Effects of Space Charges in IMPATT Source at Terahertz Regime

We have performed a theoretical investigation of the effects of space charges in the Environmental SEM (ESEM). The ElectroScan ESEM uses an electrostatic field to cause gas cascade amplification of secondary electron signals. Previous theoretical descriptions of the gas cascade process in the ESEM have assumed that distortion of the electric field due to space charges can be neglected. This assumption has now been tested and shown to be valid.In the ElectroScan ESEM, a positively biased detector is located above the sample, creating an electric field on the order of 105 V/m between the detector and sample surface. Secondary electrons leaving the sample are cascaded though the gas, amplifying the signal and creating positive ions. Because the electrons move very quickly through the gas, they do not accumulate in the specimen-to-detector gap. However, the velocity of the positive ions is limited by diffusion.

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THE INTERACTION OF ELECTRON AND POSITIVE ION SPACE CHARGES IN CATHODE SHEATHS

Plasma and Oscillations ◽

10.1016/b978-1-4831-9913-9.50015-7 ◽

1961 ◽

pp. 140-175

Keyword(s):

Space Charges ◽

Positive Ion

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The Study of Dipolar and Space Charges in Semicrystalline Polymers

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.230-232.575 ◽

2002 ◽

Vol 230-232 ◽

pp. 575-578

Author(s):

Eugen R. Neagu ◽

José N. Marat-Mendes ◽

C.J. Dias ◽

Radu Neagu

Keyword(s):

Semicrystalline Polymers ◽

Space Charges

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Simulation of tree propagation in polyethylene including air void by using cellular automata: The effect of space charges

Electrical Engineering ◽

10.1007/s00202-002-0136-4 ◽

2002 ◽

Vol 84 (4) ◽

pp. 239-240

Author(s):

G.E. Vardakis ◽

M.G. Danikas

Keyword(s):

Cellular Automata ◽

Space Charges ◽

Air Void

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Localized Deep and Shallow Traps of α-Peaks from Thermally Stimulated Current (TSC) Measurement on Thermoplastic Polymers

Solid State Phenomena ◽

10.4028/www.scientific.net/ssp.317.369 ◽

2021 ◽

Vol 317 ◽

pp. 369-376

Author(s):

Norhana Abdul Halim ◽

Siti Zulaikha Ngah Demon ◽

Norli Abdullah ◽

Nurazlin Ahmad ◽

Zul Hazrin Zainal Abidin

Keyword(s):

Deep Trap ◽

Order Kinetic ◽

Thermally Stimulated Current ◽

Thermoplastic Polymers ◽

Debye Relaxation ◽

First Order ◽

Plasticized Pvc ◽

Space Charges ◽

Shallow Traps ◽

Trap Levels

In this paper, trap levels around the glass transition temperature (Tg) of polymers have been characterized using Thermally Stimulated Current (TSC) technique. Deconvolution on α-peaks of the Tg for PE (-104 °C), plasticized PVC (-35 °C), PMMA (90 °C) and PET (96 °C) were carried out based on the first-order kinetic theory for non-Debye relaxation. Using temperature, T from TSC experimental data, we have successfully separated the α-peaks of the thermoplastic polymers. It is found that the complex curve of α-peaks can composed of four (4) to eight (8) sub peaks. Dominant sub peaks were identified at Tmax = -105 °C, -34 °C, 89 °C and 92 °C for PE, pPVC, PMMA and PET, respectively. These peaks show activation energy, Ea of shallow and deep trap centers ranged from 0.3 eV to 4.6 Ev where they represent the depolarization of localized dipoles and space charges relaxations in the polymers.

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