Pablo Martín-Luna, Alexandre Bonatto, Cristian Bontoiu
et al.
The interaction of fast charged particles with graphene layers can generate electromagnetic modes. This wake effect has been recently proposed for short-wavelength, high-gradient particle acceleration and for obtaining brilliant radiation sources. In this study, the excitation of wakefields produced by a point-like charged particle moving parallel to a multilayer graphene array (which may be supported by an insulated substrate) is studied using the linearized hydrodynamic theory. General expressions for the excited longitudinal and transverse wakefields have been derived. The dependencies of the wakefields on the positions of the layers and the substrate, the velocity and the surface density have been extensively analyzed. This study provides a deeper understanding of the physical phenomena underlying plasmonic excitations in graphene layers, paving the way for potential applications of these structures in particle acceleration, nanotechnology and materials science.
We quantify the discovery potential of future multi-TeV plasma wakefield colliders for new electroweak multiplets. We include beam-beam effects through realistic luminosity spectra, comparing five collider configurations: $e^+e^-$ and $e^-e^-$ machines with round- and flat-beams, and a $γγ$ collider. The beam-beam effects qualitatively change search strategies relative to idealized mono-energetic lepton colliders, highlighting the importance of the low-energy part of the luminosity spectrum and additional beam-induced initial-state channels. Our results have implications for accelerator R&D priorities, since key electroweak targets may remain accessible even if efficient positron acceleration and flat-beam delivery prove technically challenging at the multi-TeV scale.
We present the development and integration of a Machine Learning (ML)-based surrogate model, trained on Particle-In-Cell (PIC) simulations of laser-driven plasma wakefield acceleration source of electrons, into Geant4 simulation toolkit. Our model enables the generation and tracking of plasma-accelerated beams within complete experimental setups, unifying plasma acceleration and Monte Carlo-based simulations, which significantly reduces their complexity and computational cost. Our implementation focuses on the PALLAS laser-plasma accelerator test facility, integrating its full experimental setup into Geant4. We describe the ML model, its integration into Geant4, and key simulation results, demonstrating the feasibility of start-to-end simulations of plasma acceleration facilities and applications within a unified framework.
Recently, the construction of {μ^+}{e^-} and {μ^+}{μ^+} colliders, μTRISTAN, at KEK has been proposed. We argue that the construction of a similar {μ^+} ring tangential to LHC/Tevatron/FCC/SppC will give an opportunity to realize {μ^+}p and {μ^+}A collisions at multi-TeV scale center-of-mass energies. In this paper the main parameters of proposed colliders have been studied. It is shown that sufficiently high luminosities can be achieved for all proposals under consideration: L exceeds {10^{33} cm^{-2}s^{-1}} for {μ^+}p colliders and {10^{30} cm^{-2}s^{-1}} for {μ^+}A colliders. Certainly, proposed colliders will provide huge potential for both SM (especially QCD basics) and BSM physics searches.
Finite-element simulations of magnetostatic fields are performed in terms of magnetic vector and total scalar potentials and compared for purpose of modeling the accelerator magnets. The potentials represent the unknown variables associated with the A and V formulations of magnetostatics to describe the magnetic fields. The simulations are carried out with a single software package, the COMSOL Multiphysics, where both formulations are implemented. The numerical performance of these methods is illustrated with the model example of a superconducting dipole magnet recently developed for operation in the isochronous cyclotron SC200. The results of calculations are analyzed and compared in terms of the relevant FEM parameters accounting for performance of computation as well as the computational cost. We show in particular that the use of scalar potential as compared to its vector counterpart substantially reduces the number of degrees of freedom, the usage of computer memory and the computational time for a similar relative error.
A review of modern high intensity H- ion sources for accelerators is presented. The cesiation effect, a significant enhancement of negative ion emission from gas discharges with decrease of co-extracted electron current below negative ion current, was observed for the first time by inserting into the discharge chamber a compound with one milligram of cesium on July 1, 1971 in the Institute of Nuclear Physics (INP), Novosibirsk, Russia. This observation became the basis for the development of surface plasma negative ion sources (SPS). The efficiency of negative ion generation was increased by the invention of geometrical focusing. The magnetron-planotron with geometrical focusing SPS is discussed. The converter SPS is reviewed. Semiplanotron SPS is discussed. Penning discharge SPS, RF pulsed and CW SPS are reviewed. The history of negative ion source development is reviewed. Large development projects, including the SPS for the Large Hadron Collider (LHC) and for the International Thermonuclear Experimental Reactor (ITER) are being conducted. The development and fabrication of injectors with cesiated SPS has become a billion dollars scale industry.
We discovered a novel effect that can cause witness emittance growth in plasma wakefield accelerators. The effect appears in linear or moderately nonlinear plasma waves. The witness experiences a time-varying focusing force and loses quality during the time required for the drive beam to reach transverse equilibrium with the plasma wave. The higher the witness charge, the lower the emittance growth rate because of additional focusing of the witness by its own wakefield. However, the witness head always degrades, and the boundary between degraded and intact parts gradually propagates backward along the witness bunch.
Massimo Florio, Andrea Bastianin, Paolo Castelnovo
Preliminary evidence on the long--run trajectory of the accelerator industry suggests that it may be close to the maturity phase of its cycle. If this is the case, how can we measure the benefits of an uncertain breakthrough in acceleration technology? Who are the main stakeholders interested by such a breakthrough? We identify these subjects and sketch some avenues for answering these questions. We thus present a model for the social Cost-Benefit Analysis (CBA) of research infrastructures and illustrate the results of its implementation for assessing the benefits of accelerators in basic science and hadrontherapy. Lastly, we move from the social CBA of single research infrastructures to modeling a major change in the accelerator technology and hence in the industry. A research agenda on the potential impacts of a technological breakthrough is presented.
In this paper we extent the previously published DALI-approximation for likelihoods to cases in which the parameter dependency is in the covariance matrix. The approximation recovers non-Gaussian likelihoods, and reduces to the Fisher matrix approach in the case of Gaussianity. It works with the minimal assumptions of having Gaussian errors on the data, and a covariance matrix that possesses a converging Taylor approximation. The resulting approximation works in cases of severe parameter degeneracies and in cases where the Fisher matrix is singular. It is at least $1000$ times faster than a typical Monte Carlo Markov Chain run over the same parameter space. Two example applications, to cases of extremely non-Gaussian likelihoods, are presented -- one demonstrates how the method succeeds in reconstructing completely a ring-shaped likelihood. A public code is released here: http://lnasellentin.github.io/DALI/
The article considers an opportunity of gas-dynamic acceleration of body from the initial zero velocity till the finite velocity: five kilometers per second. When the gas flow rate of the body pre-acceleration reaches one kilometer per second, the body is accelerated at the front of the explosion wave propagating along the coils of the hexogen spiral. This wave accelerates the body and, finally, it reaches the velocity of five kilometers per second. The accelerated body has mass one-tenth of a kilogram and diameter eleven and three tenths of a millimeter. Acceleration length is six meters. At the slope of the spiral to the horizon equal to seventy degrees the flight range of the body is equal to sixteen hundred kilometers and the maximum height of the flight is eleven hundred kilometers.
An electron passing through a counter propagating intense laser beam can interact with a few laser photons with emission of a hard photon in each collision event. In contrast with the well-known nonlinear Compton backscattering process the above mentioned process may be named as multiple Compton backscattering process (MCBS). In this paper we have investigated the evolution of the electron energy distribution during MCBS process using Monte-Carlo (M-C) simulation. The main characteristics of such a distribution as mean energy and variance obtained by M-C technique were compared with analytical solutions of kinetic equations. We found the kinematic region where the analytical solutions are applicable with a good accuracy. A photon spectrum, even for the case when each electron emits one photon (in average) differs significantly from that described by the Klein-Nishina formula.
Yongsheng Huang, Naiyan Wang, Xiuzhang Tang
et al.
A new laser-proton acceleration structure combined by two relativistic electron shells, a suprathermal electron shell and a thermal electron cloud is proposed for $a\gtrapprox80σ_0$, where a is the normalized laser field and $σ_0$ is the normalized plasma surface density. In the new region, a uniform energy distribution of several GeV and a monoenergetic hundreds-of-MeV proton beam have been obtained for $a=39.5$. The first relativistic electron shell maintains opaque for incident laser pulse in the whole process. A monoenergetic electron beam has been generated with energy hundreds of MeV and charge of hundreds of pC. It is proposed a stirring solution for relativistic laser-particle acceleration.
This thesis is about the designing and constructing a microwave ion source. The ions are generated in a thermal and dense hydrogen plasma by microwave induction. The plasma is generated by using a microwave source with a frequency of 2.45 GHz and a power of 700 W. The generated microwave is pulsing with a frequency of 50 Hz. The designed and constructed microwave system generates hydrogen plasma in a pyrex plasma chamber. Moreover, an ion extraction unit is designed and constructed in order to extract the ions from the generated hydrogen plasma. The ion beam extraction is achieved and ion currents are measured. The plasma parameters are determined by a double Langmuir probe and the ion current is measured by a Faraday cup. The designed ion extraction unit is simulated by using the dimensions of the designed and constructed ion extraction unit in order to trace out the trajectories of the extracted ions.
A Monte Carlo program based on a three dimensional vector approach was developed to model multiple refractive scattering of X-ray photons in objects with a fine structure. A particular interest was paid to the investigation of lung tissue. Alveoli are low contrast and low absorbing structures. Hence, they are not visible in the conventional radiography which is based on the changes in the absorption arising from density differences and from variation in the thickness and composition of the object. Another possibility to image fine structure objects is to use the phase imaging techniques. As known, the phase change constant delta at low energies (15-30 keV) is 1000 times larger than the absorption constant beta. The Diffraction Enhance Imaging (DEI) technique is one of the recent phase sensitive techniques based on the use of an analyzer crystal placed between the sample and the detector.
Toshimasa Morita, Sergei V. Bulanov, Timur Zh. Esirkepov
et al.
We investigate proton acceleration by a laser pulse obliquely incident on a double layer target via 3D PIC simulations. It is found that the proton beam energy spread changes by the laser irradiation position and it reaches a minimum at certain position. This provides a way to control the proton energy spectrum. We show that by appropriately adjusting the size and position of the second proton layer that high energy protons with much smaller energy spread can be obtained.
A method is proposed for producing monoergetic, high-quality ion beams in vacuum, via direct acceleration by the electromagnetic field of two counterpropagating, variable-frequency lasers: ions are trapped and accelerated by a beat-wave structure with variable phase velocity, allowing for fine control over the energy and the charge of the beam via tuning of the frequency variation. The physical mechanism is described with a one-dimensional theory, providing the general conditions for trapping and scaling laws for the relevant features of the ion beam. Two-dimensional, electromagnetic particle-in-cell simulations, in which hydrogen gas is considered as an ion source, confirm the validity and the robustness of the method.