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Design and Construction of a Bent Crystal Spectrometer for Studying Soft X-Rays of Sharif Plasma Focus
, M.Sc. Thesis Sharif University of Technology ; Vosoughi, Naser (Supervisor) ; Etaati, Gholam Reza (Supervisor)
Abstract
A soft X-ray spectrometer based on Johann's method and an embedded curved crystal is designed and fabricated for Sharif University of Technology's Plasma Focus (SUT-PF) in this project. Focusing rays with the same wavelength at a point to increase the ray intensity is the reason of choosing the cylindrical curved crystal spectrometer since its performance is inspired to the Bragg's law.The optimal conditions for SUT-PF (pressure and voltage) is adjusted and examined by photodiode detector and the camera pinhole before spectroscopy experiments. The diameter of generated hot spots is measured as 80 microns in the optimal condition.The recorded spectral lines on the radiography film and the...
Feasibility Study of Deposition by SUT-PF
, M.Sc. Thesis Sharif University of Technology ; Vosoughi, Naser (Supervisor)
Abstract
Sharif University of Technology Plasma Focus (SUT-PF) is a Mather Type DPF device which has a 39 μF capacitor bank with 14 KV charging ability at its ultimate limit corresponding to 7 KJ stored energy. In the first step of this experiment, a test has been done at three distances 5, 7, 10 cm from anode tip with the different number of shots 20, 30, and 40 at 0 constant angles.In the following, a test is done at 5 and 10 degrees with 40 shots, and PF chamber has been filled up with nitrogen gas. Various tests have carried out for survey of this experiment, the result of which are as follow:The X-ray diffraction (XRD) analysis are used in order to reveal if the Nickel or Nickel nitride have...
X-ray optimization in Sharif University of Technolgy’s Plasma Focus
, M.Sc. Thesis Sharif University of Technology ; Vosoughi, Naser (Supervisor) ; Etaati, Gholamreza (Supervisor)
Abstract
In this project we studied Soft and Hard x-ray emissions from Sharif University of Technology’s Plasma Focus (SUT-PF) device filled with Argon gas. SUT-PF is a Mather type plasma focus device ( ). Our expriments have been done in various charging voltages ( ) and various filling pressures. Using different diagnostics X-ray’s intensity in each working condition (voltage and pressure) has been measured and finally these data analysed to find optimum conditions for maximum x-ray production in this device. Used diagnostics was: Rogowski coil, photodiodes combination with ultra thin metal foils, type Plastic scintillation detectors, and pinhole camera. In each shot, time resolved Rogowski coil,...
Analysis of twisted laser beam focusing and defocusing in plasma
, Article Physica Scripta ; Volume 88, Issue 3 , August , 2013 ; 00318949 (ISSN) ; Bahrampour, A. R ; Sharif University of Technology
2013
Abstract
Using the source dependent expansion method and paraxial approximation, the evolution of the beam spot size (BSS) in laser plasma interaction is investigated. Considering a collisionless mechanism, the self-focusing of a Laguerre-Gaussian (LG) light beam in a plasma medium is studied and the evolution of the BSS is solved analytically for the non-saturating nonlinearity state, and numerically for the saturating state. The self-focusing of a doughnut beam depends on the initial BSS, in which if the initial BSS gets bigger, the beam in the medium will be focused faster. We show that if the nonlinear effect of the plasma medium is saturated, the LG beam profile can remain stable and the BSS...
Relativistic Gaussian laser beam self-focusing in collisional quantum plasmas
, Article Laser and Particle Beams ; Volume 33, Issue 3 , 2015 , Pages 397-403 ; 02630346 (ISSN) ; Rezaee, S ; Yazdani, E ; Anvari, A ; Sadighi Bonabi, R ; Sharif University of Technology
Cambridge University Press
2015
Abstract
Propagation of Gaussian X-ray laser beam is presented in collisional quantum plasma and the beam width oscillation is studied along the propagation direction. It is noticed that due to energy absorption in collisional plasma, the laser energy drops to an amount less than the critical value of the self-focusing effect and consequently, the laser beam defocuses. It is found that the oscillation amplitude of the laser spot size enhances while passing through collisional plasma. For the greater values of collision frequency, the beam width oscillates with higher amplitude and defocuses in a shallower plasma depth. Also, it is realized that in a dense plasma environment, the laser self-focusing...
Deposition of metallic molybdenum thin films on 304L steel substrate by SUT-PF
, Article Surface and Coatings Technology ; 2016 ; 02578972 (ISSN) ; Nazmabadi, M ; Vosoughi, N ; Sharif University of Technology
Elsevier B. V
Abstract
The present research work aims to employ plasma focus in order to deposit molybdenum (Mo) on the 304 stainless steel substrate. The processing parameters were shot numbers as well as the distance of substrate from the anode tip. Stereo, atom force microscopy (AFM) and field emission-scanning electron microscopy (FE-SEM) equipped with energy dispersive X-ray spectroscopy (EDS) were used to study the deposited coatings. Microhardness measurements were also performed on the coatings. Results indicated that the plasma focus can be successfully applied to deposit Mo anode on the stainless steel substrate. The coatings contained discrete pores with sizes varying by processing parameters. The...
Nonlinear interaction of intense hypergeometric Gaussian subfamily laser beams in plasma
, Article Optics and Laser Technology ; Volume 81 , 2016 , Pages 40-45 ; 00303992 (ISSN) ; Vaziri, M. (Khamedi) ; Rooholamininejad, H ; Bahrampour, A. R ; Sharif University of Technology
Elsevier Ltd
Abstract
Propagation of Hypergeometric-Gaussian laser beam in a nonlinear plasma medium is investigated by considering the Source Dependent Expansion method. A subfamily of Hypergeometric-Gaussian beams with a non-negative, even and integer radial index, can be expressed as the linear superposition of finite number of Laguerre-Gaussian functions. Propagation of Hypergeometric-Gaussian beams in a nonlinear plasma medium depends on the value of radial index. The bright rings' number of these beams is changed during the propagation in plasma medium. The effect of beam vortex charge number l and initial (input) beam intensity on the self-focusing of Hypergeometric-Gaussian beams is explored. Also, by...
Studying soft X-Rays emitted by SUT-PF using a cylindrical bent crystal spectrometer
, Article Journal of Fusion Energy ; Volume 35, Issue 2 , 2016 , Pages 346-351 ; 01640313 (ISSN) ; Hosseinzadeh, A ; Nazmabadi, M ; Sharif University of Technology
Abstract
Plasma focus is a copious source of electrons, ions, neutrons, and X-rays. SUT-PF is a 7 kJ Mather type plasma focus device. In order to study soft X-rays emitted by this device a bent crystal spectrometer has been designed and constructed based on Johann method. Before recording spectral lines, using a photodiode detector and a pinhole camera, optimum parameters for maximum emission of soft X-rays have been studied and registered. Results show that ionized Argon atomic lines mostly have wavelengths between 3 and 4 Å. Among them 1s2–1s2p transition with a wavelength of 3.943 Å represents the most intense line
Effect of angular position on the quality of dense plasma focus-based additive layer manufactured molybdenum coatings
, Article International Journal of Advanced Manufacturing Technology ; Volume 99, Issue 9-12 , 2018 , Pages 2717-2725 ; 02683768 (ISSN) ; Hosseinzadeh, A ; Nazmabadi, M ; Vosoughi, N ; Sharif University of Technology
Springer London
2018
Abstract
The present research aims at depositing molybdenum on stainless steel substrate using dense plasma focus (DPF) device. The varying parameter was the angular position of substrate surface from the anode tip. The deposited layers were characterized using various analyses such as X-ray diffraction (XRD), scanning electron microscopy (SEM) equipped with energy dispersive X-ray spectroscopy (EDS), atomic force microscopy (AFM), and microhardness measurements. Microstructural observations revealed that the deposited coatings had rough surfaces containing holes as well as a stripe-featured structure covering the whole surface including the interior regions of the holes and the regions among them....
Improving the relativistic self-focusing of intense laser beam in plasma using density transition
, Article Physics of Plasmas ; Volume 16, Issue 8 , 2009 ; 1070664X (ISSN) ; Habibi, M ; Yazdani, E ; Sharif University of Technology
2009
Abstract
The propagation of a Gaussian beam in underdense plasma with upward increasing density ramp is analyzed. In this work are shown that the spot size oscillations of laser beam increases and its amplitude shrinks with proper plasma density ramp. This causes the laser beam to become more focused and penetrations deep into the plasma by reduction of diffraction effect. The related focusing parameters are optimized to get the best possible focusing at the relativistic threshold intensity of Nd-glass laser and the effect of the laser intensity in the self-focusing parameters is also investigated. The analytical calculations are presented and showed more reliable results in comparison to the...