UPDATE ON GEM/DHCAL DEVELOPMENT AT UTA
Andy WhiteU.Texas at Arlington
(for J.Yu, J.Li, M.Sosebee, S.Habib, V.Kaushik)
9/15/03
Recent developments
Moving to multi-channel prototypes GEM foil production Electronics – prototypes Module design concepts
Double GEM schematic
From S.Bachmann et al. CERN-EP/2000-151
Create ionization
Multiplication
Signal induction
Design for DHCAL using Triple GEM
Ground to avoid cross-talk
Embeded onboard readout
Multichannel prototype
- Next step: a 3 x 3 array of 1 cm2 pads.- Allows one central pad with neighbors for cross-talk tests.- Use a single layer board for simplicity.- Anode board built, prototype reworked.- First results.
Nine Cell GEM Prototype Readout
Landau Distribution from Cs137 Source
Signal Amplitude (mV)
Readout electronics for DHCAL/GEM
- Single channel electronics for first tests (high gain charge preamp + x10 voltage amp.)- Useful for initial development, but not cost effective for larger scale, multi-channel prototypes.
GEM Prototype with preamp/voltage amp
Amptek charge pre-amplifier
Readout electronics for DHCAL/GEM
- Discussions with Fermilab/PPD (Ray Yarema)- Short-term use of electronics developed for silicon readout. (T.Zimmerman)- 32 channel boards. Now at UTA.- Gain within factor of 3 of present single channel system.- Investigating DHCAL/GEM specific design- Coherence with DHCAL/RPC – VME/daughter?
Fermilab preampfor multi-channel tests
GEM Foil Production- Original production at CERN – but slow, low volume, manpower intensive and expensive.- Interest in U.S. domestic foil production by LC tracking developers and GEM/DHCAL.- 3M Corporation (Microinterconnect Systems Division), Austin, Texas has tried additive and subtractive approaches.- Foil production on 16 inch wide, 500 feet long roll.
Our Motivation: Micro Pattern Gas Detectors (MPGD) in Particle & Astro-Particle PhysicsTPC readout for LC (GEM or MICROMEGAS)Tracking device at SLHC or VLHCLow-background applications (e.g. coherent neutrino scattering) & WIMP searches
Chicago-Purdue-3MP.S. Barbeau J.I. Collar J. Miyamoto I.P.J. Shipsey
+ DHCAL/GEM developments+ Medical imaging potential+ ?
GEM Foil Production
• 3M Microinterconnect
Systems Division Reel-to-reel process, rolls of 16”’x16” templates of detachable GEMs in any pattern. Optional processes possible.
• First batch of 1,980 GEMs recently produced. Low cost per unit! (~2 USD/GEM not counting R&D)
• Two fabrication techniques (additive, substractive) tested.
Singleroll of~1,000GEMS
Reel to reelflex circuitmanufacturein clean roomconditions
hep-ex/0304013
Mass Production is based on a 3M ProprietaryFlex Circuit Manufacturing Technique
Subtractive (etching) (similar to CERN made GEMs)
Additive Cu added to patterned photo resiston Kapton
Two fabrication techniques
Subtractive Additive
1. Subtractive: Clean hole structure, microcrystals, a small part of the batch have problems with adhesion of Cu on Kapton
2. Additive: Some holes not perfectly round create hole to hole gain variation, a small part of the batch have problems with adhesion of Cu on Kapton
hep-ex/0304013
Cumicrocrystal
Additivemethodneeds improvementto be useful
3M Process Quality
ChicagoPurdue3M GEM
SEMCourtesyFabioSauli
Subtractive 3M Mass Produced GEM
ChicagoPurdue3M GEM
SEMCourtesyFabioSauli
Hole Profile
GEM Performance
Typical 55Fe spectrum uncolllimated source. Ar + 5% CH4 Lower GEM electrode. E/E = 16% typical energy resolution as goodas 14% observed.
hep-ex/0304013
So far characterization focused on subtractive GEMs
3M GEM and CERN GEMHave comparable E/E = 16%
3M GEmE/E = 16%
CERN GEME/E = 18%
http://gdd.web.cern.ch/GDD/
Ar/DME 9:1
Ar/CO2 7:3
Gain measuredon lower GEM electrode
Gain measuredon PCB below GEM
Gains of 5,000 in Ar/CO2 7:3 & Ar/DME 9:1
Gain almost identical to CERN made GEMS in same gas
xx
CERN GEM *(*) S. Bachmann et al.NIM A479 (2002) 294
Gas Gain
hep-ex/0304013
CERN
GEM Foil Production
- Latest production 2 x 2 pattern of 10x10 cm2 foils.- Use for DHCAL small prototypes and module development- 3M can make any pattern within the roll parameters (~$2K for artwork)
TESLA – HCAL Layout
Development of module concepts
DHCAL/GEM Module concepts
Use half-size modules w.r.t. TESLA design
DHCAL/GEM Module concepts
Bottom view
Side view
End view
DHCAL/GEM Module concepts
GEM layer slides into gap between absorber sheets
DHCAL-GEM Layer structure
- GEM layer -> 6mm- Electronics layer ~3mm- Absorber thickness 16mm x 40 layers-> ~ 4 interaction lengths for HCAL- 10x10 mm2 cell size -> ~1.5 x 107 channels for DHCAL-GEM
DHCAL/GEM active layer
- Basic layer structure is clear- Practical issues:
- minimizing thickness, readout layer, ground plane(s) ??- stretching foils, foil separators, wall thickness- gas in/outlets, electrical services
DHCAL/GEM active layer
- Exploring using the absorber steel gap to provide active layer rigidity.- Build jig to construct active layer with stretch foil layers, thin side walls.- Test transfer/sliding of non-rigid active layer into steel gap.- Start with available width foils from 3M
Design concept for sensitive layer
3mm ionization
layer
CONCLUSIONS
Further prototype developmentExploring electronics solutions with Fermilab/PPD Availability of U.S. domestic GEM foils Investigating active layer construction techniques