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Working Group 1 Summary
Technological Aspects and Developments of New Detector structures
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WG1: Technological Aspects and Developments of New Detector Structures
ObjectiveObjective: Detector design optimization, development of new multiplier geometries : Detector design optimization, development of new multiplier geometries and techniques.and techniques.
Task 1: Task 1: Development of large-area Micro-Pattern Gas Detectors (large-area modules, material budget Development of large-area Micro-Pattern Gas Detectors (large-area modules, material budget reduction).reduction).
Task 2: Task 2: Detector design optimization including fabrication methods and new geometries (Bulk Micromegas, Detector design optimization including fabrication methods and new geometries (Bulk Micromegas, Microbulk Micromegas, single-mask GEM, THGEM, RETGEM, MHSP, charge-dispersive readout, Ingrid).Microbulk Micromegas, single-mask GEM, THGEM, RETGEM, MHSP, charge-dispersive readout, Ingrid).
Task 3: Task 3: Development of radiation-hard and radio-purity detectors.Development of radiation-hard and radio-purity detectors.
Task 4: Task 4: Design of portable sealed detectors.Design of portable sealed detectors.
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How will we work?Obviously, the work has to start from the Applications.
There will be meetings on the various tasks to compare findings, exchange experience from the applications
The first step was to ask, end of May 2008:
- What is your preferred technology?(GEM, Micromegas, THGEM, RETGEM, MHSP, Cobra, PIMS, Microgroove, microwell, microdots…)
- What are your main applications? (calorimetry, TPC, photon detection, medical, imaging,…
- What is your timescale (small prototyping, scale 1 prototyping, delivery of detector, …)
38 institutes out of 54 expressed interest in tasks of Working Group 1 28 on Large Area Detectors (task 1)9 on Design optimization (task 2, strong overlap with WG2)
20 on Radiation hard and high radiopurity (task 3)3 on sealed detectors (task 4, recently added)
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Task 1: Task 1: Development of large-area Micro-Pattern Gas Detectors Development of large-area Micro-Pattern Gas Detectors (large-area modules, material budget reduction).(large-area modules, material budget reduction).
Bulk Micromegas
Read-out board
Laminated Photoimageable coverlay
Frame
Stretched meshon frame
Laminated Photoimageable coverlay
Exposure Development+ cure
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Task 1: Task 1: Development of large-area Micro-Pattern Gas Detectors Development of large-area Micro-Pattern Gas Detectors (large-area modules, material budget reduction).(large-area modules, material budget reduction).
Raw material
Single-side copper patterning
Chemical polyimide etching
Chemical copper reduction
Single mask GEM
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Task 1: Task 1: Development of large-area Micro-Pattern Gas Detectors Development of large-area Micro-Pattern Gas Detectors (large-area modules, material budget reduction).(large-area modules, material budget reduction).
Copper Thick GEM
Raw material
CNC drilling
Electrodes etching
Small rim if needed
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Development of large-area Micro-Pattern Gas Detectors
Bulk Micromegas Single mask GEM
RD51 effect: progress is much faster!
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300x300mm2 THGEM!
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Task 1: Task 1: Development of large-area Micro-Pattern Gas Detectors Development of large-area Micro-Pattern Gas Detectors (large-area modules, material budget reduction).(large-area modules, material budget reduction).
0.8mm0.8mm 0.6mm
Read-out boardSpacer pillar
(coverlay)
Mesh
Mechanical milling 0.6 mm tool diameter
2.4mm dead region
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Task 1: Task 1: Development of large-area Micro-Pattern Gas Detectors Development of large-area Micro-Pattern Gas Detectors (large-area modules, material budget reduction).(large-area modules, material budget reduction).
Practical limits (raw material roll width : 600 mm => GEM and mM need seams)
-Bulk Micromegas: oven size : 1000 x 2000. Laminator: 1200 x …
-GEM: 450mmx100m. No firm limitation provided seems are accepted
-THGEM: Time (10-20h for 1000x600 even with 4 drills x 2 PCBs
Rui de Oliveira
This is the point of view of the fabrication. There are also limits from the point of view of the detector operation and robustness: capacitance
Segmentation and possibly resistive components might be necessary for large size detectors. Currently R&D for SLHC muon chambers, calorimetry, etc…
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CERN
Rui de Oliveira TS-DEM
Large volume effect
Large volume effect
Volume
Price/area
GEM
Micromegas
THGEM
Depends on initial investments
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Task 1: Task 1: Development of large-area Micro-Pattern Gas Detectors Development of large-area Micro-Pattern Gas Detectors (large-area modules, material budget reduction).(large-area modules, material budget reduction).
Joerg Wotschack
Arizona, Athens (U, NTU, Demokritos), Brookhaven, CERN,Harvard, Istanbul (Bogaziçi, Doğuş), Naples, Seattle, USTCHefei, South Carolina, St. Petersburg, Shandong, Thessaloniki,…
Very big collaboration to replace some of the ATLAS Muon chambers (230 m2)
Needs triggering capabilities as well as 100 position resolution and high-rate capability (5 kHz/cm2). Micromegas bulk technology considered as candidate.
Recent test beams being analysed. 55 position resolution demonstrated with strip pitch 250 at 90°. Cosmic test will follow, 50% prototype being built.
Need to keep resolution at angles down to 45°.
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Task 1: Task 1: Development of large-area Micro-Pattern Gas Detectors Development of large-area Micro-Pattern Gas Detectors (large-area modules, material budget reduction).(large-area modules, material budget reduction).
Serge Duarte Pinto
Modules in 2 parts because limitation to 457 mm width from raw material.
‘Splicing’ needed
Single mask GEM used to avoid alignment difficulties between top and bottom copper foil.
Large GEMs for a forward tracker.
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Task 1: Task 1: Development of large-area Micro-Pattern Gas Detectors Development of large-area Micro-Pattern Gas Detectors (large-area modules, material budget reduction).(large-area modules, material budget reduction).
Serge Duarte PintoLarge GEMs for a forward tracker.
3mm seam behaves as expected
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Task 2: Task 2: Detector design optimization including fabrication Detector design optimization including fabrication methods and new geometries (Bulk Micromegas, Microbulk methods and new geometries (Bulk Micromegas, Microbulk
Micromegas, single-mask GEM, THGEM, RETGEM, MHSP, charge-Micromegas, single-mask GEM, THGEM, RETGEM, MHSP, charge-dispersive readout, Ingrid).dispersive readout, Ingrid).
KLOE and CLAS12 cylindrical trackers also need large GEMs or Micromegas.
Why not cylindrical? Low material budget, challenges Silicon
Half-cylinder vs full cylinder – integrated and sealed drift cathode.
Beam tests at CERN and Brookhaven
75° Lorentz angle in 5T for CLAS12 at Edrift =1kV/cm, reduced to 14° with Edrift=10kV/cm, lower drift velocity (tan = vB/E)
Cylindrical and flexible GEM and Micromegas (Giani Bencivenni, Frascati and Stephan Aune, Saclay)
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- - CLEAN ROOM :CLEAN ROOM : we had too many shorts in the detector: ≥ 11 shorts (5% area) in 1.2 m2 of GEM foils (to
be compared with) 0 shorts in 4.5 m2 of GEM foils for LHCb
CGEM for KLOE tracker
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Micromegas Bulk for CLAS12
vertex tracker
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•PCB: 100 µm FR4 with 5 µm thick Cu strip•100 µm amplification gap•Woven Mesh Gantois non stretched bulk with an array of 400 µm pillar every 2 mm•Dimension: 180 mm x 60 mm
First curved bulk (09-2006)
Picture: bulk curved, 100 mm radius
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SUMMARY on THGEM (Amos Breskin)● In Ar+5%CH4 the maximum achievable gains measured with UV-light (~106) are ~100-fold higher than with 55Fe (~104)● Probable explanation is the Raether limit● In Ne and Ne-CH4 (5-23%) mixtures, under gas flushing, the maximum gains with UV and 55Fe are closer (105 - 106)● Possible explanation: 55Fe photoelectron-tracks are longer in Ne and its mixtures lower density of ionization per hole lower max. gain-difference caused by charge-density effects.● In pure Ne scintillation prevents high gains & “masks” p.e. extraction quencher● For RICH: optimal would be Ne–based mixtures● Quencher additives to be optimized – for high gain and efficient p.e. extraction.● Preliminary results indicate upon ~70% extraction efficiency in Ne/23%CH4
similar to Ar/5%CH4.● Charge-up: geometry (rim), gain and rate dependent. ● It seems that rimless holes are advantageous, but need to establish detectors’ parameters (eff QE, e-transfer photon detection efficiency) with the right conditions and gas● Need to compare stability of LARGE-AREA rim/rimless THGEMs with UV photons● Tests in RICH mode? Who? When? – Trieste ordered 60x60 cm THGEMs.● 30x30cm THGEM tests: tested end 2008 at WIS● Expected results in Cryo-THGEMs Gas Photomultipliers/LXe: early 2009.
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Task 2: Task 2: Detector design optimization including fabrication Detector design optimization including fabrication methods and new geometries (Bulk Micromegas, Microbulk methods and new geometries (Bulk Micromegas, Microbulk
Micromegas, single-mask GEM, THGEM, RETGEM, MHSP, charge-Micromegas, single-mask GEM, THGEM, RETGEM, MHSP, charge-dispersive readout, Ingrid).dispersive readout, Ingrid).
MHSP (Micro Hole and Strip Plate) (Joao Veloso) and PIC+Micromegas (Atsuhiko Ochi)
Micro-mesh Micro-pixel chamber : M3PIC
400m
100m
70m230m
165m
AnodeCathode
Support wire
Micro Mesh
1cmDrift/detection area(Filled by gas)
Drift plane
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MicroHole & Strip Plate (MHSP)• Operation Principle
JFCA Veloso et al., RSI 71(2000)2371
Gas
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MicroHole & Strip Plate (MHSP)
• Present Performance:
High gains – ~ 104-105
Fast charge collection – 10 ns
Excellent energy resolution – 13.5% @ 5.9keV x-rays - Xe
High rate capability – > 0.5 MHz/mm2
High pressure operation capability
High ion blocking capability
2-D intrinsic capability – σ~125μm (with resistive line)
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First demonstration of a GPM operation in visible range
A. Lyashenko et al., NIMA (2008), http://arxiv.org/abs/0808.1556v2
102 103 104 10510-5
10-4
10-3
10-2
Edrift
=0.5kV/cm
F-R-MHSP/GEM/MHSP
Edrift
=0.2kV/cm
Ar/CH4 (95/5), 760 Torr
IBF
Total gain
0.03%
No visible feedback
Paris, 13 – 15 of October 2008
W RD51 25
2D-Imaging – using resistive lines
FP
GA
4 -
AD
Cs
to computer through USBF
PG
A 4
-A
DC
s
to computer through USB
COMPUTER -Set time window
)( BA
BA
A
BA
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yylEnergy
yy
yky
xx
xkx
Image reconstruction
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Carbon dissociated from ethane deposits on polyimide surface
5 sparks 50 sparks 150 sparks
200 sparks300 sparks
14th Octber 20082nd RD51 Paris
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Correlation between number of discharges and voltage drop after the test
14th Octber 20082nd RD51 Paris
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200 m
MESHESMESHES
ElectroformedChemically
etched Wowen
PILLARSPILLARS
Deposited by vaporization
Laser etching, Plasma etching…
Many different technologies have been developped for making meshes (Back-buymers, CERN, 3M-Purdue, Gantois, Twente…)
Exist in many metals: nickel, copper, stainless steel, Al,… also gold, titanium, nanocristalline copper are possible.
Can be on the mesh (chemical etching) or on the anode (PCB technique with a photoimageable coverlay). Diameter 40 to 400 microns.
Also fishing lines were used (Saclay, Lanzhou)
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drilling + chemical rim etching without maskMask etching + drilling; rim = 0.1mm
Detector design optimization, fabrication methods and new geometries
6 keV X-ray
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pitch = 1 mm; diameter = 0.5 mm; rim=40; 60; 80; 100; 120 mm
THGEM Example
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Development of resistive anodes and grids
RTGEM: resistive electrode THGEM
3÷10 G/ copper oxide layer
resistive foilresistive foilgluegluepadspads
PCBPCB
meshmesh
Resistive anode:Charge dispersion readout
1 M/ plastic foil
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• A few people interested, will follow up
Task 3: Task 3: Development of radiation-hard and high radio-purity detectors.Development of radiation-hard and high radio-purity detectors.
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• New task (discussion this morning)• Make gas-tight low-outgasing detectors
with locally made high-voltage, and portable (USB?) electronics
• Possible applications: radiotherapy (positioning), teaching,…
• Interested people: Amos Breskin, Paul Colas, Rui de Oliveira, Per Baecklund, Fabrizzio Murtas, Joaquim Dos Santos,…
• ==> phone meeting early November.
Task 4: Task 4: Design of portable sealed detectorsDesign of portable sealed detectors
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Interactions of WG1WG2
WG1
WG6Production
WG5 Electronics
WG7Test beams
Characterization, basic studies on performance, aging
WG4
Simulations
New materials, new geometries
Protecti
on