Search results for "Accelerator Physics"
showing 10 items of 1294 documents
Energy and frequency dependence of the alpha particle redistribution produced by internal kink modes
2014
International audience; The redistribution of alpha particles due to internal kink modes is studied. The exact particle trajectories in the total fields, equilibrium plus perturbation, are calculated. The equilibrium has circular cross section and the plasma parameters are similar to those expected in ITER. The alpha particles are initially distributed according to a slowing down distribution function and have energies between 18 keV and 3.5 MeV. The (1, 1), (2, 2), and (2, 1) modes are included and the effect of changing their amplitude and frequency is studied. When only the (1, 1) mode is included, the spreading of high energy ( E≳1 MeV) alpha particles increases slowly with the energy …
Laser Compton polarimetry at JLab and MAMI
2007
For modern parity violation experiments it is crucial to measure and monitor the electron beam polarization continuously. In the recent years different high-luminosity concepts, for precision Compton backscattering polarimetry, have been developed, to be used at modern CW electron beam accelerator facilities. As Compton backscattering polarimetry is free of intrinsic systematic uncertainties, it can be a superior alternative to other polarimetry techniques such as Moller and Mott scattering. State-of-the-art high-luminosity Compton backscattering designs currently in use and under development at JLab and Mainz are compared to each other. The latest results from the Mainz A4 Compton polarime…
A dynamic collimation and alignment system for the Helmholtz linear accelerator
2021
Review of scientific instruments 92(11), 113306 - 113306-9 (2021). doi:10.1063/5.0069824
White-light implementation of the Wigner-distribution function with an achromatic processor.
2010
A temporally incoherent optical processor that combines diffractive and refractive components is proposed for performing two different operations simultaneously: an achromatic image along an axis and an achromatic one-dimensional Fourier transformation along the orthogonal axis. These properties are properly employed to achieve the achromatic white-light display of the Wigner-distribution function associated with a one-dimensional real signal, with high redundancy and variable scale.
The optical system of the A4 laser Compton polarimeter
2007
Compton backscattering polarimeters for experiments at sub-mA accelerator facilities use optical cavities to increase the laser light intensity. Therefore, parasitic properties of the optical elements have an increased influence on the polarization state of the light and need to be analyzed carefully. This contribution shows examples of such difficulties and the possible solutions, found during the setup of the A4 Compton backscattering polarimeter at the MAMI accelerator facility of the university of Mainz.
Self-trapping of speckled light beams
2008
A speckle beam of light breaks up into small fragments as it propagates in a standard self-focusing nonlinear material. Now, by exploiting the non-local thermal response of a material, it is possible to trap a speckle beam in a self-induced waveguide.
All-diffractive achromatic Fourier-transform setup
2009
An achromatic Fourier transformation under broadband converging spherical-wave illumination is optically achieved by use of only two on-axis blazed zone plates. The novel optical configuration provides the achromatic Fraunhofer diffraction pattern of an arbitrary input signal with adjustable magnification. Further analysis of the system permits us to obtain a simple analytical expression to evaluate both the longitudinal and the transversal residual chromatic aberration, resulting in a compact achromatic Fourier transformer with low chromatic errors, even for a wide spectral content of the point source.
Collision-induced polarization scattering of dispersion managed solitons
2005
Using a multiscale expansion of coupled nonlinear Schrodinger equations we study the role of map strength and channel spacing for two colliding solitons. We numerically study then the depolarization caused by collisions of dispersion-managed vector solitons.
Analytical formulation of the axial behavior of apodized general Bessel beams
1999
We present an analytical formula for the evaluation of the axial-irradiance distribution of general Bessel beams apodized by a radially-nonsymmetric window. Our approach is based on the similarity between the axial behavior of such beams and the propagation properties of a properly modified version of the window transmittance. To illustrate our formalism, we analyze the axial behavior of some complex beams.
X-wave bullets with negative group velocity in vacuum.
2006
Propagation-invariant, X waves with negative group velocity are reported. Beam aperturing allows for a comprehensive analysis concerning the causality of the optical signal and forerunner formation.