CMOS sensors a short introduction 1 Whats a

CMOS sensors: a short introduction

1. What’s a CMOS sensor? A new technique for pixel detectors

sensor (1 million A hair: Amicroscopic view, pixels) same scale 0. 5 on millimeters A prototype its test board support 15 cm A single pixel 20 m Zooming on the sensor makes the pixels visible Sensors are produced on silicon wafers (30 to 50 units) moi

2. How does that work?

Free charges are The particle created, Charges collected Let’s cut then a pixel. goes through collected by the are integrated to We seediode its (positively composition and build an amplified what happens when a particle goes through charged) electric signal moi Micro-circuits for signal treatment Collector - - - Layer sensitive to particles - - - Supporting bulk (insensitive)

Particle crossing position is identified precisely Signal amplitude The particle goes through Hit pixel ysis anal d n a g teerin S Co lum moi nn um be r Information from each pixel are transmitted to PC ber m u n e n Li Particle crossing position is identified precisely

3. What’s for ? Tracking particles

Particles need to be tracked very near the collision point: this is the place for the thin and granular CMOS sensors e+ 10 cm e- m 25 c moi Barrel type detector made of 5 sensor layers moi

To build a tracking detector A. Individual sensor assembly on a ladder r e d o p p u s r B. Ladders are arranged on a hermetic barrel Ca n o rb in t r e b i f moi ad l g

A tracking device Barrel of ladders with sensors e 10 cm Initial particle collision point. Newly created particles are emitted in all directions e+ moimoi

Knowing the particle crossing point with a high accuracy, allows computerized algorithms to reconstruct the full trajectory of each particle. moi

3. What’s for ? Imaging

Imaging versus tracking Particle physics tracks particles in space 3 D space trajectory Tracking sensors need to detect single particles Imaging camera tracks emission sources in time Cockroach head from synchrotron light source (5. 2 ke. V X-rays) with a time CMOS sensor 2 D space + 1 time trajectory Single particle sensitivity for imaging devices offers: • Infinite dynamics • Better image definition • Noise reduction

Detecting single photons from visible light Photons hit the photocathode get Lilly root cell, and through converted into epi-fluorescence electrons microscopy using an EB-CMOS camera Electrons are accelerated by the Efield Accelerated electrons are individually detected by the CMOS sensor

4. CMOS sensor at IPHC The pioneering group for particle tracking

MIMOSA sensors: a coherent evolution Charge collection & technology studies – simple demonstrators 1999 Real size prototype - yield studies Reticule 2 x 2 cm 2006 Pixel Array Production Discriminators Zero Suppression Bias Readout Final circuits 2008 – Mimosa 22 2007 sub-blocs integration Suze 2007 Data compression Sara 2006 - digitization

More than 30 sensors designed & tested since 1999 ! Industry: Our CAD center Collaborations: The USA: Europe: SAGEM PHOTONIS China: Fermi Nat. Lab. France: Lyon Uni. , CEA Dalian Uni. Brookhaven Nat. Lab. Germany: DESY, GSI, Frankfurt Uni. Xian Uni. L. Berkeley Nat. Lab. Italian subatomic physics lab. (INFN) Switzerland: CERN, Geneva Uni.

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