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January 10, 2008 Micromegas TPC 1
Micromegas TPCPart II : experiments
P. Colas, SaclayLectures at the TPC school, Tsinghua University, Beijing,
January 7-11, 2008
January 10, 2008 Micromegas TPC 2
OUTLINEOUTLINETPC, drift and amplification
Micromegas principle of operation
Micromegas properties
Gain stability and uniformity, optimal gap
Energy resolution
Electron collection efficiency and transparency
Ion feedback suppression
Micromegas manufacturing
meshes and pillars
InGrid
“bulk” technology
Resistive anode Micromegas
Digital TPC
PART I – operation and properties
January 10, 2008 Micromegas TPC 3
OUTLINEOUTLINE
The COMPASS experiment
The CAST experiment
The KABES beam spectrometer
The T2K ND-280 TPC
The Large Prototype for the ILC
Micromegas neutron detectors
TPCs for Dark Matter search and neutrino studies
PART II – Micromegas experiments
January 10, 2008 Micromegas TPC 4
COMPASSCOMPASSCOMPASSCOMPASS
• MIP detection for measuring the nucleon
spin structure
• High particle flow : 105 kHz/cm2
• Sparks give less than 1 per mil dead time
• Space resolution < 70 m with 350 m
strips
• The largest Micromegas so far (40x40 cm2)
• In operation at CERN since 2002
efficiency>97%
Going to hadrons and new non-magnetic
cathodes in 2008 (with a new magnet)
January 10, 2008 Micromegas TPC 5
CASTCASTCASTCAST
• Solar Axion detection : con- version of
solar axions in a LHC magnet -> observe
low-energy X-rays
• 2D with overlayed crossed strips
• In operation at CERN since 2003
• Improvements in progress (energy
resolution, shielding, new detector, golden
cathode to avoid copper fluorescence,
new optics)
CERN Axion Solar Telescope
axions
Transv
erse m
agnetic fi
eld (B
)
X ray
X ray
detect
orL
January 10, 2008 Micromegas TPC 6
CASTCASTCASTCAST
• Low threshold : 600 eV !
• Low background (fluorescence)
Cu
Cuescape
Fe
Feescape
Ar
Low energy spectrum from Micromegas in CAST
6.5 keV
X
y
January 10, 2008 Micromegas TPC 7
NA48/KABESNA48/KABESNA48/KABESNA48/KABES
Micromegas TPC for CP violation expt in
operation at CERN from summer 2003
to end of 2004. Extension for K+ ->
project (25 micron gap)?
KAon BEam Spectrometer
driftE
driftE
Tdrift2
Micromegas
Gap 50 μm Micromeg
as
Gap 50 μm Tdrift
1
Tagged K track
Space resolution from drift time measurement: 70 μm
Time resolution: 0.6 ns
Tagging with reconstructed K± ± + -
(T0)KABES- (T0)DCH Spectrometer (ns)
XStation 1 or 2 - XStation 3 (cm)
January 10, 2008 Micromegas TPC 8
January 10, 2008 Micromegas TPC 9
Neutron detectionNeutron detectionNeutron detectionNeutron detection
• Use a converter to extract alphas
• Numerous applications:
neutron tomography, neutron
detection in hostile
environments
January 10, 2008 Micromegas TPC 10
• Numerous applications:
neutron tomography, neutron
detection in hostile
environments
January 10, 2008 Micromegas TPC 11
January 10, 2008 Micromegas TPC 12
X-ray Radiography (Roentgen 1895) : see bones through skin and meat
Neutron Radiography : see gas (H2) through glass and metal
Very useful for rocket engine studies
January 10, 2008 Micromegas TPC 13
T2K : Tokai to Kamiokande• Long Base Line 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
January 10, 2008 Micromegas TPC 14
T2K Physics GoalsP(P(ννμμ→→ ννμμ)≈1- cos)≈1- cos44
θθ13 13 sinsin22 22θθ23 23 sinsin22
(1.27 (1.27 ΔΔmm2223 23 L/EL/Eνν))
1-sin2(2θ23)
ΔΔ((mm2323))22EEνν(MeV)(MeV)
P(P(ννμμ→→ ννee)≈sin)≈sin22 22θθ13 13 sinsin22
(1.27 (1.27 ΔΔmm2213 13 L/EL/Eνν))
• disappearancedisappearance• Need flux and spectrum Need flux and spectrum measurement at ND280 detectormeasurement at ND280 detector• 5000 ev/year SK, 105000 ev/year SK, 1055 ev/year ND280 ev/year ND280
• 100 ev/5 years for sin100 ev/5 years for sin22(2(2θθ1313)=0.1, )=0.1, BKG 15BKG 15
• Need Need ννee contamination at ND280 and contamination at ND280 and study of other backgroundsstudy of other backgrounds
January 10, 2008 Micromegas TPC 15
Purpose of ND280• Measure the neutrino spectrum before oscillation.
• Measure the intrinsic e beam contamination from and kaon decays.
• Measure the 0 production in Neutral Current with neutrino flux close to the one at SK.
• Measure the exclusive cross-sections at the relevant energies (< 1Gev).
• Measure nuclear effects that are relevant at these energies:
– Proton and pion rescattering and charge exchange. B = 0.2 TB = 0.2 T
January 10, 2008 Micromegas TPC 16
T2K
Started in December 2004, should take data end 2009
• 3 TPCs stations; each with 2 planes of detector modules
3 TPC stations
1 m
2.5 m
x
y
z
2.5 m
Detector module
→ From the beginning, think wide operating ranges, flexible hardwaremodular architecture, design staging
January 10, 2008 Micromegas TPC 17
3 TPC
1 m
2,5
m
2,5 m
The T2K TPC
1 of 6 TPC planes(12-modules)
Outside magnetInside magnet
1 of 6 DataConcentrator
Card
12 duplexOptical fibres
x 6
Front End MezzanineCard (FEM)
288 channelFront End Card (FEC)
1728 pad Micromegas plane
Slow controlnetwork
Optical fiberto/from DCC
Power bar
Low voltagePower supply
1 of 72 modules
TCP/IP
PC Linux
6 DCCs
VME/PCIbackplane bus
GigabitEthernet
DAQ control
DetectorB
DetectorA
Global trigger
Réseau
1 of 1728 Front-End ASIC “AFTER”
72 channel x 511 time bucketsSwitched capacitor array
January 10, 2008 Micromegas TPC 18
AFTER
SCA:76x511 Cells
Technology: AMS CMOS 0.35m
Number of transistors: 400,000
Area: 7546m x 7139 m
Package: LQFP 160 pins; 30 x 30 x 1.4 mm pitch: 0.65 mm
Submission: 24 April 2006
Delivery: end of July 2006
Characterization: October 2006 – March 2007
January 10, 2008 Micromegas TPC 19
ASIC ASIC ASIC ASIC
4 channelADC
Passive Components
Connectors to detector plane
288 channel FE card
Digital output
~25 cm
~12 cm
→ Foresee FEC PRR in ~Q1-2008 and production in ~Q2-Q3 2008
January 10, 2008 Micromegas TPC 20
→ Foresee FEM Production Readiness Review in ~Q3-2008 and production in ~Q4 2008
Front-End Mezzanine
January 10, 2008 Micromegas TPC 21
Detector Module Read-out Electronics
72-channel ASIC
Quad-channel ADC
digital Front-endMezzanine card (FEM)
Optical Transceiver
FPGA
80-pin connector
288-channel analogFront-End Card (FEC)
1728-pad detector plane
Slow-controlNetwork - CANbus
Fiber toDCC
Low voltagepower
Data taking at CERN on Harp setup in Sept. 07
• electronics was very stable during the 10-day period of data taking
84 modules in total
January 10, 2008 Micromegas TPC 22
Production and Test Bench at CERNProduction and Test Bench at CERN
University of Geneva, Barcelona
January 10, 2008 Micromegas TPC
CERN
Rui de Oliveira TS-DEM
Coverlay lamination
Read-out board
Detector developed cured tested
January 10, 2008 Micromegas TPC 24
January 10, 2008 Micromegas TPC 25
January 10, 2008 Micromegas TPC 26
10
100
1000
10000
100000
280 300 320 340 360 380 400 420 440 460 480
Vmesh (V)
Gai
n
Before "cooking"
After "cooking"
After ageing
Bulk detectors are now very stable. Gains up to 60000
But run at 700-800
Ar CF4 Isobutane 95:3:2
January 10, 2008 Micromegas TPC 27
36x34 cm2
1728 pads
Pad pitch 6.9x9 mm2
January 10, 2008 Micromegas TPC 28
Gain about 800 !
1 ‘spark’ (100 nA) per 10 hours without beam.
January 10, 2008 Micromegas TPC 29
Cluster space point resolution
in T2K
2005
2007
< 700 m @ 1m 2-pad clusters
< 600 m @ 1m 2-pad clusters
B=0.2T
B=0.2T
1-pad clusters
1-pad clusters
Improved space point for 2-pad clusters
Larger fraction of > 1-pad clusters (low-noise FEE)
Preliminary values of dE/dx resolution for ~ 35cm long tracks (E=160V/cm): - 12.4% B=0.2T - 11.1% B=0.4T should fulfill requested resolutions of 10% for ~70cm long tracks on both P @ 1 GeV/c and dE/dx
January 10, 2008 Micromegas TPC 30
Micromegas Panels for Large Prototype
• Resistive anode from the start
-> resistive “bulk”• Use of T2K electronics• Several solutions for
the resistive layer and the mesh under study
January 10, 2008 Micromegas TPC 31
AFTER-chip based readout
• The most compact at present: 72 channels
• Very flexible : 10 to 100 MHz sampling, shaping: peaking time from 90 to 800 ns, can be switched off, zero suppression.
• Production decided last October 12. Will take place in Q3 2008 (140 000 channels for T2K, 14000 for LC-TPC LP)
January 10, 2008 Micromegas TPC 32
HV
Resistive layer grounding
Av. Pad pitch
3.2 x 7 mm
24 rows x 72 pads
MICROMEGAS + RESIST. FOIL PANEL
January 10, 2008 Micromegas TPC 33
connector side
Detector side
January 10, 2008 Micromegas TPC 34
TimePix multi-chip panel
2x4 matrix
SiProt+Ingrid
1 MUROS
Pad ~ 2,8 x 6, 8 mm²
Daisy-chained chips to be equipped with
InGrids
January 10, 2008 Micromegas TPC 35
ATLAS muon chambers for SLHCaverage single count rates for L=1034 cm-2s-1
January 10, 2008 Micromegas TPC 36
ATLAS Micromegas R&D Collaboration
Evaluate possible use of micromegas for ATLAS muon chamber upgrade programme
• EoI submitted in February 2007 to ATLAS Upgrade Office
• Proposal submitted in June 2007
• Expect approval by ATLAS EB in the near future
. . .
• 15 participating Institutes so far; with growing interest ...
• Regular weekly meetings at CERN since February
• TWiki pagehttps://twiki.cern.ch/twiki/bin/view/Atlas/MuonMicromegas
January 10, 2008 Micromegas TPC 37
Goals Phase I: Build and evaluate small prototype(s)
based on micromegas technology to– get familiar with technology– demonstrate required performance
Decide on – Operating parameters (gas, gas gain, HV, etc...)– Readout pattern & electronics
Phase II: Develop techniques for the construction of large-size detectors (1m x 2m)
January 10, 2008 Micromegas TPC 38
The mesh(es)
Prototype 1 (P1)Homogeneous stainless steel mesh
325 lines/inch = 78 µm pitchwire diameter: 20–25 µm
Prototype 2 (P2)Unidirectional stainless steel/plastic mesh
200 lines/inch = 127 µm pitchwire diameter: 40–45 µm
Mesh–readout electrode distance: 128 µm
January 10, 2008 Micromegas TPC 394/20/23 39
Prototype assemblingAl frame on both sides
Cathode mountingAssembled chamber
January 10, 2008 Micromegas TPC 40
Dark matter search• Look for recoiling nuclei (few 100 keV)• Directionality : see the ‘wind of wimps’ : 24h-modulation of the
direction
• Many projects, many of them use Micromegas• Negative ion TPC : take an attaching gas (CS2, CH3NO3), drift
negative ions, they are stripped in the amplification region. Very slow drift, but very low diffusion
More neutrino physics
Neutrinoless double-beta decay in 136Xe
January 10, 2008 Micromegas TPC 41
CONCLUSION
• Micromegas is a very versatile detector suited to detection of charged particles, neutrons, photons, with high rate, high resolution (E,t,x), low rad. length, large surfaces, low cost, easy operation, robustness, good aging
properties, etc…
Matter for this talk principally comes from:• IEEE/MPGD workshops, San Diego, October 29, 2006 and Honolulu, October 28, 2007,
CERN, September 11, 2008• 3rd Symposium on Large TPCs for Low Energy Rare Events, Paris, December 11-12,
2006• Recent work in Aachen, DESY, KEK, CERN, Carleton, Saclay…
January 10, 2008 Micromegas TPC 42
THANKS
• To all colleagues from whom I stole transparencies or plots: I. Giomataris, B. Peyaud, T. Lux, E. Mazzucato, M. Zito, D. Calvet, J. Wotschak, R. de Oliveira, S. Andriamonje, M. Dixit, M. Riallot, A. Delbart, D. Attié, M. Chefdeville, S. Biagi, J. Martoff
• For the animations : Gilles Barouch, Dan Burke, D. Attié
• Questions/remarks: [email protected]
January 10, 2008 Micromegas TPC 43
Information
• RD51 workshop April 16-18 in Amsterdam– http://www.nikhef.nl/pub/conferences/rd51/
• IEEE/NSS in Dresden October 19-25– http://www.nss-mic.org/2008/NSSMain.asp
• Large TPCs for Low Energy Rare Events (Paris, December 18-19)
