IEEE 2011 NSS-MIC Valencia Yiftah Silver October 26 th 2011

 Tel Aviv University, Department of Physics Yan Benhammou, Meny Ben Moshe, Erez Etzion, Yiftah Silver  University of Michigan, Department of Physics Dan Levin, Claudio Ferretti, J. Chapman, Curtis Weaverdyck, Robert Ball  Integrated Sensors, LLC. P. S. Friedman  Oak Ridge National Laboratory Robert Varner 10/26/2011 Yiftah Silver, Tel-Aviv University2 Plasma Panel Sensor (PPS) collaboration

 Widely used, commercial product Invented in units manufactured 2010 ~$0.20 / sq inch with electronics ~100,000 hour lifetime 10/26/2011 3Yiftah Silver, Tel-Aviv University Plasma Display Panel (PDP) matrix configurationcoplanar configuration 2 main technologies

 Hermetically sealed volume  no gas flow  Targeted cell size of about µm  excellent spatial resolution.  Scalable panel size  up to meter size with thickness cm  Fast cell response  rise-time ~1 ns 10/26/2011 Yiftah Silver, Tel-Aviv University4 Plasma Panel Sensor (PPS) aims to inherit PDP features Investigate plasma panels for inexpensive, large area arrays of micro-Geiger cells for detection of MIPs and heavily ionizing particles : gas mixture, pressure, pulse shape… We are trying to use plasma TV’s as radiation detectors

 Test Chamber (coplanar configuration) Surface discharge electrode studies Gas mixture, pressure studies  Commercial PDP (matrix configuration) Starting with commercial DC-PDP  Gas mixtures, pressure and Electric field  Pulse timing – rise time, recovery time  Pulse spreading Simulations (both test chamber and commercial PDP)  COMSOL: electric field and charge motion  electric field and charge motion  Estimate capacitance of cells  SPICE:  Electrical characteristics of PPS signal 10/26/2011 Yiftah Silver, Tel-Aviv University5 Current progress in Plasma Panel Sensor investigation

10/26/2011 Yiftah Silver, Tel-Aviv University6 Prototype PPS coplanar electrodes configuration  Electrode layout with lateral discharge gap e- ion+

10/26/2011 Yiftah Silver, Tel-Aviv University7 Prototype PPS test chamber  motorized Z-stage to vary drift gap  Testing glass PPS substrates  Staging Vacuum-Pressure Chamber  Integrated four component gas mixing system First measurements with the prototype PPS test chamber have recently commenced

10/26/2011 Yiftah Silver, Tel-Aviv University8 Commercial monochromatic PDP study dielectric Discharge gap glass Ni anode 800  m glass 340  m SnO2 cathodes  Columnar discharge Pixels at intersections of orthogonal electrode array  Measurements of background signal and response to a radioactive sources with different gases  Cosmic ray Muons detection Simulated E-field in the PDP pixel 5 mm 0 -5 mm E-field is localized No E-field e-

10/26/2011 Yiftah Silver, Tel-Aviv University9 Simulated β spectrum in panel HV SnO 2 Ni  2D readout is possible (both sense lines and HV) Discriminator and counter Measurements Setup (I) radioactive source response DAQ includes: 4 channels 5 GHz digitizer Collimated 90 Sr source is placed above the active area of the panel KeV

 During discharge cell becomes conductive,  Voltage drops  E field drops  discharge self-terminates  Simplified model of a capacitor discharge yield a very similar signal. (in most of the tested conditions)  A more elaborate Spice model incorporates stray capacitance and inductances 10/26/2011 Yiftah Silver, Tel-Aviv University10 Real VS. simulated signals Signal from panelSimulated results nsec 100 0

10/26/2011 Yiftah Silver, Tel-Aviv University11 Collimated 90 Sr source 20cm above the panel over different parts of the active area – 4X4 pixel array Each bin shows the hit rate on one pixel - background subtracted PDP 2D ReadOut

10/26/2011 Yiftah Silver, Tel-Aviv University12 Measurements Setup (II) – Cosmic ray muons PMT1 PMT2

 Both pure CF4 and SF6 gases shows a signal with a very fast response time.  Arrival time is defined with respect to the hodoscope trigger 10/26/2011 Yiftah Silver, Tel-Aviv University13 Cosmic ray muon detection  Pure SF6  200 Torr  1530 Volt

 With pure CF4 gas We have a discharge plateau with low background… 10/26/ Yiftah Silver, Tel-Aviv University Final voltage scan with cosmic ray muons plateau

 About 8% of all triggers were associated with signal from the panel  In order to increase the geometrical acceptance we are investigating PDPs with higher resolutions i.e. smaller pixels and smaller distances between pixels with different discharge gaps 10/26/2011 Yiftah Silver, Tel-Aviv University15 Cosmic ray muons  Pixel active area ~1.3mm 2  total active area: ~20mm 2  Hodoscope triggering area ~250mm 2  Geometric acceptance for muons ~10%  When taking into account the geometric acceptance, pixel efficiency for muon detection is in order of 80%-90%!

 The detection of cosmic muons with an off-the- shelf generic PDP is established.  Prof of concept measurements have been made with different gasses: Xe, Ar, CF4, SF6, Ar-CO2, Ar-CF4 in various mixtures.  Various operating voltages and pressures are investigated  Discharge pulses:  Have large amplitude - no need for amplification electronics  Uniform (for each gas)  Leading edge rise time of few ns  Observed pulses associated to single pixels (~1mm 2 ) with minimal discharge spreading between pixels 10/26/2011 Yiftah Silver, Tel-Aviv University16 Conclusions

 Further explore the parameters (gas content, pressure, voltage, discharge gap etc.) for optimized detector operation  Improve ReadOut electronics  Increase the number of pixels in the panel’s active area  Efficiency measurements in a muon test beam 10/26/2011 Yiftah Silver, Tel-Aviv University17 Future plans

10/26/2011 Yiftah Silver, Tel-Aviv University18 Thank you… Any questions?

10/26/2011 Yiftah Silver, Tel-Aviv University19 Backup

discharge cell: important gas processes primary ionizati on metastabl e generatio n Excitation Penning ionizati on Image from: Flat Panel Displays and CRTs (Chapter 10) L. Tannas, Jr, photon emission Metastabl e ejection ion ejected electron 10/26/2011 Yiftah Silver, Tel-Aviv University20

10/26/2011 Yiftah Silver, Tel-Aviv University21 Streamer formation

10/26/2011 Yiftah Silver, Tel-Aviv University22 Signal from 4 pixels RO 27(I) 26(II) RO 29(I) 27(II) HV 95(I) 94(II) HV 93(I+II) All the signals from all the measurements look the same! HV 9395