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Development of Plasma Panel Based Neutron Micropattern Detectors

Development of Plasma Panel Based Neutron Micropattern Detectors. Yan Benhammou Tel Aviv University for the PPS Collaboration. Oct 15, 2013. 1. 1. Collaborators. University of Michigan, Department of Physics Robert Ball, J. W. Chapman, Claudio Ferretti, Daniel Levin (PI) ,

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Development of Plasma Panel Based Neutron Micropattern Detectors

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  1. Development of Plasma Panel Based Neutron Micropattern Detectors Yan Benhammou Tel Aviv University for the PPS Collaboration Oct 15, 2013 Y. Benhammou Tel Aviv University 1 1

  2. Collaborators • University of Michigan, Department of Physics Robert Ball, J. W. Chapman, Claudio Ferretti, Daniel Levin (PI), Curtis Weaverdyck, Riley Wetzel, Bing Zhou • Integrated Sensors, LLC Peter Friedman (PI) • Oak Ridge National Laboratory, Physics Division Robert Varner (PI) , James Beene • Tel Aviv University (Israel), School of Physics & Astronomy Yan Benhammou, Meny Ben Moshe, Erez Etzion (PI), Yiftah Silver • General Electric Company, Reuter-Stokes Division (Twinsburg, OH) Kevin McKinny (PI), Thomas Anderson • Ion Beam Applications S.A. (IBA, Belgium) Hassan Bentefour (PI) Y. Benhammou Tel Aviv University 2 2 2

  3. Outline Motivation Plasma panel operational principles and description Neutrons detection Summary Y. Benhammou Tel Aviv University 3 3 3

  4. Motivations • Hermetically sealed • no gas flow • no expensive and cumbersome gas system • Over 40 years of plasma panel manufacturing & cost reductions ($0.03/cm2 for plasma panel TVs) • Potential for scalable dimensions, low mass profile, long life • meter size with thin substrate capability • Potential to achieve contemporary performance benchmarks • Timing resolution  approx 1 ns • Granularity (cell pitch)  50-200 µm • Spatial resolution  tens of µm • Potential applications in • Nuclear and high energy physics, medical imaging, homeland security, etc Y. Benhammou Tel Aviv University 4 4

  5. TV Plasma Panel Structure A Display panel is complicated structure with • MgO layer • dielectrics/rib • phosphors • protective layer Y. Benhammou Tel Aviv University 5 5 5

  6. TV Plasma Panel Structure • For detector, a simplified version with readout & quench resistor • No MgO layer • No dielectric/rib • No phosphors • No protective layer Y. Benhammou Tel Aviv University 6 6 6

  7. Commercial Plasma Panel • Columnar Discharge (CD) – Pixels at intersections of orthogonal electrode array • Electrodes sizes and pitch vary between different panels 220 –450 µm Y. Benhammou Tel Aviv University 7 7

  8. cathode Principles of Operation 10-1000 M HV(-) Charged particle track • Accelerated electrons begin avalanche • Large electric field leads to streamers • Streamers lead to breakdown- roughly follows Paschen’s law. “A Theory of Spark Discharge”, J. M. Meek, Phys. Rev. 57, 1940 50 µm -1mm anode 250 µm -1mm Gas volume in pixel • Gas gap becomes conductive • Voltage drops on quench resistor • E-field inside the pixel drops • Discharge terminates 50-100  Y. Benhammou Tel Aviv University 8 8 8 8

  9. Modified Commercial Panel (fill-factor 23.5%, cell pitch 2.5 mm) “Refillable” gas shut-off valve for R&D testing Y. Benhammou Tel Aviv University 9 9 9

  10. Signals from Panel • pulse from Xe fill 2003, tested 2010 1 mm electrode pitch  panel sealed & tested in 2013, pulse from neutron source & 3He fill Signals amplitudes: volts Good signal to noise ratios. Fast rise times O(ns) Pulse shape uniform for a given panel design 2.5 mm electrode pitch 30 V Y. Benhammou Tel Aviv University 10 10 10 10

  11. Neutron Detectionin collaboration with GE, Reuter-Stokes Objectives: high efficiency neutron detectors with high  rejection develop alternate to 3He as neutron interaction medium This test: explore PPS as a general detector structure for converting neutrons using thin gap 3He gas mixture Gas fill: 80% 3He + 20% CF4 at 730 Torr Panel: 2.5 mm pitch large panel used for CR muons Instrumented pixels = 600, Area: 6 in2 Method:irradiate panel with thermal neutrons from various sources high activity (10 mrem/hr) gammas conduct count rates experiment with & w/o neutron mask plates. Y. Benhammou Tel Aviv University

  12. Setup Gamma transparent, neutron blocking plates (~ 0.1% transmission )  PPS panel neutron sources 252 Cf , 241Am-Be, 239Pu-Be nested in stainless capsule, Pb cylinder, high density polyethylene (HDPE) Y. Benhammou Tel Aviv University

  13. Signal from neutrons • Pulse “arrival” time (includes arbitrary trigger offset) •  = timing resolution (jitter) of the detector 5 ns ~ 3ns Y. Benhammou Tel Aviv University

  14. PPS panel Results neutron source ( 252 Cf ) Neutron blocking plate efficiency plateau Background subtracted data is neutrons only Background:  from source Y. Benhammou Tel Aviv University

  15. results • GE Geant4 simulation of the neutron capture rate based on source activity: 0.70 ± 0.14 Hz • PPS measured rate: 0.67 ± 0.02 Hz Approximately 100% of the captured neutrons were detected Y. Benhammou Tel Aviv University

  16. PPS panel  Rejection • source • ( 137 Cs ) 3x105/sec at instrumented region Reasonably good  rejection before any optimizations offered by: thin substrates lower gas pressure thinner metallization Improving internal dielectrics around pixels Y. Benhammou Tel Aviv University

  17. PPS panel Spatial Position neutron source (239Pu-Be) blocking plate with 5 mm slit Y. Benhammou Tel Aviv University

  18. Summary We have demonstrated functioning of modifiedplasma displays as highly pixelated arrays of micro-discharge counters • Sensitive neutrons [with appropriate conversion (3He) ] & high  rejection • Timing resolution less than 3 ns • Spatial response at level of pixel granularity • New PPS devices start to be designed to replace the He-3 panel tested using B-10 and Gd-157 conversion layers. They should use much thinner substrates to improve gamma/neutron discrimination ratio. Should be ready next year. Y. Benhammou Tel Aviv University 18 18

  19. Microcavity-PPS Y. Benhammou Tel Aviv University 19 19

  20. E-field Equipotential lines glass Microcavity Concept radial discharge gaps cavity depth  longer path lengths individually quenched cells isolation from neighbors COMSOL simulation: Y. Benhammou Tel Aviv University 20 20 20 20 20 20

  21. Microcavity Prototype (Back Plate) Via Plug Y. Benhammou Tel Aviv University 21 21 21 21

  22. Position Sensitivity Y. Benhammou Tel Aviv University 22 22 22

  23. Collimated Source Position Scan 106Ru collimated source • Light-tight , RF shielded box • 1 mm pitch panel • 20 readout lines • 1.25 mm wide graphite collimator Motorized X-Y table Test Panel Y. Benhammou Tel Aviv University 23 23

  24. Source Moved in 0.1 mm Increments (1 mm pitch panel) Y. Benhammou Tel Aviv University 24 24 24

  25. PPS Position Scan Mean fit for β-source moved in 0.1mm increments * *Electrode Pitch 1.0 mm Centroid measurement consistent with electrode pitch Y. Benhammou Tel Aviv University 25 25 25

  26. PPS Proton Test Beam March 2012 IBA ProCure Facility - Chicago Y. Benhammou Tel Aviv University 26 26 26

  27. IBA Proton Beam Test • Beam energy 226 MeV, Gaussian distributed with 0.5 cm width • Proton rate was larger than 1 GHz on the entire spread of the beam Y. Benhammou Tel Aviv University 27 27 27 27

  28. Position Scan • Two position scans (panel filled with 1% CO2 in Ar at 600 Torr) • 1 cm steps - using brass collimator with 1 cm hole, 2.5 cm from beam center • 1 mm steps with 1mm hole directly in beam center • Rate of protons thru 1mm hole in center of beam was measured at 2 MHz The Panel Y. Benhammou Tel Aviv University 28 28 28 28

  29. 1mm Scan Reconstructed centroid of hit map vs. PDP relative displacement with respect to the panel’s initial position Number of hits per channel Y. Benhammou Tel Aviv University 29 29 29 29

  30. PPS Cosmic-Ray Muon Results Y. Benhammou Tel Aviv University 30 30

  31. Cosmic Muon Measurement Setup Trigger is 3”x 4’’ scintillation pads 24 RO channels 30 HV lines Y. Benhammou Tel Aviv University 31 31 31 31

  32. Time Spectrum  = 40.1  0.9 Ar / 1% CF4 at 730 Torr 1100V Pulse “arrival” time (includes arbitrary trigger offset)  = timing resolution (jitter) of the detector We repeat this measurement with various gases and voltages Y. Benhammou Tel Aviv University 32 32

  33. Time Spectrum Ar / 1% CF4 at 730 Torr Y. Benhammou Tel Aviv University

  34. Timing Resolution using 65% He 35 % CF4 at 730 Torr  ~ 10 ns HV =1290 V • trigger time subtracted; • arbitrary cable offset Y. Benhammou Tel Aviv University

  35. PPS Muon Test Beam November 2012 H8 at CERN

  36. Setup 8 HV lines 100 MΩ quenched Ni-SnO2 PPS Ar / 7% CO2 600 Torr HV = 1090 V OR 16 channels 180 GeV BEAM AND AND 2 scintillation pads 4 cm2 each Panel active area is 2cm x 4cm Y. Benhammou Tel Aviv University 36 36

  37. Time Resolution • Timing resolution with Ar-CO2 better than 10 nsec • Geometrical acceptance times efficiency ≈ 2% (pixel efficiency is much higher). Did not have beam time to optimize or even raise the voltage! • Active area fill-factor for PPS detector is 23.5% Y. Benhammou Tel Aviv University 37 37 37 37 37

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