Download or read book Towards Understanding Initiation Reactions of Explosives Via Ultrafast Laser Quantum Control written by and published by . This book was released on 2010 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Optimal control can be utilized to control the initiation reaction of explosives, where time dependent phase shaped electric fields drive the chemical systems towards a desired state. For quantum controlled initiation (QCI) of explosives a pulse is created which seeks to achieve initiation by employing shaped ultraviolet light. QCI will enhance the understanding of energetic material reactions by yielding insight into the characteristics, such as critical 'hot spot' size and reaction dynamics, necessary for initiation. Quantum control experiments require the ability to: (1) phase and amplitude shape an ultrafast laser pulse, (2) measure the effect of pulse shape, and (3) optimize the desired outcome. Pulse shaping is performed with a 4-focal length dispersed fused silica acousto-optic modulator (AOM) at 400 nm in the ultraviolet (UV). Transient absorption spectroscopy is used to measure the pulse shape effects. Both global and local optimization search routines such as genetic algorithm, differential evolution, and downhill simplex are used to search for the optimal pulse shape. Hexanitroazobenzene (HNAB), Trinitroanaline (TNA) and Diaminoazozyfurazan (DAAF) are excited to the first electronic state with 400 nm light. Our initiation experiments are studying the effect of phase shaped 400 nm pulses on HNAB, TNA and DAAF. Novel transient absorption spectra for each material have been obtained and note worthy regions further investigated with single parameter control (second order spectral phase and energy). Many systems have simple intensity control such as that shown by DAAF. TNA and HNAB have spectral features that are not single parameter driven and are being further investigated with complex control.
Download or read book Quantum Control for Initiation and Detection of Explosives written by and published by . This book was released on 2010 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: We employ quantum control methods towards detection and quantum controlled initiation (QCI) of energetic materials. Ultrafast pulse shaping of broadband Infrared ((almost equal to)750 nm to 850 run) and ultraviolet (266 nm, 400 nm) light is utilized for control. The underlying principals behind optimal control can be utilized to both detect and initiate explosives. In each case, time dependent phase shaped electric fields drive the chemical systems towards a desired state. For optimal dynamic detection of explosives (ODD-Ex) a phase specific broadband infrared pulse is created which increases not only the sensitivity of detection but also the selectivity of an explosive's spectral signatures in a background of interferents. QCI on the other hand, seeks to initiate explosives by employing shaped ultraviolet light. QCI is ideal for use with explosive detonators as it removes the possibility of unintentional initiation from an electrical source while adding an additional safety feature, initiation only with the proper pulse shape. Quantum control experiments require: (1) the ability to phase and amplitude shape the laser pulse and (2) the ability to effectively search for the pulse shape which controls the reaction. In these adaptive experiments we utilize both global and local optimization search routines such as genetic algorithm, differential evolution, and downhill simplex. Pulse shaping the broadband IR light, produced by focusing 800 nm light through a pressurized tube of Argon, is straightforward as commercial pulse shapers are available at and around 800 nm. Pulse shaping in the UV requires a home built shaper. Our system is an acoustic optical modulator (AOM) pulse shaper in which consists of a fused silica AOM crystal placed in the Fourier plane of a 4-f zero dispersion compressor.
Download or read book Towards Mitigating Explosive Threats Using Quantum Controlled Initiation written by and published by . This book was released on 2010 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Quantum control of localized energy deposition into an energetic material is being investigated as a method to allow controlled initiation and propagation of action without transition to detonation. Quantum controlled initiation (QCI) of explosives utilize time dependent phase shaped ultraviolet (UV) electric fields to drive the energetic chemical systems towards reaction. QCI searches for an optimally shaped ultrafast laser pulse that will guide energy flow along a desired path. QCI can be exploited as a stand-off mitigation technology that strives to reduce the impact of explosive blasts on people and property by initiating controlled low order reaction. Quantum controlled initiation experiments require: (1) optimally shaped light pulses, (2) pulse shaping measurement, (3) feedback control algorithms, and (4) feedback measurement methods. Femtosecond laser pulse shaping in the UV at 400 nm employs a fused silica acousto-optic modulator (AOM) pulse shaper that consists of a 4-f zero dispersion compressor. Tr sient absorption spectroscopy is used to measure the pulse shaper effects. Both global and local optimization search routines such as genetic algorithm, differential evolution, and downhill simplex are used to search for the optimal pulse shape. Hexanitroazobenzene (HNAB), Trinitroanaline (TNA) and Diaminoazozyfurazan (DAAF) are excited to the first electronic state with 400 nm light. Our initiation experiments are studying the effect of phase shaped 400 nm pulses on HNAB, TNA and DAAF. The transient absorption spectra for each material have been obtained and note worthy regions further investigated with single parameter control (second order spectral phase and energy). Many systems have simple intensity control such as that shown by DAAF. TNA and HNAB have spectral features that are not single parameter driven and are being further investigated to obtain fully optimized complex control.
Download or read book Towards Coherent Control of Energetic Material Initiation written by and published by . This book was released on 2009 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Direct optical initiation (DOI) of energetic materials using coherent control of localized energy deposition requires depositing energy into the material to produce a critical size hot spot, which allows propagation of the reaction and thereby initiation, The hot spot characteristics needed for growth to initiation can be studied using quantum controlled initiation (QCI). Achieving direct quantum controlled initiation (QCI) in condensed phase systems requires optimally shaped ultrafast laser pulses to coherently guide the energy flow along the desired paths. As a test of our quantum control capabilities we have successfully demonstrated our ability to control the reaction pathway of the chemical system stilbene. An acousto-optical modulator based pulse shaper was used at 266 nm, in a shaped pump/supercontinuum probe technique, to enhance and suppress th relative yields of the cis- to trans-stilbene isomerization. The quantum control techniques tested in the stilbene experiments are currently being used to investigate QCI of the explosive hexanitroazobenzene (HNAB).
Download or read book Towards Quantum Controlled Initiation of Explosives written by and published by . This book was released on 2010 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: As a first step toward understanding and controlling excited state dynamics in explosives, transient absorption spectra of Hexanitroazobenzene (HNAB) in acetone, Trinitroaniline (TNA) in acetone and Diaminoazoxyfurazan (DAAF) in dimethylsulfoxide (DMSO) were investigated in an ultrafast shaped pump/supercontinuum probe experiment for their dependence on single parameter control schemes. Two single parameter control methods, second order spectral phase (linear chirp) and the effect of pump energy on the amount of transmitted pump light were investigated. Novel transient absorption spectra were obtained for the three explosives. The spectral features found in the HNAB and TNA solutions had evidence of more complex control possibilities, while the spectral features of DAAF were dominated by intensity control.
Download or read book Theoretical Studies on the Reaction Pathways of Electronically Excited DAAF written by and published by . This book was released on 2009 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The use of temporally and spectrally shaped ultrafast laser pulses to initiate, as well as detect, high explosives is being explored at Los Alamos. High level ab initio calculations, presented here, are employed to help guide and interpret the experiments. The ground and first excited electronic states of 3,3(prime)-diamino-4,4(prime)-azoxyfurazan (DAAF) are investigated using complete active space self-consistent field (CASSCF) and time-dependent density functional theory (TD-DFT). The geometrical and energetic character of the excited state minima, conical intersections and reaction pathways of DAAF are described. Two radiative and two non-radiative excited state population quenching mechanisms are outlined, and possible pathways for photochemical and spectroscopic control are discussed. The use of laser light to control chemical reactions has many applications. The initiation and the detection of explosives are two such applications currently under development at Los Alamos. Though inherently experimental, the project can be aided by theory through both prediction and interpretation. When the laser light is in the UV/visible region of the electromagnetic spectrum, the absorbing molecule is excited electronically and excitation decay may occur either radiatively (fluorescence or phosphorescence) or non-radiatively (through internal conversion). In many cases decay of the excitation occurs through a mixture of processes, and maximizing the desired result requires sophisticated laser pulses whose amplitude has been optimally modulated in time and/or frequency space. Control of cis-stilbene photochemistry was recently demonstrated in our group, and we aim to extend this work to high explosive compounds. Maximizing radiative decay leads to increased fluorescence quantum yields and enhances the possibility of spectral detection of the absorbing molecule. Maximizing non-radiative decay can lead to chemistry, heating of the sample and possibly detonation initiation in an explosive compound. Here we describe high level quantum chemistry calculations aimed at mapping the electronic states involved in excitation of 3,3(prime)-Diamino-4,4(prime)-azoxyfurazan (DAAF) with 400-nm light. DAAF is a high-nitrogen high explosive that is of interest for its relative insensitivity to shock compression. The goal of the theoretical work described here is to determine the competing pathways for radiative and non-radiative electronic state quenching in an effort to help guide spectroscopic experiments being conducted in tandem.
Download or read book Femtosecond Optical Frequency Comb Principle Operation and Applications written by Jun Ye and published by Springer Science & Business Media. This book was released on 2006-06-15 with total page 373 pages. Available in PDF, EPUB and Kindle. Book excerpt: Over the last few years, there has been a convergence between the fields of ultrafast science, nonlinear optics, optical frequency metrology, and precision laser spectroscopy. These fields have been developing largely independently since the birth of the laser, reaching remarkable levels of performance. On the ultrafast frontier, pulses of only a few cycles long have been produced, while in optical spectroscopy, the precision and resolution have reached one part in Although these two achievements appear to be completely disconnected, advances in nonlinear optics provided the essential link between them. The resulting convergence has enabled unprecedented advances in the control of the electric field of the pulses produced by femtosecond mode-locked lasers. The corresponding spectrum consists of a comb of sharp spectral lines with well-defined frequencies. These new techniques and capabilities are generally known as “femtosecond comb technology. ” They have had dramatic impact on the diverse fields of precision measurement and extreme nonlinear optical physics. The historical background for these developments is provided in the Foreword by two of the pioneers of laser spectroscopy, John Hall and Theodor Hänsch. Indeed the developments described in this book were foreshadowed by Hänsch’s early work in the 1970s when he used picosecond pulses to demonstrate the connection between the time and frequency domains in laser spectroscopy. This work complemented the advances in precision laser stabilization developed by Hall.
Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1994 with total page 804 pages. Available in PDF, EPUB and Kindle. Book excerpt: Lists citations with abstracts for aerospace related reports obtained from world wide sources and announces documents that have recently been entered into the NASA Scientific and Technical Information Database.
Download or read book International Aerospace Abstracts written by and published by . This book was released on 1999 with total page 974 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Book of Abstracts written by American Chemical Society. Meeting and published by . This book was released on 1984 with total page 1256 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Femtosecond Laser Micromachining written by Roberto Osellame and published by Springer Science & Business Media. This book was released on 2012-03-05 with total page 485 pages. Available in PDF, EPUB and Kindle. Book excerpt: Femtosecond laser micromachining of transparent material is a powerful and versatile technology. In fact, it can be applied to several materials. It is a maskless technology that allows rapid device prototyping, has intrinsic three-dimensional capabilities and can produce both photonic and microfluidic devices. For these reasons it is ideally suited for the fabrication of complex microsystems with unprecedented functionalities. The book is mainly focused on micromachining of transparent materials which, due to the nonlinear absorption mechanism of ultrashort pulses, allows unique three-dimensional capabilities and can be exploited for the fabrication of complex microsystems with unprecedented functionalities.This book presents an overview of the state of the art of this rapidly emerging topic with contributions from leading experts in the field, ranging from principles of nonlinear material modification to fabrication techniques and applications to photonics and optofluidics.
Download or read book Infrared and Raman Spectroscopic Imaging written by Reiner Salzer and published by John Wiley & Sons. This book was released on 2014-11-03 with total page 656 pages. Available in PDF, EPUB and Kindle. Book excerpt: This second edition of the successful ready reference is updated and revised with approximately 30% new content to reflect the numerous instrumental developments and improvements, as well as the significant expansion of this rapidly developing field. For example, the combination of IR imaging with AFM has enhanced the achievable lateral resolution by an order of magnitude down to a few hundred nanometers, thus launching a multiplicity of new applications in material science. Furthermore, Raman and IR spectroscopic imaging have become key technologies for the life sciences and today contribute tremendously to a better and more detailed understanding of numerous biological and medical research topics. The topical structure of this new edition is now subdivided into four parts. The first treats the fundamentals of the instrumentation for infrared and Raman imaging and mapping and an overview on the chemometric tools for image analysis. The second part describes a wide varie-ty of applications ranging from biomedical via food, agriculture and plants to polymers and pharmaceuticals. This is followed by a description of imaging techniques operating beyond the diffraction limit, while the final part covers special methodical developments and their utility in specific fields. With its many valuable practical tips, this is a must-have overview for researchers in academic and industrial laboratories wishing to obtain reliable results with this method.
Download or read book Emerging Energetic Materials Synthesis Physicochemical and Detonation Properties written by Dabir S. Viswanath and published by Springer. This book was released on 2018-01-02 with total page 477 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book summarizes science and technology of a new generation of high-energy andinsensitive explosives. The objective is to provide professionals with comprehensiveinformation on the synthesis and the physicochemical and detonation properties ofthe explosives. Potential technologies applicable for treatment of contaminated wastestreams from manufacturing facilities and environmental matrices are also be included.This book provides the reader an insight into the depth and breadth of theoreticaland empirical models and experimental techniques currently being developed in thefield of energetic materials. It presents the latest research by DoD engineers andscientists, and some of DoD’s academic and industrial researcher partners. The topicsexplored and the simulations developed or modified for the purposes of energetics mayfind application in other closely related fields, such as the pharmaceutical industry.One of the key features of the book is the treatment of wastewaters generated duringmanufacturing of these energetic materials.
Download or read book Handbook of Spectroscopy written by G¿nter Gauglitz and published by John Wiley & Sons. This book was released on 2006-03-06 with total page 1168 pages. Available in PDF, EPUB and Kindle. Book excerpt: This handbook provides a straightforward introduction to spectroscopy, showing what it can do and how it does it, together with a clear, integrated and objective account of the wealth of information that can be derived from spectra. The sequence of chapters covers a wide range of the electromagnetic spectrum, and the physical processes involved, from nuclear phenomena to molecular rotation processes. - A day-by-day laboratory guide: its design based on practical knowledge of spectroscopists at universities, industries and research institutes - A well-structured information source containing methods and applications sections framed by sections on general topics - Guides users to a decision about which spectroscopic method and which instrumentation will be the most appropriate to solve their own practical problem - Rapid access to essential information - Correct analysis of a huge number of measured spectra data and smart use of such information sources as databases and spectra libraries
Download or read book Physics of and Science with X Ray Free Electron Lasers written by J. Hastings and published by IOS Press. This book was released on 2020-12-18 with total page 272 pages. Available in PDF, EPUB and Kindle. Book excerpt: Many X-Ray Free-Electron Lasers (X-FELs) have been designed, built and commissioned since the first lasing of the Linac Coherent Light Source in the hard and soft X-ray regions, and great progress has been made in improving their performance and extending their capabilities. Meanwhile, experimental techniques to exploit the unique properties of X-FELs to explore atomic and molecular systems of interest to physics, chemistry, biology and the material sciences have also been developed. As a result, our knowledge of atomic and molecular science has been greatly extended. Nevertheless, there is still much to be accomplished, and the potential for discovery with X-FELs is still largely unexplored. The next generation of scientists will need to be well versed in both particle beams/FEL physics and X-ray photon science. This book presents material from the Enrico Fermi summer school: Physics of and Science with X-Ray Free-Electron Lasers, held at the Enrico Fermi International School of Physics in Varenna, Italy, from 26 June - 1 July 2017. The lectures presented at the school were aimed at introducing graduate students and young scientists to this fast growing and exciting scientific area, and subjects covered include basic accelerator and FEL physics, as well as an introduction to the main research topics in X-FEL-based biology, atomic molecular optical science, material sciences, high-energy density physics and chemistry. Bridging the gap between accelerator/FEL physicists and scientists from other disciplines, the book will be of interest to all those working in the field.
Download or read book Femtosecond Laser Filamentation written by See Leang Chin and published by Springer Science & Business Media. This book was released on 2010-03-10 with total page 138 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book attempts to give a discussion of the physics and current and potential applications of the self-focusing of an intense femtosecond laser pulse in a tra- parent medium. Although self-focusing is an old subject of nonlinear optics, the consequence of self-focusing of intense femtosecond laser pulses is totally new and unexpected. Thus, new phenomena are observed, such as long range lam- tation, intensity clamping, white light laser pulse, self-spatial ltering, self-group phase locking, self-pulse compression, clean nonlinear uorescence, and so on. Long range propagation at high intensity, which is seemingly against the law of diffraction, is probably one of the most exciting consequences of this new sub- eld of nonlinear optics. Because the intensity inside the lament core is high, new ways of doing nonlinear optics inside the lament become possible. We call this lamentation nonlinear optics. We shall describe the generation of pulses at other wavelengths in the visible and ultraviolet (UV) starting from the near infrared pump pulse at 800 nm through four-wave-mixing and third harmonic generation, all in gases. Remotely sensing uorescence from the fragments of chemical and biological agents in all forms, gaseous, aerosol or solid, inside the laments in air is demonstrated in the labo- tory. The results will be shown in the last part of the book. Through analyzing the uorescence of gas molecules inside the lament, an unexpected physical process pertaining to the interaction of synchrotron radiation with molecules is observed.
Download or read book Energetic Materials written by and published by Elsevier. This book was released on 2003-11-21 with total page 475 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume provides an overview of current research and recent advances in the area of energetic materials, focusing on explosives and propellants. The contents and format reflect the fact that theory, experiment and computation are closely linked in this field. The challenge of developing energetic materials that are less sensitive to accidental stimuli continues to be of critical importance. This volume opens with discussions of some determinants of sensitivity and its correlations with various molecular and crystal properties. The next several chapters deal in considerable detail with different aspects and mechanisms of the initiation of detonation, and its quantitative description. The second half of this volume focuses upon combustion. Extensive studies model ignition and combustion, with applications to different propellants. The final chapter is an exhaustive computational treatment of the mechanism and kinetics of combustion initiation reactions of ammonium perchlorate. Overall, this volume illustrates the progress that has been made in the field of energetic materials and some of the areas of current activity. It also indicates the challenges involved in characterizing and understanding the properties and behaviour of these compounds. The work is a unique state-of-the-art treatment of the subject, written by pre-eminent researchers in the field. - Overall emphasis is on theory and computation, presented in the context of relevant experimental work - Presents a unique state-of-the-art treatment of the subject - Contributors are preeminent researchers in the field
