Time resolved emittance measurement of a pulsed high current electron beam with the Modified Three Gradient Method

Time resolved emittance of a low-energy, high-current, and short-pulse electron beam is measured with Modified Three Gradient Method (MTGM). MTGM makes possible the non-destructive measurements of emittance of the space charge dominated beam. The MTGM is based on three gradient type measurements of beam radius and on the subsequent use of a computer code incorporating the K-V envelope equation. The beam radius is measured through use of Cerenkov Radiation (CR). The CR light containing the beam radius information is accepted by a recording system containing a streak camera and a film. A numerical matching program, MTGMCODE, based on the root-mean-square envelope equation, was developed to determine the emittance.