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The THGEM: a THick robust Gaseous Electron Multiplier for radiation detectors

The THGEM: a THick robust Gaseous Electron Multiplier for radiation detectors. Breskin, M. Cortesi, R. Alon, J. Miyamoto, V. Peskov, G.Bartesaghi, R. Chechik Weizmann Institute of Science, Rehovot, Israel V. Dangendorf PTB, Braunschweig, Germany J. Maia and J.M.F. dos Santos

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The THGEM: a THick robust Gaseous Electron Multiplier for radiation detectors

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  1. The THGEM: a THick robust Gaseous Electron Multiplier for radiation detectors • Breskin, M. Cortesi, R. Alon, J. Miyamoto, V. Peskov, G.Bartesaghi, R. Chechik • Weizmann Institute of Science, Rehovot, Israel • V. Dangendorf • PTB, Braunschweig, Germany • J. Maia and J.M.F. dos Santos • University of Coimbra, Portugal MOTIVATION: Robust, economic, large-area radiation imaging detectors FAST, HIGH-RATE, MODERATE LOCALIZATION RESOLUTION Rachel Chechik Weizmann Institute TIIPP09 Tsukuba March 2009

  2. Typical dimensions: Hole diameter d = 0.3 - 1mm Pitch a = 0.7- 7mm Thickness t = 0.4 - 3mm 1mm h=0.1 mm rim:prevents discharges  high gains !  Cu G-10 Manufactured by standard PCB techniques of precise drilling in G-10 (and other materials) and Cu etching. First publication: R.Chechik et al. NIM A535 (2004) 303 Recent review: A.Breskin et al. NIM A598 (2009) 107 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. THGEM – a family of hole gas multipliers: Avalanche “confined” inside a hole in an insulating plate -> Reduced secondary effects, independent holes ECONOMIC & ROBUST ! Rachel Chechik Weizmann Institute TIIPP09 Tsukuba March 2009

  3. THGEM – Operation principle (like GEM, similar voltages and fields) Upon application of voltage across the plate (V=400-1200V function of gas and thickness): a dipole field in the holes focusese- into the holes defocuses e- out the hole 1e- in E~40kV/cm 104-105 e- out 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 holes Efficient cascading of elements: 10-100 times higher gain Rachel Chechik Weizmann Institute TIIPP09 Tsukuba March 2009

  4. THGEM – Operation principle Semi-transparent photocathode e- focused into the holes by the hole dipole field Reflective photocathode Detector properties governed by: e- transport (e.g. efficiency to single e-) multiplication charge induction on readout electrodes ion-backflow Multiplication of e- induced by radiation in gas or from solid converters (e.g. a photocathode) Rachel Chechik Weizmann Institute TIIPP09 Tsukuba March 2009

  5. With mask, Weizmann Etch w mask + drill Large rim No mask, Weizmann Drill + etch under the Cu Small and zero rim displacement Cu Cu Surface damaged No displacement Detached Cu RIM Nice edge RIM THGEM production methods With mask, Eltos, Italy Drill +etch w mask Large rim CERN, Zero rim: drill + short etching to remove sharp edges from drilling. Rachel Chechik Weizmann Institute TIIPP09 Tsukuba March 2009

  6. The THGEMsat Weizmann 3x3 cm: basic studies, many geometries 10x10 cm: 2D imaging 30x30 cm: n detector 2003 2008 All produced with mask Rim=0.1mm Rachel Chechik Weizmann Institute TIIPP09 Tsukuba March 2009

  7. THGEM efficiency for single photoelectrons Gain=100 Edrift =0 Hole dimensions >> e- diffusion  efficient transport from the conversion gap e- focused into the holes by the dipole field Reflective photocathode Semitransparent photocathode e- extraction requires Edrift >0.5kV/cm e- extraction optimal @ Edrift =0kV/cm Edrift = 1kV/cm VHOLE [Volt] Full efficiency: at THGEM gain = 30-100 !! Full efficiency: at THGEM gain = 10-30 !! In GEM: 500-1000 Under study in Ne and Ne/CH4 mixtures Rachel Chechik Weizmann Institute TIIPP09 Tsukuba March 2009

  8. Single THGEM gain With single photoelectrons 105-106 104-105 x100 higher gain compared to single GEM Very high gain in 100% Ne and Ne mixtures At very low voltages  !! 100% Ne: Gain 105 @ <500V Voltage increases w increased CH4 % General: Gain limit (x-ray) << Gain limit (UV) (charge density!) in Ne mixtures on x3 lower (diffusion) Rachel Chechik Weizmann Institute TIIPP09 Tsukuba March 2009

  9. double THGEM gain Ne mixtures, x-rays >106 >106 Edrift=0.2kV/cm Etrans=3kV/cm • Hole dimensions >> e- diffusion  efficient transport in the transfer gap  efficient cascading of THGEMs • Much higher gain at lower voltages Ar mixtures, single photoelectrons Etrans=3kV/cm Efficient cascading  Total gain = Gain1 x gain2 Very high gain even with x-ray At very low voltages   !! 100% Ne: Gain 106 @ ~300V Rachel Chechik Weizmann Institute TIIPP09 Tsukuba March 2009

  10. >104 Rim=0.12mm THGEM - rim effect and stabilization time Single THGEM, 6 keV x-rays THGEMs produced by chemical etching (no mask) @ PE, Israel Larger rim  higher voltages  Higher gains 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 gain = 104, UV light, e- flux ≈ 104 Hz/mm2 From: Trieste group (RD51): larger rim -> longer stabilization time Further R&D in progress @ CERN-RD51 Old data: Chechik et al. Proceedings of SNIC2006, eConf C0604032, 0025 (2006) Rachel Chechik Weizmann Institute TIIPP09 Tsukuba March 2009

  11. THGEM counting rate and pulses single photoelectrons rise time < 10 ns gain=~106 Fast signals in atm. pressure Ar/30%CO2 Double THGEM ( t=1.6 d=1, a=1.5 mm) Rate capability = 10MHz/mm2 @ GAIN ~104 Ar/CH4 (1 atm) 9 keV x-rays 100% Ne ~X10 slower gas More CH4 faster pulses, Higher voltages 75 ns 30 ns Rachel Chechik Weizmann Institute TIIPP09 Tsukuba March 2009

  12. Reflective CsI PC pulsed UV lamp 0.3 mm 0.4 mm MIPS 0.7 mm THGEM timing (UV photons and b particles) * UV photons • Multi-GEM: 5-12 ns depending on gas • faster with Ar/CF4 • slower with Ar/CO2 mixtures) Similar resolution with semitransparent PC Compatible with e- transport Double-THGEM: b particles & cosmics: s=10-13 ns Triple-GEM (same setup): s=7-9 ns *Breskin et al NIM A483 (2002) 670 Rachel Chechik Weizmann Institute TIIPP09 Tsukuba March 2009

  13. 2D imaging-detector w/economic readout 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) EDrift EHole ETrans EHole EInd Induced-signal width matched to readout-pixel size. Rachel Chechik Weizmann Institute TIIPP09 Tsukuba March 2009

  14. 2D imaging: results with 6-8 keV x-ray Ar/CH4 (95/5) Gain ~ 6x103 21% 55Fe Gain uniformity FWHM ± 10% From edge analysis Mask: Raw Data 10 lp/cm 1 mm pitch THGEM + 2 mm pitch Readout + DL interpolation --> Localization Resolution ~0.7 mm FWHM Rachel Chechik Weizmann Institute TIIPP09 Tsukuba March 2009

  15. 2D imaging: results with 5-9 keV x-ray Ne/5%CH4 preliminary The THGEM electrode The 2D image x-rays < 5keV Flat-field illumination: hole pattern is visible/ Resolution ~0.3mm FWHM Rachel Chechik Weizmann Institute TIIPP09 Tsukuba March 2009

  16. 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-camerasfor nuclear medicine imaging  e.g. PET, Compton… for LARGE-VOLUME Noble-gas detectors for rare eventsand others. Ar/Xe Gas E e- Liquid cathode WIMP THGEM Operation in Noble gases: Ar, Xe Advantages for THGEM vs. GEM: reduced effect of condensation on surfaces Rachel Chechik Weizmann Institute TIIPP09 Tsukuba March 2009

  17. E Avalanche & photons Outside the hole. Ne, Ar have energetic photons Need to optimize sizes and fields according to the gas. THGEM Operation in Noble gases Avalanche confinement in holes is not hermetic -> Field extends out by ~hole diameter -> Photon secondary effects might be important depending on geometry and gas. Rachel Chechik Weizmann Institute TIIPP09 Tsukuba March 2009

  18. R. Alon et al. 2008_JINST_3_P01005 THGEM in Ar, Xe Not purified 6keV x-rays 105 Purified gases 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 Rachel Chechik Weizmann Institute TIIPP09 Tsukuba March 2009

  19. THGEM in Xe,Ar/Xe R. Alon et al. 2008_JINST_3_P01005 THGEM: t=0.4mm, d=0.3mm, a=1mm, rim=0.1mm Double-THGEM, t=0.4mm, d=0.5mm, a=0.9mm Ar/Xe (95/5) Xe Ar/Xe (95/5) Penning mixture, Good energy resolution Gain > 104 at all pressures Low voltages  Rachel Chechik Weizmann Institute TIIPP09 Tsukuba March 2009

  20. THGEM in liquid-Ar temperatures BINP/Weizmann: Bondar et al, 2008 JINST 3 P07001 Stable operation in two-phase Ar, T=84K Double-THGEM Gains: 8x103 2-THGEM KEVLAR 2-THGEM G-10 3-GEM 1-THGEM G-10 Experimental setup GOOD PROSPECTS FOR CRYOGENIC-PHOTOMULTIPLIER OPERATION IN THE LXe-CAMERA

  21. Radio-clean THGEM for rare-event physics (M.Gai-UCONN / D.McKinsey-YALE / A.Breskin-WEIZMANN) • 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 2-phase THGEM LXe Dark-Matter detector concept THGEM photonDetector EG e- e- WIMP interaction LXe EL Photon The Cirlex-THGEM CsI Photo-Cathode Rachel Chechik Weizmann Institute TIIPP09 Tsukuba March 2009

  22. THGEM CsI photocathode g LXe conversion volume Segmented Anode Gas photomultiplier MgF2 window THGEM-GPM for LXe Gamma Camera Subatech-Nantes/Weizmann Rachel Chechik Weizmann Institute TIIPP09 Tsukuba March 2009

  23. Photon detectors for RICH: reflective CsI PC deposited on the THGEMphotoelectron extraction into gas, surface electric field by the hole dipole 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). Ref PC Distance = 0 e- Efficient Extraction From PC Min. field 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 Immediate interest: COMPASS & ALICE, R&D in RD51 Rachel Chechik Weizmann Institute TIIPP09 Tsukuba March 2009

  24. Relative Photon detectors for RICH: reflective CsI PC deposited on the THGEM Photoelectron collection into the holes by the dipole field MIP Edrift E e E=0 E Ref. PC • Maximum efficiency at Edrift =0. • Slightly reversed Edrift (50-100V/cm) => • good photoelectron collection & low sensitivity to MIPS (~5-10%) ! Reduced sensitivity to MIPS proved with multi-GEM detectors of PHENIX Currently R&D for upgrade of COMPASS & ALICE RICH Rachel Chechik Weizmann Institute TIIPP09 Tsukuba March 2009

  25. New concept: Digital sampling calorimetry for ILCwith A. White Univ. Texas Arlington/Weizmann General scheme of a detector HCal 2 sampling layers with THGEM-based elements Sampling the jet + advanced pattern recognition algorithms -> Very high precision jet energy measurement. Reconstructed jet: Simulated energy resolution Simulated event with 2 hadronic jets Rachel Chechik Weizmann Institute TIIPP09 Tsukuba March 2009

  26. Fast-neutron Imaging-detector Weizmann/PTB/Soreq gas • neutrons scatter on H • in plastic-radiator foil, p escape the foil. • pinduce 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% THGEM 1 THGEM 2 Double THGEMs: • High multiplication factors • High stability • w Ne mixtures: high gain and dynamic range. B, Li, Gd…converter: thermal neutron detector e.g. position sensitive n-dosimetry for BNCT(with Univ.& INFN, Milano) Rachel Chechik Weizmann Institute TIIPP09 Tsukuba March 2009

  27. Fast Neutron Resonant Radiography (FNRR)for element-resolved radiography sample Neutron imaging detector with fast timing capability ! Betarget pulsed, white neutron beam neutron source: nsec-pulsed broad energy deuteron beam Steel C rods All C only Triple-GEM 10 x 10 cm 2 Dangendorf et al. NIM A542(2005)197 Weizmann/PTB/Soreq • Operation principle: • n energy selected by TOF • Image “on” ad “off” resonance • Ratio of images => element selection • 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 cost Rachel Chechik Weizmann Institute TIIPP09 Tsukuba March 2009

  28. Summary Robust, economic, large-area radiation imaging detectors HIGH-GAIN, FAST, HIGH-RATE, MODERATE 2D- RESOLUTION • Single-photon imaging. • e.g. Ring Imaging Cherenkov (RICH) detectors. • FastParticle 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-ray and n imaging. • Possible low-pressure operation: Nuclear Physics applications Rachel Chechik Weizmann Institute TIIPP09 Tsukuba March 2009

  29. 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 Rachel Chechik Weizmann Institute TIIPP09 Tsukuba March 2009

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