Transcript Status ‘Si readout’ TPC at NIKHEF NIKHEF Auke-Pieter Colijn Alessandro Fornaini Harry van der Graaf Peter Kluit Jan Timmermans Jan Visschers Saclay CEA DAPNIA Maximilien Chefdeville Paul Colas Yannis Giomataris Arnaud Giganon Univ.

Status ‘Si readout’ TPC at NIKHEF
NIKHEF
Auke-Pieter Colijn
Alessandro Fornaini
Harry van der Graaf
Peter Kluit
Jan Timmermans
Jan Visschers
Saclay CEA DAPNIA
Maximilien Chefdeville
Paul Colas
Yannis Giomataris
Arnaud Giganon
Univ. Twente/Mesa+
Jurriaan Schmitz
CERN/Medipix Constm
Erik Heijne
Xavie Llopart
Michael Campbell
ECFA Workshop Durham 4/9/2004
PhD student
per 1/9/04
Thanks to:
Wim Gotink
Joop Rovenkamp
Goals
• Gas multiplication GEM or Micromegas foil(s)
• Charge collection with granularity matching
primary ionisation cluster spread
• Needs sufficiently low diffusion gas
• dE/dx using cluster counting?
( M. Hauschild)
• Proof of principle based on existing Medipix2
readout chip
With Paul Colas & Ioannis Giomataris:
MediPix2 & Micromegas
55Fe
Cathode (drift) plane
Micromegas
Drift space: 15 mm
Baseplate
Very strong E-field above (CMOS) MediPix!
MediPix2 pixel sensor
Brass spacer block
Printed circuit board
Aluminum base plate
He/Isobutane
80/20
Modified MediPix
31 March 2004
Sensitive area:
14 x 14 x 15 mm3
Drift direction:
Vertical
max = 15 mm
He/Isobutane
80/20
Modified MediPix
31 March 2004
He/Isobutane
80/20
Modified MediPix
31 March 2004
He/Isobutane
80/20
Modified MediPix
31 March 2004
δ-ray?
Example of a track reconstructed
This track:
•#hits = 24
•#clusters = 11
•length (3d) = 16.8 mm
•1.4 e-/mm; 0.65 cl./mm
On average:
•1.8 e-/mm; 0.5 cl./mm
Detection of single electrons using MediPix2/Micromegas
assembly as Direct Pixel Segmented Anode
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Analysis of cosmic data 31/3-2/4 finalised
NIM paper submitted 31/8/04
#pixels hit/mm track length = 1.83
#clusters/mm track length = 0.52
Single electron efficiency 0.9
Moire effects: mismatch in pixel and hole
pitch: 60/(60-55) = 12 pixels repetition
Explanation for Moire effect: pitch Micromegas holes: 60 μm
pitch MediPix pixels: 55 μm
Periodic position of hole w.r.t. pixel: repeats after 12 pixels!
Non Modified
Modified
Modified
Non Modified
InGrid: perfect alignment of pixels and grid holes!
Small pad: small capacitance!
InGrid
Integrate GEM/Micromegas and pixel sensor
‘GEM’
‘Micromegas’
By ‘wafer post processing’
Wafer dia.: 100 mm
30 fields with variety of pillar geometry
First trials with pillars look OK
Some problems with ‘Micromegas’ grid
(hope to have first sample in few weeks
INGRID: some first trials
Various pitches, shapes
Other applications of TimePixGrid:
-
μ-TPC (e.g. KABES in NA48/3 ?)
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upgrades of TPCs: STAR, ALICE
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Transition Radiation Detectors
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GOSSIP: tracker for intense radiation environment
GOSSIP: Gas On Slimmed SIlicon Pixels
MIP
MIP
Micromegas
Cathode foil
CMOS pixel chip
CMOS pixel array
Drift gap: 1 mm
Max drift time: 10 ns
Essentials of GOSSIP:
• Generate charge signal in gas instead of Si (e-/ions versus e-/holes)
•Amplify # electrons in gas (electron avalanche versus FET preamps)
Then:
• No radiation damage in depletion layer or pixel preamp FETs
• No power dissipation of preamp FETs
GOSSIP:
1 mm gas layer + 20 μm gain gap + CMOS (digital!) chip
After all: it is a TPC with 1 mm drift length (parallax!)
Max. drift length: 1 mm
Max. drift time: 10 ns
Resolution: 0.1 mm  1 ns
Efficiency
Position resolution
Rate effects
Ageing
Radiation hardness
HV breakdowns
Power dissipation
Material budget
More details in
http://www.nikhef.nl/~d90/tesla/NIPHAD_GOSSIP.ppt
Ongoing/Coming activities:
•Cosmic trigger setup ready
•New Micromegas available very soon (Paul C.)
•New Medipix2 available
•First Ingrid1 tests
•Simulations
Longer term:
•Ingrid2 together with MediPix
•Development of Timepix1 (for TPC) and Timepix2
(for GOSSIP) CMOS chips
New collaborators are welcomed!