16 Mar. 2006

Time Projection Chamber (TPC)
Applications
andILC-TPC R&D Studies
Mike Ronan
LBNL (Berkeley)“TPC Applications and ILC-TPC R&D”

M. Ronan, LBNL

1

16 Mar. 2006

Outline●Time Projection Chamber (TPC)●TPC Applications– Particle and Nuclear Physics Applications●

International Linear Collider (ILC)– Callenges for multi-jet Higgs measurements●

International LC-TPC R&D Studies– Micro-Pattern Gas Detectors (MPGD's)– GEM and Micromegas based TPC studies– Pixel TPC's“TPC Applications and ILC-TPC R&D”

M. Ronan, LBNL

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16 Mar. 2006

A Brief Introduction to TPC's●

e+e- Colliding Beam Configuration●

PDG “Review of Particle Properties” description●

TPC gating grid●

PEP TPC dE/dx measurements & most probableenergy deposition predictions●

TPC Particle Identification●

The 2003 Time Projection Chamber Symposium●

References“TPC Applications and ILC-TPC R&D”

M. Ronan, LBNL

3

TPC studies of e e collisions+ -16 Mar. 2006

From 2004 CERN Courier article by
Spencer Klein, LBNL
“TPC Applications and ILC-TPC R&D”

M. Ronan, LBNL

4

Time-projection chambers

16 Mar. 2006

Review of Particle Properties, P.L. B 592,1 ('04)
Written Nov. 1996 by M.T. Ronan
Detectors with long drift distances perpendicular to a multi-anode proportional (wire) plane
provide three-dimensional information, with one being the time projection. A (typicallystrong) magnetic field parrallel to the drift direction suppresses transverse diffusion (s =r2Dt) by a factor D(B)/B(0) = 1/(1+w2t2), where D is the diffusion coefficient, w = eB/mc is
the cyclotron frequency, and t is the mean time between collisions. Multiple measurementsof energy deposit along the particle trajectory combined with the measurement of
momentum in magnetic field allows excellent particle identification [91], as can be seen in
Fig. 28.5. See next slide.
A typical gas-filled TPC consists of a long uniform drift region (1-2 m) generated by acentral high-voltage membrane and precision concentric cylindrical field cages within auniform, parallel magnetic field []. Details of construction and electron trajectories near theanode end are shown in Fig. 28.6. See following slide. Signal shaping and processing using
analog storage devices or FADC's allows excellent pattern recognition, track reconstruction
and particle identification within the same detector.
Typical values:
Gas: Ar + (10-20%) CH4
Pressure(P) = 1-8.5 atm.
E/P = 100-200 V/cm/atm.
B = 1-1.5 Tesla
vdrift = 5-7 cm/us
ωτ = 1-8
σx or y = 100-200 um
σz = 0.2 – 1 mm
σEdep = 2.5-5.5 %See also www-tpc.lbl.gov, i.e. www-tpc server at lbl.gov“TPC Applications and ILC-TPC R&D”

M. Ronan, LBNL

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16 Mar. 2006

“TPC Applications and ILC-TPC R&D”

M. Ronan, LBNL

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16 Mar. 2006

TPC Gating Grid

Electric fields for the MWPC PEP-II Mini-TPC

A TPC gating grid (GG) is used to control
the backflow of positive ions generated inelectron signal amplification by anodewires or Micropattern Gas Detectors(MPGD's), such as GEM's or Micromegas.
In a MWPC readout of a TPC, the gating
grid is placed just before the virtual groundprovided by the shielding grid and ismaintained at proper average voltage, but
has alternating positive and negative
potential when closed.
Note: A gating grid was not included in theoriginal PEP TPC proposal or the Bevatron
prototype. The idea to include one may
have originated from a comment by
G.Charpak at the 1978 Vienna Wire
Chamber conference. The early decision todevelop the GG upgrade for the PEP-TPC
was critical.
See CERN 1981 TPC seminar by M.T. Ronan.
“TPC Applications and ILC-TPC R&D”

M. Ronan, LBNL

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16 Mar. 2006

“TPC Applications and ILC-TPC R&D”

M. Ronan, LBNL

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TPC Workshop

16 Mar. 2006

We have organized a TPC applications
workshop for this spring. We'll havetalks that review physics opportunities in
Particle and Nuclear physics and past
TPC applications. The expected
performance of TPC's for LinearCollider and Heavy-Ion physics,
neutrino oscillations, dark mattersearches, double-beta decay and neutron
detection will be presented in various
talks on different gaseous and liquid
TPC detector designs.
We'll have invited talks on recent GEM
and Micromegas developments by theexperts, and on summaries of R&D
results and plans for next-generation
Micro-Pattern Gas Detector (MPGD)
based TPC's. We'll also havepresentations on new TPC electronics
developments. Recent softwaredevelopments in TPC data analysis,
simulation and reconstruction, and invisualization
tools
will be R&D”
presented.
M. Ronan, LBNL
“TPC
Applications
and ILC-TPC

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16 Mar. 2006

Particle Physics Applications●

PEP TPC – Study of jet fragmentation●

TOPAZ TPC – Search for top quark●

ALEPH TPC – Large 1 atm. detector●

DELPHI TPC – Central 1 atm. detector●

TESLA TPC - “Technical Design”●

ILC TPC(s) – Large gaseous conceptual designs– LDC The “Large Detector Concept” medium size TPC– GLD The “Global (or Gaseous) Large Detector”“TPC Applications and ILC-TPC R&D”

M. Ronan, LBNL

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Proposed TPC Detector

Dec. 30, 1976

16 Mar. 2006

Liquid Argon ECal

Superconducting coil
B = 1.2T
TPC P10 @ 10atm
r=1m, max. drift =1m“TPC Applications and ILC-TPC R&D”

M. Ronan, LBNL

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Dave Nygren

16 Mar. 2006

Dave during his talk at the Berkeley TPC Symposium
17 Oct. 2003

Dave Nygren (left) and Fred Catania during TPC detector
assembly in PEP IR2 at SLAC, circa 1980.
M. Ronan, LBNL
“TPC Applications and ILC-TPC R&D”

Dave Nygren in M.R.'s office
3 Nov. 200412

16 Mar. 2006

PEP-4 TPC

“TPC Applications and ILC-TPC R&D”

M. Ronan, LBNL

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16 Mar. 2006

B Jet Physics
One event from PEP4/9
commissioning run in
1989.

Straw tube Vertex Chamber

TPC End view
“TPC Applications and ILC-TPC R&D”

M. Ronan, LBNL

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The TOPAZ Detector at Tristan, KEK“TPC Applications and ILC-TPC R&D”

M. Ronan, LBNL

16 Mar. 200615

16 Mar. 2006

ALEPH
ALEPH

Presented by Ron Settles,
TPC Symposium, Oct. 2003
see http://www-tpc.lbl.gov/symposium2003“TPC Applications and ILC-TPC R&D”

M. Ronan, LBNL

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16 Mar. 2006

DELPHIDELPHI

Presented by Vincent Lepeltier,
TPC Symposium, Oct. 2003
see http://www-tpc.lbl.gov/symposium2003“TPC Applications and ILC-TPC R&D”

M. Ronan, LBNL

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The “PTA” Collaboration
An informal collaboration ofpresent and formet PEP-TPC
fellows working on a common
analysis of data from the

16 Mar. 2006

αS

PEP / Topaz / Aleph TPC's
Mainly,M.R.
PEP
M. Yamauchi Topaz
R. ItohG. Cowan
ALEPH“TPC Applications and ILC-TPC R&D”

M. Ronan, LBNL

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“TPC Applications and ILC-TPC R&D”

M. Ronan, LBNL

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TPC Applications to
Beam Instrumentation●●●

PEP-II Mini-TPC – Used for measuring B-Factory
backgrounds at IP before BaBar.
KABES – Used for tagging and tracking K+/Kbeams in NA48 CP Violation ExperimentBeam Diagnostic TPC – Proposed to measure
beam halos for ILC R&D, M. Ronan at 2005 TPC
R&D Meeting, http://www-tpc.lbl.gov/meeting05.

“TPC Applications and ILC-TPC R&D”

M. Ronan, LBNL

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16 Mar. 2006

PEP-II Mini-TPC“TPC Applications and ILC-TPC R&D”

M. Ronan, LBNL

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16 Mar. 2006

PEP-II IR2 Commissioning

First Asymmetric e+e- annihilation event“TPC Applications and ILC-TPC R&D”

M. Ronan, LBNLe+ (3.1 GeV)e- (9 GeV)

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16 Mar. 2006

NA48: KABES

Micromegas beam-instrumentation TPC's to measure incoming K+ and Kbeam trajectories.

“TPC Applications and ILC-TPC R&D”

M. Ronan, LBNL

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16 Mar. 2006

ILC-TPC Beam Test Proposal
Test beam

Scraper
New MPGD TPC
Goals:
1.) Test GEM and Micromegas readout technologies in accelerator
environment.
2.) Develop beam halo diagnostic tool using TPC measured tracks topoint back scattered particles to scraper.
3.) Study and develop beam line simulation model and study detector
response to different backgrounds, i.e. γ's, electrons and neutrons.
“TPC Applications and ILC-TPC R&D”

M. Ronan, LBNL

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16 Mar. 2006

Nuclear Physics Applications●

EOS TPC – “Equation of State” planar detector●

STAR TPC – Large “Pads Partout” detector●

ALICE TPC – LHC“TPC Applications and ILC-TPC R&D”

M. Ronan, LBNL

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16 Mar. 2006

The EOS TPC
E910 – fixed target in a magnetic field• Cubic meter scale• Inherits technology from PEP4
• Contemporary of NA35

5
1.

m

1m

•
•
•
•

Anode & field wires, w/Gating Grid
15,360 channels
12 mm x 8 mm pads
Multiplicity goal ~200 tracks“TPC Applications and ILC-TPC R&D”

Presented by Jim Thomas,
TPC Symposium, Oct. 2003
see http://www-tpc.lbl.gov/symposium2003
M. Ronan, LBNL

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TPC Gas Volume & Electrostatic Field Cage

16 Mar. 2006

420 CM●

Gas: P10 ( Ar-CH4 90%-10% ) @ 1 atm●

Voltage : - 28 kV at the central membrane
135 V/cm over 210 cm drift path

“TPC Applications and ILC-TPC R&D”

M. Ronan, LBNL

Self supporting Inner Field Cage:
Al on Kapton using Nomex
honeycomb; 0.5% rad length27

STAR-TPC Installation“TPC Applications and ILC-TPC R&D”

M. Ronan, LBNL

16 Mar. 200628

16 Mar. 2006

STAR-TPC Au-Au Event

A side view of tracks from 200 GeV per nucleon
for a gold-on-gold collision at RHIC, asreconstructed in the TPC of the STAR experiment
From 2004 CERN Courier article by
Spencer Klein, LBNL
“TPC Applications and ILC-TPC R&D”

M. Ronan, LBNL

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16 Mar. 2006

Neutrino Physics Applications●

ICARUS – Massive Liquid Argon TPC●

T2K – Near Detector TPC Tracker●

MICE – Muon Ionization Cooling Experiment●

NOSTOS - Spherical TPC Proposal●

HELLAZ

●

MUNU

●

...

“TPC Applications and ILC-TPC R&D”

M. Ronan, LBNL

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16 Mar. 2006

ICARUS

The technology of the Liquid Argon Time Projection Chamber (LqTPC), first
proposed by C. Rubbia in 1997, provides completely uniform imaging with highaccuracy for massive volumes.

Being developed at the INFN Gran
Sasso Laboratory for study ofsolar and atmospheric neutrinos● nucleon decay● neutrinos from Supernovae● accelerator neutrino oscillations●

Large T600 detector system test was carried out on surface in 2001.
“TPC Applications and ILC-TPC R&D”

M. Ronan, LBNL

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ICARUSTPC

16 Mar. 2006

The ICARUS LqAr TPC, 3.6 m wide by 3.9
m long by 19.6 m in length, is divided into
two halves by the center cathode plane.

“TPC Applications and ILC-TPC R&D”

M. Ronan, LBNL

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16 Mar. 2006

Stereo wire readout
Pseudo-3D data from direct electron
signals, without amplification, arerecorded on stereo wires as a functionof drift time in 3 different views: 2
from induced pulses and 1 fromcharge collection.
Excellent pattern recognition software
has been developed.

“TPC Applications and ILC-TPC R&D”

M. Ronan, LBNL

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16 Mar. 2006

T2K TPC
Large GEM or Micromegas TPC
for studying systematics of neutrino
detection in Tokai to Kamioka(T2K) experiment.

Cosmic rays seen by Micromegas TPC Prototype“TPC Applications and ILC-TPC R&D”

M. Ronan, LBNL

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16 Mar. 2006

Dark Matter Search Applications●

XENON TPC – Large Liquid Xenon detector●

DRIFT TPC – Negative Ion drift detector“TPC Applications and ILC-TPC R&D”

M. Ronan, LBNL

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16 Mar. 2006

Presented by Elena Aprile, Columbia at the 2003 TPC Symposium,
see http://www-tpc.lbl.gov/symposium03.
“TPC Applications and ILC-TPC R&D”

M. Ronan, LBNL

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16 Mar. 2006

WIMP Direction

Presented by Neil Spooner at the 2004 Paris TPC Meeting,see http://www.unine.ch/phys/tpc.html“TPC Applications and ILC-TPC R&D”

M. Ronan, LBNL

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Direct Detection of WIMPs

16 Mar. 2006

Presented by Dan Snowden-Ifft at the 2005 TPC R&D Meeting,see http://www-tpc.lbl.gov/meeting05“TPC Applications and ILC-TPC R&D”

M. Ronan, LBNL

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WIMP Cross Section Limits“TPC Applications and ILC-TPC R&D”

M. Ronan, LBNL

16 Mar. 200639

16 Mar. 2006

Argon Nucleus Recoils“TPC Applications and ILC-TPC R&D”

M. Ronan, LBNL

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16 Mar. 2006

Negative Ion TPC

Presented by Jeff Martoff, Temple at the 2003 TPC Symposium,
see http://www-tpc.lbl.gov/symposium03“TPC Applications and ILC-TPC R&D”

M. Ronan, LBNL

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16 Mar. 2006

Double-Beta Decay Applications●●●

Gotthard - 5 atm. Xenon TPC (5 kg)
Enriched Xenon Observatory (EXO) - 10 ton
Xenon detector with event-by-event Barium
spectroscopy. Either 20 atm. gas or liquid TPC.
First stage 200 kg enriched LqXe TPC.
New high-pressure gas TPC detector conceptsndbeing developed for 2 round proposals, e.g.
D.Nygren at upcoming TPC Applications
Workshop http://www-tpc.lbl.gov/workshop.

“TPC Applications and ILC-TPC R&D”

M. Ronan, LBNL

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16 Mar. 2006

A Xenon TPC for Double Beta Decay
TPCs compared to solid state detectors (76Ge and 130Te):
Pro:•Monolithic design has optimal surface area to volume ratio•Full three dimensional event reconstruction•Fluid can be purified in situ
•Noble gas isotope enrichment relatively easy and safe
•No crystal growthCon:•Energy resolution much worse (110 keV vs 3 keV FWHM)

Presented by Carter Hall, SLAC at the 2003 TPC Symposium,
see http://www-tpc.lbl.gov/symposium03“TPC Applications and ILC-TPC R&D”

M. Ronan, LBNL

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16 Mar. 2006

The Gotthard Xenon TPC (1993)
180 liters of xenon at 5 atmospheres (5 kg)
Single electron event
Double beta candidate“TPC Applications and ILC-TPC R&D”

M. Ronan, LBNL

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Gas TPC EXO: conceptual design“TPC Applications and ILC-TPC R&D”

M. Ronan, LBNL

16 Mar. 200645

16 Mar. 2006

Liquid Xenon EXO conceptual design• Use ionization andscintillation light in the
TPC to determine theevent location, and to do
precise calorimetry.
• Extract the Barium ionfrom the event location(electrostatic probe)• Deliver the Barium toa laser system for Ba136
identification.

“TPC Applications and ILC-TPC R&D”

M. Ronan, LBNL

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16 Mar. 2006

Fixed Target TPC Applications●

LEGS – Laser Electron Gamma Spectometer●

BoNuS – Neutron structure function radial TPC●

MIPP – Main Injection Particle Production●

PANDA Experiment“TPC Applications and ILC-TPC R&D”

M. Ronan, LBNL

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16 Mar. 2006

BoNuS TPC

“TPC Applications and ILC-TPC R&D”

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16 Mar. 2006

PANDA TPC

“TPC Applications and ILC-TPC R&D”

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16 Mar. 2006

Other TPC Applications●

LXeGRIT - Compton telescope●

Neutron direction measurements“TPC Applications and ILC-TPC R&D”

M. Ronan, LBNL

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16 Mar. 2006

Presented by Elena Aprile, Columbia at the 2003 TPC Symposium,
see http://www-tpc.lbl.gov/symposium03.
“TPC Applications and ILC-TPC R&D”

M. Ronan, LBNL

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16 Mar. 2006

International Linear Collider (ILC)
The ILC will look something like

“TPC Applications and ILC-TPC R&D”

M. Ronan, LBNL

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Linear Collider Higgs Physics

16 Mar. 2006

Use Higgstrahlung process e+e- --> ZH withZ decaying into leptons to measure /confirm Higgs mass from LHC, and to
determine branching ratios precisely.
N.B. Also, need to calibrate Higgs
multi-jet reconstruction
efficiency.

“TPC Applications and ILC-TPC R&D”

M. Ronan, LBNL

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16 Mar. 2006

TESLA TPC Proposalor

A TPC for a Linear Collider Detector

R.-D. Heuer
Hamburg University“TPC Applications and ILC-TPC R&D”

TPC Symposium
Berkeley, Oct.2003

M. Ronan, LBNL

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ILC Gaseous TPC Detector Models

16 Mar. 2006

Large gaseous TPC detector look somethink like

“TPC Applications and ILC-TPC R&D”

M. Ronan, LBNL

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Multijet Higgsstrahlung events“TPC Applications and ILC-TPC R&D”

e.g. e+e- --> Z + Higgs --> 2-4 jets

M. Ronan, LBNL

16 Mar. 200656

16 Mar. 2006-- Overall momentum resolution
One can use LCDTRK to calculate the expected momentum resolution
for different detector designs including intermediate and forward tracking.
Here is a comparison of a modified
version of the American LD detector
to the TESLA TPC performance.

DP/P**2

LCDTRK

Both TPC's are taken to have thesame pad size and point resolution.
The TESLA TPC has better low
momentum resolution since its
inner radius is smaller.
The assumed intermediate tracker
resolutions are taken from thecorresponding studies resulting
in a difference at high momenta.
There should be no difference in theassumed SIT resolution. The comparison
indicates how the SIT could improve overall
momentum resolution.
“TPC Applications and ILC-TPC R&D”

Comparison of TESLA TPC and updated American
Large Detector (LD2.5) momentum resolution.

M. Ronan, LBNL

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16 Mar. 2006

ILC Time Projection Chamber (TPC)
It will look somethink like

“TPC Applications and ILC-TPC R&D”

M. Ronan, LBNL

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16 Mar. 2006

“TPC Applications and ILC-TPC R&D”

M. Ronan, LBNL

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American Large Detector Simulations
Geant4 Detector Simulation
Provides detector hits

e+e- -> ZH -> 4 jets

16 Mar. 2006

e+e- -> ZH

LCD Analysis Modules:
Hit smearing
TPC Pattern recognition
Calorimeter clustering
Event display...
LCIO
JAS histograms
AIDA tuples
Detector: ldmar01
Hits: TPC (cyan),
Inner trackers (cyan)
EM Cal (blue)
Tracks (red)Clusters (green)“TPC Applications and ILC-TPC R&D”

M. Ronan, LBNL

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16 Mar. 2006

TPC Tracker Design and R&D

Current TPC design and R&D focus is on gas choice and readout technology.
Hope to begin studying front-end electronics (FEE) designs soon.
Gas options:
Ar CH4
Ar CO2 CH4
Ar CF4...
Readout pad plane
Gating device ??
MPGD
GEM
Micromegas
Pads partout
Electronics
Very low noise
Full integration ?
“TPC Applications and ILC-TPC R&D”

ECal

TPC

FEE
Endplane
Gating grid ?
MPGD
Pad plane
Support...

ECal

Si diskM. Ronan, LBNL

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GEM: Gas Electron Multiplier

16 Mar. 2006

Thin metal-coated polymer foil pierced by a high density of holes (50-100/mm2)
Typical geometry: 5 µm Cu on 50 µm Kapton, 70 µm holes at 140 mm pitch

70 µm

140 µm

F. Sauli, Nucl. Instrum. Methods A386(1997)531

Presented by Fabio Sauli, TPC Symposium, Oct. 2003
see http://www-tpc.lbl.gov/symposium2003
M. Ronan, LBNL
“TPC Applications and ILC-TPC R&D”

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16 Mar. 2006

GEM holes
Standard Double-Conical

5 µm

50 µm

55 µm
70 µm

Technology developed at CERN-EST“TPC Applications and ILC-TPC R&D”

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16 Mar. 2006
(Fields computed by S. Kappler)Low field to high field:

High field to high field:

200 V/cm

2.5 kV/cm

2.5 kV/cm

2.5 kV/cm

S. Bachmann et al, Charge amplification and transfer processes in the gas electron multiplierNucl. Instr. and Meth. A438(1999)376“TPC Applications and ILC-TPC R&D”

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16 Mar. 2006

Electron avalancheElectron transparency is very
good.
GEM's require large (~1kV)
transfer fields to extractelectrons from the holes.
Diffusion in transfer region
can be relatively large,
leading to defocusing effects.

“TPC Applications and ILC-TPC R&D”

M. Ronan, LBNL

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FREEDOM IN SHAPES

16 Mar. 2006
COMPASS GEM (31x31 cm ):2

GEM for ESA-INTEGRAL (25 cm Ø):

12 sectors+ central beam killer~ 100 manufactured at CERN
C. Altumbas et al,
Nucl. Instr. Meth. A490(2002)177“TPC Applications and ILC-TPC R&D”

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MULTIPLE GEM

16 Mar. 2006

Cascaded GEMs allow larger gains and safer operation in harsh environments
Triple GEM:
DRIFT

ED

DRIFT

ET1

TRANSFER 1

ET2

TRANSFER 2

EI

INDUCTION

GEM 1
GEM 2
GEM 2
READOUT

C. Buttner et al, Nucl. Instr. and Meth. A 409(1998)79
S. Bachmann et al, Nucl. Instr. and Meth. A 443(1999)464“TPC Applications and ILC-TPC R&D”

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FAST ELECTRON SIGNAL

16 Mar. 2006

Ar-CO2 70-30

I+e-

Induction gap

e-

S1

S2 S3 S4

No positive ion tailvery good multi-track and time resolution“TPC Applications and ILC-TPC R&D”

M. Ronan, LBNL

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Micromegas: Micro-mesh Gas Detector

16 Mar. 2006

Presented by Yannis Giomataris,
TPC Symposium, Oct. 2003
see http://www-tpc.lbl.gov/symposium2003“TPC Applications and ILC-TPC R&D”

M. Ronan, LBNL

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Advantages of a Micromegas Detector

16 Mar. 2006

MICRO MEsh GAS Detector Construction●●

A very thin (3-5 µm) metallic (Ni, Cu) mesh with a 20 to 100 µm pitch,is located at a small distance (50 – 100 µm) from the anode plane.
A strong electric field is applied (40-80 kV/cm) across the gap causing
avalanche multiplication of electrons coming from the drift volume.
Y. Giomataris et al, Nucl. Instru. Meth. A376, 29 (1996).

Advantages of a Micromegas TPC●

no ExB effect●good energy resolution, high gain●

very fast signal, no positive ion 1/t tail●small positive ion feedback into drift space●possibly no or thin frames“TPC Applications and ILC-TPC R&D”

Woven mesh
M. Ronan, LBNL

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Positive ion backflow

16 Mar. 2006

Backflow = # ions / (# electrons * gain)

Field ratio = Eamp / Edrift
Electrons spread
due to diffusion“TPC Applications and ILC-TPC R&D”

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16 Mar. 2006

Gain stability
Atmospheric pressure, theoretical curve
1000000
300Volts
He + 6% Isobutane

350 Volts
400 Volts

100000Good energy resolution

450 Volts
10000

Gain

1000

Cd

109
100

10

1
0.001

0.01

0.1
Gap(mm)pd/T

1

Optimum gap : 30 - 100 microns
Ref: Y. Giomataris, NIM A419, p239 (1998)

Ref: A. Delbart et al, NIM A461, p84 (2001)

Stable gain and relative immunity to flatness defects or pressure
variation–
Good energy resolution–“TPC Applications and ILC-TPC R&D”

M. Ronan, LBNL

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TPC R&D Groups
EuropeAmerica

Asia

16 Mar. 2006

R. Settles, 2005 Vienna

Other

RWTH Aachen
Hiroshima U
MIT (LCRD)
Carleton U
CERN
Temple/Way
Cornell/Purd Minadamo SU-IIT
DESY
Kinki Une Stateue
U Hamburg
U Osaka(UCLC)
Indiana U
U Freiburg
Saga ULBNL
U KarlsruheTokyo UATMIT
UMM Krakow
U TokyoU Montreal
Lund
Kogakuin U TokyoU Victoria
MPI-Munich
KEK Tsukuba
Yale
NIKHEFU Tsukuba
BINP Novosibirsk
Tsinghua U
LAL Orsay
IPN Orsay
U Rostock
NB: Started as subset of these groups working
CEA Saclay
together reporting to the DESY PRC; it was not yet a
PNPIformal “collaboration”. An MOA is the next step.
StPetersburg“TPC Applications and ILC-TPC R&D”

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R. Diener“TPC Applications and ILC-TPC R&D”

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“TPC Applications and ILC-TPC R&D”

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16 Mar. 2006

Online event display
Rows 4 & 5“TPC Applications and ILC-TPC R&D”

M. Ronan, LBNL

1 X 10 mm283

16 Mar. 2006

LC-TPC gas choices

Drift velocity

Gases:

Ar-CF4: 5%

Ar-CH4 e.g. P10 – 90:10 %Standard TPC gas, but some concern about neutron
background sensitivity with hydrogen.
Ar-CO2
Slow gas, requiring larger drift fields.
Tesla TDR Gas (Ar-CH4-CO2)
Chosen for the reference design to have less hydrogen ata lower drift field.
Ar-Isobutane e.g. 95:5 %High gains. Reasonably fast but larger diffusion.

Ar-CF4 Attachment / Amplification

Ar-CF4 e.g. 3-5 % CF4
Very interesting! Very fast, no hydrogen.
ωτ ~20 @ B=4T
transverse diffusion less than 200 µm fordrifts up to 1m.
However, need to worry about electron attachment andchemical reactions, e.g. aging.
ED~0.2V/cm“TPC Applications and ILC-TPC R&D”

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Micromegas TPC Operation
We found the chamber to have very uniform
gain response, and the electronic noise to bequite low.

16 Mar. 2006

Pulse sums
2mm pads

2mm pads

Plots are shown of
the number of pads
forming each cluster
and of the summed
amplitude signals
for both 2X10 mm2
pad rows (#0,#1,#8 & #9)
and the 1X10 mm2 padrows (#4 & #5).

1mm pads

1mm pads

ArCF4: 3%@ B=1T# pads hit“TPC Applications and ILC-TPC R&D”

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Gas Property Measurements●

16 Mar. 2006

Drift velocity

We measure the drift velocity of different gases using the data itself. The longest drift time tracks
observed are from tracks passing through the far end of the chamber, 50 cm from the readout plane.
●

Electron attachment

Using the variation in the average energy deposition, measured by the truncated mean, with drift
distance allows us to determine the electron attachment coefficient.
●Transverse diffusion

Measured through maximim likelihood fits to the distribution of signals on pads collecting
ionization electrons from individual tracks. Relevant pads with no signals provide information as well.
●

Magnetic field suppression

We measure the variation in the transverse diffusion as a function of the magnetic field todetermine the suppression factor defined as (DT[B]/DT[0])-1/2 ~ ωτ.

From 2004 Rome IEEE Nuclear Science Symposium,
Mike Ronan, LBNL
see http://www-ilc.lbl.gov/detector/talks“TPC Applications and ILC-TPC R&D”

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16 Mar. 2006

Drift velocity measurements
We measure the drift velocity from the drift
time distribution of cosmic ray tracks as shown.

# tracks

The trigger delay to the readout system andpedestal stabilization results in a loss of
information for short drift times. The far endof the chamber at roughly 50 cm begins to cut
off the distribution at about 100 clock ticks
depending on track dip angle. We take themax. drift time from the distribution to be
105 +- 2 ticks.

50 cm

We can also determine the drift velocity
from individual tracks which are found to exit
the far end of the chamber.
In time we'll develop a full Monte Carlosimilation to improve the drift velocity
determination.

Drift time

For Ar-CF4:3% we determine the drift velocity to be

vD = 8.8 +- 0.2 cm / microsec.
This corresponds to roughly 90 microns / nsec. So thatan overall track absolute z position measurement errorof about 100 microns yields track timing at 1 nsec level.
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Electron attachment measurements
We have not studied dE/dx information
very carefully but have made a truncatedmean calculation using the lowest signals
on 4 out of 6 pad rows.

16 Mar. 2006

ArCF4 B = 1T

Using the calculated TrMean we cancheck the attenuation length in ArCF4
with our relatively long drift length.
We find that the attenuation length due to electron
attachment in ArCF4 is larger than 4.4 m at 90%
confidence.
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16 Mar. 2006

Transverse diffusion measurements
We determine the transverse diffusionfrom max. likelihood fits to individual
anode pad signals on 6 pad rows
(4 w/ 2mm pitch and 2 rows w/ 1mm pitch).
The fitted track spread is used to measure
the transverse diffusion.

B = 1TWe find no evidence of any track angle
dependence in the measurement, shown
below, as expected.

For Ar-CF4:3% at B = 1 Tesla, we measure in one analysis

DT = 68 +- 0.9 +- 3 microns / sqrt(cm)This implies an expected transverse spread of about 360
microns after 2.5 m drift in a 3 Tesla magnetic field, and adiffusion limited point resolution of 60 microns for 6 mm pads.
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16 Mar. 2006
B = 0.1T

B = 0.3T

Ar CF4

Ar CH4 (P10)

B = 1T

Ar Isobutane(DT[B]/DT[0])-1/2B = 0.1T

Ar CH4 (P10)

B = 1.5T“TPC Applications and ILC-TPC R&D”

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Micromegas TPC Performance●

16 Mar. 2006

Gas gain
We obtained high gains (~5000) at modest meshvoltages, 300-350 V, except for ArCH4:10% (P10).

●

Detector stability
Significant signal variation with magnetic field (larger athigher fields) was observd that is not understood at this
time.

●

Electronic noise
We operated the STAR front end electronics at very low
noise levels (~1000 e's), typically 1-2 ADC counts.

●

Point resolution measurement
We determine the point resolution by comparing theposition measurements of the two center 1mm padrows, correcting for track angles and for track fitting
errors. The resolution measurements are binned in drift
distance and fit with a linear dependence. We take thezero drift interept as the intrinsic Micromegas position
resolution.

“TPC Applications and ILC-TPC R&D”

M. Ronan, LBNL

Note: We measure intrinsic (“zerodrift”) Micromegas resolutions of 60100 microns, even with ArCH4 (P10)
operating at low gain (~1000) as shown
above.
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Point resolution vs. Drift distance
Similar point resolution results
were obtained for both ArMethane: 10% (P10) and ArIsobutane: 5%. The larger
diffusion in Ar-Isobutane iscompensated by a larger numberof effective electrons.

16 Mar. 2006

B = 1.0 T- - - MC Simulation

We find
Ar CH4
Ar Isobutane

Data19.1 +- 4.6
32.1 +- 4.8

Monte Carlo19.4 +- 0.5
30.8 +- 1.3

The extrapolated point resolution
at zero drift is at or below 50
microns for both gases.

Measured Micromegas TPC point resolution vs. drift distance for
Argon-Methane: 10% (P10) and Argon-Isobutane: 5% at amagnetic field of 1. tesla. A Monte Carlo simulation of primary
ionization, electron drift and avalanche, and TPC readout is foundto be in excellent agreement with the measurements.

However, Ar-CF4 is quite different.
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16 Mar. 2006

KEK Test Beam
A TPC built at MPI has
been used for GEM andMicromegas TPC studies ina KEK test beam using
the thin superconducting
JACEE magnet (ID 850 mm, 1m long).
New studies of gas properties, TPC point resolution andcomparisons with detailed Monte Carlo simulations havebeen made.

“TPC Applications and ILC-TPC R&D”

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data quality control: event display

16 Mar. 2006

MPI TPC event display

Carleton Ottawa TPC

spreading of charge due to foil can be seen
acrossamplitude
six padsvs time distributions
Presented by Vincent Lepeltier LAL Orsayat the ECFA Vienna LC Meeting, November 14-18th 2005
“TPC Applications and ILC-TPC R&D”

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V. Lepeltier 16 Mar. 2006

results: resolution vs Z
Ar/iC4H10:95/05@1T

σ(mm) Carleton Ottawa
TPC
π+ beam
E=80V/cm

MPI TPC π+ beam
E=220V/cm

σ0 = 83 ± 22 µm
CD/√Neff = 57 ± 3 µm/√cm

preliminary

VERY preliminary!!
analysis program not
optimised for PRF
Vincent Lepeltier LAL Orsay ECFA Vienna, November 14-18th 2005

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Pixel TPC

Americium source

16 Mar. 2006

Cosmic ray
w/ delta ray

Micromegas electron gas
amplification
He-Isobutane 20%
gain ~ 20000
MediPix2 pixel readout chip
50 x 50 micron“TPC Applications and ILC-TPC R&D”

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16 Mar. 2006

InGrid process
1) Oxide the Si wafer, insulating
SiO2 layer on top
2) Deposition of 0.2 µm of Al for
anode, and patterning3) Deposition of 50 µm photoresist and UV exposure4) Deposition and patterning of
the grid: 0.8 µm of pure Al
5) Removal of the exposed
photoresist
RESULT : a thin mesh (0.8 µm compared to
3-5 µm with best standard techniques),
sustained at an accurate 50 µm from theanode.

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16 Mar. 2006

INGRID: some first trials
Various pitches, shapes“TPC Applications and ILC-TPC R&D”

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16 Mar. 2006

Results in Argon + 20% isobutane
Advantages• grid thinness & robustness• gap accuracy (unprecedented

Fe Kα

55

resolution (6.5%) and uniformity)• no frame (no loss of active
surface)• possibility to fragment theAr escape

Fe Kβ

55

mesh (noise reduction and extralocalization usable for zerosuppression)

Future : Si TPC (with the Timepix
VLSI CMOS readout) 55 µm pads
EUDET-funded“TPC Applications and ILC-TPC R&D”

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K. Desch

GEM Digital TPC

16 Mar. 2006

using lower thresh.
only

using upper and lower
thresholdTracks from 106Ru“TPC Applications and ILC-TPC R&D”

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Electron Charge Distributions

M. Hauschild

16 Mar. 2006

electron charge distribution
on MediPix surface

with typical MediPix
threshold of ~1000 e­
most pixels stay below
thresholdno threshold, ALLelectrons counted

threshold:1000 e­ per pixel

generated e­ positions
projectione­ positions after diffusion(on top of first GEM)

1000 e­ threshold“TPC Applications and ILC-TPC R&D”

multi­electron cluster,
only clusters with > 1 electron
reach the MediPix threshold(or many dense single­electron clusters)

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Digital TPC

M. Hauschild

16 Mar. 2006

• ...at the ILC...
– 100 GeV muon, B = 4 T, TESLA-TDR gas, 100 cm drift
identical events: same generated primary clusters/electrons

Freiburg triple­GEM set­up“TPC Applications and ILC-TPC R&D”

NIKHEF MicroMegas set­up

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16 Mar. 2006

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LBNL: TPC Readout R&D

16 Mar. 2006

Tests of MPGD (GEMs and Micromegas) in collaboration with
CERN, Orsay, Saclay, Purdue U. and U. New Mexico
Study of point resolution with Micromegas using BOS TPC
with cosmics, based on LBNL-developed electronics for STAR;
R&D for proof of principle of VLSI TPC readout using
ATLAS pixel chip (possible collaboration with NIKHEF/Freiburg);“TPC Applications and ILC-TPC R&D”

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16 Mar. 2006

Commissioned new MPGD test setup at LBNL;
Tested both GEM (produced at CERN) andMicroMegas (produced by 3M for Purdue U.) with90
Sr and 55Fe using ArCo2 and ArIsobutane:

Characterized ATLAS pixel chip charge threshold.

“TPC Applications and ILC-TPC R&D”

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A. Vogel“TPC Applications and ILC-TPC R&D”

M. Ronan, LBNL

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Summary●●●

16 Mar. 2006

The Time Projection Chamber (TPC) is a proven detector for doing bothe+e- and nuclear physics.
The TPC has been used for beam instrumentation at very high rates andbackground conditions.
New liquid and gaseous TPC's are being designed for many different
applications– Dark Matter Searches– Double-beta Decay Experiments
– ...

●

●

●

A high-precision TPC design for the International Linear Collider (ILC)
offers many interesting challenges and excellent future physics.
Interesting new detector R&D in progress on MPGD's, gaseous pixel TPC's,
high-pressure gas and liquid TPC's, ...
We look forward to increased collaboration between the 3 regions.

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