52 research outputs found
Hydrodynamic Model for Particle Beam-Driven Wakefield in Carbon Nanotubes
No full textThe charged particles moving through a carbon nanotube (CNT) may be used to excite electromagnetic modes in the electron gas produced in the cylindrical graphene shell that makes up a nanotube wall. This effect has recently beenproposed as a potential novel method of short-wavelength-high-gradient particle acceleration. In this contribution, the existing theory based on a linearized hydrodynamic model for a localized point-charge propagating in a single wall nanotube (SWNT) is reviewed. In this model, the electron gas is treated as a plasma with additional contributions to the fluid momentum equation from specific solid-state properties of the gas. The governing set of differential equations is formed by the continuity and momentum equations for the involvedspecies. These equations are then coupled by Maxwell’s equations. The differential equation system is solved applying a modified Fourier-Bessel transform. An analysis has been realized to determine the plasma modes able to excite a longitudinal electrical wakefield component in the SWNT to accelerate test charges. Numerical results are obtained showing the influence of the damping factor, the velocity of the driver, the nanotube radius, and the particle position on the excited wakefields. A discussion is presented on the suitability and possible limitations of using this method for modelling CNT-based particle acceleration
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Beam Dynamics Studies for the First Muon Linac of the Neutrino Factory
No full textWithin the Neutrino Factory Project the muon acceleration process involves a complex chain of accelerators including a (single-pass) linac, two recirculating linacs and an FFAG. The linac consists of RF cavities and iron shielded solenoids for transverse focusing and has been previously designed relying on idealized field models. However, to predict accurately the transport and acceleration of a high emittance 30 cm wide beam with 10 % energy spread requires detailed knowledge of fringe field distributions. This article presents results of the front-to-end tracking of the muon beam through numerically simulated realistic field distributions for the shielded solenoids and the RF fields. Real and phase space evolution of the beam has been studied along the linac and the results are presented and discussed
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Solenoid Fringe Field Effects for the Neutrino Factory Linac - MAD-X Investigation
No full textInternational Design Study for the Neutrino Factory (IDS-NF) assumes the first stage of muon acceleration (up to 900 MeV) to be implemented with a solenoid based Linac. The Linac consists of three styles of cryo-modules, containing focusing solenoids and varying number of SRF cavities for acceleration. Fringe fields of the solenoids and the focusing effects in the SRF cavities have significant impact on the transverse beam dynamics. Using an analytical formula, the effects of fringe fields are studied in MAD-X. The resulting betatron functions are compared with the results of beam dynamics simulations using OptiM code
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Investigation of Beam Loading Effects for the Neutrino Factory Muon Accelerator
No full textThe International design study (IDS) study showed that a Neutrino Factory [1] seems to be the most promising candidate for the next phase of high precision neutrino oscillation experiments. One part of the increased precision is due to the fact that in a Neutrino Factory the decay of muons produces a neutrino beam with narrow energy distribution and divergence. The effect of beam loading on the energy distribution of the muon beam in the Neutrino Factory decay rings has been investigated numerically. The simulations have been performed using the baseline accelerator design including cavities for different number of bunch trains and bunch train timing. A detailed analysis of the beam energy distribution expected is given together with a discussion of the energy spread produced by the gutter acceleration in the FFAG and the implications for the neutrino oscillation experiments will be presented
High intensity neutrino oscillation facilities in Europe
No full textThe EUROnu project has studied three possible options for future, high intensity neutrino oscillation facilities in Europe. The first is a Super Beam, in which the neutrinos come from the decay of pions created by bombarding targets with a 4 MW proton beam from the CERN High Power Superconducting Proton Linac. The far detector for this facility is the 500 kt MEMPHYS water Cherenkov, located in the Fréjus tunnel. The second facility is the Neutrino Factory, in which the neutrinos come from the decay of μ+ and μ- beams in a storage ring. The far detector in this case is a 100 kt magnetized iron neutrino detector at a baseline of 2000 km. The third option is a Beta Beam, in which the neutrinos come from the decay of beta emitting isotopes, in particular 6He and 18Ne, also stored in a ring. The far detector is also the MEMPHYS detector in the Fréjus tunnel. EUROnu has undertaken conceptual designs of these facilities and studied the performance of the detectors. Based on this, it has determined the physics reach of each facility, in particular for the measurement of CP violation in the lepton sector, and estimated the cost of construction. These have demonstrated that the best facility to build is the Neutrino Factory. However, if a powerful proton driver is constructed for another purpose or if the MEMPHYS detector is built for astroparticle physics, the Super Beam also becomes very attractive
Excitation of wakefields in carbon nanotubes: a hydrodynamic model approach
No full textThe interactions of charged particles with carbon nanotubes may excite
electromagnetic modes in the electron gas produced in the cylindrical graphene
shell constituting the nanotube wall. This wake effect has recently been
proposed as a potential novel method of short-wavelength high-gradient particle
acceleration. In this work, the excitation of these wakefields is studied by
means of the linearized hydrodynamic model. In this model, the electronic
excitations on the nanotube surface are described treating the electron gas as
a 2D plasma with additional contributions to the fluid momentum equation from
specific solid-state properties of the gas. General expressions are derived for
the excited longitudinal and transverse wakefields. Numerical results are
obtained for a charged particle moving within a carbon nanotube, paraxially to
its axis, showing how the wakefield is affected by parameters such as the
particle velocity and its radial position, the nanotube radius, and a friction
factor, which can be used as a phenomenological parameter to describe effects
from the ionic lattice. Assuming a particle driver propagating on axis at a
given velocity, optimal parameters were obtained to maximize the longitudinal
wakefield amplitude
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