Nikhef Annual Meeting13 Dec 2001

Future Vertexing

Els Koffemanfor

Nikhef Vertex Group

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Topics

• No report on Zeus, Hermes, Alice, LHC-B, Atlas in spite of much progress

• No report on beautiful infrastructure• R&D vertex detectors

– Very High Luminosity Hadron Colliders• Extreme radiation hardness (1x 1016 /cm-2)

– Linear Colliders• High precision (1-5 micron point resolution)

• Low material (0.1 X0 per layer)

• ‘small’ detectors

• Medipix• Time Projection Chamber

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Electronic Department

• Recent projects– Alice: analoge buffer/line driver, digital control ic (jtag +

glue logic), power supply is prevented for single event latchup

– LHCB: analog line driver en comparators voor beetle chip– pixel: 4 bits adc per pixel– zeus: fail safe token voor helix– general: low noise amplifier

• Four FTE engineers working on VLSI• Education

– EPFL (Lausanne)– Advanced Analog IC Design (5 people)– Advanced Digital IC Design (3 people)– Practical Aspects in Analog & Mixed Mode ICs (3 people) – Transistor-level Analog IC Design (2 people)– expected: low voltage analog IC (2 people)

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NP

Quick Reminder

• Silicon as a sensor – 300 micron thick wafer– High resistivity, purity– Surface strips, pixels, pads

• Silicon as readout– Poor quality wafer– Photolitography makes

Integrated Circuits – All structure contained in few

micron thickness– Most important component is

transistor – Current technology

‘CMOS 0.25 micron’

P

Silicon pixel,pad,strip

gate

contact

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Signal!

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Crystal Damage !(vacancy, interstitials)

Charge generationInside CMOS!

Leakage currentsNeed High VoltageLess collected

charge

Transistor performancedegradesChip ‘blows up’

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R&D vertexing

• CERN– RD 19 Pixels– RD 39 Cryogenic operation of silicon– RD 42 Diamond detectors– RD 48 ROSE radhard silicon– RD 49 Radhard Electronics– Proposal for new R&D group

• LCFI (linear collider flavour identification)– CCD detector for TESLA– 8 UK institutes, CERN, SLAC

• MIMOSA – Monolithic pixels– Proposal submitted to DESY PRC – Strassbourg, Geneve, Nikhef, Liverpool, Glasgow, RAL, …

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Radiation Hardness of Silicon

• The leakage current damage parameter is material independent

• Radiation damage very different for different particles (expressed in hardness factor K)– 24 GeV protons K =1– Slow neutrons K=0.9– Fast neutrons K=1.7– Gamma 60-Co K=2x10-6

• ‘Effective doping changes’ (or increasing depletion voltage) improved by oxygenation of the material

• A macroscopic damage parameter model has been developed which can be used to predict detector parameters in a given radiation environment including annealing effects

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Radiation harder with oxygen?

•Two methods were found to highly oxygenate silicon.

– Firstly, at the ingot growing stage.

– Secondly by diffusion of oxygen into ANY wafer using a high temperature drive-in

– Technology has been successfully transferred to several silicon detector manufacturers (SINTEF,Micron, ST, CIS) and full-scale microstrip detectors have been produced.

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Pixel systems

• MCM multi chip module– ‘traditional’ 300 um thick

pixel sensor bump bonded to a chips with amplifiers and readout.

• CCD – Charge collection in thin

surface layer– charge transferred through

the wafer

• Monolithic pixel– use standard CMOS wafer– simple readout per pixel

sensor

chip

sensor

Surface

sensor

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Monolithic Pixels

• No depletion layer• charge diffusion

only• < 1000 electrons• cell =• Monolithic:part of

the CMOS is used as detector element

• Will it work ?

2μm 20 x 20 μm 10

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MIMOSA - I

4000 pixels !

1.2 x 1.2 mm2

2μm 20 x 20

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MIMOSA

Signal / noise = 40

Efficiency = 99%

Resolution μm 1.8

NIKHEF proposeda ladder ‘concept’thickness 0.05 mm12 cm long3 x 2 cm wide

0.9 g silicon 0.8 g support

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Diamond – Pixel detector

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Medipix- recent developments

• Chip Design (0.25 mm) (TMR EU project)

– DAC's for Alice/LHCb chip (radhard)– DAC's for Medipix2 chip

• MUROS2 Interface for Medipix2

• Multi-Chip Board for 2x4 multichip Medipix2 imager

• Dynamical Defectoscopy – micro-crack development in Aluminium (Marie Curie EU

project)

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Multi-Chip Board

MUROS2 Chi

pboa

rd

8 ASIC chips Medipix2 chip size 14 x 16 mm2

1 Sensor 28 x 56 mm2 (fully sensitive area)

512 x 1024 Pixels of 55 x 55 mm2 (0.5 Megapixel)

Prototype, useful for e.g. Small Animal Imaging

Vbias

SCSI-5 Cable160 Mhz LVDS

PC+DIO

10 Mhz

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3 different micro ADC's

<100 x 100 mm area<1 mW power

David San Segundo Bello

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Chipboard Top layer metal

High Density Interconnect Technology9 metal layers (5 in kapton build-up)1840 staggered m-via's 366 drilled-through via's 80 SMT capacitors

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1mm Hole 7

X-ray Defectoscopy

Si GaAs

Si + FlatField Correction

5 mm 0.5 mm

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TPC for a linear collider

• Traditional TPC: signal collected on wires • Principle of GEM introduced by Sauli• Used in conjunction with MSGC’s or plain

electrodes

• New idea: get the electrons directly in a chip! (Harry v.d Graaf, Jan Visschers, Erik Heijne)

• If successful (with 60 *60 micron pitch) – Resolution limited by diffusion– Optimise gas max for this– Much better track separation– Can improve all time favorite Aleph TPC with 30-40 %

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TPC + medipix chip

GEM

Medipix chipkathode

~ 1mm

~ 1mSensitive area

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TPC plans

• Build proto type• If charge measured

= > connect to Medipix chip.

• Develop prototype for TESLA….

• Need 15 m2 of chips!

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Conclusion….

• Medipix• Diamond • CMOS sensors• micro-electronics• Novel TPC

R&D is in good shape

we need a vertex group !Do we need a vertex group ? R & D

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