Length Measurement of High-brightness Electron Beam thanks to the 3-Phase Method

T. Vinatier (1) , C. Bruni (2) , S. Chancé (2) , P. Puzo (2)

1 Dept. Accelerateurs
2 LAL - Laboratoire de l'Accélérateur Linéaire

The goal of 3-phase method is to determine the length of an electron beam without dedicated diagnostics by varying the measurement conditions of its energy spread, through a change in the RF phase of an accelerating structure. The originality here comes from the fact that it is applied on high-brightness electron beams of few MeV generated by RF photo-injectors. It allows testing the accuracy of 3-phase method, since the length to reconstruct is known as being that of the laser pulse generating the beam. It requires establishing the longitudinal transfer matrix of a RF photo-injector, which is difficult since the electron velocity vary from 0 to relativistic during its path*. The 3-phase method in RF photo-injector has been simulated by ASTRA and PARMELA codes, validating the principle of the method. First measurement has been done on PHIL accelerator at LAL, showing a good agreement with the expected length. I will then show results obtained at PITZ with a standing wave booster and a comparison with those coming from a Cerenkov detector. Finally, measurements at higher energy performed on the SOLEIL LINAC with travelling wave accelerating structures will be exposed.

Domaines: Physique des accélérateurs [physics.acc-ph]

T. Vinatier, C. Bruni, S. Chancé, P. Puzo. Length Measurement of High-brightness Electron Beam thanks to the 3-Phase Method. Christine Petit-Jean-Genaz, Gianluigi Arduini, Peter Michel, Volker RW Schaa. 5th International Particle Accelerator Conference IPAC'14, Jun 2014, Dresden, Germany. Joint Accelerator Conferences Website, THPME095, pp.3459-3461, 2014. ⟨in2p3-01006701⟩