recent developments of micromegas detectors for high energy physics
DESCRIPTION
Recent developments of Micromegas detectors for High Energy Physics. ICHEP 2004, Beijing. P. Colas, DAPNIA Saclay. Principle of operation Advantages Experiments in progress Compass, CAST, NA48/Kabes Developments in progress LC-TPC, neutron detection, NOSTOS neutrino experiment,…. - PowerPoint PPT PresentationTRANSCRIPT
Beijing, August 18, 2004 P. Colas - Micromegas for HEP 1
Recent developments of Recent developments of Micromegas detectors for Micromegas detectors for
High Energy PhysicsHigh Energy Physics
• Principle of operationPrinciple of operation• AdvantagesAdvantages• Experiments in progressExperiments in progress
– Compass, CAST, NA48/KabesCompass, CAST, NA48/Kabes• Developments in progressDevelopments in progress
– LC-TPC, neutron detection, LC-TPC, neutron detection, NOSTOS neutrino experiment,…NOSTOS neutrino experiment,…
P. Colas, DAPNIA Saclay
ICHEP 2004, Beijing
Beijing, August 18, 2004 P. Colas - Micromegas for HEP 2
Micromegas: Micromegas: Principle of operationPrinciple of operation
Micromegas : a micromeshsustained by 50-100 m - high insulating pillars. The multiplication takes place between the anode and the mesh
200 m
Small size ->Fast signals ->Short recovery time ->High rate capabilities
Beijing, August 18, 2004 P. Colas - Micromegas for HEP 3
Micromegas Micromegas further advantagesfurther advantages
S1/S2 ~ Eamplif / Edrift
S1
S2
Can choose the gap/HV to have the gain maximum w.r.t. the gap and pressure -> excellent energy resolutionIon feedback suppressed by Edrift/Eamplif
Beijing, August 18, 2004 P. Colas - Micromegas for HEP 4
COMPASSCOMPASS• 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 2002efficiency>97%
Beijing, August 18, 2004 P. Colas - Micromegas for HEP 5
CASTCAST• 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
CERN Axion Solar Telescope
axions
Transverse m
agnetic field (B
)
X ray
X ray
detector
L
Beijing, August 18, 2004 P. Colas - Micromegas for HEP 6
CASTCAST• Low threshold : 600 eV !• Low background (fluorescence)
6.5 keV
X
y
Cu
Cuescape
Fe
Feescape
Ar
Low energy spectrum from Micromegas in CAST
Beijing, August 18, 2004 P. Colas - Micromegas for HEP 7
NA48/KABESNA48/KABES
• CP violation• In operation at CERN since
summer 2003• Principle : TPC +
micromegas
KAon BEam Spectrometer
driftE
driftE
Tdrift2
Micromegas
Gap 50 μm Micromega
s
Gap 50 μm Tdrift1
Beijing, August 18, 2004 P. Colas - Micromegas for HEP 8
NA48/KABESNA48/KABES
• Excellent time resolution
Tagged K track
Space resolution from drift time
measurement: 70 μm
Time resolution: 0.6 nsUsing TOT to correct time
slewing
Tagging with reconstructed K± ± + -
(T0)KABES- (T0)DCH Spectrometer (ns)
XStation 1 or 2 - XStation 3 (cm)
Beijing, August 18, 2004 P. Colas - Micromegas for HEP 9
Challenging requirements:High two-track separation in jets both in Z and in R (O(8mm))High background from photons and neutrons (600 n/BX)Excellent jet resolution (E-flow)
Particle identification
High granularityLow ion feedbackLow H-content of the gas
High granularity, small diffusion
electrons
ionsionscham
ber =>
Micropattern detectors
Low material budget of the endplate (thin frame)Good dE/dx resolution
TPC for the Linear Collider TPC for the Linear Collider
Beijing, August 18, 2004 P. Colas - Micromegas for HEP 10
Detector
1024 pads
Pad layout
Field cage
Readout
Berkeley-Orsay-Saclay TPC
Beijing, August 18, 2004 P. Colas - Micromegas for HEP 11
LC-TPCLC-TPCFUTURE PROJECTS, R&D
Cosmic ray data taking in May 2004. Accurate measurements of diffusion coefficients in progress.First results show that <100 m point resolution should be reached
Beijing, August 18, 2004 P. Colas - Micromegas for HEP 12
Spherical TPC for Spherical TPC for neutrino detectionneutrino detection
• NOSTOS project : – Neutrino oscillation from Tritium– Supernova detection, burst time
structure– Coherence in -A interactions to
be tested at a reactor• Uses the longitudinal diffusion
in the gas to estimate the distance to center
FUTURE PROJECTS, R&D
Tritium source surrounded by a Micromegas
Beijing, August 18, 2004 P. Colas - Micromegas for HEP 13
Spherical TPC for Spherical TPC for neutrino detectionneutrino detection
• Observe tritium e oscillation and measure 13
• Measure the magnetic moment of the neutrino
• Measure the weak mixing angle at low energy
• Detect supernovae explosions
FUTURE PROJECTS, R&D
Beijing, August 18, 2004 P. Colas - Micromegas for HEP 14
Micromegas readout by Micromegas readout by silicon pixelssilicon pixels
• CERN-NIKHEF-Saclay-Twente• MIPs have been seen in a
combination micromeg.+Medipix• InGrid (integrated grid) project
pillars on silicon
FUTURE PROJECTS, R&D
10 mm
Beijing, August 18, 2004 P. Colas - Micromegas for HEP 15
Neutron detectionNeutron detection
• Use a converter to extract alphas
FUTURE PROJECTS, R&D
• Numerous applications: neutron tomography, neutron detection in hostile environments
Beijing, August 18, 2004 P. Colas - Micromegas for HEP 16
New developmentsNew developments
• Bulk Micromegas obtained by lamination of a woven grid on an anode with a photo-imageable film
Large area robust detectors can be made for neutrino detection or photodetection
Beijing, August 18, 2004 P. Colas - Micromegas for HEP 17
New developmentsNew developments
• Resistive layers (Ottawa-Saclay)
Spreads the charge -> improves resolution with large pads (70 m obtained with 2mm pads with 3keV X-rays)
Might protect from discharges
• New materials for meshes• Two-stage micromegas
Beijing, August 18, 2004 P. Colas - Micromegas for HEP 18
CONCLUSIONCONCLUSION
• Existing Micromegas detectors perform well since over a year
• Micromegas offers exciting perspectives for HEparticle detection:– High granularity and suppressed ion back-flow for TPCs– Single electron detection, with a very fast electron signal– Record-breaking time resolution– Low matter budget