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Article
Some Optical Properties of an Electrostatic Immersion Lens Using the Charge Density Method

Authors: B.H. Hamad --- A.K. Ahmad --- S.M. Jumaa
Journal: Iraqi Journal of Applied Physics المجلة العراقية للفيزياء التطبيقية ISSN: 18132065 23091673 Year: 2005 Volume: 1 Issue: 4 Pages: 21-27
Publisher: iraqi society for alternative and renewable energy sources and techniques الجمعية العراقية لمصادر وتقنيات الطاقة البديلة والمستجدة

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Abstract

A computational investigation has been carried out in the field of nonrelativistic charged-particle optics using the charge density method as a boundary value problem with the aid of a personal computer under the absence of space-charge effects. This work has been concentrated on designing a two-electrode electrostatic immersion lens whose electrodes are cylindrical in shape separated by an air gap. The variable parameters of the two electrodes are the applied voltage ratio and the air gap separating them. The axial potential distribution of an electrostatic immersion lens has been computed by taking into consideration the distribution of the charge density due to the voltages applied on the two cylindrical electrodes. Potentials have been determined anywhere in space by using Coulomb’s law. The optical properties of the immersion lens have been investigated under finite and zero magnification conditions.


Article
Design of a Multi-Electrode Immersion Lens for Ion-Optical Systems

Authors: F.A.J. Almoudarris --- S.M. Jumaa --- A.K. Ahmad
Journal: Iraqi Journal of Applied Physics المجلة العراقية للفيزياء التطبيقية ISSN: 18132065 23091673 Year: 2006 Volume: 2 Issue: 1-2 Pages: 27-30
Publisher: iraqi society for alternative and renewable energy sources and techniques الجمعية العراقية لمصادر وتقنيات الطاقة البديلة والمستجدة

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Abstract

The present work puts forward an electrostatic optical device for application in an ion-optical system. A design has been achieved computationally for a multi-electrode immersion lens of low relativespherical and chromatic aberration coefficients with the aid of thefollowing suggested expression for the potential field: U(z)=[(a*z)/(z2+c)]+b where a, b, and c are constants, z is the optical axis, and U(z) is the axial potential distribution. These results suggest that operating the proposed lens under zero magnification conditions is more favorable. Therefore, the proposed expression for the potential distribution is recommended for representing an electrostatic immersion lens of low relative chromatic aberration coefficient.


Article
(3-5) μm and (8-12) μm Wavelengths Ultra-Short Tunable Laser Pulses Using Optical Parametric Oscillation Technique

Authors: A.A. Al- Dergazly --- F.F. Rasheed --- S.M. Jumaa
Journal: Iraqi Journal of Applied Physics المجلة العراقية للفيزياء التطبيقية ISSN: 18132065 23091673 Year: 2008 Volume: 4 Issue: 4 Pages: 35-39
Publisher: iraqi society for alternative and renewable energy sources and techniques الجمعية العراقية لمصادر وتقنيات الطاقة البديلة والمستجدة

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Abstract

A computational investigation has been carried out on optical parametric oscillation (OPO) technique. Non-collinear phase matching between the pumping wave and the two generated signal and idler waves has been taken into consideration. In order to separate the two generated waves a design has been put forward for a resonator for each wave within the same cavity and interrelated by mirror that transmits the pumped laser beam. The cavity configuration takes into account the three types of phase matching between the three waves. Solid state lasers were considered for pumping the nonlinear crystal. Furthermore, attention has been paid on the solid state Er:YAG laser for pumping the positive uniaxial AgGaSe2 crystal to generate a signal wave of (8-12)μm wavelength so the generated idler wave from 3.82 to 4.55μm wavelength.

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