Construction and tests of a Micromegas
TPC endplate prototype for the LC
D. Attié, P. Colas, K. Fujii,T. Matsuda,
M. Riallot, A. Sugiyama, W. Wang
Thanks to
M. Dixit, Yun-Ha Shin, S. Turnbull,Yulan Li
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Large prototype TPC
 Need to make a large prototype to:
 Study gases and detector design (both GEM and Micromegas)
 Assess technical issues : integration, operability, stability,… at a realistic
scale
 Since December 2008 we test Micromegas+ resistive foil and GEM
modules at the EUDET facility. PCMAG improvement in AIDA.
 Theoretical understanding of the point resolution. Present step :
study of gain fluctuations.
 Electronics developments
 Integration
 Power pulsing
 Software developments
June 15, 2010
P. Colas, K. Fujii - D-RD2
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Large TPC Prototype for ILC
French-Canadian team :
one module was installed
in the centre of the large
TPC each time. Read out
by T2K electronics
June 15, 2010
Asian+Lund team : 3 GEM
modules readout by
ALTRO electronics
P. Colas, K. Fujii - D-RD2
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Large TPC Prototype for ILC
ALTRO
readout electronics
Cooling duct
Micromegas
June 15, 2010
GEM
P. Colas, K. Fujii - D-RD2
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Detector Modules
2 Resistive Kapton
~3 MΩ/□
Resistive Kapton
Standard
~5 MΩ/□
GEM GEM
Resistive ink
~2(?) MΩ/□
June 15, 2010
P. Colas, K. Fujii - D-RD2
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Beijing, 30/03/2010
P. Colas - FJPPL-FCPPLLCTPC Analysis meeting
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Preliminary Data Analysis Results ( B=1T )
20cm drift
PRF(Pad Response Functions) for GEMs, z ~ 20 cm
June 15, 2010
P. Colas, K. Fujii - D-RD2
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Preliminary Data Analysis Results ( B=1T )
Γ ~ 4 mm
δ ~ 14 mm
Γ ~ 2.6 mm
δ ~ 10 mm
B=1T data : comparison of resistive ink and Carbon-loaded Kapton
PRF(Pad Response Functions) fits, z ~ 5 cm
June 15, 2010
P. Colas, K. Fujii - D-RD2
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Preliminary Data Analysis Results ( B=1T )
Position residuals xrow-xtrack
June 15, 2010
P. Colas, K. Fujii - D-RD2
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Preliminary Data Analysis Results ( B=1T )
Mean Residual vs Row Number
Z=5cm
 Z-independent distortions
 Distortions up to 50 microns
for resistive paint (blue points)
 Rms 7 microns for CLK film (red
points)
Z=35cm
Z=50cm
June 15, 2010
P. Colas, K. Fujii - D-RD2
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Resolution at z=5cm (µm)
Preliminary Data Analysis Results ( B=1T )
90
80
70
60
50
40
30
20
Resistive CLK
10
0
350
360
370
380
390
400
410
Vmesh (V)
Dependence of resolution with data taking conditions
June 15, 2010
P. Colas, K. Fujii - D-RD2
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Drift velocity measurements ( B=0T )
(200 ns shaping)
Tmax (μs)
10
9
y = 0.13x + 1.9022
Vdrift = 7.698 +- 0.040 cm/µs
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at E=230 V/cm
7
y = 0.1298x + 1.8957
(Magboltz : 7.583+-0.025(gas
comp.))
6
5
The difference is 1.5+-0.6 %
4
3
Module 4
2
Module 5
1
0
0
10
20
30
40
50
60
Z (cm)
June 15, 2010
P. Colas, K. Fujii - D-RD2
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Drift velocity measurements ( B=0T )
Vd (cm/μs)
9
8
7
Drift Velocity in Ar/CF4/Iso
butane : 95/3/2 compared
with Magboltz simulations
for
- P=1035 hPa,
- T=19°C
- 35 ppm H20
6
5
Simulations
(Magboltz)
Measurements
4
3
2
1
0
0
100
200
300
400
Ed (V/cm)
June 15, 2010
P. Colas, K. Fujii - D-RD2
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Data Analysis Results (B=0T)
Resolution as a function of drift distance. Modules 4 and 5 are
identical, except the routing and PCB technique
Module_4
c2 / NDOF = 10.6 /10
  0
June 15, 2010
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Cd2  z

N eff
Module_5
c2 / NDOF = 13.9 /10
2% uncertainty on Cd : ±1.4 on Neff
P. Colas, K. Fujii - D-RD2
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Preliminary Data Analysis Results ( B=1T )
  0
2
Cd2  z

N eff
c2 / NDOF = 29.1 /11
c2 / NDOF = 38.5 /10
Module_CLK
Module_INK
Resolution as a function of drift distance
June 15, 2010
P. Colas, K. Fujii - D-RD2
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Uncertainties :
Use CD=94.2 ±1.8 at B=1T
and B field (± 0.02 T) ->±1.6
Resistive ink very non-uniform.
All Carbon-loaded kapton very consistent : average them
Neff = 38 ± 2
Expected : Neff = 47.7 * <G>2 / <G2>
This implies rather low gain fluctuations.
June 15, 2010
P. Colas, K. Fujii - D-RD2
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Advanced TPC endplate (2010-2012)
Small pads (1 x 4 mm) for high double-track separation and high resolution:
Thin endplate for PFA (15% radiation length + low voltage power cables)
 Light mechanical structure of TPC endplate (Cornel/Saclay/DESY)
 High density readout electronics S-ALTRO for MPGD detectors
(CERN/Saclay/Lund/TPC Japan)
 (a) Development of S-ALTRO:
A 64ch analog-digital mixed chip
mount directly on the backside of
pad plane of MPGD detector.
 (b) Issues of power switching, power
delivery and cooling (2P-CO2)
 (c) Issue of mechanical stability in high
magnetic field
ALICE TPC (LHC)
LC (ILD) TPC
(a)  A 16ch S-ALTRO prototype in fall 2010 (CERN)
(b)  A test board with ADC/FPGA in preparation
One of 12 sections of the test board (TPC Japan/CERN) 
(c)  A test module (Bulk MicroMEGAS) in preparation
to be tested in DESY 5T magnet (Scalay)
June 15, 2010
P. Colas, K. Fujii - D-RD2
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Intermediate step : new T2K electronics
NEW ELECTRONICS – FLAT ON THE BACK OF THE MODULE
Goal: Fully equip 7 modules with
more integrated electronics, still
based on the T2K AFTER chip: use
naked Silicon, wire-bounded on
small cards, ADC on the mezzanine,
remove/optimize protections,…
First prototype basically ready, tests
at fall 2010
Then production and
characterization of 9 modules in
2011 at the CERN T2K clean room
June 15, 2010
P. Colas, K. Fujii - D-RD2
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New T2K Electronics
Backend ready. Gain of
factors of 2 in evt rate and
thruput
♦
2 Mezzanine prototypes
under test
♦
FECs : in the process of
choosing between tenders.
More complicated, but no
show stopper
♦
Detector PCB ready to be
ordered, process under study
♦
June 15, 2010
P. Colas, K. Fujii - D-RD2
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June 15, 2010
P. Colas, K. Fujii - D-RD2
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Tracking Software development
Current Status : test beam data with different readout modules have been analyzed with
different tracking programs developed independently by different groups.
Desired Environment
A common tracking framework (MarlinTPC) to compare different readout technologies on
the same software test bench.
In order to realize this we need the implementation of
a) multi-module handling
b) non-uniform B field
The developed software is to be fed back to the LC-TPC tracking.
Hits
Tracks
Track = subset of hits
1) Topological track finding
+ kalman filter based track
fitting
2) Combinatorial Kalman filter in
which track finding and
fitting proceed
simultaneously
• Multi-module handling: almost
finished
• Non-uniform B field under
development
June 15, 2010
Readout
Technology
Dependent
Hit Point Making
Two packages being developed
in the FJPPL activities
Common Tracking
Set of
Pulses
Hit Making
Set of Hits
Set of Tracks
Tracking = Track Finding x Track Fitting
P. Colas, K. Fujii - D-RD2
Set of Track
Param. Vectors
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SC solenoid modification
PCMAG
Originally built for a balloon experiment
Used in TPC small prototype beam tests at
KEK/PS in 2004-2006.
Being used for LCTPC Large Prototype beam
test at DESY (LCTPC/EUDET).
Open solenoid of 1T.
Thin coil and cryostat (20% radiation length).
Require 1,000L Liq. He for an initial cooling
and ～200L in a refilling for 6-7 days
PCMAG at DESY with GEM/ALTRO TPC
Modification funded in AIDA
Safe/easy operation by TPC R&D groups.
Portability to any beams lines in the world
Save Liquid He cost
Remove Liq. He reservoir
Add two 4KGM refrigerators
Schedule: in 2011 (6 months)
(Thanks for full cooperation s
of the KEK cryogenic group and Toshiba)
Modified PCMAG with 4K GM refrigerators
June 15, 2010
P. Colas, K. Fujii - D-RD2
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Conclusions and outlook
Since 2005, common analysis work led to deep
understanding of the resolution of a GEM or a
Micromegas.
♦
Next steps: 7 Micromegas modules to fully equip
the present endplate and work on improvement of
the common testing facility, endplate, electronics
and multi-module software.
♦
June 15, 2010
P. Colas, K. Fujii - D-RD2
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June 15, 2010
P. Colas, K. Fujii - D-RD2
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