2023-12

Science Journal of University of Zakho (Issue : 4) (Volume : 11)

This paper investigates the impact of an axial magnetic field on several plasma parameters of hollow electrode argon abnormal glow discharge. The discharge is generated by applying a DC voltage ranging from 0-6KV. By varying the pressure and magnetic field strength (0-25mT), the plasma potential, frequency, and degree of ionization were measured. The plasma potential, frequency, and degree of ionization were evaluated using spectroscopic measurements of the electron temperature and density. The results of the experiment show that the plasma potential decreases as the magnetic field strength increases, while the plasma frequency increases for lower pressure but reaches a constant value for higher pressure due to the increasing number of excitation collisions among the plasma-charged particles. The degree of ionization, determined using the ideal gas law, shows a near-linear relationship with the axial magnetic field at both low and high pressure.

2019-12

Science Journal of University of Zakho (Issue : 4) (Volume : 7)

This paper investigates the characteristics some of argon plasma parameters of glow discharge under axial magnetic field. The DC power supply of range (0-6000) V is used as a breakdown voltage to obtain the discharge of argon gas. The discharge voltage-current (VI) characteristic curves and Paschen’s curves as well as the electrical conductivity were studied with the presents of magnetic field confinement at different gas pressures. The magnetic field up to 25 mT was obtained using four coils of radius 6 cm and 320 turn by passing AC current up to 5 Amperes. Spectroscopic measurements are employed for purpose of estimating two main plasma parameters electron temperature (T e) and electron density (n e). Emission spectra from positive column (PC) zone of the discharge have been studies at different values of magnetic field and pressures at constant discharge currents of 1.5 mA. Electron temperature (T e) and its density are calculated from the ratio of the intensity of two emission lines of the same lower energy levels. Experimental results show the abnormal glow region characteristics (positive resistance). Breakdown voltage versus pressure curves near the curves of paschen and decrease as magnetic field increases due to magnetic field confinement of plasma charged particles. Also the electrical conductivity increases due to enhancing magnetic field at different gas pressures. Both temperature density of electron and the intensities of two selected emission lines decrease with increasing pressure due decreasing of mean free path of electron. Electron density increase according to enhancing magnetic field, while the intensity of …

2019-04

2019 International Conference on Advanced Science and Engineering (ICOASE) (Issue : 01) (Volume : 01)

In this paper, the optical properties of a pinhole nanorod are studied using finite element package (COMSOL Multiphysics). Both electric and magnetic field distribution for different radius of a hollow nanorod and variable pinhole position has been measured. Furthermore, the scattering cross-section for both fields is calculated. The magnetic field enhancement has been increased by adding a pinhole made of air. The magnetic field enhancement improved 20 percent. In case of scattering cross-section, the response is changed as a function of the pinhole position and diameter. The results provide the ability to tune optical properties through an appropriate geometric feature of the nanorods.

2015-03

Journal of Modern Physics (Issue : 05) (Volume : 6)

During operating of the X-ray machines, if the protection of X-ray rooms is insufficient, not only the patient but also clinical staffs as well as public are exposed to high X-ray dosage and they are affected from X-ray related to the dose level. In the present survey, by testing the radiological leakage and scatter from X-rays machines in radiology departments of 7 randomly selected hospitals in Duhok governorate, the effects dose of X-ray to the both control panel area and the patients waiting or visiting area who are located near the radiography room, were measured. The dose was recorded for a range of peak kilovoltage (kVp) and mAs values to find efficiency of shielding materials (barriers) of radiography rooms for different X-rays level. The measurements were performed at one meter above the ground surface which was the same height of X-rays tube by using Gamma Scout dosimeter. From the measurement results, it was seen that the most hospitals barriers (doors and walls) were not appropriate to the standards except 2 hospitals. The maximum effective doses were measured in uncontrolled area of Khazer hospital which was 82.48 ± 0.73 mSv·yr-1 that was much more than the reference dose limits and in controlled area of Haval Banda Zaroka hospital which was 12.98 ± 0.16 mSv·yr-1. In result, the knowledge about the radiation dose affecting the radiologists and public in the selected hospitals was obtained, and by informing the radiologists and the hospitals managements, the necessary regulations would be planned.