Nuclear-Pumped Lasers

Transcription

1 Nuclear-Pumped Lasers

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3 Mark Prelas Nuclear-Pumped Lasers

4 Mark Prelas Electrical & Computer Engineering Department University of Missouri Columbia, MO, USA ISBN ISBN (ebook) DOI / Library of Congress Control Number: Springer Cham Heidelberg New York Dordrecht London Springer International Publishing Switzerland 2016 This work is subject to copyright. All rights are reserved by the Publisher, whether the whole or part of the material is concerned, specifically the rights of translation, reprinting, reuse of illustrations, recitation, broadcasting, reproduction on microfilms or in any other physical way, and transmission or information storage and retrieval, electronic adaptation, computer software, or by similar or dissimilar methodology now known or hereafter developed. The use of general descriptive names, registered names, trademarks, service marks, etc. in this publication does not imply, even in the absence of a specific statement, that such names are exempt from the relevant protective laws and regulations and therefore free for general use. The publisher, the authors and the editors are safe to assume that the advice and information in this book are believed to be true and accurate at the date of publication. Neither the publisher nor the authors or the editors give a warranty, express or implied, with respect to the material contained herein or for any errors or omissions that may have been made. Printed on acid-free paper Springer International Publishing AG Switzerland is part of Springer Science+Business Media (

5 Katića and Jure Born in troubled times and forced into slave labor during World War II, having unimaginable strength, they survived the horror. They were kind and generous and approached life with unyielding compassion, faith, and dignity. They provided love, security, optimism, and a future for their children. Where there was evil they worked towards good; where there was pain and suffering, they provided comfort; where there was hunger they provided sustenance; where there was hate they provided love; where there was injustice and despair, they provided hope; and when they departed they left the world a better place. Mark Prelas, a grateful son.

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7 Preface The book Nuclear-Pump Lasers evolved from a graduate level course (titled Nuclear-Pumped Lasers and Applications) that I developed and taught during the summer of 1985 as part of the nuclear engineering curriculum at the University of Missouri. There were two motivating factors for developing and teaching this course. The first was that the US Strategic Defense Initiative (SDI) program had been proposed by President Ronald Regan on March 23, 1983, and the Strategic Defense Initiative Organization (SDIO) was set up in 1984 within the US Department of Defense to oversee SDI. The second reason was that two efforts within the SDI program centered on nuclear-pumped laser technologies: the Centaurus and the Falcon programs. The goal of these two programs was to take advantage of the high-energy/high-power capability of nuclear-pumped laser technology to provide a laser platform (space-based or ground-based) with sufficient energy to destroy a ballistic missile during its flight. Nuclear-pumped lasers were viewed as one of the few concepts with sufficient energy/power, scalability, and minimal mass for a space-based platform that met SDI mission requirements. Nuclear-pumped laser (NPL) technology dates back to It was always viewed as being a means of beaming large quantities of energy. This technology fits well with SDI objectives, and as a result, Centaurus and Falcon were set up to compete against other SDI technologies such as chemical lasers, free electron lasers, the thermonuclear bomb pumped x-ray laser, particle beams, and kinetic energy weapons. NPLs faded from the United States research agenda at the end of the 1980s due to a change in focus within SDO centered on kinetic energy weapons. However, NPLs remained an active research agenda in other countries. Most notably Russia, other nations in the former Soviet Union, and China [1] (which had a cooperative agreement with Russia [2]) remain active in the field. The reason for this broad interest in the technology is that an NPL can scale to high-energy/ high-power levels (potentially up to 100 MW continuous-wave (CW) beam power). Military applications have historically driven the NPL research agenda. It should be noted that there are significant humanitarian applications for high-energy/highpower lasers as described in Chap. 6. For example, a high-energy/high-power vii

8 viii Preface CW NPL could be used to deflect a moderately sized asteroid. Other potentially important applications include space propulsion, power transmission, and mining. Despite the promise, nuclear-pumped lasers still have significant problems which need to be solved [3 5], and these issues will be discussed throughout the text. High-energy/high-power gas lasers by their nature require high pumping power densities (defined as the Watts/cm 3 deposited in the laser medium). That is why powerful gas lasers are typically pulsed. Nuclear-pumping does not generate highpower densities like electrical pumping, but it does generate high-energy densities. This limits the type of high-energy/high-power laser systems that can be driven by nuclear-pumping technologies as discussed in Chap. 4. Other issues involve the design of reactor cores dedicated to the production of laser energy. The nuclearpumped laser system design is covered in Chap. 5. There are promising approaches that have been developed which could reduce the scale and mass of NPL spacebased systems. One such approach is the nuclear-driven flashlamps [6]. A nucleardriven flashlamp can increase the effective pumping power density through photon focusing while reducing the mass of the system. This capability is applicable to both gaseous- and solid-state candidate laser media. Due to a renewed interest in nuclear-pumped lasers, the graduate level course was updated and taught during the spring semester of 2014 at the University of Missouri. The course included lectures that covered introductory material, past and present research in the field, logical directions for potential future research, and possible long-term and short-term applications. The field of nuclear-pumped lasers is truly interdisciplinary. It represents the integration of diverse areas such as nuclear engineering, quantum electronics, gaseous electronics, optics, photonics, materials, chemistry, physics, thermodynamics, and astronautics. The graduate students that took the course were nuclear engineers who had some additional experiences in these diverse areas. The students worked on a design project involving an advanced reactor/laser that used a thermal pumping mechanism to drive a carbon dioxide laser. The heat source for the laser was an ultrahigh temperature core reactor concept that was inspired by the nuclear rocket research programs in the United States and Russia. In Chap. 5, there is a section on the design of a thermally pumped carbon dioxide laser driven by an ultrahigh temperature core reactor that emerged from this design study. The diversity of expertise within this group of students was a strategic part of the learning experience. The intended audience for this book includes graduate students (or perhaps senior level undergraduates in an honors program) who have skill sets in the disciplines described above and researchers interested in high-power/high-energy lasers. This book is organized in six chapters and four Appendices. Chapter 1 focuses on fundamental properties of lasers, nuclear-pumping, and some basic concepts. In Chap. 2, the nuclear reactions that may be used as drivers for nuclear-pumped lasers are discussed. Chapter 3 focuses on the efficient transport of energy from the ionizing radiation to the laser medium and the corresponding processes and mechanisms involved. Once the energy is deposited in the laser medium, the operational characteristics of existing nuclear-pumped lasers are considered, which are discussed in Chap. 4. The integration of the various systems needed to produce

9 Preface ix the radiation, transport the energy from the radiation source to the laser medium, and cool the system; the gain medium which produces the laser beam; and the Gaussian limited optics necessary to steer the beam from the laser to its intended target is examined in Chap. 5. Finally Chap. 6 covers the long-term applications of high-power/high-energy nuclear-pumped lasers as well as some near-term prospects for the use of technologies developed in nuclear-pumped laser research. References 1. Yang C, Chen H, Zheng C, Zhao X, Han H (2002) The progress of nuclear pumped laser in CFBR-II reactor. Chin Opt Lett 1: Select-Committee-United-States-House-of-Representatives (1999) U.S. National Security and Military/Commercial Concerns with the People s Republic of China. U.S. Government Printing Office, Washington, DC 3. Miley GH, McArthur DA, Deyoung RJ, Prelas MA (1989) Fission reactor pumped laser: history and prospects. In: Carlson JW, Behrens AD (eds) 50 years of nuclear power. National Academy of Science and NIST, American Nuclear Society, LaGrange Park, IL, pp Boody FP, Prelas MA, Anderson JH, Nagalingam SJS, Miley GH (1978) Progress in nuclearpumped lasers. In: Billman K (ed) Radiation energy conversion in space, vol 61. AIAA, New York, pp Melnikov SP, Sizov AN, Sinyanskii AA, Miley GH (2015) Lasers with nuclear pumping. Springer, New York 6. Prelas MA, Boody FP, Miley GH, Kunze J (1988) Nuclear driven flashlamps. Laser Part Beams 6:25 62

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11 Contents 1 Introduction to Nuclear-Pumped Lasers Introduction Nuclear-Pumped Lasers Energy Input (Drivers) Photon Sources Electron Swarm Pumping (e.g., D.C., RF, Microwave) Thermal Oven Chemical Reaction Ion Beam Pumped Laser Fission Fragment Pumped Laser Gain Medium Three and Four Level Lasers Power Buildup in a Laser Fluorescence Experiments Summary References Radiation Interaction with Matter Fission Fragments Alpha Particles Beta Particles and Positrons Neutrons Gamma Rays Scale Length Matching Energy Deposition Spatial Energy Distribution Summary References xi

12 xii Contents 3 Direct Energy Conversion Principles as Applied to Lasers Introduction Surface Source Volume Source Multiphase Laser Systems Contrasting the Surface Source, Volume Source and Multiphase Source Energy Conversion Physical Considerations for the Production of Excited Atomic and Molecular States (Lasers) Nuclear Driven Flashlamps Neutron Sources Accelerator Based Neutron Sources Radioisotope Based Neutron Sources Fission Reactor Based Neutron Sources Power Density Summary References Nuclear-Pumped Lasers Introduction Thermonuclear Explosion Radioisotopes NPL Research Nuclear-Pumped Lasers Summary References Reactor and Laser Coupling Introduction Engineering a Nuclear-Pumped Laser System Laser Medium (Phase) Gas Liquid Solid Phase of Fuel Solid Phase Liquid Fuel Gaseous Fuel Reactor/Laser Coupling Solid/Gas (Most Common) Solid-Liquid Solid-Solid Liquid-Gas Liquid-Liquid

13 Contents xiii Liquid-Solid Gas-Gas Gas-Liquid Gas-Solid Indirect Coupling (Photolytic) Reactor Criticality Reactor/Nuclear-Pumped Laser System Designs Sandia Fast Burst Reactor/Subcritical Nuclear-Pumped Laser and Gas Dynamic Carbon Monoxide Nuclear-Pumped Laser Designs ( ) NASA Uranium Hexafluoride Fueled Reactor/Nuclear-Pumped Laser Design (1979) Reactor/Nuclear-Pumped Laser System Studies the University of Missouri ( ) Photolytic Nuclear-Pumped Laser Designs University of Missouri ( ) Direct Drive Nuclear-Pumped Semiconductor Lasers (University of Missouri 2013) Thermally Pumped Carbon Dioxide Laser (University of Missouri 2014) Reactor/Nuclear-Pumped Laser Designs in USSR and Russia ( ) Summary References Applications Introduction Strategic Defense Initiative System Evaluation Polyus-Skif Laser Propulsion Asteroid Deflection Space Based Mining Power Beaming Near Term Applications of Nuclear-Pumped Laser Technology Summary References Appendices A1 Neutron Cross Sections from Neutron Resonance Parameters and Thermal Cross Sections References

14 xiv Contents A2 Plasma Basics A2.1 Plasma Species A2.2 Elementary Theory of Discharges A2.3 Definitions References A3 Maxwell Boltzmann Distribution Function A3.1 Maxwellian Distribution A4 Thermal Neutron Cross Sections for Some Elements and Compounds for 2200 m/s Neutron Speed References Index