Author: Ying Gao
Publisher:
ISBN:
Category :
Languages : en
Pages :

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Author: Raspberry Simpson
Publisher:
ISBN:
Category :
Languages : en
Pages : 0

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Since the innovation of chirped pulse amplification by Donna Strickland and Gerard Morou in 1985, laser technology has evolved such that we can create short pulses of light (10−15 − 10−12 seconds) with high peak powers (1015 Watts) in small, focused spots (∼a few microns). A prolific area of research that has emerged over the last two decades is the use of these high-intensity lasers to drive particle beams. Possible applications of these particle sources include isotope production for medical applications, proton cancer therapy, and fusion energy schemes. This thesis focuses on laser-driven proton acceleration and adds to the existing foundation of work in the area by investigating new empirical relationships, conducting new measurements of the accelerating electric field responsible for laser-driven proton acceleration, and developing a new data analysis methodology using machine learning. This work first examines laser-driven proton acceleration in the multi-picosecond regime (>1ps) at laser intensities of 1017 - 1019 W/cm2. This is motivated by recent results on laser platforms like the National Ignition Facility-Advanced Radiographic Capability laser and the OMEGA-Extended Performance laser, which have demonstrated enhanced accelerated proton energies when compared to established scaling laws. A detailed scaling study was performed on the Titan laser, which provided the basis for a new analytical scaling presented in this thesis. In addition, high-repetition-rate (HRR) lasers that can operate at 1 Hz or faster are now coming online around the world, opening a myriad of opportunities for accelerating the rate of learning on laser-driven particle experiments. To unlock these applications, HRR diagnostics combined with real-time analysis tools must be developed to process experimental measurements and outputs at HRR. Towards this goal, this thes is presents a novel automated data analysis framework based on machine learning and proposes a new methodology based on representation learning to integrate heterogeneous data constrain parameters that are not directly measurable. Taken together, these thrusts enable a new preliminary framework for enhanced analysis of complex HRR experiments and a foundational step towards realizing the goal of tunable laser-driven particle sources.

Author: Simon Carrier-Vallieres
Publisher:
ISBN:
Category :
Languages : en
Pages : 0

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Particle accelerators attract a lot of attention in the scientific and non-scientific community as a result of their wide applicability in fields ranging from fundamental sciences, medicine to industrial applications. This doctoral work stands at the forefront of laser-based ion accelerators, and pushes forward their development to make them more competitive ion sources compared to conventional particle accelerators. For achieving higher competitiveness, laser-driven ion sources must be compact, cost-effective, reliable, intense and operated at high repetition-rates, which all together yield ion beam characteristics that cannot be realistically matched by any other kind of ion accelerator. To do so, the general effort of this doctoral work tackled three different aspects of laser-based ion acceleration, namely precise target alignment, improved targetry using nanostructures and the development of efficient particle diagnostics. The endeavor required to perform equivalent amounts of numerical work, through simulations using High Performance Computing, as well as experimental work, by implementing a cutting-edge ion beamline at the Advanced Laser Light Source (ALLS) 100 TW facility and to carry out several experimental campaigns abroad.The first part of the work aims at improving the reliability of ion beams through the precise positioning of solid targets used in laser-driven ion acceleration. For this purpose, a Target Positioning Interferometer (TPI) that reaches subwavelength positioning precision was developed. The TPI's novel design is a modified Michelson interferometer that incorporates an aspherical converging lens in the target arm to transform it from a relative to an absolute positioning device, having a single unambiguity point in space. The high positioning accuracy is also achieved by a numerical fringe analysis algorithm that maximizes the extraction of signals with high signal-to-noise ratio, in an optimized timeframe. The development of a fast algorithm is crucial to make the TPI a viable solution for its implementation in a laser-based ion accelerator.The second part of the work is focused on enhancing the acceleration mechanism to generate higher ion numbers and kinetic energies, leading to more intense ion bunches. The solid targets used are typically flat metallic targets which allow for less than 10% of laser energy absorption, thereby limiting the laser-to-ion conversion efficiency to a few percent. A way to increase this conversion efficiency is by using target surface nanostructuration to trap the incoming laser pulse, ultimately leading to a greater energy transfer to the ions. We have shown, both theoretically and experimentally, that a careful optimization of a nanostructure's geometrical parameters, in particular for nanospheres and nanowires, leads to multiple-fold enhancements of ion numbers and kinetic energies, compared to the use of the same laser pulse incident on flat targets of the same material.The final part of the work is dedicated to the development of efficient particle diagnostics suitable for being implemented on high repetition-rate laser-based ion beamlines. We first performed the absolute number calibration of the new EBT-XD type of radiochromic films (RCF). The EBT-XD exhibit larger dose detection range and higher minimum energy threshold compared to their EBT3 counterpart, hence more suitable for intense ion beamlines. A severe response quenching was remarked when the Bragg peak of the measured particle falls directly within the active layer of the RCF, causing significant particle number misestimation errors. Finally, we have developed a Thomson Parabola (TP) and Time-of-Flight cross-calibrated set of particle diagnostics that were incorporated on the ALLS 100 TW ion beamline. The TP spectrometer uses a microchannel plate (MCP) detector that was calibrated from single proton impacts to reconstruct the response function of the MCP detection system.

Author: C.K. Birdsall
Publisher: CRC Press
ISBN: 1482263068
Category : Science
Languages : en
Pages : 504

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Divided into three main parts, the book guides the reader to an understanding of the basic concepts in this fascinating field of research. Part 1 introduces you to the fundamental concepts of simulation. It examines one-dimensional electrostatic codes and electromagnetic codes, and describes the numerical methods and analysis. Part 2 explores the mathematics and physics behind the algorithms used in Part 1. In Part 3, the authors address some of the more complicated simulations in two and three dimensions. The book introduces projects to encourage practical work Readers can download plasma modeling and simulation software — the ES1 program — with implementations for PCs and Unix systems along with the original FORTRAN source code. Now available in paperback, Plasma Physics via Computer Simulation is an ideal complement to plasma physics courses and for self-study.

Author: Peter Mulser
Publisher: Springer Science & Business Media
ISBN: 3540506691
Category : Science
Languages : en
Pages : 424

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Introduction and handbook to high-power laser-matter interaction, laser generated plasma, nonlinear waves, particle acceleration, nonlinear optics, nonlinear dynamics, radiation transport, it provides a systematic review of the major results and developments of the past 25 years.

Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 6

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Particle accelerators enable scientists to study the fundamental structure of the universe, but have become the largest and most expensive of scientific instruments. In this project, we advanced the science and technology of laser-plasma accelerators, which are thousands of times smaller and less expensive than their conventional counterparts. In a laser-plasma accelerator, a powerful laser pulse exerts light pressure on an ionized gas, or plasma, thereby driving an electron density wave, which resembles the wake behind a boat. Electrostatic fields within this plasma wake reach tens of billions of volts per meter, fields far stronger than ordinary non-plasma matter (such as the matter that a conventional accelerator is made of) can withstand. Under the right conditions, stray electrons from the surrounding plasma become trapped within these "wake-fields", surf them, and acquire energy much faster than is possible in a conventional accelerator. Laser-plasma accelerators thus might herald a new generation of compact, low-cost accelerators for future particle physics, x-ray and medical research. In this project, we made two major advances in the science of laser-plasma accelerators. The first of these was to accelerate electrons beyond 1 gigaelectronvolt (1 GeV) for the first time. In experimental results reported in Nature Communications in 2013, about 1 billion electrons were captured from a tenuous plasma (about 1/100 of atmosphere density) and accelerated to 2 GeV within about one inch, while maintaining less than 5% energy spread, and spreading out less than 1/2 milliradian (i.e. 1/2 millimeter per meter of travel). Low energy spread and high beam collimation are important for applications of accelerators as coherent x-ray sources or particle colliders. This advance was made possible by exploiting unique properties of the Texas Petawatt Laser, a powerful laser at the University of Texas at Austin that produces pulses of 150 femtoseconds (1 femtosecond is 10-15 seconds) in duration and 150 Joules in energy (equivalent to the muzzle energy of a small pistol bullet). This duration was well matched to the natural electron density oscillation period of plasma of 1/100 atmospheric density, enabling efficient excitation of a plasma wake, while this energy was sufficient to drive a high-amplitude wake of the right shape to produce an energetic, collimated electron beam. Continuing research is aimed at increasing electron energy even further, increasing the number of electrons captured and accelerated, and developing applications of the compact, multi-GeV accelerator as a coherent, hard x-ray source for materials science, biomedical imaging and homeland security applications. The second major advance under this project was to develop new methods of visualizing the laser-driven plasma wake structures that underlie laser-plasma accelerators. Visualizing these structures is essential to understanding, optimizing and scaling laser-plasma accelerators. Yet prior to work under this project, computer simulations based on estimated initial conditions were the sole source of detailed knowledge of the complex, evolving internal structure of laser-driven plasma wakes. In this project we developed and demonstrated a suite of optical visualization methods based on well-known methods such as holography, streak cameras, and coherence tomography, but adapted to the ultrafast, light-speed, microscopic world of laser-driven plasma wakes. Our methods output images of laser-driven plasma structures in a single laser shot. We first reported snapshots of low-amplitude laser wakes in Nature Physics in 2006. We subsequently reported images of high-amplitude laser-driven plasma "bubbles", which are important for producing electron beams with low energy spread, in Physical Review Letters in 2010. More recently, we have figured out how to image laser-driven structures that change shape while propagating in a single laser shot. The latter techniques, which use t ...

Author: National Research Council
Publisher: National Academies Press
ISBN: 030908637X
Category : Science
Languages : en
Pages : 177

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Recent scientific and technical advances have made it possible to create matter in the laboratory under conditions relevant to astrophysical systems such as supernovae and black holes. These advances will also benefit inertial confinement fusion research and the nation's nuclear weapon's program. The report describes the major research facilities on which such high energy density conditions can be achieved and lists a number of key scientific questions about high energy density physics that can be addressed by this research. Several recommendations are presented that would facilitate the development of a comprehensive strategy for realizing these research opportunities.

Author: Dino A. Jaroszynski
Publisher: CRC Press
ISBN: 1584887796
Category : Science
Languages : en
Pages : 454

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A Solid Compendium of Advanced Diagnostic and Simulation ToolsExploring the most exciting and topical areas in this field, Laser-Plasma Interactions focuses on the interaction of intense laser radiation with plasma. After discussing the basic theory of the interaction of intense electromagnetic radiation fields with matter, the book covers three ap

Author: Antonio Giulietti
Publisher: Springer
ISBN: 3319315633
Category : Science
Languages : en
Pages : 326

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This book deals with the new method of laser-driven acceleration for application to radiation biophysics and medicine. It provides multidisciplinary contributions from world leading scientist in order to assess the state of the art of innovative tools for radiation biology research and medical applications of ionizing radiation. The book contains insightful contributions on highly topical aspects of spatio-temporal radiation biophysics, evolving over several orders of magnitude, typically from femtosecond and sub-micrometer scales. Particular attention is devoted to the emerging technology of laser-driven particle accelerators and their application to spatio-temporal radiation biology and medical physics, customization of non-conventional and selective radiotherapy and optimized radioprotection protocols.

Author: Paul Gibbon
Publisher: World Scientific
ISBN: 1911298844
Category : Science
Languages : en
Pages : 328

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This book represents the first comprehensive treatment of the subject, covering the theoretical principles, present experimental status and important applications of short-pulse laser-matter interactions.Femtosecond lasers have undergone dramatic technological advances over the last fifteen years, generating a whole host of new research activities under the theme of “ultrafast science”. The focused light from these devices is so intense that ordinary matter is torn apart within a few laser cycles. This book takes a close-up look at the exotic physical phenomena which arise as a result of this new form of “light-matter” interaction, covering a diverse set of topics including multiphoton ionization, rapid heatwaves, fast particle generation and relativistic self-channeling. These processes are central to a number of exciting new applications in other fields, such as microholography, optical particle accelerators and photonuclear physics.Repository for numerical models described in Chapter 6 can be found at www.fz-juelich.de/zam/cams/plasma/SPLIM/./a