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Nikhef Annual Meeting13 Dec 2001
Future Vertexing
Els Koffemanfor
Nikhef Vertex Group
dec 2001 els koffeman 2
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
dec 2001 els koffeman 3
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)
dec 2001 els koffeman 4
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
dec 2001 els koffeman 5
Signal!
dec 2001 els koffeman 6
Crystal Damage !(vacancy, interstitials)
Charge generationInside CMOS!
Leakage currentsNeed High VoltageLess collected
charge
Transistor performancedegradesChip ‘blows up’
dec 2001 els koffeman 7
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, …
dec 2001 els koffeman 8
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
dec 2001 els koffeman 9
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.
dec 2001 els koffeman 10
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
dec 2001 els koffeman 11
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
dec 2001 els koffeman 12
MIMOSA - I
4000 pixels !
1.2 x 1.2 mm2
2μm 20 x 20
dec 2001 els koffeman 13
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
dec 2001 els koffeman 14
Diamond – Pixel detector
dec 2001 els koffeman 15
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)
dec 2001 els koffeman 16
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
dec 2001 els koffeman 17
3 different micro ADC's
<100 x 100 mm area<1 mW power
David San Segundo Bello
dec 2001 els koffeman 18
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
dec 2001 els koffeman 19
1mm Hole 7
X-ray Defectoscopy
Si GaAs
Si + FlatField Correction
5 mm 0.5 mm
dec 2001 els koffeman 20
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 %
dec 2001 els koffeman 21
TPC + medipix chip
GEM
Medipix chipkathode
~ 1mm
~ 1mSensitive area
dec 2001 els koffeman 22
TPC plans
• Build proto type• If charge measured
= > connect to Medipix chip.
• Develop prototype for TESLA….
• Need 15 m2 of chips!
dec 2001 els koffeman 23
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
dec 2001 els koffeman 24