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[email protected] Trends and New Developments in Gaseous Detectors Photo: Alice TPC field cage by m.hoch X th Vienna Conference on Instrumentation 2004
Trends and New Developments in Gaseous Detectors
Photo: Alice TPC field cage by m.hoch
Xth Vienna Conference on Instrumentation 2004
• Traditional Wire Chambers― TPC: STAR, ALICE ― Drift Tubes ATLAS
• Resistive Plate Chamber RPC― Trigger-, Timing-, Multigap RPC
• Micro Pattern Gaseous Detectors MPGD― Mircomegas, GEM
• Introduction― History, Basics, Tools
ContentContent
PPCParallel Plate Counter
MWPCMultiwire Proportional Chamber
G.Charpak et al 1968 TPCTime Projection Chamber
D.R.Nygren et al 1974
PestovCounter
V.Pestov 1982
MSGCMicrostrip Gas Chambers
A.Oed 1988
µMMicromegas
I.Giomataris et al 1996
PCProportional Counter
Geiger CounterH.GeigerW.Mueller 1928
Gas Detector HistoryGas Detector History
GEMGas Electron Multiplier
F.Sauli 1997
RPCResistive Plate Chambers
R.Santonico R.Cardarelli 1981
• Good spatial resolution • Fast & big signals • Good dE/dx• Two track resolution • Many possible detector configuration
Low radiation length • Large area coverage• ….
Arguments in Favor for Gaseous DetectorsArguments in Favor for Gaseous Detectors
Simulation Tools: Simulation Tools:
• Energy deposit • Electric Field• Drift & Velocity• Amplification & Attachment
Efficient detector development is today possible with existing
precise and reliable simulation tools
Simulation Tools: Simulation Tools: • MAXWELL Ansoft
electrical field maps in 2D & 3D, finite element calculation for arbitrary electrodes & dielectrics
• HEED I.Smirnovenergy loss, ionization
• MAGBOLTZ Steve Biagielectron transport properties: drift, diffusion, multiplication attachment
• Garfield R.Veenhoffields, drift properties, signals(interfaced to programs above)
• PSpice Cadence D.S.electronic signal processingThese tools allow to simulate accurately detector configurations before construction
Example: Gaseous Detector in the LHC Experiments Example: Gaseous Detector in the LHC Experiments
ALICE: TPC (tracker), TRD (transition rad.), TOF (MRPC), HMPID (RICH-pad chamber), Muon tracking (pad chamber), Muontrigger (RPC)
ATLAS: TRD (straw tubes), MDT (muondrift tubes), Muon trigger (RPC, thin gap chambers)
CMS: Muon detector (drift tubes, CSC), RPC (muon trigger)
LHCb: Tracker (straw tubes), Muon detector (MWPC, GEM)
Traditional Wire
ChambersMWPC & TPC, Drift Tubes
The Time Projecting Chamber TPC:The Time Projecting Chamber TPC: Principle & HistoryPrinciple & History
particle track
anode planecathode plane
gating plane
Induced charge on the plane
E
Z (e- dr
ift ti
me)
Y
X
liberated e-
neg. high voltage plane
pad plane
D.R.Nygren et al Proposal PEP no4, Appendix A6H.J.Hilke et al,Performance ot a Time Projection Chamber, NIM 161 (1979)383.
Idea:1976; proposal for PEP no4 at LBLRealization:1982; PEP no4 at LBL 1989 TPCs at Cern - LEPAleph, Delphi90s heavy ion TPCsCeres Cern SPSNA49 Cern-SPS, STAR BNL – RHICUnder construction 2004:ALICE Cern - LHC
The Time Projecting Chamber TPC:The Time Projecting Chamber TPC: Principle & HistoryPrinciple & History
ALICE
NA49
STAR
ALEPH
PEP no4
Ceres NA45
D.R.Nygren et al Proposal PEP no4, Appendix A6H.J.Hilke et al,Performance ot a Time Projection Chamber, NIM 161 (1979)383.
420 cm
410cm
•Gas: Ar/CH4 90/10% •Drift Volume : 56m3
•Voltage : -28 kV •Drift field: E=135 V/cm
STAR TPC @ RHICSTAR TPC @ RHIC J.W.Harris et al. STAR detector overview, NIM A 499(2003) 624;
Space point resolution ~ 500 µmTwo-track separation 2.5 cmRapidity coverage –1.5 < η < 1.5 Momentum Resolution dp/p 2% (1GeV)Particle Identification with dE/dx 7%
STAR TPC @ RHICSTAR TPC @ RHIC J.W.Harris et al. STAR detector overview, NIM A 499(2003) 624;
Au-Au collisions @ CM energy 130GeV/n:
typically central event ~ 2000 tracks/event inside TPC
ALICE TPCALICE TPC
ALICE @ LHC:Obtain a fundamental
understanding of the microscopic structure in hadronic interactionat high densities and temperatures
Measure observables to study signature of a possible
Quark-gluon plasma QGP
LHC heavy ion program : Pb-Pb collisions at CM energy of 7.5 TeV/nWith dNch/dy ≤ 8000 (max expected)⇒2 x 104 tracks/ event in the sensitive
volume of the TPC
E E
520 cm
E E88µs
560cm
•HV central electrode: -100 kV •Drift length 250cm => E=400 V/cm•Gas: Ne-CO2 [90/10%]•Drift Volume: 88m3
ALICE TPCALICE TPC
Data challenge:570 132 (pads) x 500 (time bins)
2.85*108 space points/ event
Expected Performances:• Space point resolution ~500µm• Two-track separation 0.5 cm• dp/p <2% @ 1GeV, 10% @10GeV• dE/dx <7% • Rapidity coverage –0.9 < η < 0.9more infos: talk of Ch.Garabatos
•Materials with good stability–mass ratio•minimized radiation length
total detector X0=3%
Drift Tubes for the ATLAS Drift Tubes for the ATLAS MuonMuon--SpectrometerSpectrometer
30m
m 50µm
electronics electronics ‘tuned’ to be ‘tuned’ to be sensitive to first sensitive to first avalancheavalanche
Single tubes:Ar/CO2 (93/7%) with 3 barsingle tube resolution: ~100µm
Chambers:2 multilayers with 3 or 4 monolayers
MDT position resolution σsagitta~50µmOverall resolution:
rigorous control of:• assembly• deformation • calibration• alignment
2500mm
more infos: talk of F.Cerutti
Drift Tubes for the ATLAS Drift Tubes for the ATLAS MuonMuon--SpectrometerSpectrometer
Muon-Spectrometer provides standalone momentum resolutiondp/p ~10% at ~1TeV/cdp/p ~3% at ~100GeV/c⇒need overall dssagitta ~ 50µm⇒need low radiation length≤ 10%
Cover 5500m2
more infos: talk of F.Cerutti
Ageing Wire ChambersAgeing Wire Chambers
• Aging still a concern, specially for high luminosity collider experiments at LHC
• Last years big efforts have been made to avoid aging effects• All elements and materials in contact with the counting
gas have to be extensively tested and to be finally approved
TedlarAraldit
2013 3M DP190
C.Garabatos for the ALICE TPC collaboration, web page
Ageing Wire ChambersAgeing Wire Chambers
Traditional Wire ChambersTraditional Wire Chambers
Wire Chambers:
Well known technology widely used in HEP experiments
Proven to be robust, precise and reliable devices
Operating gases can be tuned and optimized to fulfill requirements of the given application
MPGDsMicro Pattern
Gaseous DetectorsMicromegas, GEM
CAT, µCat, µGroove, µDot, FGLD,….
Micromegas
50-100µm
70 -100µm
2000µm200µm
5µm
Micro Strip Gas ChamberMSGC
50µm
140µm
Gas Electron MultiplierGEM
Multi-Wire Proportional ChamberMWPC
Typical cell size in MWPC : ≥ 1mmPrecise etching technology allows to reduce cell size to ~100µm level.But due to small dimensions streamers develop more easily into sparks
…..
MicromegasMicromegas principleprinciple Y.Giomataris et al, NIM A 376 (1996) 29
50-100µm
50 -100µm
800µm50µm
MicromegasMicromegas PerformancePerformance D.Thers et al NIM A 469 (2001) 133
1000 10000 20000 30000 time[min]
aging: Ar-C4H10 94-6% up to 24.3mC/mm2
10 years LHC
1
0.8
0.6
0.4
0.2
1.8*1012 particles/mm2
1
0.9
0.8
0.7
0.6
10-4
10-5
10-6
10-7
10-8
discharge probability
effic
iency
Efficiency & discharge probability
High Voltage [V] high voltage [V]
350 450400 500 550 600 650
103
102
104
105105
gain
gain
energy resolution ~ 10%
55 FeAr + 10% C4H10
MicromegasMicromegas @ Compass@ Compass
420 V operating point~3-4.103 Gain
Large efficiency plateau > 40 V
σ = 9 ns
Time resolution : 9 nsSpatial resolution < 70 µm
σ =70 µ
Successful 2 years running !
300mm
420 V operating point~3-4.103 Gain
Large efficiency plateau > 40 Vσ = 9 ns
Time resolution : 9 ns
Spatial resolution < 70 µm
σ =70 µ
MicromegasMicromegas @ Compass@ Compass
Cathode
GEM 1
Anode
ED
EI
conversion & drift
induction
hole pitch140 µm Ø 75 µm
50µm
75µm
Gas Electron Multiplier GEM: principleGas Electron Multiplier GEM: principle F.Sauli NIM A 386 (1997) 531
Cathode
GEM 1
Anode
ED
EI
conversion & drift
induction
hole pitch140 µm Ø 75 µm
induction
conversion & drift
transfer 1
Cathode
GEM 1
Anode
GEM 2Et1
EI
ED
induction
conversion & drift
transfer 1transfer 2
Cathode
GEM 1
Anode
GEM 2GEM 3
Et1
EI
ED
Et2
50µm
75µm
Gas Electron Multiplier GEM: principleGas Electron Multiplier GEM: principle F.Sauli NIM A 386 (1997) 531
GEM PerformanceGEM Performance S. Bachmann et al, NIM. A479 (2002) 294
rate capability
gain
discharge probability
Compass GEM agingAr/CO2 70/30%
aging5.2*1011 particles/mm2
GEM @ GEM @ CompassCompass C. Altumbas et al, NIM A490(2002)177
time res.σ= 12.4 ns
spatial resolutionY strips
σ=52µm
spatial resolutionX strips
σ=47µm
• 3GEM foils, active area: 30.7 x 30.7 cm2
• 2D readout, 400 µm pitch• Radiation length 0.7% X0
x x
(80µm)dx
y
y
dy(340µm)
dh(50µm)
dx, dy, dh optimizedget the same signal on
x and y strip
copper strips InsulatorKapton
more infos: talk of B.Ketzer
GEM @ GEM @ CompassCompass C. Altumbas et al, NIM A490(2002)177
time res.σ= 12.4 ns
spatial resolutionY strips
σ=52µm
spatial resolutionX strips
σ=47µm
more infos: talk of B.Ketzer
GEM for GEM for LHCbLHCb MuonMuon StationStation D.Raspino et al; Proceedings ICATPP Como (2003)
Ar/CO2/CF4
(45/15/40)
rms = 4.5ns
counts
t0 [ns]
coun
ts
Ar/CO2/CF4 45/15/40Fast & Non-flammable
rate capability up to 0.5 MHz/cm2
efficiency > 96% in a 20 ns time binAging requirement:10 years LHCb ≡ 1.6 C/cm2
≡ 1.2 1012 part./mm2
The length of the detected signal corresponds to the electron drift time in the induction gap:•-> geometrical parameter •-> drift velocity
Multi-GEM Gas Photomultipier A. Breskin et al. The Weizmann Institute
reduced ion feedback less background
no photon feedback no backgroundfrom scintillating hν
thick photo cathode high Quantum EfficiencyCsI: RICH detectors
D. Mörmann et al., NIM A516(2004)315
D. Mörmann et al. NIM A 478 (2002) 230
50mV 10ns
gain 105, no photon feedback
Multi-GEM / CsI
more infos: talk of R.Chechik
• high gain >106 single photon sensitivity!• high 2D precision [0.1-0.2 mm] • fast signals good timing:~ 1.5ns for single photons~ 0.3ns for ~ 200 photons
• can operate at high magnetic fields
Multi-GEM Gas Photomultipier A. Breskin et al. The Weizmann Institute
more infos: talk of R.Chechik 50mV 10ns
gain 105, no photon feedback
Multi-GEM / CsI
CF4: windowless Cherenkov detectorssame gas in UV detector & radiator!(application: PHENIX-RHIC/BNL)
D. Mörmann et al. NIM A 478 (2002) 230
Multi-GEM Gas Photomultipier F.Sauli et al. GDD CERN
Single photoelectron cluster charge distribution:
Gas: 100% CH4Photo-cathode: CiI
Single electron pulse height spectrum for increasing UV light attenuation:
more infos: talk of L.Ropelewski
Sealed gaseous PMT for visible lightGas-sealed detector:- 3 Kapton GEMs- Semitransparent K-Cs-Sb photocathode
0%
5%
10%
15%
300 400 500 600
wavelength, nm
Qua
ntum
effi
cien
cy,
QE in transmissive mode Ar/CH4 95/5%
Wavelength [nm] 300 400 500 600
15%
10%
5%
0%
Qua
ntum
effi
cien
cy
Bialkali pc in Ar/CH4 (95/5)
13%
gain: 100-1000 in DC mode (ion feedback limit)>105 in ion-gating mode
1800 1900 2000 2100 2200 2300
0.1
1
10
100
250 260 270 280 290 300 310 320 330 340102
103
104
105
106
107
m430_gain_bi-alkali
gain
∆VGEM [V]
4-GEM gainAr/CH4 (95:5) 700torrgated operation with bi-alkali
singleelectrons
Vres [V]
pul
sehe
ight
>105
stable for at least1 month
more infos: talk of J.Veloso D. Mörmann et al. NIM A504(2003)93M.Balcerzyk et al. IEEE Trans. Nucl. Sci.NS50 (2003) 847
TPC with TPC with MPGDsMPGDs for a new LC Linear for a new LC Linear ColliderCollider
e+- e- collider with GeVs 500=
bunch train frequency: 5Hzbunch train: 1msec with 3000 bunches
Basic TESLA Detector Concept:Small high precision silicon vertex detectorLarge central tracking detector (TPC)High granularity calorimeterB-field up to 4 Tesla
Physics requirements for the LC Central Tracker: TPC•Space point resolution ~100µm•Momentum resolution δpt/pt
2 < 2x10-4/GeVc• Multi-track separation 2.3mm(r - φ),10mm(z)•Precise dE/dx < 5%• low radiation length X0 <3% more infos: talk of J.E.Augustin
MicromegasMicromegas TPC TPC FeliceFelice Micromegas FELICE group (LBL/DAPNIA-Saclay/LAL Orsay/IPN Orsay)
Ar/CF4 98/2%
Very thin amplification gap (50 to 100 Very thin amplification gap (50 to 100 µµm) m) => fast signals=> fast signals
Gain stability:a good potential for dE/dx
Gas studies :Gas studies : ArAr+2% CF+2% CF44 ωτωτ = 20 at B=4 T= 20 at B=4 Tvvee-- ~7 cm/~7 cm/µµs s atat 180 V/cm plateau 180 V/cm plateau
Natural ions feedback suppressionNatural ions feedback suppressionion feedback ion feedback in Ar/Cin Ar/C44HH1010 90/10% 90/10% 0,5%0,5%
((meshmesh::1000 LPI,1000 LPI, EEdd // EEaa= 200/70000)= 200/70000)ion feedback in Ar/CFion feedback in Ar/CF44 98/2 % 98/2 % 0.25%0.25%
(mesh: 1500LPI (mesh: 1500LPI EdEd / / EaEa= 200/70000)= 200/70000)
more infos: talk of P.Coals & poster V.Lepeltier 0 50 100 150 200 250 300 350field ratio
10-1
10-2
10-3
100
ion
feed
back
[%
]
feedback 2.5 %0
gain 330
Current measurement from X-ray source
V. Lepeltier et at, Proceedings IEEE, Protland (2003)
ionamplificat
driftfeedback E
EI ≈+
(for a mesh 1500lpI ~ 70mm pitch)
S. Kappler et al, IEEE Nucl. Sci. Symposium (Portland October 2003)more infos: talk of S.Roth
S.Roth et al, Proceedings ICCTP,Como 2003
I+/e-collected
B [ T ]
TPC with double GEM readout for 4T field)GEM GEM -- TPCTPC
MicromegasMicromegas and GEM in and GEM in RunningRunning & Future & Future ExperimentsExperiments
Micromegas:• COMPASS, NA48, n-TOF, TESLA….• CAST,HELLAZ,NOSTOS...• MEDICAL APPLICATIONS
GEM:• COMPASS, TESLA, MICE, TOTEM….• gas photomultiplier...• medical applications, astrophysics• Plasma imaging
Intrinsic ion feedback suppression
High granularity readout pattern in any shape
MPGD
109109CdCd
RefRef: A. : A. DelbartDelbart et al, NIM A461, p84 (2001)et al, NIM A461, p84 (2001)
Good energy resolution
fast signals &
high rate capability RefRef: F.: F.SauliSauli et al, NIM A, (2001)et al, NIM A, (2001)
Two-dimensional symmetry (no E×B effects)
Resistive Plate Chamber
RPCs historically used as trigger detector working in the streamer modeNew readout electronic allows to follow a new trend to work in the avalanche mode ATLAS & CMS will use their trigger
RPC in avalanche modeATLAS : ~3650m2 CMS : ~2000m2
RPCs with thin gas gap improved timing
Resistivity limits the rate capability, new developments open doors for high rate applications
Resistive Plate ChamberResistive Plate Chamber
Eclusters
Only avalanches that originate close to cathode grow big enough to give detectable signal
resistive electrode
resistive electrode
gas gap
HV
GND
readout strips
readout strips
Resistive Plate ChamberResistive Plate ChamberTrigger RPC; R. Cardarelli, R. SantonicoGas: CC22HH22FF44 / C/ C44HH1010 / SF/ SF66 -- 94.7 / 5 / 0.3 % Pic94.7 / 5 / 0.3 % up electrode x coordinate
2mm Bakelite ρ~1010Ωcm2mm gas gap E: 50kV/cm2mm Bakelite ρ~1010ΩcmPic up electrode y coordinate
Timing RPC; P. Fonte, V. PeskovGas: CC22HH22FF44 / i/ i--CC44HH1010 / SF/ SF66 -- 85/ 5 / 10 %85/ 5 / 10 %
HV: 10kV, E: 50kV/cm
Pic up electrode coordinate3mm glass ρ~1012ΩcmHigh rate: ρ~109Ωcm
2mm Aluminium electrode0.3mm gas gap E: 100kV/cm
HV: 3kV, E: 100kV/cm
Multigap RPC; C.WilliamsGas: CC22HH22FF44 / i/ i--CC44HH1010 / SF/ SF66 -- 90/ 5 / 5 %90/ 5 / 5 % Pic up electrode pads
0.4 mm glass plates ρ~1012Ωcm250µm gas gaps E: 100kV/cm
Pic up electrode padsHV: 13kV, E: 100kV/cm
RPC signal development Simulation RPC signal development Simulation MeasurementMeasurementTime Resolution depends on:• eff.Townsend coefficient (α − η)• Drift Velocity (v)
Efficiency depends on:• total gas gap
Efficiency for single gap:( Simulation for threshold 20fC )Trigger RPC ~ 95%Multigab PRC ~ 70%
Total Efficiency measured:Trigger RPC 1 gaps >97%Multigab PRC 10 gaps >99%
Time resolution:( Simulation )
Trigger RPC ~1nsMultigap PRC ~52psvt )(
28255.1ηα
σ−
=
Townsend coeff. α
Attachment coeff. η
Trigger RPC
Multigap RPCTiming-,
P. Fonte et al, NIM A449 (2000) 295
measurement simulation
W.Riegler,C.Lippmann,R.Veenhof NIM A 500(2003) 144
Trigger RPC for ATLAS Trigger RPC for ATLAS
Graphite electrodes
ground planes
Gas
Each ATLAS RPC Unithas two independentRPC layer!!
layer 2
layer1
y readout strips
x readout stripsBakelite plates foamHV x readout strips
PET spacers
y readout strips
High efficiency > 95%
Time resolution ∼ 1ns
Rate capability ∼ 100Hz/cm2
Resolution of 5-10 mm in the Y projection
Gas Gas mixturemixture:: Working in Working in AvalancheAvalanche ModeMode
CC22HH22FF44 / C/ C44HH1010 / SF/ SF66 -- 94.7 / 5 / 0.3 %94.7 / 5 / 0.3 %
2D 2D orthogonalorthogonal strip strip Readout :AllowsAllows toto measuremeasure x and y coordinatex and y coordinate
More than 1000 RPCs will be installed in the BARREL region and have to cover an area of 3650 m2
Francesco Conventi University of Naples, INFN and ROMA1, Atlas, presented at the RPC Workshop France 2003
Trigger RPC for ATLASTrigger RPC for ATLASTest beam at Cern (H8)
Efficiency > 95%
Cluster Size
Efficiency across the chamber
• X• Y
• X• Y
• X• Y
Paulo Iengo University of Naples, INFN, Atlas, presented at the RPC Workshop France 2003
MultigapMultigap RPCRPC
Timing depends on individual gaps(effective Townsent coeff. & drift velocity)
Efficiency depends on the sum of all gas gaps
Due to the superposition of the avalanches the pulse height spectrum is almost Gaussian.
The low signals in the distribution are dominated by value of Townsend coefficient α (αD ~ 30)
The large signals in the distribution are defined by saturation in avalanche growth due to space charge -> No tai le
Despina Hatzifotiadou et al., INFN Bologna, ALICE, presented at the RPC Workshop France 2003
MultigapMultigap RPCRPC
Timing depends on individual gaps(effective Townsent coeff. & drift velocity)
Efficiency depends on the sum of all gas gaps
Despina Hatzifotiadou et al., INFN Bologna, ALICE, presented at the RPC Workshop France 2003
MultigapMultigap RPC for the ALICE TOFRPC for the ALICE TOF
130 mmactive area 70 mm
M5 nylon screw to hold fishing-line spacer
honeycomb panel (10 mm thick)
external glass plates 0.55 mm thick
internal glass plates (0.4 mm thick)
connection to bring cathode signal to central read-out PCB
Honeycomb panel (10 mm thick)
PCB with cathode pickup pads
5 gas gaps of 250 micron
PCB with anode pickup pads
Silicon sealing compound
PCB with cathode pickup pads
Flat cable connectorDifferential signal sent
from strip to interface card
Mylar film (250 micron thick)
Double stack-> each stack has 5gaps => 10 gaps in total
Resistive plates ‘off-the-shelf’ soda lime glass 1012 MΩ/square
400 µm internal,500µm external glasswith resistive coating: 5 MΩ/square
Spacer: 250 µm nylon fishing lineReadout pads: 2.5x3.5cm2
Time resolution <50psEfficiency 99.9%Rate capability : up to 1kHz/cm2
Despina Hatzifotiadou et al, INFN Bologna, ALICE, presented at the RPC Workshop France 2003
High High RateTimingRateTiming RPCRPCActive area : 3x3 cm2 No spacers
TFE (R-134a ):CC22HH22FF44 / C/ C44HH1010Gas Mixture: TFE (R-134a) / SF6 = 90% / 10%
Resistive electrode : ρ ~ 4×109 Ω cm
ENSITAL® SD (ENSINGER) (Commercial material)
Gas in out
The time resolution remains essentially unchanged from:
2 kHz/cm2 to 25 kHz/cm2
with photon at a level around σ = 90 psmore infos: talk of P.Fonte
High High RateTimingRateTiming RPCRPC
For a given counting rate, an increase of the electric field doesn't considerably improve the time resolution.
The time resolution remains essentially unchanged from:
2 kHz/cm2 to 25 kHz/cm2
with photon at a level around σ = 90 psmore infos: talk of P.Fonte
RPC AgingRPC Aging
0
50
100
150
200
250
300
350
400
10/11/02 11/30/02 1/19/03 3/10/03 4/29/03 6/18/03 8/7/03 9/26/03 11/15/03
ρ (G
Ohm
cm
) a 2
0 °C
0
20
40
60
80
100
120
140
160
Inte
grat
ed C
harg
e (m
C/c
m2 )
gap 1 Argongap 2 Argongap 3 Argongap 4 Argongap 5 Argongap 6 ArgonGap1 eff. plateauGap2 eff. plateauGap3 eff. plateauGap4 eff. plateauGap5 eff. plateauGap6 eff. plateaumC/cm^2RH
ATLAS RPC resistivity evolutionATLAS Bakelite RPC aging test:Gas mixture: C2H2F4/C4H10/SF6 -96/3.5/0.5%Bakelite resistivity: increases Rate capability: drops with larger resistivityhumid flow: H2O vapor added to the gas mixture
sourceon
sourceoff
I [µA]
ALICE MPRC aging test:Gas mixture:C2H2F4/C4H10/SF6 - 90/5/5%Resistivity: unchanged Efficiency: no drop dark current: no increase
Resistive Plate ChamberResistive Plate Chamber
Avalanche mode operation is possible with modern low noise electronics and a step forward to realize reliable trigger detectors for big experiments
Multigap RPCs achieve efficiencies of 99.9% and very good timing resolution <50ps, application in Time Of Flight TOF detectors
High rate Timing RPC proved rate capability of up to 25kHz/cm2 and even higher should be possible
Gaseous detectors
Well known, proven technology providing high precision measurements and large area coverage.
Flexible devices, adaptable to many applications.
Non flammable gases have been developed to ensure safe operation of the detectors.
Modern, sensitive low noise electronics enlarges the range of applications
Accurate simulation tools available
Thank you for yourattention.
Photo: Alice TPC field cage by m.hoch
