Studies on X-ray and Ion Emission from Dense Plasma Focus and Its Application in Material Modification.

摘要

In the recent years, the radiations, namely X-rays and ions, from high temperature and high density plasma have become extremely important because of their applications in diverse areas. In micro- and nano-electronics industries, the current predominant trend of shrinkage of integrated circuits demands powerful, clean and bright pulsed X-ray sources. These sources are in hunt for not only electronics industries but also for other disciplines like micro-radiography, microscopy, crystallography etc.. Likewise, the quest for plasma based ion sources has been growing phenomenally during last decades for the synthesis of novel materials. These novel materials have plenty of applications in automotive, aerospace, biomedical and electronics industries. The need of present hour is to develop compact, cost-effective and efficient plasma based radiation sources so as to fulfill industrial requirements.;Chapter 1, in addition to a brief introduction to the importance of plasma physics, provides information on X-ray and ion sources and their current scenario of industrial applications. Besides, this chapter provides a short introduction to DPF device along with current sheet dynamics and other related plasma phenomena.;Chapter 2 presents the design and fabrication details of CPP DPF facility (pulsed power driver, plasma focus tube with pumping system) along with the basic diagnostic techniques (Rogowski coil and resistive voltage divider). In addition, the discharge performance of DPF facility, which is evaluated using Rogowski coil and resistive voltage divider, is presented in this chapter. Chapter 3 contains the study of current sheet dynamics in axial acceleration phase. In order to accomplish the study, we have fabricated a high frequency multiple magnetic probe assembly having response time of ~ 1 ns. The tiny structure of magnetic probe is well suited to sense the magnetic field associated with pulsed plasma, without perturbing the plasma severely.;The work presented in this thesis mainly focuses on how to operate the Dense Plasma Focus facility of Centre of Plasma Physics (CPP DPF) in an enhanced X-ray and ion emission mode. Four research problems are addressed in this thesis: (i) study of current sheet dynamics; (ii) investigation of X-ray emission; (iii) analysis of ion emission; and (iv) utilization of ions for material modification. Salient features of the different chapters of this thesis are described hereafter.