ABSTRACTWe have studied the current waveform as well as the time- and spectrally-resolved optical... more ABSTRACTWe have studied the current waveform as well as the time- and spectrally-resolved optical emission from a monochrome ac plasma display panel as a function of driving voltage. The voltage driver provided a 18 ns risetime pulse which allowed for a clean separation between the displacement current pulse, ∼25 ns wide, and the discharge pulse. The commercial panel was specially filled with pure He to facilitate comparisons with numerical modeling of the discharge based on relatively new computational procedures which are applied to a local-field approximation for the plasma. The delay in the discharge pulse and the light emission at 668 nm (3d 1D→2p 1P), ranges from ∼100 ns just above the sustain threshold (± 110V) to ∼30 ns at higher voltage (±150 V).
Inner-Shell and X-Ray Physics of Atoms and Solids, 1981
The electron spectra of autoionizing levels in helium excited by photons, electrons and light ion... more The electron spectra of autoionizing levels in helium excited by photons, electrons and light ions has been the subject of extensive studies1. Due to Wigner’s spin conservation rule no appreciable formation of triplet levels in doubly excited HeI** has been found by proton impact on He target gas. However, triplet states can be formed via electron exchange2, using bombardment of structured ions such as He+. For sufficiently low-velocity ions autoionization may be influenced by the proximity of the projectile during the decay of the helium excited states. Decay of excited states of the quasi-molecule formed during slow collisions has been observed to produce shifts in the energy of excited states3 as well as Stark mixing of magnetic substates which decay in the electric field of the projectile. The latter effect influences the angular distributions of ejected electrons.4 Little is known regarding the excitation of helium autoionization states by heavy multiply charged ions. Excitation by fast 30 MeV 05+ resulted in strong excitation of He(2s2p)1D series with essentially no triplet state excitation5. The present measurements extend the range of velocity and charge states of the incident ions to provide greater detail on the relative importance of collision parameters on the excitation and de-excitation process.
Photoionization of the N 2p 2 3p 2 S 1/2 state. Constantine E. Theodosiou Department of Physics a... more Photoionization of the N 2p 2 3p 2 S 1/2 state. Constantine E. Theodosiou Department of Physics and Astronomy, The University of Toledo, Toledo, Ohio 43606. Received 30 October 1987 The 3p photoionization cross section ...
Short-time behavior in multiphoton ionization. Constantine E. Theodosiou * and Lloyd Armstrong, J... more Short-time behavior in multiphoton ionization. Constantine E. Theodosiou * and Lloyd Armstrong, Jr. Department of Physics, The Johns Hopkins University, Baltimore, Maryland 21218. M. Crance and S. Feneuille Laboratoire ...
We have studied current approaches to numerical simulation of the plasma discharge associated wit... more We have studied current approaches to numerical simulation of the plasma discharge associated with the firing of a single pixel in a plasma display panel of opposing and co-planar electrode structures. We found that in all methods studied, the adoption of a suitable 3-dimensional model as a basis from which to simulate the pixel results in a prohibitively large number of calculations, which in turn reduces the effectiveness of these methods from an industrial development standpoint. Consequently, we have undertaken the task to pinpoint which areas of a 3-dimensional simulation might paralellized, with the preliminary goal of reducing the run time of the simulation by fifty to seventy percent. We will present results of our efforts and their implementation in ``JSimulator," a particle simulator package.
Photoionization of excited Cs i states. Constantine E. Theodosiou Department of Physics and Astro... more Photoionization of excited Cs i states. Constantine E. Theodosiou Department of Physics and Astronomy, The University of Toledo, Toledo, Ohio 43606. Received 21 October 1985 Recent measurements and Hartree-Slater calculations ...
We have made both experimental measurements and model calculations in a plasma display panel pixe... more We have made both experimental measurements and model calculations in a plasma display panel pixel cell. We have measured the breakdown voltage, range of bistability, and the light emission from the discharge. The measurements were made in a model chamber where the gas pressures and concentrations were varied. The calculations were made using a 1-D code with variable gas components. Calculations for the breakdown voltage, bistability range, and uv light output have been made.
In low-pressure discharges, where the electron mean free path is larger or comparable with the di... more In low-pressure discharges, where the electron mean free path is larger or comparable with the discharge length, the electron dynamics is essentially nonlocal. Moreover, the electron energy distribution function ~EEDF! deviates considerably from a Maxwellian. Therefore, an accurate kinetic description of the low-pressure discharges requires knowledge of the nonlocal conductivity operator and calculation of the non-Maxwellian EEDF. The previous treatments
We have built a vacuum chamber for the study of gas mixtures in plasma display panels. The vacuum... more We have built a vacuum chamber for the study of gas mixtures in plasma display panels. The vacuum chamber is designed to deposit the MgO secondary electron layer in situ onto the electrode structure and then to backfill the chamber with a gas mixture. The electrode structure can then drive a gas discharge. We can then measure electrical and optical properties of the discharge as a function of pressure and gas composition. By depositing the MgO layer in situ we can insure that the MgO surface is clean, and near simulates real PDP conditions. We will present data on the break down voltage, window of bistability, and light emission all as a function of pressure and composition.
ABSTRACTWe have studied the current waveform as well as the time- and spectrally-resolved optical... more ABSTRACTWe have studied the current waveform as well as the time- and spectrally-resolved optical emission from a monochrome ac plasma display panel as a function of driving voltage. The voltage driver provided a 18 ns risetime pulse which allowed for a clean separation between the displacement current pulse, ∼25 ns wide, and the discharge pulse. The commercial panel was specially filled with pure He to facilitate comparisons with numerical modeling of the discharge based on relatively new computational procedures which are applied to a local-field approximation for the plasma. The delay in the discharge pulse and the light emission at 668 nm (3d 1D→2p 1P), ranges from ∼100 ns just above the sustain threshold (± 110V) to ∼30 ns at higher voltage (±150 V).
Inner-Shell and X-Ray Physics of Atoms and Solids, 1981
The electron spectra of autoionizing levels in helium excited by photons, electrons and light ion... more The electron spectra of autoionizing levels in helium excited by photons, electrons and light ions has been the subject of extensive studies1. Due to Wigner’s spin conservation rule no appreciable formation of triplet levels in doubly excited HeI** has been found by proton impact on He target gas. However, triplet states can be formed via electron exchange2, using bombardment of structured ions such as He+. For sufficiently low-velocity ions autoionization may be influenced by the proximity of the projectile during the decay of the helium excited states. Decay of excited states of the quasi-molecule formed during slow collisions has been observed to produce shifts in the energy of excited states3 as well as Stark mixing of magnetic substates which decay in the electric field of the projectile. The latter effect influences the angular distributions of ejected electrons.4 Little is known regarding the excitation of helium autoionization states by heavy multiply charged ions. Excitation by fast 30 MeV 05+ resulted in strong excitation of He(2s2p)1D series with essentially no triplet state excitation5. The present measurements extend the range of velocity and charge states of the incident ions to provide greater detail on the relative importance of collision parameters on the excitation and de-excitation process.
Photoionization of the N 2p 2 3p 2 S 1/2 state. Constantine E. Theodosiou Department of Physics a... more Photoionization of the N 2p 2 3p 2 S 1/2 state. Constantine E. Theodosiou Department of Physics and Astronomy, The University of Toledo, Toledo, Ohio 43606. Received 30 October 1987 The 3p photoionization cross section ...
Short-time behavior in multiphoton ionization. Constantine E. Theodosiou * and Lloyd Armstrong, J... more Short-time behavior in multiphoton ionization. Constantine E. Theodosiou * and Lloyd Armstrong, Jr. Department of Physics, The Johns Hopkins University, Baltimore, Maryland 21218. M. Crance and S. Feneuille Laboratoire ...
We have studied current approaches to numerical simulation of the plasma discharge associated wit... more We have studied current approaches to numerical simulation of the plasma discharge associated with the firing of a single pixel in a plasma display panel of opposing and co-planar electrode structures. We found that in all methods studied, the adoption of a suitable 3-dimensional model as a basis from which to simulate the pixel results in a prohibitively large number of calculations, which in turn reduces the effectiveness of these methods from an industrial development standpoint. Consequently, we have undertaken the task to pinpoint which areas of a 3-dimensional simulation might paralellized, with the preliminary goal of reducing the run time of the simulation by fifty to seventy percent. We will present results of our efforts and their implementation in ``JSimulator," a particle simulator package.
Photoionization of excited Cs i states. Constantine E. Theodosiou Department of Physics and Astro... more Photoionization of excited Cs i states. Constantine E. Theodosiou Department of Physics and Astronomy, The University of Toledo, Toledo, Ohio 43606. Received 21 October 1985 Recent measurements and Hartree-Slater calculations ...
We have made both experimental measurements and model calculations in a plasma display panel pixe... more We have made both experimental measurements and model calculations in a plasma display panel pixel cell. We have measured the breakdown voltage, range of bistability, and the light emission from the discharge. The measurements were made in a model chamber where the gas pressures and concentrations were varied. The calculations were made using a 1-D code with variable gas components. Calculations for the breakdown voltage, bistability range, and uv light output have been made.
In low-pressure discharges, where the electron mean free path is larger or comparable with the di... more In low-pressure discharges, where the electron mean free path is larger or comparable with the discharge length, the electron dynamics is essentially nonlocal. Moreover, the electron energy distribution function ~EEDF! deviates considerably from a Maxwellian. Therefore, an accurate kinetic description of the low-pressure discharges requires knowledge of the nonlocal conductivity operator and calculation of the non-Maxwellian EEDF. The previous treatments
We have built a vacuum chamber for the study of gas mixtures in plasma display panels. The vacuum... more We have built a vacuum chamber for the study of gas mixtures in plasma display panels. The vacuum chamber is designed to deposit the MgO secondary electron layer in situ onto the electrode structure and then to backfill the chamber with a gas mixture. The electrode structure can then drive a gas discharge. We can then measure electrical and optical properties of the discharge as a function of pressure and gas composition. By depositing the MgO layer in situ we can insure that the MgO surface is clean, and near simulates real PDP conditions. We will present data on the break down voltage, window of bistability, and light emission all as a function of pressure and composition.
Uploads
Papers