Laser-Compton scattering as a tool for electron beam diagnostics

Abstract

Laser-Compton scattering (LCS) experiments were carried out at the Idaho Accelerator Center (ICA) using the 5 ns (FWHM) and 22 MeV electron beam. The electron beam was brought to an approximate head-on collision with a 7 ns (FWHM), 10 Hz, 29 MW peak power Nd:YAG laser. We observed clear and narrow X-ray peaks resulting from the interaction of relativistic electrons with the 532 nm Nd:YAG laser second harmonic line on top of a very low bremsstrahlung background. We have developed a method of using LCS as a non-intercepting electron beam monitor. Unlike the method used by Leemans et al. (1996), our method focused on the variation of the shape of the LCS spectrum rather than the LCS intensity as a function of the observation angle in order to extract the electron beam parameters at the interaction region. The electron beam parameters were determined by making simultaneous fits to spectra taken across the LCS X-ray cone. We also used the variation of LCS X-ray peak energy and spectral width as a function of the detector angles to determine the electron beam angular spread, and direction and compared the results to the previous method. Experimental data show that in addition to being viewed as potential bright, tunable and monochromatic X-ray source, LCS can provide important information on electron beam pulse length, direction, energy, angular, and energy spread. Since the quality of LCS X-ray peaks, such as degree of monochromaticity, peak energy and flux, depends strongly on the electron beam parameters, LCS can therefore be viewed as an important non-destructive means for electron beam diagnostics.

A broadband laser plasma x-ray source for application in ultrafast chemical structure dynamics

“…While x-ray generation from condensed matter targets has been explored by many groups for several decades, 7,8 much attention has recently been directed to the possibility of more or less collimated laser-generated broadband beams obtainable by relativistic electron acceleration, [9][10][11] high harmonic generation, 12,13 and reverse Compton scattering. 14 The latter approaches are undergoing intensive development at the present time, and the possibility of in-house pump-probe Laue crystallography 2 using the low shot rates but high collimated fluxes of broadband femtosecond betatron beams 15 may be worth particular suggestion. Meanwhile the extreme laser power requirements, low flux soft x-ray beams, and need for implementation of a relativistic electron beam in these respective sources motivates ongoing work with simpler laser-based sources.…”

Ultrashort-pulse MeV positron beam generation from intense Compton-scattering γ-ray source driven by laser wakefield acceleration

“…Compton scattering has been proposed as a means of generating tunable, short pulses of X/γ rays with narrow bandwidth Chouffani et al, 2006;Luo et al, 2010). The most intense Compton scattered photons are produced when the laser light is backscattered off the electrons.…”

Nevada National Security Site-Directed Research and Development FY 2011 Annual Report

“…Magnetic coil diagnostics give information on total charge, but no information on energy or the angular distribution of the beam with respect to the axis. Compton scattering has been used mainly to produce tunable x-ray beams but can be used for diagnostic purposes (Chouffani 2006). Unlike previous work, this SDRD effort is based on an ab initio theoretical treatment, and does not make any assumptions about the beam parameters.…”