 35 40

1011

1012

1013

1014

1015

MIMOSA-9

MIMOSA-9

MIMOSA-15 (2006)MIMOSA-18 (2008)

MIM

OSA-18 AHR (2011)*


Ra

dia

tion

to

lera

nce

[n

eq/c

m²]


CBM goal


99.5% detection efficiencyAfter 1013 neq/cm² + 1 MRad !


M. Deveaux

Why is this important?

27

Pixel with pedestal correction

~1000 discriminators

On - chip cluster-finding processor

Output: Cluster information(zero suppressed)

50 µ

s/frame

25 µ

s/frame

12 µ

s/frame

~2000

20x20µm² 20x40µm²

Requires 0.18µm CMOSTest chip submitted

M. Deveaux

Why is this important

28





50 µ

s/frame

25 µ

s/frame

12 µ

s/frame

~2000

20x20µm² 20x40µm²


M. Deveaux

MAPS are too slow for CBM

Why is this important

29

There is a clear strategy for reaching the readout speed neededfor CBM





50 µ

s/frame

25 µ

s/frame

12 µ

s/frame

~2000

20x20µm² 20x40µm²


M. Deveaux

30

Update on sensor R&D

M. Deveaux

CBMSIS300

MAPS*(2003)

MAPS* (2013)

MIMOSA-26

Binary, 0











MIMOSA-32 and ionizing radiation

M. Deveaux 31

0 1 2 3 4 5 6 7 8 9 100369

1215182124273033

EN

C [e]

Ionizing radiation dose [Mrad]

0.35µm 0.18µm

Noi

seSensor irradiated with X-rays @ CERN

Noise increases much slower (as expected)Higher initial noise (not expected)

D. D

oering

32


+3.3VOutput

SiO2 SiO2

N++

N+SiO2 SiO2

P++ P++ P++

GND GND

+3.3V

Study noise with varied size of transistor gate

Comparison with 0.18µm vs. AMS 0.35

M. Deveaux 33

0 10 20 30 40 50 60 70 80 90 1001

10

100

Ent

ries

Noise [e]

Mi18AHR A2 Mi32ter P2 Std. Mi32ter P5 Tiny SF

Dennis Doering

D. D

oerin

g

0.35 µm, big 0.18µm, small

0.18µm, tiny

Going into details

34

0 10 20 30 40 50 60 70 80 90 1001

10

100

Ent

ries

Noise [e]

Mi18AHR A2 Mi32ter P2 Std. Mi32ter P5 Tiny SF

Dennis Doering

M. W

inter et al.

Random Telegraph Signal

35

M. W

inter et al.

RTS, illustration

Sensors see difference between two samples

Side peaks due to change of state.

Problem understood, => Need bigger gates

36

So what?

M. Deveaux

CBMSIS300

MAPS*(2003)

MAPS* (2013)

MIMOSA-26

Binary, 0








99.5% det. efficiency (S/N ~30)After 3 MRad at +15°C!

37M. Deveaux

So what?

CBMSIS300

MAPS*(2003)

MAPS* (2013)

MIMOSA-26

Binary, 0








99.5% det. efficiency (S/N ~30)After 3 MRad at +15°C!

Next steps in the R&D

38





Prototype MIMOSA-22THRsubmitted

Already excellent butGet rid of RTS4 prototypes submitted

Prototype SUZE - 2submitted

First prototypes in 0.18µm CMOS show spectacular results.Full engineering run (11 CBM relevant prototypes) submitted.More to come => Stay tuned.

M. Deveaux

How to integrate the sensors?

M. Deveaux, CBM Collaboration Meeting, Kolkata, 24-28. Sept 2012 39

MIMOSA-26 (600 kPixel, 104 frames/s, zero suppression) Thinned to 50µm, at IKF Frankfurt

See next talk (M. Koziel)

Summary

40

Sensors for MVD (since 2010)

• Radiation tolerance (non-io.) was improved by factor 10• Radiation tolerance (io) was improved by factor > 3• All sensor requirements for CBM are individually demonstrated• Still room for improvement in 0.18µm process

• Ongoing effort to combine all functionalities

Simulation

• MVD needs 3 or 4 stations for good performance

Prototype and integration: Very promising (see next talk)

M. Deveaux, CBM Collaboration Meeting, Kolcata, 24-28. Sept 2012 41The prototype DAQ at night

PICSEL Group IPHC, Strasbourg (sensor R&D + test)Thanks to: S. Amar-Youcef, B. Milanovic, Q. Li (Prototype firmware and analysis) M. Koziel, T.Tischler (mechanical integration)B. Neumann (JTAG slow control), M. Wiebusch (analog electronics)C. Trageser (simulation)C. Schrader (DAQ concept and coordination, now with BOSCH),

status of the micro vertex detector m. deveaux, goethe university frankfurt for the cbm-mvd...

Documents

mvd stations

mvd design

target mvd

standard mvd

deveaux slide

cbmmvd collaboration

l1 mvd track

vacuum slide