Transcript Production of Gaseous Detector Elements

20 Dec., ‘04
Production of
Gaseous Detector
Elements
 History
EST-DEM
R. De Oliveira
of Gas Detectors in Workshop
 Fabrication of GEM Detectors
 Fabrication of Micro-megas
 Readout Circuits
 Other Detectors
20 Dec., ‘04
History of Gas
Detectors in
Workshop
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‘96: first GEM about 50 x 50mm with a gain of 10.
‘97: first GEM 100 x 100mm with gain of 10000.
‘98 - ‘99: first GEM 400 x 400mm; 1D and 2D readouts; first
micro-groove and micro-well detectors.
‘00: first 3D GEM readout; first 1D readout for Micro-megas in
COMPASS.
‘01: first PIXEL GEM readout; first 2D Micro-megas readout.
‘03: first PIXEL Micro-megas readout.
20 Dec., ‘04
Fabrication of
GEM Detector
 Theory
of Operation
 Cross-section of GEM
 Manufacturing Process
 Examples
 GEM Capabilities
 How to Buy a GEM?
Around 500 GEMs produced per year in CERN.
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Theory of Operation
Particle trajectory
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Electrode
-3000V
1 x e-
Gas
GEM
Readout
board 2D
0V
Lines X
8000 x e-
Top View
Lines Y
Cross-section of GEM
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Manufacturing Process
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Raw Material
Vacuum deposited
copper on polyimide
Applying Resist
Patterning Resist
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Image Transfer
UV Exposure
& Development
Copper Etching
Resist Stipping
Polyimide Etching and Cleaning
Manufacturing Process
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
Image transfer with film
pocket
R. De Oliveira

Copper Etching in a
Drawer Machine
Manufacturing Process
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Defect
Good
Perfect

Polyimide Etching in a
Static Bath with
Temperature Control

Hole Shape Control
Manufacturing Process
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
Electrode patterning

Cleaning

Electrical Test
(Less than 10nA at 600V
with humidity below 35%)
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Examples
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40 cm diameter
50 x 50 mm standard copper
28 x 28 mm active area
100 x 100 mm standard Ni/Au
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Examples
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R. De Oliveira
COMPASS Experiment (100 GEMs) segmented
HERA-B Experiment (300 GEMs)
Test for CMS, 45 cm long
Examples
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R. De Oliveira
Fine segmentation test with printed polarization resistors
GEM Capabilities
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20 Dec., ‘04





mm2
Gem size : up to 450 x 450
Hole diameter : from 25µm and up
Thickness of dielectric : 25, 50 or 100µm*
Platings : passivated copper, Ni/Au, Ni or Au
Spacers : from 1 to 3mm in multi GEM detectors
R. De Oliveira
300µm
width,
2mm
height
* Material not in stock
How to Buy a GEM?
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20 Dec., ‘04
R. De Oliveira
http://www.cern.ch/dem/products/gem
 standard
products :
100 x 100 mm active area
 50 x 50 mm active area
 with or without frame
 passivated copper or Ni/Au

 non-standard
workshop
products : please contact the
20 Dec., ‘04
Fabrication of
Micro-megas
MicroMegas:




Theory of Operation
Manufacturing Process
Possibilities
Examples
Bulk MicroMegas:



Manufacturing Process
Possibilities
Examples
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R. De Oliveira
MicroMegas:
Theory of Operation
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20 Dec., ‘04
R. De Oliveira
Particle trajectory
Electrode
-3000 V
e-
Gas
Frame
Grill
Spacer
Readout circuit
0V
MicroMegas:
Manufacturing Process
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20 Dec., ‘04
R. De Oliveira
Raw Material
Image Transfer +
Copper Etching
Frame Gluing
Polyimide Etching +
Cleaning
MicroMegas:
Possibilities
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20 Dec., ‘04
 Size
of the grill :
R. De Oliveira
max 40cm diameter
 Bigger sizes under development

 Pattern
 Metals
: mini 500 mesh, 1000 under study
: copper, nickel, titanium
 Spacers :
 on the grill : 25 or 50µm thick (polyimide)
 on the readout : from 50µm to 0.5mm (modified epoxy)
MicroMegas:
Examples
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R. De Oliveira
CAST Experiment (special Plexiglas frame)
Zoom on polyimide dots
on the grill
KABES Experiment
Bulk MicroMegas:
Manufacturing Process
20 Dec., ‘04
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Bulk MicroMegas:
Possibilities
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
R. De Oliveira
Size of the bulk:

max 40cm x 40cm

Pattern : mini 600 mesh

Metals: stainless steel

Spacers:


75µm height (150µm, 225µm…), modified epoxy
Multi grid systems (under study)
Bulk MicroMegas:
Examples
20 Dec., ‘04
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Readout Circuits
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1 Direction
2 Directions
3 Directions “3D”
Pixel
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2D
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Polyimide
50 um
Image the
micro-vias
Chemical
drilling
Metallization
15 um
Photolitho
S of X = S of Y
Glue to substrate
Example of Single Side
(1D)
20 Dec., ‘04
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Close-up of readout board
Readout board for NA48 Experiment
Example of 2D Readout
Circuit
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20 Dec., ‘04
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Readout active area
2D readout board glued on low intrinsic radiation Plexiglas substrate
Example of “3D”
20 Dec., ‘04
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Readout for TPC with
backside connection
30cm diameter
18000 pads
Pixel
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20 Dec., ‘04
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1024 pads on a diameter of 35mm
Smallest pad produced : 250µm
Pitch: 300µm
Close-up view
Pad : 1mm
Pitch : 1.05mm
Readout Possibilities
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20 Dec., ‘04
 Supporting
 FR4
 Metals
materials :
 Flexible :
 without substrate
 Low

 Low
mass :
Carbon composite
intrinsic radiation :
Plexiglas
 Kevlar Composite

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Other Detectors
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 Micro-groove
 Micro-well
*
*
* R. Bellazzini group, INFN-Pisa, and University of Pisa
Micro-groove
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Close-up view
12 x 10cm groove detector
Bottom lines
Top lines
Micro-well
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20 Dec., ‘04
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Close-up view
3 x 3 cm well detector
Bottom lines
Top electrode