CMOS sensors: a short introduction
description
Transcript of 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
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