Transverse phase space tomography using a solenoid applied to a thermal emittance measurement

Abstract

Recently, Stratakis and collaborators performed the tomographic phase space mapping of intense particle beams in the energy range of a few keV using a pair of solenoids [D. Stratakis et al., Phys. Plasmas 14, 120703 (2007)]. In this paper, we report the tomographic phase space mapping for the relativistic electron beam from a photocathode radio-frequency gun using a single solenoid at an energy of a few MeV. The experiment is conducted at a very low charge level aiming at mapping the phase space distributions of thermal emittance dominated beam. The phase space distribution is reconstructed with the algebraic reconstruction technique using the 14 beam profiles measured under various solenoid currents. Results from the computerized tomography (CT) technique are in good agreement with that from the solenoid scan method. The reconstructed phase space from the CT technique is further analyzed and shows a stochastic distribution which is a strong confirmation for the measurement of thermal emittance. Details on measurement principles and experimental implementation of the CT technique and solenoid scan method are presented.