Author: Satomi Shiraishi Publisher: Springer ISBN: 3319085697 Category : Science Languages : en Pages : 133
Book Description
This thesis establishes an exciting new beginning for Laser Plasma Accelerators (LPAs) to further develop toward the next generation of compact high energy accelerators. Design, installation and commissioning of a new experimental setup at LBNL played an important role and are detailed through three critical components: e-beam production, reflection of laser pulses with a plasma mirror and large wake excitation below electron injection threshold. Pulses from a 40 TW peak power laser system were split into a 25 TW pulse and a 15 TW pulse. The first pulse was used for e-beam production in the first module and the second pulse was used for wake excitation in the second module to post-accelerate the e-beam. As a result, reliable e-beam production and efficient wake excitation necessary for the staged acceleration were independently demonstrated. These experiments have laid the foundation for future staging experiments at the 40 TW peak power level.
Author: Brian Henry Shaw Publisher: ISBN: Category : Languages : en Pages : 111
Book Description
For over 10 years, laser plasma acceleration (LPA) has been a rapidly growing technology used to create electron beams on length-scales much smaller than that of a conventional RF-accelerator [1]. As electron beam properties improve, research for LPAs is expanding to take advantage of the creation and accessibility of high-quality electron beams from plasma targets. Two applications which are currently being explored are a multi-stage plasma accelerator to reach energies greater than those a single-stage accelerator can achieve and exploring the possibility of an LPA based free-electron laser (FEL) light source. Research supporting both of these efforts has been performed on the 50 TW TREX laser system at the BELLA Center at the Lawrence Berkeley National Lab, and the results of these efforts are described in this dissertation. Using chirped-pulsed amplification to produce high-quality laser pulses up to petawatt levels, experimental results have yielded laser driven electron beam energies up to 4.25 GeV [2]. By tuning the density of the target, the accelerating gradients sustained by the plasma can grow beyond 100 GeV/m [3] (10^3 times larger than that of a conventional RF accelerator). However, limiting factors such as dephasing of the electron beam from the plasma wake, defocusing of a laser pulse, and energy depletion of the laser into the plasma limit the maximum sensible length of a plasma accelerator. Staging the LPA with two or more accelerating modules could be the next step towards producing beams with energies greater than those possible with a single stage. One requirement for staged acceleration is that the laser pulse used to drive the first accelerating stage must be coupled out of the beamline, and a fresh laser pulse must be coupled in for the second stage to post accelerate the electrons. To do this while maintaining a short scale length between the two stages requires an optic to be placed near the final focus of the second laser pulse. Because damage will occur when the laser pulse interacts with a steering optic near focus, the coupling optic must be capable of replacing the surface following damage on each successive shot. This thesis comprises a detailed investigation of the physics of using a plasma mirror (PM) from a tape by reflecting ultrashort pulses from a laser-triggered surface plasma. The tapes used in the characterization of the PM are VHS and computer data storage tape. The tapes are 6.6 m (computer storage tape) and 15 m (VHS) thick. Each tape is 0.5 inches wide, and 10s of meters of tape are spooled using a tape drive; providing thousands of shots on a single reel of tape. The amount of reflected energy of the PM was studied for different input intensities. The fluence was varied by translating the focus of the laser upstream and downstream of the tape, which changed the spot size on the tape surface and hence changed the fluence. This study measured reflectances from both sides of the two tapes, and for input light of both s and p-polarizations. Lastly, an analytic model was developed to understand the reflectance as a function of fluence for each tape material and polarization. Another application that benefits from the advancements of LPA technology is an LPAbased FEL. By sending a high quality electron bunch through an undulator (a periodic structure of positive and negative magnetic poles), the electrons oscillate transversely to the propagation axis and produce radiation. The 1.5 m THUNDER undulator [4] at the BELLA Center has been commissioned using electron beams of 400MeV beams with broad energy spread (35%) [5]. To produce a coherent LPA-based FEL, the beam quality would need to improve to sub-percent level energy spread. A seed source could be used to help induce bunching of the electron beam within the undulator. This thesis described the experimental investigation of the physics of using solid-based surface high-harmonic generation (SHHG) from a thin tape as a possible seed source for an FEL. A thin tape placed within centimeters of the undulator's entrance could act as a harmonic generating source, while simultaneously transmitting an electron beam. This removes the need for transport optics for the XUV photons and the need for additional optics to overlap the seed beam with the electron beam at the undulator entrance. By operating at sub-relativistic laser strengths, harmonics up to the 17th order of 800 nm light are produced using an SHHG technique known as coherent wake emission (CWE). CWE pulse properties such as divergence, energy, conversion efficiency, and spectrum are measured for a wide range of tape materials and drive laser conditions. A clear correlation between surface roughness and harmonic beam divergence is found. The measured pulse properties for the 15th harmonic from VHS tape (conversion efficiency 6.5x10^-7 and an rms divergence of 12 mrad), the 100 mJ-level, 40-50 fs-class drive laser, produces peak powers of several MW's of XUV pulses. The results of a 1D model indicate that these CWE pulses with MW level powers are sufficient for seed-induced FEL gain.
Author: Shao-Wei Chou Publisher: Sudwestdeutscher Verlag Fur Hochschulschriften AG ISBN: 9783838151069 Category : Languages : en Pages : 192
Book Description
This work covers several aspects related to Laser WakeField Acceleration (LWFA). A strong and ultrashort laser pulse can generate plasma waves with accelerating gradients up to 100s GV/m, four orders of magnitude higher than a conventional radio frequency linear accelerator. The LWFA electrons have been characterized as an ultra-short and high brilliance source. These remarkable properties lead to a compact accelerator which is of great scientific interest for building a table-top coherent free electron laser as well as a single-shot electron diffraction device. On the other hand, a new application of LWFA is to utilize the high peak current LWFA electron bunch to drive a wakefield efficiently inside a high density underdense plasma. The resulting wakefield quickly decelerates the driver bunch or accelerates a properly designed witness bunch, and therefore the plasma is utilized as a compact beam dump or an afterburner staged after a regular LWFA.
Author: Xinlu Xu Publisher: Springer Nature ISBN: 9811523819 Category : Science Languages : en Pages : 138
Book Description
This book explores several key issues in beam phase space dynamics in plasma-based wakefield accelerators. It reveals the phase space dynamics of ionization-based injection methods by identifying two key phase mixing processes. Subsequently, the book proposes a two-color laser ionization injection scheme for generating high-quality beams, and assesses it using particle-in-cell (PIC) simulations. To eliminate emittance growth when the beam propagates between plasma accelerators and traditional accelerator components, a method using longitudinally tailored plasma structures as phase space matching components is proposed. Based on the aspects above, a preliminary design study on X-ray free-electron lasers driven by plasma accelerators is presented. Lastly, an important type of numerical noise—the numerical Cherenkov instabilities in particle-in-cell codes—is systematically studied.
Author: Publisher: ISBN: Category : Languages : en Pages :
Book Description
Physics considerations for a next-generation linear collider based on laser-plasma accelerators are discussed. The ultra-high accelerating gradient of a laser-plasma accelerator and short laser coupling distance between accelerator stages allows for a compact linac. Two regimes of laser-plasma acceleration are discussed. The highly nonlinear regime has the advantages of higher accelerating fields and uniform focusing forces, whereas the quasi-linear regime has the advantage of symmetric accelerating properties for electrons and positrons. Scaling of various accelerator and collider parameters with respect to plasma density and laser wavelength are derived. Reduction of beamstrahlung effects implies the use of ultra-short bunches of moderate charge. The total linac length scales inversely with the square root of the plasma density, whereas the total power scales proportional to the square root of the density. A 1 TeV center-of-mass collider based on stages using a plasma density of 1017 cm−3 requires tens of J of laser energy per stage (using 1 [mu]m wavelength lasers) with tens of kHz repetition rate. Coulomb scattering and synchrotron radiation are examined and found not to significantly degrade beam quality. A photon collider based on laser-plasma accelerated beams is also considered. The requirements for the scattering laser energy are comparable to those of a single laser-plasma accelerator stage.
Author: Publisher: ISBN: Category : Languages : en Pages : 7
Book Description
Two independently-driven laser accelerators were operated together in series for the first time in a proof-of-principle experiment to demonstrate staging. The ability to stage together these devices is important for eventually building practical laser-driven accelerators. The laser accelerators consisted of two identical inverse free electron lasers (IFEL), where the first IFEL served as a prebuncher, which created (almost equal to)3-fs long microbunches that were accelerated by the second IFEL. Precise and stable control of the phasing between the microbunches and laser wave inside the second IFEL was demonstrated. The effects of over-modulation of the prebuncher were also investigated. In all cases there was good agreement with the model. Additional details of the microbunch characteristics could be inferred by using the model. Plans for demonstrating monoenergetic laser acceleration are also presented.
Author: Publisher: ISBN: Category : Power resources Languages : en Pages : 906
Book Description
Semiannual, with semiannual and annual indexes. References to all scientific and technical literature coming from DOE, its laboratories, energy centers, and contractors. Includes all works deriving from DOE, other related government-sponsored information, and foreign nonnuclear information. Arranged under 39 categories, e.g., Biomedical sciences, basic studies; Biomedical sciences, applied studies; Health and safety; and Fusion energy. Entry gives bibliographical information and abstract. Corporate, author, subject, report number indexes.
Author: Mourou Gerard Publisher: World Scientific ISBN: 9811217149 Category : Science Languages : en Pages : 268
Book Description
Recent advancements in generation of intense X-ray laser ultrashort pulses open opportunities for particle acceleration in solid-state plasmas. Wakefield acceleration in crystals or carbon nanotubes shows promise of unmatched ultra-high accelerating gradients and possibility to shape the future of high energy physics colliders. This book summarizes the discussions of the 'Workshop on Beam Acceleration in Crystals and Nanostructures' (Fermilab, June 24-25 , 2019), presents next steps in theory and modeling and outlines major physics and technology challenges toward proof-of-principle demonstration experiments.
Author: Ozan Artun Publisher: BoD – Books on Demand ISBN: 1839682620 Category : Science Languages : en Pages : 106
Book Description
Since the mid-twentieth century, accelerators and colliders have been at the forefront of science and technology in the fields of space, medicine, energy, and others. This book presents sophisticated knowledge about accelerators and colliders and their crucial technological applications. With six chapters, the book presents information about currently available accelerators and colliders as well as novel schemes for future systems. Other topics covered include vacuum systems, elementary particles, and quantum chromodynamics.
Author: Satomi Shiraishi
Author: Brian Henry Shaw
Author: Shao-Wei Chou
Author: K. C. ROGERS
Author: Xinlu Xu
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Author: Mourou Gerard
Author: Ozan Artun