Front GEM Chambers Design concepts –Foils –Mechanics Electronics and DAQ Performance Current...
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Transcript of Front GEM Chambers Design concepts –Foils –Mechanics Electronics and DAQ Performance Current...
Front GEM Chambers
• Design concepts– Foils– Mechanics
• Electronics and DAQ• Performance
• Current activity and plan
Evaristo Cisbani / INFN-Rome Sanità group
2012 May 25 / A1n Meeting / JLab E. Cisbani 1
People
V. Bellini coordination
E. Cisbani montecarlo, analysis, daq, test, coordination
M. Capogni digitization, montecarlo, test
S. Colilli tech
V. De Smet gas simulation, assembling procedure, test
R. Fratoni tech
F. Giuliani tech
M. Gricia tech
F. Librizzi tech
M. Lucentini tech
F. Mammoliti analysis
S. Minutoli electronics
P. Musico electronics, daq, test
F. Noto mechanics
R. Perrino gas system, test
G. Ruscica analysis
F. Santavenere tech
C. Sutera assembling, testMost of the material presented at the SBS meeting in Feb and May/2012
Chamber design Reqs and Guidelines
• Hit spatial resolution ~70 mm
• Stand large background flux (~250 MHz/cm2 g and
~1/1000 charged particles)
• Active area 120x40 cm2
• Event acquistion rate ~20 kevt/s
Minimize R&D (follow COMPASS main design)
Reconfigurability (to some extend)
Reuse solutions for SBS rear tracker
2012 May 25 / A1n Meeting / JLab E. Cisbani 2
SBS Tracker GEM Chambers configuration
Chambers are made of smaller
modules
Electronics along the borders and
behind the frame (at 90°) – cyan
and blue in drawing
Carbon fiber support frame
around the chamber (cyan in
drawing); dedicated to each
chamber configuration
Front TrackerGeometry
x6
Back Trackers Geometry
x(4+4)
GEp(5) SBS
2012 May 25 / A1n Meeting / JLab E. Cisbani 3
Foils
2012 May 25 / A1n Meeting / JLab E. Cisbani 4
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Drfit, GEM and Readout foils
20 HV sectors on one side of the GEM
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40x50 cm2
• Large GEM module with small dead area
• Low material budget/Light Structure
• Modular design
• Flexible configuration
• Balanced weight
Improvements after first prototype• Protection resistors on the border
of the module frame (accessible)• Balance strips capacity (larger
strips are now the shortest, smaller are the longest)
• Replaced ZIF terminals (from 4 to 2 – more robust, easer to plug)
• Thanks to Kondo suggestions:– Added ring of grounding
around the readout foil (connected to the front end card GND)
– Corrected a trivial (but essential) bug in the readout layers order
2012 May 25 / A1n Meeting / JLab E. Cisbani 6
Mechanics
2012 May 25 / A1n Meeting / JLab E. Cisbani 7
Inner FrameGas Flow
Outer Service Frames
Inner Frame
• Permaglas, 8 mm
width, 2 or 3 mm
thick
• 21 slots for
protection resistors
• 3 Gas In/ 3 Out-lets
• 10 Reference holes
• Internal spacers (3
vertical 2 horizontal)
2012 May 25 / A1n Meeting / JLab E. Cisbani 8
F. Noto
Gas Flow / COMSOL MultiPhysics Simulation
V. De Smet + F. Noto
COMSOL/Thin-Film Flow ModelMaximize uniformity and steady fluxMinimize spacer apertures
Final design
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Flow:
60 cm3/m = 2 Vol/h
Pressure drop (Pa):
Inlet: 0.0590
Spacers: 0.0015
Module: 0.0462
Outlet: 0.0575
Total: 0.1642
(underestimated)
Gas / Current solutions under testingRILSAN
pipe
GEM
10 mm
In 4 mm
Out 6 mmIn 4 mm
«Side» view
Top view →
No metallic partsCustom and commercial jointsCommercial joints are rather large (13 mm!)
Glued Permaglas
IN or OUT
SMC/KR
2012 May 25 / A1n Meeting / JLab
E. Cisbani 10
Pressure drop: 3.16 Pa/m
Out 13 mm
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Assembling the first 40x50 cm2 module
Stretching
Gluing the nextframe with spacers
Foil Tension: T = 1 kg/cmSpacer Sector: S = 170 cm2Expected maximum pressure on foil P 10 N/m2
Maximum foil deformation:u 0.0074 * P * S / T = 12 mm
Use stretching and spacersto keep foil flat
Stretcher design from LNF / Bencivenni et al.
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Outer service frame 20
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Mechanical support of:• GEM modules• Electronics (PCBs + cables)• Additional services (gas system ...)
Carbon fiberLong bars made by 3 piecesDesign is in progressFirst prototype beginning of summer
FE cards between frame and backplanes
F. Noto
1650 mm
780
mm
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Service Frame / Detail 20
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Reference pin as small mechanical support
FE Cards
Backplane
Eye bold hole
23x100 mm2
30x100 mm2
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Material WeightGEM Chamber Weight
Module Chamber Unit WeightModule Weight
Chamber Weight
g g gFrame Honeycomb 1 3 112,09224 112,09224 336,27672Frame GEM Gap 3 9 57,4832 172,4496 517,3488Frame Drift 1 3 86,2248 86,2248 258,6744Frame Window 2 6 57,4832 114,9664 344,8992GEM foil 3 9 35,704 107,112 321,336Readout Foil 1 3 71,408 71,408 214,224Drift Foil 1 3 24,952 24,952 74,856Mylar Foil 1 3 5,68 5,68 17,04
Electronics: FE 18 54 11,92 214,56 643,68Electronics: Backplanes 4 12 150,74 602,96 1808,88Electronics: Patch Panels 0 2 150,74 0 301,48Elettronics: 3-meter HDMI-A cables 8 24 240 1920 5760FE-Backplane screws 72 216 1,5 108 324
Gas: 3 m pipes 6 18 43,3333333 260 780Gas: Patch panel 0 1 301,48 0 301,48Gas: Connectors 6 27 10 60 270
HV: cabling 2 6 100 200 600HV: Voltage Divider 1 3 150,74 150,74 452,22HV: Patch Panel 0 1 150,74 0 150,74
LV: 3m cables 8 24 100 800 2400LV: Patch Panel 0 1 150,74 0 150,74
"Fascette" 38 mm 50 200 4,5 225 900Screws 0 100 2 0 200
Total (g) 5236,15 17127,88
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Max deformation 20
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New
Material Short side (vertical)
Long side (Horizontal)
Carbon Fiber
0.004 0.081
Aluminium 0.018 0.330
Assume 20 kg of
payload
Weight applyed in the
center of the beam
Two points support
mm
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Electronics and DAQ
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APV25 Front-End cardBackplane
MultiPurposeDigitizer (VME module)
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Electronics Components
GEM FEC MPD DAQ
Main features:• Use analog readout APV25 chips• 2 “active” components: Front-End card and VME64x custom module • Copper cables between front-end and VME• Optional backplane (user designed) acting as signal bus, electrical
shielding, GND distributor and mechanical support
2D R
eado
ut
75 mm
49.5
mm
8 mm
Up to 10mtwisted,shielded
copper cable(HDMI)
Passive backplane(optional)
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Readout Electronics / FE v4
• Front-end cards: first 25 samples of revision 4 under testing
New connector: sligtly different connection scheme (middle spare pins are connected to ground)
Old connectors
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Readout Electronics / MPD v4
• Design of v4 under finalization
– Move to HDMI type B only
– Remove 2 Lemo connectors and
USB (more space and firmware
resources)
– Add piggy back connector for
future extension
– Trigger sampling at maximum
clock speed (240 MHz), time
resolution expected at the level of
few ns
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(128+12)x25 ns
(2x128+7)x20 ns
+ VME64x spare readout
FEMPD transfer/processing time: ~9 ms/sample
APV long analog pipeline (>4 us): use second level trigger
Zero suppressed data
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DAQ
Bus Interface
Generic Model(virtual class)
MPDLibrary
Low Level
I2C
Trigger
ADC
Other
High Level
Initialize
Configure
Discovery
Read
WrapperDB
Module
Structured text file for
configuration
Based on libconfig++
Main
Implemented on C++
• Run on Linux
• MPD as independent library
• One configuration file (text
format)
• Use open source libconfig++
• Self consistent output binary
raw data
DAQ Software 20
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Analysis software:
• Based on C++/Root
• One geometry configuration file (text)
• Ingest raw data and fill a Root tree for
further analysis
Largely rewritten in the past few weeksBug fixing in progress
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Some performance
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Desy – Mainz Test beam
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Beam test @ DESY / Full Module Size 40x50 cm2 20
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One 40x50 GEM moduleOne 10x10 GEM chamberAn ustrip Si telescopeSmall scintillators for trigger
Low intensity electron beam 2-6 GeV(few KHz trigger rate)
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Different event patternsWe extracted «good events» and measured:
• Cluster charge, and x-y correlation and ratio
• Cluster size
• Noise (RMS)
• Selection Efficiency
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Bad event
Good event
Standard processing:
• Hot channels masking
• Common noise suppression (median)
• Pedestal subtraction
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Cluster charge, size and noise 20
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Charge distribution and cluster size consistent with COMPASS data
We do not expect dramatic difference respect to COMPASS
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Charge correlation, beam spot and SNR
Pretty good run (011)
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?
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Noise (RMS pedestal) vs capacitance
Progress since DESY/2010:
better grounding, stable firmware
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Runs differ for different GND connection
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Latest Test under intense beam (Mainz/MAMI)12-16/09/2011
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Online monitor / Mainz test
Low beam current
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Event
x1
x2
x3
y2
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Online monitor / Mainz test
High beam current
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See Vahe analysis report at SBS meeting
x1
x2
x3
y2
Event
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Real Experiment: Olympus, Feb/2012
From Jürgen Diefenbach
The APV electronics has been installed on the Olympus 3xGEM tracker made of 6 10x10 chambers with 2D readout (pad/strip – about 2500 chs), operating in a magnetic field at the level of few kG.
Two events with opposite magnet polarity; particles bend left o right in the x-histogram
(Red triangles show hit candidates)
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Current activity and Plan
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----
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What we have 20
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Electronics:
All readout electronics ordered (order in standby); samples of the latest
(final?) FE/backplane version produced
Low Voltages and High Voltage power supplies in hands
GEM and readout foils:
About 1/3 ordered, only small part delivered
About another 1/3 funded in 2012
Mechanics:
All inner frames ordered, about ½ delivered
Outer frame prototype ordered
About 2/3 outer frames funded in 2012
Gas system:
Mostly funded and procured
Assembling:
Everything ready (or under minor improvement)
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• Electronics and DAQ:– production and test
– complete firmware implementation / improve software library
– optmimize readout performance
– (additional user: ATLAS group working on mMeGas prototype)
• Mechanics– finalize outer service frame design and produce first prototype
• HV– Final decision on HV divider to be taken
• Gas– Near chamber configuration to be finalized
• GEM modules– assembling and test (as soon as possible)
Working on / Open activities 20
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• As soon as possible:
– When the readout foils will arrive (few days ?) start assembling the first 40x50 module (about 1 module/month-> 0.5 module/week)
– latest FE electronics version release for 1 module (on hand)
• July-Sept. 2012:
– test the module and electronics with rad. source; if fine aks CERN form production
• July 2012:
– get outer service frame / electronics review at JLab (?)
• Sep 2012:
– start mass productions of electronics
• Dec 2012:
– 1st chamber completed (?)
– Electronics available, ready for testing
• Dec 2013 (+2M): 4 chambers completed (?)
Plan 20
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