Speaker
Description
Electron beams produced via Laser Wakefield Acceleration are notoriously known for their pointing instability, which makes the retrieval of the energy spectrum via magnetic spectrometers prone to energy miscalculations. Here, we demonstrate an improved scheme of a previously published spectrometer employing two scintillating screens and a magnetic dipole in between. The first screen provides the pointing angle and is placed upstream of the dipole, while the second one is installed behind the dipole for energy measurements. A collimator is installed in front of the dipole allowing only a portion of the beam to be detected, resulting in an improved energy resolution. For the electrons entering the collimator, a numerical procedure is laid out to retrieve the exact entrance angle of each transverse beamlet, which in turn allows a weighted sum procedure to be carried out to retrieve the final spectrum. We find that the first scintillator screen used in our setup contributes significantly at scattering the impinging electrons. We thus performed Monte Carlo simulations to account for this effect, finally correcting the observed spectrum to retrieve the actual one at the position of the vacuum chamber exit.
