Latest Results of the ILC
Large TPC Prototype(LPTPC)G. De Lentdecker
Université Libre de Bruxelles
Brussels, Belgium
On behalf of the LCTPC Collaboration

Overview• Introduction• Motivations, experiment and collider concepts• TPC• Micro Pattern Gaseous Detectors (MPGD)• The Large Prototype TPC (LPTPC)• Beam test setup in DESY
• 3 detector technologies• Test-beam results• Future developments• Conclusions

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Future e+e- Linear Colliders• Why ?
• There are two paths for discovery:• Large Energy Range (Tevatron, LHC, HL-LHC,…)• Direct discovery of new particles• High Precision (LEP, ILC, CLIC,…)• Inferring new physics effects from high energy scales through precise
measurements at lower energy• Combining both strategies gives much more complete
understanding than either one alone• Let’s take a (random) example…

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The Higgs• The LHC has just discovered a new particle with a massaround 125-126 GeV/c2, consistent with the Brout-EnglertHiggs boson. But is it the SM Higgs boson ?

Gauge
Principle

Symetry Breaking&
Mass Generation

Established by
precision EWKstudies

We cannow test it

Relativistic Quantum Field theory
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Any deviation from thestraight line would indicate
BSM physics !
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Why precision ?
Assumed luminosities:

LHC = 14 TeV, 300fb-1 (*)
HLC = ILC 250 GeV, 250fb-1
ILC = ILC 500 GeV, 500fb-1
ILCTeV = ILC 1 TeV, 1000fb-1(*) 300fb-1 à ~ 2020

1 σ confidence intervals
M. Peskin arXiv:1207.2516v2 [hep-ph]

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5% deviation band fromSM prediction of thecoupling
5Experiment concept for ILC• “Visualize events as viewing Feynman diagrams”• We should be able to reconstruct any final state in termof partons (quarks, leptons, gauge bosons)• Concept of particle flow (PF)• High granularity calorimetry: 1000 x LHC channels"%
1$• High resolution tracking : ! $ p '' = 0.1( LHC# t&• Hermiticity:– Down to 10 mrad or lower– Everything incl. HCAL
in Solenoid (B>3.5 T)

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Bird’s Eye View of the ILC Accelerator
Damping ring

Detectors

Accelerator tunnel

Illustration by Rei Hori

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e+e- main linac
Energy: 250 GeV + 250 GeV
Length : 11km + 11km
# of DRFS Klystron = 7280
# of Cryomodules = 1680
# of Cavities= 145607Detectors design•••

Si vertex detector
Large TPC
(L=4.3m, Ø=3.6m)
Si envelope (in- & outside)• Precise calor. impact
Calorimeter•

Muon chambers•

SiD• All Si tracker~10 discrete position
measurements with
σrφ~10 µm
and a lever arm of ~1m
in a 5T magnetic field

ILD

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TPC principle

Readout plane

B
E

Projected trajectory

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ionizing particle

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ILD TPC with MPGD
• Micro Pattern Gas Detector (MPGD) instead of MWPC for theelectron amplification stage: Not limited by the ExB effects

MICROMEGASORGEM (Gas ElectronMultiplier)• 200 hits/track• δ1/pt ~ 9 10-5 /GeV/c (TPC only)• δ1/pt ~ 2 10-5 /GeV/c (Full Tracker)• σ (rφ) < 100 µm• Rad length: 0.04X0 – 0.25 X0• dE/dx resol ~ 5%2012/11/13

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MICROMEGAS & GEM

MICROMEGAS

GEM~50 µm
~1 kV/cm~50 kV/cm~100 µm~50 kV/cm

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The Large Prototype TPC (LPTPC)• Dimensions:• Length = 61cm
• Diameter = 77cm

• Endplate :• Aluminium• Can accommodate 7
detectors/dummy modules• GEM and Micromegas
modules have same shapeàinterchangeable

MICROMEGAS/Multi-GEM

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The field cage
Radiation Length: 1.31% of X 0•

HV : up to 20kV

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New endplate
Endplate material budget:••••

readout : 5% X0
Cooling : 2% X0
Power cables :10% X0Mechanical structure : 8% X0

New lighter endplate, space frame, completedend of March 2012:2012/11/13

Old endplate

16,9 % X0

New
endplate
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7,5 % X014

DESY set-up
CosmicTrigger setup

e-

•

•

LPTPC slided into asuperconducting solenoid of
up to 1.25 T
1 < p < 6 GeV/c e-

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e-

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DESY set-up developments• LCTPC Collaboration with EUDET

and AIDA:DESY – KEK collab
PCMAG upgraded:
new crycoolers and closed
cooling cirtcuit(not shown here)
Thanks to KEK-IPNS cryo.
Group & KEK cryo. center

3D moving table+ detector, electronics, developments …
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Tested MPGD technologies• 4 MPGD readout options are tested with the LPTPC:• Analog TPC (Subject to gas gain fluctuation in the gas amplification)• Multi layer GEM with standard pads
– The charge is spread on the pad plane by diffusion• MICROMEGAS with resistive-anode pads

– To spread the very narrow avalanche charge on the pad plane• Muli layer GEM with pixel readout– To cope with high occupancy• Digital TPC (Free from gas gain fluct. Expect improvement on
position resolution by 20-30%)• Gridpix– pixel device with implemented Micromegas mesh (Timepix of the pixel
size of 55 µm) detecting individual primary electrons with 100% efficiency.

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Multi layer GEM with standard pads
• 2-3 layers of GEM provide sufficient gas
gain O(1000) for low noise electronics• The gap between the GEMs and theE fields determine the charge spreadà determine the point resolution• 2 types of GEM modules have beensuccessfully tested:• Asian GEM• Double thick (100µm) GEMs
• Stretching to minimise deadregion on the sides.

• DESY GEM• Triple CERN GEM
With thin (1mm) ceramic frame)
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Asian GEM Set-up @ DESY•••

ALTRO chip (ALICE TPC Read Out) has 16 channels• Digitize and buffer the signal5152 pads of 1.2 x 5.4 mm2• Perform zero-suppression(28 staggered rows)
1 FEC has 8 ALTRO chips
For LCTPC, CERN designed a new preamp: PCA16• Tuneable gains, polarity, peaking/decay time,…

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Some Double GEM Events

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Spatial Resolution

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Developments• Recent:• New segmented GEM foils (to reduce the discharge probability)• 3 modules will be tested at DESY in December 2012

• Future (2013):• New readout electronics: the SALTRO16• Tested successfully on electronics testbench• Power pulsing demonstrated– Power consumption reduced by a factor 60 with 5 Hz cycle
25 mm

32.5 mm2012/11/13

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MICROMEGAS with resistive anodes
Z=20cm, 200 ns shaping•

Resistive coating on top of an
insulator: Continuous RC network
which spreads the charge from σ(avalanche)~15µ to mm: matching
pad width improves position
sensitivity
M. Dixit, A. Rankin, NIM A 566 (2006) 28

2012/11/13•

x(pad) – x(track) (mm)

PAD RESPONSE: Relative
fraction of ‘charge’ seen by
the pad, vs x(pad)-x(track)

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First MICROMEGAS tests•

3 bulk MICROMEGAS modules tested• Regular anodes• Resistive anodes (carbon loaded kapton)with a resistivity ~ 5-6 MΩ/□• Resistive anodes (resistive ink) with aresistivity ~ 1-2 MΩ/□•

1726 (24x72) pads of ~3x7 mm²•

T2K AFTER-based electronics (72 ch./chip):• low-noise (700 e-) pre-amplifier-shaper• 100 ns to 2 µs tunable peaking time
• full wave sampling by SCA

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Some events
B=1T, T2K gas: Ar/CF4/iso-C4H10 (95:3:2)

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Spatial resolution• Measured drift velocity (Edrift = 230 V/cm),
7.56 ± 0.02 cm/µs• Magboltz: 7.548 ± 0.003 cm/µs
for Ar/CF4/iso-C4H10/H2O (95:3:2:100ppm)
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New Compact T2K electronics••

New resistive anode with improved grounding
Compact T2K electronics directly mounted on the backside of the MICROMEGAS
moduleRemove protection
Remove the packaging
Transfer power
regulation and ADC to
the mezzanine module
card.
Summer 2012:
6 modules mounted on LPTPC
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First results

onlineoffline• Also improvements in offline track reconstruction:• Uses now KalmanFilter (K. Fujii) in MarlinTPC (ILCSOFT) framework
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Study of the cracks• Having now almost the full LPTPC endplate equipped withmodules allow to study the features of the Large TPC prototype
Study the hit reconstruction efficiency
at or near the crack: take data withbeam, moving bysteps of 2mm

Beamdirection

Upper crack
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Lower crack

Outside crack

In crack

Pad-row number (3x24=72)
Hits with ADC>150, event w/. 1 track

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Scan around the cracks
Number of hits per track vs x

Number of hits per track vs x

àEffect of cracks is felt in an area ~1cm around.

More results to come soon (spatial resolution, etc.)
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Field distortions

MMegasAfter software correction

Residuals (mm)Need to control E field at the scale of O(100) µm

GEM

Pad row
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Digital TPC with Gridpix• In Gridpix, the MICROMEGAS is built on the Timepix chip by awafer post-process providing the ideal alignment between thegrid holes and the CMOS Timepix pixels.
• Cell pitch: 55-60 µm• Si layer to protect• Gain 5k-10k

2 beta’s from 90 Sr in 0.2 T
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GridPix tested with LPTPC• The octopuce protoype, 8
GridPix’s on daughter board• Powerful tool to performfundamental studies for gaseous
detectors:• Ionisation• Fano factor measurements• Avalanche fluctuations

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GridPix tested with LPTPC• He/Iso 80/20• Vmesh = 400V
• Time mode

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Ion back flow
• Simulation of positive ion back flow
• Estimate the effect of the primary ions and the secondary ions(from amplification) on the drifting electron trajectory with andwithout a gating device• Ion feedback ratio ~10-3(measured with both devices)• Gain ~1000• Gate device probably needed• Wire gate
• Very thin GEM gate

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Future developments••

Some already shown (Endplate, SALTRO)
Towards final electronics: GdSP
• gaseous detector signal processing (or Go digital as Soon as Possible)• CERN-based collaboration lead by Paul Aspell, including Saclay: F.
Guilloux and E. Delagnes, continuing SALTRO evolution.
• Common development for CMS GEM µ-chambers and LC TPC. Recently
considering ALICE upgrade (GEM TPC and µ chambers).
• Main developments : 130 nm technology, 64 or 128 channels, low noise
and ultra-low consumption, many power domains to ease powerswitching• First Si test to be submitted in February 2013 (AIDA)• Goals for the FE: for 10 pF detector capacitance and 100 ns peaking time
ENC<900 e- and power < 1mW/ch (SALTRO~10mW/ch)Parameter

VFAT2(IBM 0.25)

SALTRO(IBM 0.13)

VFAT3 / GdSP(IBM 0.13)

Linear range+- 12fC

150fC

Max 200fC

Input capacitance (pF)

20

0-20

5 – 10 – 30 – 60

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Noise~500e- ! 40-60e-/pF~ 650e- !15e-/pF
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Lentdecker - KEK seminar@De
25ns@ 120ns< SAltro /VFAT
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Conclusions• The LCTPC Collaboration has already achieved many
important milestones• Successfully tested the LPTPC with several MPGD devices andreadout electronics• The pad-readout MPGD TPCs satisfy the spatial resolution for
500 GeV ILC• Main electronics integration issues are now being adressed• Still a lo to do• Continue to reduce the material budget on the TPC endplate(electronics mounting and cooling)• Come up with a design of gate device• Address engineering issues for stable and reliable operation(distortions)

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THANK YOU
AND ESPECIALLY TO:
K. FUJII, T. MATSUDA,
D. ATTIE, P. COLAS
AND
THE LCTPC COLLABORATION
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Back-up slides

Electron Linear Collider Projects• Compact Linear Collider:• ECM=1.0 - 3.0 TeV• L~1035 cm-2 s-1• 2-Beam accelerator scheme• Normal (warm) conducting accelerating cavities– High accelerating gradients (100MV/m) and frequency (12 GHz)

• 0,7 ns bunch spacing !

•Expect CDR end of 2010, construction > 20172012/11/13

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2012/11/13

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Push-Pull options
The concept is evolving
and details being
worked out

may beaccessible
during run

detectorA

accessible
during run

Platform for electronic andservices (~10*8*8m). Shielded(~0.5m of concrete) from fivesides. Moves with detector. Also
provide vibration isolation.

detectorB
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From outside to inside• The muon system:• Instrumented iron return yoke
• A few ns time resolution (Note: no trigger)• mm – cm spatial resolution range• RPCs with 3-4 cm wide strips

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Imaging/Tracking calorimeter• The HCAL
• High granularity Sampling calorimeter• Steel as absorber• Scintillator tiles (analog) VS. gaseous device (digital)•
3 x 3 cm2VS.
1 x 1 cm2
•
SiPM
VS.
GlassRPC
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From outside to inside II• The ECAL
• High granularity, particle separation, compactness• => Sampling calorimeter (~30 layers)• Silicon diodes or scintillator separated by tungstene• Lateral cell size : 5 x 5 mm2• 100 Million of channels• FE electronics embedded in detection layerØ Small dead zone areaØ All modules are identical (Tungsten wrapped by Cfi)
2012/11/13
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Lentdecker - KEK seminarassemblingØ The detector slabs would be tested before

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Pixel and Si detector• Main issue is the Material Budget !
• Vertex detector••••

3 double or 5 single pixel layers 15 < r < 60 mm
Should provide a point resolution ~ 3µm
Should intercept tracks with theta such that |cosθ| < 0.97
Size : 10x10 – 30x30 um2• Si Tracking detector• Around the TPC• Silicon Internal Tracker (SIT)• Silicon External Tracker (SET)• Forward Tracking Detector (FTD)• Endcap Tracking Detector (ETD)• Improve time and spatial resolution• Provide ECAL entry point
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B

E

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Space-frame endplate
mass
kg

LP1

calculated
measuredmaterial deflection stressdeflection
%X0
µm
MPa
µm
(100 N) (yield: 241) (100 N)

18.87

16.9

29

1.5

33

8.38

7.5

23

4.2

27

Lightened

8.93

8.0

68

3.2

Al-C hybrid

7.2(68-168)(3.2-4.8)(channeled plus fiber)

Al 7.35
C 1.29Channeled

Al 7.35

6.5

168

4.8

LP2 Space-Frame(strut or equivalent plate)

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Resistive anodes:• In TPC, the physics limit for the resolution comes fromtransverse diffusion
DTr2 # z
2
!x "

N eff

Neff = effective no. of electrons contributing to position determination.

• For best resolution, choose gas with smallest diffusion• BUT, with MPGD-TPC resolution is limited by pad width w.
The resolution gets worse for wide pads (~mm) in absenceof diffusion.
w2
2
!x "

12

as z " 0Solution:
Resistive anodes

meshResistive foil
Glue
pads

PCB

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Resistive anodes

2C!0 + D z
Ne2

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DAQ
• Triggers provided by scintillators (beam/cosmics)

Brussels contributions

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Carbon Loaded Kapton VS. Resistive ink
Carbon Loaded Kapton

à σz=5cm = 68 µm
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Resistive Ink

Γ = 7 mm

Γ = 11 mm

δ = 10 mm

δ = 13 mm

à σz=5cm = 130 µm !
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MICROMEGAS + Silicon modules• Last november, the Vienna group installed Si modules aroundthe TPC• DAQ synchronisation based on Brussels DAQ board.

16/12/2009
2012/11/13

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Lentdecker- KEK
seminarInternal
seminar54

Double GEM structure

5152 pads of 1.2 x 5.4 mm2(28 staggered rows)

Optional: gating GEM• ALTRO (ALICE) Electronics + new PCA16 preamp. (tunable gain,
peak. and decay time, polarity,…), noise ~ 314 electrons
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3-GEM Structure & TimePix
3-GEM + CMOS pixel readout
14 mm

Readout: 2 quadboards eachwith 4 TimePix chips of
256x256 ch (55µmx55µm)
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3-GEM Structure & TimePix
Largest amount of readout channels
on one anode for a TPC so far: # ch ! 500 k
10 cm
T2K-Gas2012/11/13

40 cm
T2K-Gas

50 cm
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!""#$%&'($)*'+,*-./'!0+
1$-'*/-)'2"%342)$%&',#-)/.
589',#-)/.

5*/67-#'2"%)-2).

+8!0+',$,/.

!

2012/11/13!

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Laser Calibration Setup•UV light pulses sent via
fibres to top and bottomof TPC endplate•Light distribution constantover central module•Position of reconstructedhits to calculate distortions,diffusion, drift velocity…

Photoelectrons
produced at
cathode=> pattern seen with Micromegas
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TPC Performance

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LP-TPC Endplate61
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30 cm

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Readout Electronics: AFTER

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Jet Energy Resolution

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Particle Flow

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PF Calorimetry

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PF Algorithm

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