January 10, 2008Micromegas TPC1 Micromegas TPC Part II : experiments P. Colas, Saclay Lectures at the TPC school, Tsinghua University, Beijing, January

January 10, 2008 Micromegas TPC 1

Micromegas TPCPart II : experiments

P. Colas, SaclayLectures at the TPC school, Tsinghua University, Beijing,

January 7-11, 2008


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


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


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)


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


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


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)



Neutron detectionNeutron detectionNeutron detectionNeutron detection

• Use a converter to extract alphas

• Numerous applications:

neutron tomography, neutron

detection in hostile

environments


• Numerous applications:

neutron tomography, neutron

detection in hostile

environments



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


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


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


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


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


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


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


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


→ Foresee FEM Production Readiness Review in ~Q3-2008 and production in ~Q4 2008

Front-End Mezzanine


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


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




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


36x34 cm2

1728 pads

Pad pitch 6.9x9 mm2


Gain about 800 !

1 ‘spark’ (100 nA) per 10 hours without beam.


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


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


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)


HV

Resistive layer grounding

Av. Pad pitch

3.2 x 7 mm

24 rows x 72 pads

MICROMEGAS + RESIST. FOIL PANEL


connector side

Detector side


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


ATLAS muon chambers for SLHCaverage single count rates for L=1034 cm-2s-1


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

https://twiki.cern.ch/twiki/bin/view/Atlas/MuonMicromegas


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)


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


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


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…


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]


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)

http://www.nikhef.nl/pub/conferences/rd51/

http://www.nss-mic.org/2008/NSSMain.asp

Documents

January 10, 2008Micromegas TPC1 Micromegas TPC Part II : experiments P. Colas, Saclay Lectures at the TPC school, Tsinghua University, Beijing, January