Orateur
Description
Linear Induction Accelerator Flash X-ray radiography uses electron beams produced by injectors, then accelerated and focused on high Z material targets. Spot size of the focused beam depends on the emittance of the injector’s beam.
In the context of the development of an injector using a cold cathode, we are conducting a study in order to characterize and understand the emittance associated with the extraction of a beam from the cathode surface, including in case of multipulse operation. Experiments are performed with a dual-pulse generator used to drive a diode designed to produce at the cathode an electric field similar to the one in a LIA injector.
A first diagnostic is beam imagery at the anode foil, performed thanks to the light produced by Cerenkov Effect when the electrons interact with a few millimeter-thick silica convertor. This diagnostic shows inhomogeneity in the electron density at the anode, somehow related to the inhomogeneity at the beam creation.
Another diagnostic uses a multi-pinhole mask at the anode plane coupled with a drift zone before interaction with the Cerenkov radiator. This arrangement enables to measure the transverse velocity distribution (equivalent to an effective transverse temperature) of the electrons at several radial positions in the beam.
