[email protected] – binp, novosibirsk – march 1 st, 20081 tpc review david attié 10-th...

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INSTR08 – BINP, Novosibirsk – March 1st, 2008 1

TPC ReviewTPC Review

David Attié

10-th INTERNATIONAL CONFERENCEON INSTRUMENTATION

FOR COLLIDING BEAM PHYSICS

Novosibirsk, March 1st, 2008

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Outline

1. The Time Projection Chamber

• Description

• Characteristics

2. Examples of TPCs

• TPCs for High Energy Physics: Particle Physics and ions Physics

• TPCs for rare event detection: neutrinos, dark matter

3. TPC R&D

• Readout for TPC: Micro Pattern Gaseous Detector (GEM, Micromegas)

• Gas studies

• Spatial resolution measurements and techniques

4. The LC-TPC collaboration

• The Large Prototype

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• TPCs have been operated often as the main tracker in a wide range of physics experiments:

– particle physics– heavy ion collision– underground experiments

• Need for Physics measurements:– momentum resolution– pattern recognition– low material budget to preserve good jet energy resolution

• Physics knowledge depend on the sensitivity and the performance of the instrument

Introduction

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1. The Time Projection Chamber

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TPC description

Gas volumeReadout

z

x

y

gas system

field cage for the E field

magnet for the B field

amplification system at the anode

gating grid to suppress the ion feedback

laser calibration system

readout electronics

trigger

• Ingredients:

• The TPC is a gas-filled cylindrical chamber with one or two endplates

• Particle detector invented by D. R. Nygren in 1974

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• Track point recorded in 3-D

(2-D channels in x-y) x (1-D channel in z = vdrift x tdrift)

• Low occupancy large track densities possible

• Particle identification by dE/dx

long ionization track, segmented in 100-200 measurements

STAR ion TPC BNL-RHIC

ALICE simulation

events

- LBL STAR TPC - at BNL RHIC ion collider

Characteristics of a TPC

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2. Examples of TPCs

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Experiments with a TPC

TPC Reference PEP4 PEP-PROPOSAL-004, Dec 1976 TOPAZ Nucl. I nstr. and Meth. A252 (1986) 423 ALEPH Nucl. I nstr. and Meth. A294 (1990) 121 DELPHI Nucl. I nstr. and Meth. A323 (1992) 209-212 NA49 Nucl. I nstr. and Meth. A430 (1999) 210 STAR I EEE Trans. on Nucl. Sci. Vol. 44, No. 3 (1997)

TOPAZ (KEK)

ALEPH (CERN)

DELPHI (CERN)

PEP4 (SLAC) STAR (LBL)Some detectors in Particle and ions Physics using a TPC

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Today: ALICE at LHC

• ALICE (A Large Ion Collider Experiment)

• search for a quark-gluon plasma

• in heavy ion collisions Pb-Pb

• at a centre of mass energy of 5.5 TeV per nucleon

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First cosmic-rays events in ALICE TPC

• 3-dimensional view of a shower induced by cosmic rays

L. Musa et al.January 2008

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Performance needed for the ILC-TPC

• LC-TPC should provide a good resolution on the momentum measurement

Precise and model-independent measurement of the Higgs-Mass in the Zμμ recoil

• Momentum: σ1/p ~ 5x10-5/GeV(1/10 x LEP)

- Z mass reconstruction from charged leptons

- Higgs-Strahlung:

• Need to support high density of tracks and/or final states with 6+ jets:

– high granularity

– good two tracks separation

– track identification

e+,μ+e–,μ–

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ILC-TPC simulations

Simulation GEANT4 of LC-TPC, A. Vogel

• TPC for the International Linear Collider, e+e- collisions at 500 GeV

• Includes beam background

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Future TPC for rare events detection

• Rare events topics:– neutrinos physics (double-beta decay, T2K long baseline

experiment)– Dark Matter search, WIMPs, axions

• TPC medium can also be used as the target

• Main TPC characteristics for this physics:– a large volume and/or a dense medium: pressurized gas or liquid– a “quiet” TPC (for example, no needs for gating gate)– generally underground experiments with low activity materials

• Examples :– ICARUS: Imaging Cosmic And Rare Underground Signals– GLACIER: Giant Liquid Argon Charge Imaging ExpeRiment – DRIFT project: Directional Recoil Identification From Tracks– T2K: Tokai to Kamiokande

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• ICARUS (Imaging Cosmic And Rare Underground Signals) at Gran Sasso

• the biggest one ever build

• Observation:- high energy neutrinos (17 GeV) from CERN- solar ν (5-14 MeV)- supernovae ν (10-100 MeV)- atmospheric ν (1GeV)

• 300t of Liquid Argon (idea from C. Rubbia, 1977): -Argon is not electronegative: electrons may drift over very long distances- many e- are produced (60000/cm for a MIP particle) - + scintillation in Ar (50000 ph./cm for a MIP particle)- Argon is inexpensive (1% in the atmosphere)

• future: 100kT GLACIER LAr detector?

ICARUS for neutrinos Physics

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ICARUS for neutrinos Physics

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GLACIER TPC• Giant Liquid Argon Charge Imaging ExpeRiment (A. Rubbia, hep-ph/0402110)

A scalable design:

10 kton

Ø = 70 m

h = 20 m

Passive perlite insulation

100 ktonElectronics crates

• Two phases Argon TPC

• LEM (Large Electron Multiplier) = thick macroscopicGEM readout, very long drift

• Single module cryo-tanker based on industrial Liquefied Natural Gas (LNG) technology

• Could potentially be magnetized

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• DRIFT (Directional Recoil Identification From Tracks)

• negative ion TPC (C. Martoff, N. Spooner et al.)

• the most exotic !

• For detection:- WIMP- Axion

• electronegative gas additive (CS2) captures primary e- negative ions

• Excellent background discrimination

• future: large underground observatory

4m

8m

DRIFT for Dark Matter

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T2K : Tokai to Kamiokande

• Long Baseline neutrino experiment with an intense beam (0.75MW)

• Aiming at 13 , and “atmospheric oscillation” measurements

• 2 detectors: far (SK) and near at 280 m from target • Off-axis beam• JPARC currently under construction first beam 2009

The 280 m detector is used to check the initial beam composition, it includes 3 largeMicromegas TPCs

B = 0.2 TB = 0.2 T

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3. TPC R&D

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Plan of TPC R&D

• Develop the readout technologies– Tests with small prototypes

• Studies of the gas mixtures– Limit the diffusion– Find a stable state

• Improve the spatial resolution: resistive or digital anode– Resolution with short drift length is dominated by

• Readout pad pitch• Width of induced charge on pad plane

– To decrease pad pitch• Digital TPC• Increase signal width

Resistive anode pad readout, but two track separation might be less good

• Built and test a larger prototype to make the technology choice

• Design and produce the final TPC for the specific experiment

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Micromegas & GEMs (MPGD)

50 µm

40 kV/cm

~1000 µm

1 kV/cm

GEM

~50 µm

80 kV/cm

Micromegas

Technology choice for TPC readout: Micro Pattern Gaseous Detector

• more robust than wires

• no E×B effect

• better ageing properties

• easier to manufacture

Avalanche

• fast signal & high gain

• low ion backdrift

• Gas Electron Multiplier (F. Sauli, 1997)

• 2 copper foils separated by kapton

• multiplication takes place in holes

• use of 2 or 3 stages

• MICROMEsh GAseous Structure(Y. Giomataris et al., 1996)

• metallic micromesh (typical pitch 50μm)

• sustained by 50μm pillars, multiplication between anode and mesh, high gain

• Gas Electron Multiplier (F. Sauli, 1997)

• 2 copper foils separated by kapton

• multiplication takes place in holes

• low gain

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Micromegas & GEMs (MPGD)

• 2- or 3- stage amplification

• easy operation

• low field above the electronics

• low discharge probability

• simplicity

• single stage of amplification

• natural ion feedback suppression

• discharges non destructive

GEMMicromegas

Technology choice for TPC readout: Micro Pattern Gaseous Detector

• more robust than wires

• no E×B effect

• better ageing properties

• easier to manufacture

• fast signal & high gain

• low ion backdrift

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Bulk Micromegas technology

Copper segmented anode

Lamination of Vacrel

Positioning of Mesh

Encapsulation

Development

FR4

Photo-imageablepolyamide film

Stainless steelwoven mesh

Border frame

Spacer

Contact to Mesh

Base Material

I. Giomataris et.al., NIM A560 (2006) 405

• Process to have an encapsulated mesh on a PCB

(mesh = stretched wires)

• Motivations for using bulk Micromegas

– the mesh is held everywhere:

no dead space, no frame

– robustness because it is closed to dust

– can be segmented

– repairable

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Bulk-Micromegas prototypes of TPC for T2K

Geneva-Barcelona test bench

Test of a T2K module with a 55Fe source

Micromegas prototypes: • Bulk: 34x36 cm2, 128 m gap • 1728 pads of 6.9x9 mm²

HARP test at CERN (PS/T9)

MM1 detector + FEE + Cooling system

HARP solenoid (0.7 T)

Field cage1.5 m drift length

• Sep. 19th – Oct. 3rd 2007 (Analysis in progress)• Electronics: AFTER ASIC from Saclay

By T2K/TPC-Europe

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Bulk-Micromegas prototypes for T2K

Signal from 55Fe source

= 8.5% rms @ 5.9 keV

= ~8% rms @ 5.9 keV

Lab Test HARP test at CERN (PS/T9)

Energy resolution consistent with lab. test results

• E = 160 V/cm, B = 0.2 T• Source located at 1.54 m from MM detector

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Bulk-Micromegas prototypes for T2K

15 GeV/c p-Pb interactions in front of the TPCCosmic rays in the

TPCY

X

T

Y

55Fe source

HARP test: events display

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Ion feedback measurements

Gain ~ 200σt = 9.5 μm

• 20 μm pitchp1 = 1.01

• 32 μm pitchp1 = 0.90

• 45 μm pitchp1 = 0.96

• 58 μm pitchp1 = 1.19

BF = p0/FRp1

• Measurements with a 45 μm gap InGrids

• Backflow fraction (BF) down to 1 permil at low picth and high field ratio

M. Chefdeville et al. IEEE/NSS 2007

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Gating for ILC

• If natural ion backflow suppression is not sufficient, gating can reduce the number ions feeding back in the drift space

• Time structure: one ms train every 200 ms

• Gating can be done with wires or a GEM operated at unit gain

Wire gating GEM gating

Gate Open

Gate Closed

50mm/ms

- -

- -

- -

- -

- -

- -

- -

+ +

+ +

+ +

+ +

+ +

+ +

+ +

Previous beam train x-ings

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Gas properties studies

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100

1000

10000

100000

50 55 60 65 70 75 80 85 90 95 100

Field (kV/cm/atm)

Ga

in

Iso : 1%

Iso : 2%

Iso : 3%

Iso : 4%

Iso : 5%

CF4 : 3%, Iso : 1%

CF4 : 3%, Iso : 2%

CF4 : 3%, Iso : 3%

CH4 : 6%

CH4 : 7,5%

CH4 : 9%

CH4 : 10%

CH4 : 5%, CF4 : 3%

CH4 : 5%, CF4 : 5%

CH4 : 5%, CF4: 10%

CH4 : 10%, CF4 : 3%

CH4 : 5%, CO2 : 3%

CH4 : 10%, CO2 : 10%

CO2 : 10%

CO2 : 20%

CO2 : 30%

CO2 : 10%, Iso 2%

CO2 : 10%, Iso 5%

CO2 : 10%, Iso 10%

CF4 : 3%, CO2 : 1%

CF4 : 3%, CO2 : 3%

CF4 : 3%, CO2 : 5%

Iso : 2%, CH4 : 10%

Iso : 5%, CH4 : 10%

Iso : 10%, CH4 : 10%

Ethane 10%

Ethane 5%

Ethane 3,5%

Ethane 2%

Ethane 3,5% - CO2 10%

Ethane 3,5% - CF4 3%

Ethane 3,5% - CF4 10%

Ethane 3,5% - Iso 2%

Mixtures of gases containing argon: gain curves

iC4H10

CO2, CH4C2H6

Micromegas Mesh : 50 m gap of 10x10 cm² size

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5%

10%

15%

20%

25%

30%

35%

40%

100 1000 10000 100000 1000000

Gain

RM

S

Iso : 1%

Iso : 2%

Iso : 3%

Iso : 4%

Iso : 5%

Energy resolution vs. gain

Argon/Isobutane

• Best RMS for a gain between 3.103 & 6.103

• Degradation increase in inverse proportion to the quencher

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Spatial resolution studies

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Spatial resolution: 5 T cosmic-ray test at DESY

5T magnet at DESY + COSMo TPC

Resistive anode

Micromegas

COSMo TPC

resistive foilgluepads

PCB

mesh

(r,t) integral over pads

(r)

r (mm)

Q(t)

t (ns)

M.S.Dixit et.al., NIM A518 (2004) 721

• COSMo (Carleton Ottawa Saclay Montréal) TPC+ 10 x 10 cm² Micromegas (50 μm gap) + resistive anode used to disperse the charge(126 pads of 2x6 mm²size)

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Spatial resolution at 0.5T vs. gain

• B = 0.5 T, resolution fit by where Neff number of effective e-

• Resolution 0 ( at z = 0) ~ 50 µm still good at low gain (will minimize ion feedback)

• Mean of Neff = 27

Gain = 4700 Gain = 2500

Neff=25.2±2.1 Neff=28.8±2.2

x 02 Cd2 zNeff

0 = 1/40 of the pad pitch

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Spatial resolution at 5T vs. gas mixtures

Ar Iso (95:5)

B = 5T

Ar Iso (95:5)

B = 5T

50 m

At high magnetic field (5T) ~ 50 µm independent of the drift distance

Dixit, Attié, et al., NIMA 581, 254 (2007)

Extrapolate to B = 4T with T2K gas for 2x6 mm² pads:

• DTr = 23.3 µm/cm, • Neff ~ 27,• 2 m drift distance,

Resolution of Tr 80 m will be possible !!!

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Tsinghua: TPC prototype with GEM Readout

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Tsinghua: 1 T cosmic-ray test at KEK

Test in Dec. 2007

Preliminary results !

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Digital TPC

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• Chip (CMOS ASIC) upgraded in the EUDET framework from the Medipix chip developed first formedical applications

• IBM technology 0.25 µm

• Characteristics:– surface: 1.4 x 1.6 cm2

– Matrix of 256 x 256– pixel size: 55 x 55 µm2

• For each pixel:– preamp/shaper– threshold discriminator– register for configuration– TimePix synchronization logic– 14-bit counter

55 m

55 m

Description of the TimePix chip

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TimePix/Micromegas chambers

• NIKHEF– Next-1,2 & 3– standard Micromegas– amorphous-Silicon protection

against discharges– Ingrid: Integrated Micromegas

using post-processing

• Saclay– Micro-TPC– standard Micromegas– amorphous-Silicon

protectionagainst discharges

– 6 cm height field cage

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Cosmic-ray

time

• Chamber Next-1 at NIKHEF

• TimePix chip + SiProt + Ingrid

• Gas mixture : He/Iso (80:20)

• Maximum drift: 10 mm

• Amplification gap: 50 μm

• Cosmic-ray track:– Length : ~ 18 mm– Width : ~ 200 μm

• Before SiProt chips used to die due tosparking but now …

NIKHEF

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• Image of discharges are being recorded

• Round-shaped pattern of some 100 overflow pixels

• Perturbations in the concerned column pixels

– Threshold?– Power?

Chip keeps working !!

Discharges are observed

• Provoke discharges by introducing small amount of Thorium in the Ar gas

- Thorium decays to Radon 222 which emits 2 alphas of 6.3 & 6.8 MeV- Depose on average 2.5.105 & 2.7.105 e- in Ar/iC4H10 80/20- at -420 V on the grid, likely to trigger discharges

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TimePix/Micromegas Micro-TPC of Saclay

• Micro-TPC

• Timepix chip+ SiProt 20 μm+ Micromegas

• 90Sr

• Ar/Iso (95:5)

• Time Mode

• z ~ 40 mm

• Vmesh = -340 V

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TimePix & GEMs

Freiburg (+Bonn)

Beam DESY II

Trigger (scint.) &Si-telescope

- Standard GEMs 100x100 mm2 with 140 μm of hole pitch

- News GEMs 24x28 mm2 with 50μm of hole pitch

puce TimePix :14 mm

• Test beam at DESY in 2007• Several gas mixture and two GEM systems were tested

Time

TOT

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ILC-TPC collaboration

41 institutes

120 physicists

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Small prototypes

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Large Prototype for ILC• Endplate of 7 panels, ø = 80 cm

• Two readout technology : GEM & MICROMEGAS (bulk)

• anode, resistive anode, pixels

80 cm

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EUDET/LCTPC setup at DESY

• Field cage (DESY)

• 1 T magnet (KEK)

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Conclusions

• Gaseous detectors have a long history behind them andthey, especially TPCs, have a promising future

• The new MPGD technologies are now mature unite in world-wide RD51 collaboration

• Physicists working on TPC R&D are now inside a huge collaboration over the world towards the future Linear Collider

• The ALICE TPC is getting ready for data taking at LHC

• T2K experiment will commission a large new generation TPC in 2009

• TPCs will permit a large development of many applications, not only in particle tracking, as usually in high energy and heavy ions physics,but also in rare event detection

[email protected] – binp, novosibirsk – march 1 st, 20081 tpc review david attié 10-th...

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