rachel chechik weizmann institute tiipp09 tsukuba march 2009 the thgem: a thick robust gaseous...
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Rachel Chechik Weizmann Institute TIIPP09 Tsukuba March 2009
The THGEM: The THGEM: a THick robust Gaseous Electron a THick robust Gaseous Electron Multiplier for radiation detectorsMultiplier for radiation detectors
A. Breskin, M. Cortesi, R. Alon, J. Miyamoto, V. Peskov, G.Bartesaghi, R. Chechik
Weizmann Institute of Science, Rehovot, IsraelV. Dangendorf
PTB, Braunschweig, Germany J. Maia and J.M.F. dos Santos
University of Coimbra, Portugal
MOTIVATIONMOTIVATION:: Robust, economic, large-area radiation imaging detectorsFAST, HIGH-RATE, MODERATE LOCALIZATION RESOLUTION
Rachel Chechik Weizmann Institute TIIPP09 Tsukuba March 2009
THGEM – a family of hole gas multipliers:THGEM – a family of hole gas multipliers:
ECONOMIC & ROBUST ECONOMIC & ROBUST !!
Avalanche “confined” inside a hole in an insulating plate ->Avalanche “confined” inside a hole in an insulating plate ->Reduced secondary effects, independent holes
h=0.1 mm rim: prevents discharges high gains !
Cu G-10
1mm
Typical dimensions:Hole diameter d = 0.3 - 1mmPitch a = 0.7- 7mmThickness t = 0.4 - 3mm
Manufactured by standard PCB techniques of precise drilling in G-10 (and other materials) and Cu etching.
Other groups independently developed similar structures: Optimized GEM: L. Periale et al., NIM A478 (2002) 377. LEM: P. Jeanneret, PhD thesis, 2001. P.S.Barbeau et al, IEEE NS50 (2003) 1285.
First publication: R.Chechik et al. NIM A535 (2004) 303 Recent review: A.Breskin et al. NIM A598 (2009) 107
Rachel Chechik Weizmann Institute TIIPP09 Tsukuba March 2009
THGEM – Operation principle THGEM – Operation principle (like GEM, similar voltages and fields)(like GEM, similar voltages and fields)
Advantages of large hole dimensions:Hole dimensions >> mean free path High gains within the hole
Hole dimensions >> e- diffusion Easy electron transport into and out of the holesEfficient cascading of elements: 10-100 times higher gain
E~40kV/cm
Upon application of voltage across the plate (V=400-1200V function of gas and thickness): a dipole field dipole field in the holes focusesfocuses e- into the holes defocusesdefocuses e- out the hole
1e- in
104- 105 e- out
Rachel Chechik Weizmann Institute TIIPP09 Tsukuba March 2009
THGEM – Operation THGEM – Operation principle principle Multiplication of e- induced by
radiation in gas or from solid converters (e.g. a photocathode)
Detector properties governed by:e- transport (e.g. efficiency to single e-)multiplicationcharge induction on readout electrodesion-backflow
Reflectivephotocathode
Semi-transparent photocathode
e- focusedfocused into the holes by the hole dipole field
Rachel Chechik Weizmann Institute TIIPP09 Tsukuba March 2009
THGEM production methodsTHGEM production methodsNo mask, Weizmann
Drill + etch under the CuSmall and zero rim
Surface damaged
Cu
RIM
Cu
Nice edge RIM
With mask, WeizmannEtch w mask + drill
Large rim
displacement
With mask, Eltos, ItalyDrill +etch w mask
Large rim
No displacementDetached Cu
CERN, Zero rim: drill + short etching to remove sharp edges from drilling.
Rachel Chechik Weizmann Institute TIIPP09 Tsukuba March 2009
3x3 cm: basic studies, many geometries
10x10 cm: 2D imaging
30x30 cm: n detector
All produced with mask Rim=0.1mm
The THGEMsThe THGEMs at Weizmannat Weizmann
2003
2008
THGEM efficiency for single THGEM efficiency for single photoelectronsphotoelectrons
Rachel Chechik Weizmann Institute TIIPP09 Tsukuba March 2009
Hole dimensions >> e- diffusion efficient transport from the conversion gap
e- focused into the holes by the dipole field
Full efficiency: at THGEM gain = 10-30 !!
Edrift = 1kV/cm
VHOLE [Volt]
Gain=100
Semitransparentphotocathode
e- extraction requires Edrift >0.5kV/cm
Edrift =0
Reflectivephotocathode
e- extraction optimal @ Edrift =0kV/cm
In GEM: 500-1000
Full efficiency: at THGEM gain = 30-100 !!
Under study in Ne and Ne/CH4 mixtures
Single THGEM gainSingle THGEM gain
x100 higher gain compared to single
GEM
Rachel Chechik Weizmann Institute TIIPP09 Tsukuba March 2009
Very high gain in 100% Ne and Ne mixtures
At very low voltages !!100% Ne: Gain 105 @ <500VVoltage increases w increased
CH4 %
General:Gain limit (x-ray) << Gain limit (UV) (charge density!)in Ne mixtures on x3 lower (diffusion)
104-105105-106
With single photoelectronsWith single photoelectrons
Rachel Chechik Weizmann Institute TIIPP09 Tsukuba March 2009
double THGEM gaindouble THGEM gainHole dimensions >> e- diffusion efficient transport in the transfer gap efficient cascading of THGEMsMuch higher gain at lower voltages
>106
Ar mixtures,Ar mixtures,single photoelectronssingle photoelectrons
Etrans=3kV/cm
Very high gain even with x-rayAt very low voltages
!!100% Ne: Gain 106 @ ~300V
>106
Edrift=0.2kV/cmEtrans=3kV/cm
Ne mixtures, x-raysNe mixtures, x-rays
Efficient cascading Total gain = Gain1 x gain2
Rachel Chechik Weizmann Institute TIIPP09 Tsukuba March 2009
THGEM - rim effect and stabilization THGEM - rim effect and stabilization timetime
From: Trieste group (RD51): larger rim -> longer stabilization time
Old data: Chechik et al. Proceedings of SNIC2006, eConf C0604032, 0025 (2006)
Larger rim Insulator Charging up few hours of stabilization gain variation ~ x2. Stabilization time depends on:voltages, currents, gas type and purity, materials, geometry, production method
Rim=0.12mmFurther R&D in progress @ CERN-RD51
gain = 104, UV light, e- flux ≈ 104 Hz/mm2
Larger rim higher voltages Higher gains
>104
THGEMs produced by chemical etching (no mask) @ PE, Israel
Single THGEM, 6 keV x-rays
Rachel Chechik Weizmann Institute TIIPP09 Tsukuba March 2009
THGEM counting rate and pulsesTHGEM counting rate and pulses
Rate capability = 10MHz/mm2
@ GAIN ~104 Ar/CH4 (1 atm)
single photoelectronssingle photoelectrons
Fast signals in atm. pressure Ar/30%CO2 Double THGEM ( t=1.6 d=1, a=1.5 mm)
gain=~106
rise time < 10 ns
9 keV x-rays9 keV x-rays
100% Ne ~X10 slower gasMore CH4 faster pulses,Higher voltages75 ns 30 ns
Rachel Chechik Weizmann Institute TIIPP09 Tsukuba March 2009
THGEM timing (UV photons and THGEM timing (UV photons and particles) particles)
Similar resolution with semitransparent PCCompatible with e- transport
*Breskin et al NIM A483 (2002) 670
pulsed UV lamp
Reflective CsI PC
0.3 mm
0.4 mm
0.7 mm
MIPS
Double-THGEM: particles & cosmics: =10-13 nsTriple-GEM (same setup): 7-9 ns
Multi-GEM: 5-12 ns depending on gas-faster with Ar/CF4
-slower with Ar/CO2 mixtures)
1 10 100 10000
2
4
6
8
10
12
[n
s]
# of Photoelectrons
Reflective CsI PC Ar/CH4 (95:5) 1 atm
double THGEM
triple GEM w CF4
**UV photonsUV photons
EHole
EHole
ETrans
EInd
EDrift
Induced-signal width matched to readout-pixel size.
8 keV X-Ray • 10x10cm2 THGEMs t=0.4, d=0.5, a=1 mm
C-paint Resistive anode (match induced signal size)• 2-sided pad-string readout 2mm pitch • Delay-line readout (SMD)
2D imaging-detector w/economic readout2D imaging-detector w/economic readout
Rachel Chechik Weizmann Institute TIIPP09 Tsukuba March 2009
Rachel Chechik Weizmann Institute TIIPP09 Tsukuba March 2009
Gain uniformity FWHM ± 10%
55Fe
Gain ~ 6x10Gain ~ 6x1033
21%
1 mm pitch THGEM + 2 mm pitch Readout + DL interpolation -->
2D imaging: results with 6-8 keV x-ray2D imaging: results with 6-8 keV x-ray Ar/CHAr/CH4 4 (95/5)(95/5)
Localization Resolution ~0.7 mm FWHM
35 40 45 50-5
0
5
10
15
20
PS
F
X Coordinate (mm)
~0.7 mm FWHMMask: Raw Data
10 lp/cm
From edge analysis
Rachel Chechik Weizmann Institute TIIPP09 Tsukuba March 2009
2D imaging: results with 5-9 keV x-ray2D imaging: results with 5-9 keV x-ray Ne/5%CHNe/5%CH44
preliminary
x-rays < 5keVFlat-field illumination: hole pattern is visible/ Resolution ~0.3mm FWHM
The THGEM electrode
The 2D image
Recently numerous proposed solutions to charge and light detection in the gas
phase of noble liquids“TWO-PHASE DETECTORS”
Possible applications of noble liquids:- Noble liquid ionization calorimeters - Liquid argon TPC (solar neutrinos) - Scintillation detectors and two-phase emission
detectors exotic particles searches (WIMP …)
- Development of γ-cameras for nuclear medicine imaging e.g. PET, Compton… cathod
e
WIMP
Gas
Liquid
e-E
Ar/Xe
Rachel Chechik Weizmann Institute TIIPP09 Tsukuba March 2009
THGEM Operation in Noble gases: Ar, THGEM Operation in Noble gases: Ar, XeXefor LARGE-VOLUME Noble-gas detectors for rare
eventsand others.
Advantages for THGEM vs. GEM: reduced effect of condensation on surfaces
Rachel Chechik Weizmann Institute TIIPP09 Tsukuba March 2009
THGEM Operation in Noble gasesTHGEM Operation in Noble gasesAvalanche confinement in holes is notnot hermetic -> Field extends out by ~hole diameter ->Photon secondary effects might be important depending on geometry and gas.
-2 -1 0 1 20
5
10
15
20
Eho
le k
V/c
m
Z [mm]
THGEMthickness
d=0.3 mmd=1.0 mm
VTHGEM
=1kV
Avalanche & photonsOutside the hole. Ne, Ar have energetic photonsNeed to optimize sizes and fields according to the gas.
E
THGEM in Ar, XeTHGEM in Ar, Xe
Ar/Xe =Penning mixt. x20 higher gain, lower voltages.The lower gain in “purified” Ar secondary effects due to “energetic” UV-photon feedback Under investigations
6keV x-rays
R. Alon et al. 2008_JINST_3_P01005
105
0 400 800 1200 1600100
101
102
103
104
105
106
6
5
4
32
1
Ne
Ar
Ar/5%Xe
Gai
n
VTHGEM
[V]
1 bar
XeAr
Double THGEM
Kr
Not purified
Purified gases
Rachel Chechik Weizmann Institute TIIPP09 Tsukuba March 2009
Rachel Chechik Weizmann Institute TIIPP09 Tsukuba March 2009
THGEM in Xe,Ar/XeTHGEM in Xe,Ar/Xe R. Alon et al. 2008_JINST_3_P01005
1000 2000 3000100
101
102
103
104
105
2.9 bar2 bar1 bar
0.5 bar
open: Single THGEMclosed: Double THGEM
Gain
VTHGEM
[V]
Xe
THGEM: t=0.4mm, d=0.3mm, a=1mm, rim=0.1mm Double-THGEM, t=0.4mm, d=0.5mm, a=0.9mm
0 500 1000 1500101
102
103
104
105
106
2 bar10.7
0.50.3
0.2
Gain
VTHGEM
[V]
Ar:Xe (95:5)
0.1
Ar/Xe (95/5) Penning mixture,Good energy resolutionGain > 10Gain > 1044 at all pressuresLow voltages
Xe Ar/Xe (95/5)
200 400 600 800 1000 12000
10
20
30
40
50Co
unts
/Cha
nnel
Double THGEM, t=0.4mm, d=0.5mm, a=0.9mm
FWHM = 19%
Ar:Xe (95:5) 1 bar
Channel
THGEM in liquid-Ar temperaturesTHGEM in liquid-Ar temperatures
Stable operation in two-phase Ar, T=84KDouble-THGEM Gains: 8x103
Experimental setup
BINP/Weizmann: Bondar et al, 2008 JINST 3 P07001
2-THGEMG-10
1-THGEMG-10
2-THGEMKEVLAR
3-GEM
GOOD PROSPECTS FOR CRYOGENIC-PHOTOMULTIPLIER OPERATION IN THE LXe-CAMERA
Rachel Chechik Weizmann Institute TIIPP09 Tsukuba March 2009
Radio-clean THGEM for rare-event Radio-clean THGEM for rare-event physicsphysics
• Motivation: need charge and scintillation-light readout elements for noble-liquid detectors with very low natural radioactivity.
• E.g. Cirlex (a polyimide like Kapton) is 30 times radio-cleaner compared to PMT-glass
• Cirlex-THGEM preliminary tests: M. Gai et al. arXiv:0706.1106
•
The Cirlex-THGEM
WIMPinteractio
nLXe
e-
THGEM photon Detector
Photon
e-
CsI Photo-Cathode
EG
EL
The 2-phase THGEM LXe Dark-Matter detector
concept
(M.Gai-UCONN / D.McKinsey-YALE / A.Breskin-WEIZMANN)
THGEM
Segmented
Anode
MgF2 window
LXe conversion volume
CsIphotocathode
THGEM-GPM for LXe Gamma CameraTHGEM-GPM for LXe Gamma CameraSubatech-Nantes/Weizmann
Gas photomultiplier
Rachel Chechik Weizmann Institute TIIPP09 Tsukuba March 2009
Rachel Chechik Weizmann Institute TIIPP09 Tsukuba March 2009
Photon detectors for RICH: Photon detectors for RICH: reflective CsI PC deposited on the THGEMreflective CsI PC deposited on the THGEMphotoelectron extraction into gas, surface electric field by the hole dipoleRICH RICH Requires: • High field on the PC surface (for high QE). • Good e- focusing into the holes (for high detection
efficiency). • Low sensitivity for MIPS background radiation (e.g. in
RICH).
Immediate interest: COMPASS & ALICE, R&D in RD51
efficient photoelectron extraction over the entire PC area: pitch 0.7mm, d=0.3mm: any voltage > 400V any gas, including Ne, Ne/CH4
pitch 1mm, d=0.5mm: similar results
Distance = 0
Min. field
-0.30 -0.15 0.00 0.15 0.300
2
4
6
8
10d = 0.3 mm, h = 0.1 mm, a = 0.7 mm, t=0.4mm
Ele
ctric
Fie
ld (
kV/c
m)
Distance form the center between hole (mm)
VTHGEM
= 400 V
VTHGEM
= 800 V
VTHGEM
= 1200 V
VTHGEM
= 1600 V
EDrift
= ETran
= 0 kV/cm
EfficientExtractionFrom PC
e-Ref PC
Rachel Chechik Weizmann Institute TIIPP09 Tsukuba March 2009
Maximum efficiency at Edrift =0.
• Slightly reversed Edrift (50-100V/cm) =>
good photoelectron collection & low sensitivity to MIPS (~5-10%) !
-0.6 -0.4 -0.2 0.0 0.2 0.4 0.60.0
0.5
1.0
1.5
2.0
0
Gain~103
1 Atm. Ar/CH4(95:5)
40
20
80
60
100
e- tra
nsf
er
effic
iency
[%
]
Edrift [kv/cm]
Re
lativ
e
Photon detectors for RICH: Photon detectors for RICH: reflective CsI PC deposited on the THGEMreflective CsI PC deposited on the THGEM
Photoelectron collection into the holes by the dipole field
Currently R&D for upgrade of COMPASS & ALICE RICH
Reduced sensitivity to MIPS proved with multi-GEM detectors of PHENIX
e
MIP
EE E=0
Edrift
Ref. PC
New concept: Digital sampling calorimetry New concept: Digital sampling calorimetry for ILCfor ILC with A. White with A. White Univ. Texas Arlington/Weizmann
Rachel Chechik Weizmann Institute TIIPP09 Tsukuba March 2009
Sampling the jet + advanced pattern recognition algorithms -> Very high precision jet energy measurement.
Simulated event with 2 hadronic jets
Reconstructed jet:Simulated energy resolution
General scheme of a detector
HCal
2 sampling layers with THGEM-based elements
Rachel Chechik Weizmann Institute TIIPP09 Tsukuba March 2009
Fast-neutron Imaging-detectorFast-neutron Imaging-detector
• neutrons scatter on H in plastic-radiator foil, p escape the foil.
• p induce electrons in gaseous conversion gap.
• electrons are multiplied and localized in cascaded-THGEMs imaging detector.
• require high gain and large dynamic range (p spectrum)
• efficiency 1 layer: 0.1-0.2%
• High multiplication factors• High stability• w Ne mixtures: high gain and dynamic range.
Weizmann/PTB/Soreq
THGEM 1
THGEM 2
gas
B, Li, Gd…converter: thermal neutron detectore.g. position sensitive n-dosimetry for BNCT (with Univ.& INFN, Milano)
Double THGEMs:
Rachel Chechik Weizmann Institute TIIPP09 Tsukuba March 2009
Operation principle:
• n energy selected by TOF• Image “on” ad “off” resonance• Ratio of images => element selection
Fast Neutron Resonant Radiography Fast Neutron Resonant Radiography (FNRR)(FNRR)forfor element-resolved radiography element-resolved radiography
Detector requirements • area: >30x30 cm2 • detection eff. @ 2-10 MeV : ~ 5-10%• Insensitivity to gamma• counting rate : > MHz cm-2
• Time Resolution ~ few ns• Position resolution: ~ 0.5 mm• 25-50 layers. => THGEM will reduce THGEM will reduce costcost
Weizmann/PTB/Soreq
Dangendorf et al. NIM A542(2005)197
C rodsC rods
Triple-GEM 10 x 10 cm 2
AllAll
SteelSteel
C onlyC only
Be target
pulsed, white
neutron beam
Neutron imaging detector with fast timing capability !
nsec-pulsed broad energy deuteron
beam
neutron source: sample
• Single-photonSingle-photon imaging.
e.g. Ring Imaging Cherenkov (RICH) detectors.
• Fast ParticleParticle tracking at moderate (sub-mm) resolutions + high
rates.
• Moderate-resolution TPC (Time Projection Chamber) readout
elements.
• Sampling elements in calorimetry.
• Ionization & scintillation recording from Noble-Liquid & High-
pressure
detectors, including 2-phase detectors
(Dark-Matter, neutrino, double-beta decay, Gamma Cam…)
• Moderate-resolution (sub-mm), fast (ns) X-rayX-ray and nn imaging.
• Possible low-pressure operation: Possible low-pressure operation: Nuclear Physics applicationsNuclear Physics applications
SummarySummary
Robust, economic, large-area radiation imaging detectorsHIGH-GAIN, FAST, HIGH-RATE, MODERATE 2D- RESOLUTION
Rachel Chechik Weizmann Institute TIIPP09 Tsukuba March 2009
Rachel Chechik Weizmann Institute TIIPP09 Tsukuba March 2009
Weizmann Group THGEM papers:
R.Chechik et al. NIM A535 (2004) 303 (first idea)
R.Chechik et al. NIM A553 (2005) 35 (application to photon detectors)
C.Shalem et al. NIM A558 (2006) 475 & NIM A558 (2006) 468 (atm. And
low-p)
M.Cortesi et al. 2007_JINST_2_P09002 (imaging)
M.Cortesi et al. NIM A572 (2007) 175 (2D imaging)
R.Alon et al. 2008_JINST_3_P01005 (Ar, Xe)
R.Alon et al. 2008 JINST 3 P11001 (timing)
R.Chechik and A.Breskin NIM A595 (2008) 116 (application to photon
detectors)
A.Breskin et al. NIM A598 (2009) 107 (a concise review)
R.Chechik,et al. /http://www.slac.stanford.edu/econf/C0604032/papers/
0025.PDFS. (including long term stability)
C. Shalem MSc 2005 JINST TH 001
R. Alon MSc 2008 JINST TH 001