CMOS sensors: a short introduction

CMOS sensors:CMOS sensors:a short a short

introductionintroduction

1.1.What’s a CMOS What’s a CMOS sensor?sensor?

A new techniqueA new techniquefor pixel detectorsfor pixel detectors

A prototype on its test board support

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A sensor (1 million pixels)

Sensors are produced on silicon wafers(30 to 50 units)

15 cm

A single pixelA single pixel

20 m

A hair: microscopic view,A hair: microscopic view,same scalesame scale

Zooming on the sensor makes the pixels visible

0.5 millimeters

2.2.How does How does thatthat

work?work?

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The particlegoes

through

Layer sensitive toparticles

Supporting bulk (insensitive)

Charges collected are integrated to

build an amplified electric

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Micro-circuits for signal treatment

Collector

Free charges are created, then

collected by the diode (positively

charged)

Let’s cut a pixel. We see its composition and

what happens when a particle goes through

Steering and analysis

The particle goes

through

Information from each pixel are

transmitted to PC

Particle crossing positionis identified precisely

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Particle crossing position is identified precisely

Sign

al a

mpl

itude

Column number Line number

Hit pixel

Tracking particlesTracking particles

3. What’s for3. What’s for ? ?

Particles need to be tracked very near the collision point: this is the place for the

thin and granular CMOS sensors

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25 cm

10 cm

Barrel type detectormade of 5 sensor layers

e-

e+

Carbon fiber su

pporting ladder

To build a tracking detector

A. Individual sensor assembly on a ladder

B. Ladders are arranged on a

hermetic barrel moi

Barrel of ladders with sensors

A tracking deviceInitial particle collision

point.Newly created particles

are emitted in all directions

e- e+

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10 cm

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Knowing the particle crossing point with a high accuracy,

allows computerized algorithms to reconstruct the full trajectory of each particle.

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ImagingImaging

3. What’s for3. What’s for ? ?

Imaging versus tracking

3D space trajectory

2D space + 1 time trajectory

Particle physics tracks particles in space

space

Imaging camera tracks emission sources in

time

time

Tracking sensors need to detect single particles

Single particle sensitivity for imaging devices offers:

•Infinite dynamics•Better image definition•Noise reduction

Cockroach head from synchrotron light source (5.2 keV X-rays) with a

CMOS sensor

Accelerated electrons are individually

detected by the CMOS sensor

Detecting single photons from visible light

Lilly root cell, through epi-fluorescence

microscopy using an EB-CMOS cameraElectrons are

accelerated by the E-field

Photons hit the photocathode and get converted into

electrons

The pioneering group The pioneering group for particle trackingfor particle tracking

4. CMOS sensor4. CMOS sensorat IPHCat IPHC

Charge collection & technology studies – simple demonstrators

Production

MimoStar3

MimoTEL Imager10µ Imager12µ

Mimosa16 Mimosa16

Latchup ADC ADC MyMap

TestStruct

Real size prototype - yield studiesReticule 2x 2 cm 2006

Data compression - digitizationSara 2006Suze 2007

MIMOSA sensors: a coherent evolution

Final circuits – sub-blocs integration

Mimosa22

2008

Pixel Array

DiscriminatorsZero Suppression

Bias Readout

2007

1999

More than 30 sensors designed & tested since 1999 !

Our CAD center

Collaborations:The USA: Fermi Nat. Lab.Brookhaven Nat. Lab.L.Berkeley Nat. Lab.

Europe: France: Lyon Uni., CEAGermany: DESY, GSI, Frankfurt Uni.Italian subatomic physics lab. (INFN)Switzerland: CERN, Geneva Uni.

China: Dalian Uni.Xian Uni.

Industry: SAGEMPHOTONIS

The The endend