Search results for "accelerator"
showing 10 items of 1507 documents
Nonlinear Multimode Fiber Optics
2018
We overview recent advances in the nonlinear optics of multimode optical fibers, including ultrabroadband sideband and supercontinuum generation, Kerr and Raman beam cleanup, modal modulation instabilities, four wave mixing, and second harmonic beam cleaning.
Control of nonlinear instabilities in Bessel beams using shaped longitudinal intensity profiles
2017
International audience; We show that tailored longitudinal intensity shaping of a non-diffracting Bessel beam can strongly reduce four wave mixing induced oscillations and stabilize nonlinear propagation at ablation-level intensities
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…
Radiation dose distribution around a mobile linear accelerator Mobetron using Monte Carlo simulation
2016
The aim of this work is to analyze the scattered radiation produced by the mobile accelerator Mobetron. To do so detailed Monte Carlo simulation using two different codes, Penelope2011 and Geant4, were performed. Experimental measurements were also done to validate them. To quantify the attenuation of the internal structures present in the accelerator head on the scattered radiation produced, some of the main structural shielding in the Mobetron has been incorporated into the simulation. Results are compared with experimental measurements. Some discrepancies between the calculated and measured dose values were found. These differences can be traced back to the importance of the radiation co…
EP-1187: Measurements and Monte Carlo modeling of the back scatter from linac secondary collimator into beam monitor chamber
2013
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.
Source of Polarized Electrons for MAMI B
1991
A source of polarized electrons has been set up in order to inject polarized electrons into the 855 MeV c.w. electron accelerator MAMI B at the Mainz nuclear physics institute. It is based on photoemission of the 3/5 semiconductor GaAsP and will provide a d.c. current of 100 µA with a beam emittance of 1π mm mrad, and a polarization of about 40%.
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.