الفهرس 
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Abstract
In this work, a cold conical cathode ion source has been designed and constructed for production of high brightness ion beam for different applications. It consists of copper anode disc of diameter equals 37 mm and copper conical cathode of inner diameter equals 23 mm, outer diameter equals 37 mm and central aperture of diameter equals 2 mm. Two confinement rings made from perspex insulator of outer diameter equals 37 mm, different inner diameters equal to 5, 7, 9 and 11 mm respectively and thickness equals 2 mm have been used. The two confinement rings are fixed, one on the anode disc inner surface and the other on the conical cathode inner surface to confine the discharge in the central zone between them. The anode disc and the conical cathode are placed inside an insulating cylinder made from perspex material of length equals 5 cm, inner diameters equals 4 cm and outer diameter equals 5 cm.
The working gas has been admitted to the ion source through a hole of 1 mm diameter in the outer surface of the perspex insulating cylinder. The copper collector plate which is used to collect the output ion beam has been situated at a distance equals 4 cm from the ion exit aperture of the conical cathode.
The discharge characteristics of the ion source such as discharge current, discharge voltage and output ion beam current have been measured at different anode – cathode distances equal to 6, 8, 10 and 12 mm with different inner diameters of two confinement rings equal to 5, 7, 9 and 11 mm for different pressures using nitrogen and argon gases. It has been found that the optimum anode – cathode distance equals 10 mm with the optimum inner diameter of the two confinement rings equals 7 mm for stable electrical discharge current and a maximum output ion beam current. The maximum output ion beam current which obtained equal to 325 A and 220 A at discharge current equals 1.4 mA using nitrogen and argon gases.
The ion collector plate ِhas been placed at different distances from the ion exit aperture of the cathode equal to 2, 3, 4, 4.5, 5, 5.5 and 6 cm respectively at pressure equals 4 x 10-4 mmHg and discharge current equals 1.2 mA for obtaining a maximum ion beam current with low divergence angle. It has been found that the maximum value of the output ion beam current emerging from the ion source reaches 340 A and 255 A using nitrogen and argon gases at distance between ion exit aperture of the cathode and ion collector plate equals 5 cm which corresponding ion beam divergence angle equal to 1.14o and 2.29o respectively.
Also, the effect of applying negative voltage on the copper collector plate on the output ion beam current has been studied at different distances between ion exit aperture of the conical cathode and ion collector plate equal to 3, 4, 5 and 6 cm at pressure equals 4 x 10-4 mm Hg, and discharge current equal 0.4 mA using nitrogen and argon gases. It is found that the output ion beam current increases until reach about 75 % its initial value at negative voltage applied to the ion collector plate equals 1400 volt.
The aspect ratio, S, of the ion source (the ratio between the radius of the ion exit aperture from the cathode to the distance between the ion exit aperture from the cathode and ion collector plate) has been determined at pressure equals 4 x 10-4 mmHg and discharge current equals 1.2 mA using nitrogen and argon gases. It has been found that the maximum values of output ion beam current is obtained at aspect ratio equals .02 and reach 340 A and 255 A for nitrogen and argon gases respectively.
The feasibility of enhancing the physical properties of Makrofol polycarbonate detector using Ar+ ion beam irradiation has been investigated.
The effects of Ar+ ion beam irradiation on the structural and optical properties of Makrofol polycarbonate have been investigated. Samples from 300m thickness Makrofol sheet were exposed to Ar+ ions beam in the fluence range 5 x 1016 – 5 x 1018 ion / cm2.
The transmission of these samples in the wavelength range 250 – 2300 nm, as well as any color changes, was studied. Using the transmission data both the tristimulus and CIELAB coordinates values were calculated for both irradiated and non irradiated samples. Also, the color difference between the non irradiated sample and those irradiated with different doses were calculated. The results indicated that the Makrofol detector has a response to color changes by Ar+ ion beam irradiation.
In addition, the Ar+ ions beam induced modifications in the chemical and physical structure of Makrofol polycarbonate were studied using Fourier Transform Infrared Spectroscopy (FTIR). The intensities of the characteristic absorption bands were affected predominantly with the increasing Ar+ ion dose indicating the degradation followed by crosslinking of this polymer by Ar+ ions irradiation.