gridpix een detector r & d project voor: - large tpc for ilc - gossip & the atlas sct...
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GridPix
Een Detector R & D project voor:
- Large TPC for ILC- GOSSIP & the ATLAS SCT Upgrade
Harry van der GraafNIKHEF, Amsterdam
Electronische Afdeling,Nikhef April 4, 2007
Time Projection Chamber (TPC): 2D/3D Drift ChamberThe Ultimate Wire (drift) Chamber
E-field(and B-field)
Wire Plane+Readout Pads
track ofchargedparticle
Wire plane
Pad plane
Problem
With wires: measure charge distribution over cathode pads:c.o.g. is a good measure for track position;With GEMs or Micromegas: narrow charge distribution(only electron movement)
wireavalanche
Cathode pads
GEMMicromegas
Solutions: - cover pads with resisitive layer- ‘Chevron’ pads- many small pads: pixels!
The MediPix2 pixel CMOS chip
- 256 x 256 pixels- pixel pitch: 55 x 55 μm2
- Within each pixel:- preamp + shaper + discr- 14-bits counter- discr. thresholds
- Developed by MediPix Consortium, CERN
We apply the ‘naked’ MediPix2 chipwithout X-ray convertor!
MediPix2 pixel sensorBrass spacer blockPrinted circuit boardAluminum base plate
Micromegas
Cathode (drift) plane
55Fe
Baseplate
Drift space: 15 mm
MediPix2 & Micromegas
Very strong E-field above (CMOS) MediPix!
He/Isobutane80/20Modified MediPix
δ-ray!
Efficiency fordetecting single electrons: < 95 %
Integrate GEM/Micromegas and pixel sensor:
InGrid‘GEM’ ‘Micromegas’
By ‘wafer post processing’
InGrid VS MicromegasInGrid VS Micromegas
MicromegasMicromegasElectroforming tech.Electroforming tech.
– Large areasLarge areas– Large pillar Large pillar Ø (250 µm)Ø (250 µm)– Hybrid detectorHybrid detector
Manual mountingManual mounting
InGridInGrid
Micro-electronic tech.Micro-electronic tech.– Wafer scale areasWafer scale areas– Minimum pillar Minimum pillar Ø (30 µm)Ø (30 µm)– Integrated detectorIntegrated detector
Compact / Mass producibleCompact / Mass producible
– All geometric parameters All geometric parameters accurately controlledaccurately controlled
Gap, Holes, Supporting structuresGap, Holes, Supporting structures
Processing InGridsProcessing InGrids
Strips Litho.
50 µm SU8 UV Exposure
0.8 µm Al Holes Litho.
Development
Suspended membrane 50 µm above the wafer
PrototypesPrototypes
19 different fields of 15 mm Ø19 different fields of 15 mm Ø2 bonding pads / fields2 bonding pads / fields
Square / Walls Square / PillarsSquare / Pillars
Hex / Pillars
Experimental SetupExperimental Setup
Cathode to HV
Grid to HV
Anode to ground
55Fe collimated source
Gas sealed chamber
Connectors to 10 MΩ resistors in series with
electrodes
Energy resolution in Argon Energy resolution in Argon IsoCIsoC44HH1010 80/20 80/20
• Observation of two lines:
Kα @ 5.9 keV
Kβ @ 6.4 keV
• FWHM of the Kα distribution
16.7 %
• Gain fluctuations
< 5%
Very good energy resolution:
Very precise dimensions d < 0.1 μm
Other applications of GridPix:
- μ-TPC- Transition Radiation Detectors- GOSSIP: tracker for intense radiation environment
The ATLAS DetectorThe ATLAS Detector
ATLAS Semiconductor Tracker (SCT)
Inner Tracker: record all tracksInner Tracker: record all tracksof charged particlesof charged particles
For instance: lifetime measurementFor instance: lifetime measurement
Heavy quark mesons….Heavy quark mesons….
Lifetime measured from secondary vertex Lifetime measured from secondary vertex cc~ 100 micron~ 100 micron
Take Lorentz boost into account Take Lorentz boost into account
KKD
DD slow*
m
Eγ
ALEPH event display
VertexingVertexingHigh spatial resolutionHigh spatial resolutionlow masslow masslow powerlow powerfastfast
Semiconductor pixel detectorSemiconductor pixel detectorVertex determinationVertex determinationFew pointsFew pointsaccuracy O(0.001-0.01 mm)accuracy O(0.001-0.01 mm)
Semiconductor (pixel, strip) Semiconductor (pixel, strip) detectorsdetectors
Depleted Si, 300 μm
(pixel) chip withpreamps, shapers,discriminators
Vbias = 150 V
electron-holepairs
ATLAS pixel: basic elementATLAS pixel: basic element
C-C support
sensor
Flex Hybrid
bumps
MCC Side view
not to scale
Wire-bonding FE’sWire-bonding MCC
FE chipFE chip
Flex module 2.xFlex module 2.x
The ATLAS Vertex Pixel DetectorThe ATLAS Vertex Pixel Detector
~2.0 m~2.0 m22 of sensitive of sensitive area with area with 0.8 0.8 10 1088 channelschannels
50 50 m m 400 400 mm silicon pixels (50 silicon pixels (50 m m 300 300 m in the B-m in the B-layer)layer)
Three barrel layers
Three disk layers
Barrel SCT unit
EndCap SCT unit
barrel SCTbarrel SCT
Two of the SCT barrel support structures
Barrel and EndCap SCT
Transition Radiation Tracker
e-
π-
X-ray quanta
Si (vertex) track detector GOSSIP
CMOS chip
Si depletion layer
Vbias
• Si strip detectors• Si pixel detectors• MAPs
Gas: 1 mm as detection medium99 % chance to have at least 1 e-
Gas amplification ~ 1000:
Single electron sensitive
All signals arrive within 16 ns
Cluster3
Cathode (drift) plane
Integrated Grid (InGrid)
Cluster2
Cluster1
Slimmed Silicon Readout chipInput pixel
1mm,100V
50um, 400V
50um
GOSSIP: Gas On Slimmed SIlicon Pixels
CMOS pixel array
MIP
InGrid
Drift gap: 1 mmMax drift time: 16 ns
MIP
CMOS chip‘slimmed’ to 30 μm
Cathode foil
Gas instead of SiPro:- no radiation damage in sensor: gas is exchanged- modest pixel (analog) input circuitry: low power, little space- no bias current: simple input circuit- CMOS pixel chip main task: data storage & communication (rad hard)- low detector material budget: 0.06 % radiation length/layer
typical: Si foil. New mechanical concepts: self-supporting pressurized co-centric balloons; ‘laundry line’
- low power dissipation : little FE power (2 μW/pixel); no bias dissipation- operates at room temperature (but other temperatures are OK)- less sensitive for neutron and X-ray background- 3D track info per layer if drift time is measured
Con:- Gaseous chamber: discharges (sparks): destroy CMOS chip- gas-filled proportional chamber: ‘chamber ageing’- Needs gas flow- Parallax error: 1 ns drift time measurement may be required
DischargesVonken
CMOS Chip protection against - discharges- sparks- HV breakdowns- too large signals
Emperical method:Try RPC technology
Amorph Si (segmented)
Silicon Protection: SiProt
Met 3 μm SiProt:
- ‘Directe’ schade door heet plasma: afwezig- te groot ladingssignaal voor pixel electronica
- Dikkere SiProt laag (20, 30 , 40, 50 μm ! )- Protectie circuit in pixel- SiProt aan onderkant van InGrid
!!Als dikkere SiProt niet werkt:- MPW test (Gossipo-3)- 600 kE nodig voor nieuwe full-scale pixel chip!!
MediPix+SiProt+InGridLevensduur: 12 hHe/Isobutane
A-Si not adequate? Then TwinGrid
Irradiation with 8 keV X-rays:Irradiation with 8 keV X-rays:
No No rate effectsrate effects up to anode up to anode current density of 0.2 current density of 0.2 μA / mm / mm22
very fast track counting very fast track counting possible!possible!
After 0.3 Coulomb/mm2:
(eq. 3.7 x 1016 MIPs/cm2 !!)
deposit of carbon polymer on anode is clearly visible. Micromegas is clean (!?)Little deposit on cathode, and……Chamber still worked!
Ageing
Nieuwe Pixel Chips voor GridPix/Gossip
Very low (parasitic) capacitanceat the input (Cpar → 10 fF) .
Cpar = 10fF…50fF
Coaxial-like layout of the input-feedback interconnection.
Parasitic metal-to-metal fringe capacitances.
Input pad
Substrate
Cfb=1fF
Ground plane
Output
M1
M2
M3
M6
LM
Ground
GOSSIPO-1:
- test of preamp-shaper-discriminator for GOSSIP
- ‘MultiProjectWafer’ in 0.13 μm technology
GOSSIPO chipSubmitted December 2005.
- match extreme small source capacity: 10 fF- peaking time: 40 ns- noise (expected: 60 e- input eq.)- power: 2 μW/pixel (!)- Triple Well technology: separation of analog and digital ground
- Threshold setting (6 x 60 e-) fine!- Effect of digital switching on pixel analog signal negligible
GOSSIPO (RO-FE) chip design
100 MHz clock close to analog circuit
Vthreshold = 350 e-
discriminator output
Maart – Juni 2006: Gossip-DAQ werkgroep
test ofpreamp-shaper-discriminator
and
700 MHz TDC per pixel
• 0.13 μm technology• containing 16 x 16 pixels• Submission Nov 29, 2006• Can be used for GOSSIP demo!
GOSSIPO-2
3 x 2 mm2
Proposed FE architecture for data communication
avalancheinput pad
AmpShaDisc
700 MHzoscillator
start
stop
BXcounter
BX clock
40 MHz
memory 1BX-ID +Tdrift +Ttime-over-threshold
16 bits
DAQbus
valid BX
pixel-ID + Tdrift + TtimeOverthreshold
memory 2BX-ID +Tdrift +Ttime-over-threshold
16 bits
pixel
New mechanical concept(virtual) target: pixel B-layer @ SLHC
1. Inventarisation of all services to detector units2. Integration of services, detectors and support mechanics
services:
- cooling- power- data communication- gas
New mechanics + cooling concepts for Gossip
- As little as possible material- detector consists of foil!- less power required ( less cooling) w.r.t. Si
string: power, chip support, cooling
in 2030….
‘balloon’
‘laundry line’
Minimum Material Budget(% rad length)
Z = 0 mm Z = +/-600 mm
Gossip detector (50 μm Si) 0.06 0.06
Cooling (stainless steel tube) 0.001 0.001
Power (max 0.28 mm aluminium) 0.0 0.3
Data transfer (max 1.7 mm kapton)0.0 0.6
total 0.06 1
angle correction x √2 0.09 x 2 x √2 3
New concepts for optical fiber data transfer
laser
Interferometer
- rates up to 40 Gb/s- geen materiaal en dissipatie op chip- met 240 Gb/s: ‘all data to shore’: trigger possible
FE chip
- Ladder strings fixed to end cones- Integration of beam pipe, end cones & pixel vertex detector- 5 double layers seems feasible
Virtual goal: ATLAS pixel vertex
Stainless steel tube: - string- power- CO2 cooling
Gossip chip + InGriddrift gapcathode foil
ladder cross sectiondata lines (Cu/kapton)
casted aluminium
ladder side view
ladder top view
First practical GOSSIP
with CMS Vertex Pixel FE chip: PSI 46 (+ ATLAS FE pixel chip?)
- apply A-Si protection layer- apply InGrid- mount Gossips on pcb: ‘ beam telescope’- Testbeam end 2006
Nijmegen, NIKHEF (,PSI?)
Gossip projects at NIKHEF/Univ. Twente/Saclay/CERN
- Discharge protection- InGrid/TwinGrid/TripleGrid- Construction of detector: MediPix2 + SiProt + InGrid NewNext-1!- Construction of detector: TimePix + SiProt + InGrid NewNext-1- Gossipo chip developments- Development of ‘beam telescope’ Gossip demo- Vertex track simulations: signal development, DAQ data streams- Study of ‘services’ required for Gossip/SLHC: assume dose rate of 12 tracks/(cm2 . 25 ns)
definition of cooling; definition of data transfer connection; definition of power lines
- Ladder prototype: thermal modeling; Design of SS/Alu multifunctional string;test (mech + thermal) of mechanical model
- CO2 cooling: ATLAS/NIKHEF project- Ageing studies