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Gas Based Detectors

Gas Based Detectors. B.K. Singh Physics Department, BHU. Diffusion influences the spatial resolution. 1 st Townsend Coefficient is the probability of an ionization per unit path length. Admixture of electronegative gases influences the detection efficiency & Energy resolution of detector.

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Gas Based Detectors

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  1. Gas Based Detectors B.K. Singh Physics Department, BHU DST SERC EHEP SCHOOL (Nov 7-27, 2017)

  2. DST SERC EHEP SCHOOL (Nov 7-27, 2017)

  3. DST SERC EHEP SCHOOL (Nov 7-27, 2017)

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  5. Diffusion influences the spatial resolution. DST SERC EHEP SCHOOL (Nov 7-27, 2017)

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  7. 1st Townsend Coefficient is the probability of an ionization per unit path length. DST SERC EHEP SCHOOL (Nov 7-27, 2017)

  8. Admixture of electronegative gases influences the detection efficiency & Energy resolution of detector.. DST SERC EHEP SCHOOL (Nov 7-27, 2017)

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  10. Mobility of charges influences the timing behavior of gas detectors. DST SERC EHEP SCHOOL (Nov 7-27, 2017)

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  14. Avalanche process via ionization important for gain factor & gas detectors DST SERC EHEP SCHOOL (Nov 7-27, 2017)

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  21. cathode e- e- anode wires ion cathode OLD GOOD WIRE CHAMBERS - GAIN RESOLUTION CHARPAK 1968 ATLAS 2015 ~50 years… 1924 – 2010 1992 WIRE CHAMBERS Gain ~ 104 Resolution ~ 100mm Timing ~ 10s-100s ns Rate ~ 104 Hz/mm2 Thin-Gap wire Chambers (TGC) being upgraded for LHC… Status:50mm resolution

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  23. ANODESTRIP CATHODE STRIPS Leading MICRO-PATTERN GAS DETECTORS Oed 1988 Sauli 1997 Giomataris 1998 MICRO-STRIP CHAMBER MSGC GAS ELECTRON MULTIPLIER (GEM) MICROMEGAS DRIFT ELECTRODE Resolution: Few 10smm <100 mm 140 mm Drift + thin multiplication-strips on insulator MICRO-PIXEL THGEM 2004 Resolution: Few 100smm

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  26. From MWPC to Micro-pattern detector: Electron multiplication Typical cell size>1 mm Multiwire Proportional Chamber GEM/THGEM Microstrip Gas Chamber μcat, μGroove, μDot Micromegas Typical cell size ~ 100μm Due to small dimensions, Streamers develop easily into sparks! DST SERC EHEP SCHOOL (Nov 7-27, 2017)

  27. GEM Etching Technology..(CERN) GEM are being made now by various techniques such as laser based etc. DST SERC EHEP SCHOOL (Nov 7-27, 2017)

  28. THGEM.. A new device which has to be studied! DST SERC EHEP SCHOOL (Nov 7-27, 2017)

  29. Edrift EHole Etrans Multiplication of electrons induced by radiation in gas or from solid converters (e.g. a photocathode) Semi-transparent photocathode Reflective photocathode Multiplication inside holes reduces secondary effects. (No Photon feedback) THGEMs screen the photocathode DST SERC EHEP SCHOOL (Nov 7-27, 2017)

  30. GEM AND THGEM: 1mm Cu G-10 Chechik et al. NIM A535 (2004) 303 Shalem et al. NIM A558 (2006) 475 Manufactured by standard PCB techniques of precise drilling in G-10 (+ other materials) and Cu etching. ECONOMIC & ROBUST! Hole diameter d=0.3 - 1 mm Distance between holes a=0.7- 7 mm Plate thickness t=0.4 - 3 mm THGEM Standard GEM 105 gain in single-TGEM 103gain in single-GEM A Breskin/weizmann 0.1mm F. Sauli (CERN) 0.1mm rim:prevents discharges  high gains! DST SERC EHEP SCHOOL (Nov 7-27, 2017)

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  33. GEM Performance DST SERC EHEP SCHOOL (Nov 7-27, 2017)

  34. GEM@COMPASS DST SERC EHEP SCHOOL (Nov 7-27, 2017)

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  36. DST SERC EHEP SCHOOL (Nov 7-27, 2017)

  37. MICROMEGAS Performance DST SERC EHEP SCHOOL (Nov 7-27, 2017)

  38. Micromegas @COMPASS (CERN) DST SERC EHEP SCHOOL (Nov 7-27, 2017)

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  42. Application to physics experiments DST SERC EHEP SCHOOL (Nov 7-27, 2017)

  43. Gaseous photon detectors: photoelectron production Figure: Typical wire chamber (MWPC) based Geometry with a solid photoconverter. Figure :Photoelectron production via a photo- Sensitive gas mixture or by a solid photocathode. DST SERC EHEP SCHOOL (Nov 7-27, 2017)

  44. G. Croci et al., NIM A732 (2013) 217. Triple GEM detectors with a solid state thermal neutrons converter cathode. Histogram of events counting rate in one run. Protons current and GEM events Counting rate as a function of time. DST SERC EHEP SCHOOL (Nov 7-27, 2017)

  45. PHENIX HBD Concept @ BNL ALICE/HMPID concept of CsI RICH -CsI coated directly on GEM -CF4 gas as radiator -Reverse drift field (Hadron blind) -Proximity focussing geometry (leptons produce a blob of 35 photons in about 10 cm2) - liquid C6 F14 radiator - proximity focussing geometry - small gap MWPC (~2 mm) - cathode pads coated with CsI MWPC pad cathode covered with CsI film front-end electronics NA44 / TIC @ CERN (0.3 m2) finished STAR / RICH @ BNL (1 m2) finished PHENIX / HBD @ BNL (0.7 m2) finished HADES / RICH @ GSI (1.5 m2) finished ALICE / HMPID @ CERN (11m2) running COMPASS / RICH1 @ CERN (5.8 m2) running Experiments with CsI RICH (active area m2) DST SERC EHEP SCHOOL (Nov 7-27, 2017)

  46. e- Hadron Blind Detector (PHENIX Experiment at BNL, US) Cherenkov photons To detect Cherenkov radiating electrons: primary ionization • Deposit 350 nm CsI photocathode layer on top GEM E-field photo electron • Electron radiates Cherenkov light in CF4 avalanche electrons • Photoelectrons follow field lines through GEM holes to avalanche region • Primary ionization in drift gap is swept towards mesh in RB E-field • 3-stage avalanche leads to gain between 103 – 104. R/O Pad DST SERC EHEP SCHOOL (Nov 7-27, 2017)

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  49. Fig. 1:The time projection polarimetry uses a simple strip anode to form pixelized image of photoelectron tracks. Fig. 2b: The resulting image on the right shows the interaction point, emission angle, and end of the track. Each circle has a size proportional to the deposited charge in each virtual pixel. Fig. 2a:The TPC forms an image by digitizing the signal on each anode strip. Signal proportional to the charge deposited on each strip are shown on the left. DST SERC EHEP SCHOOL (Nov 7-27, 2017)

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