A comparative study of emittance measurements using different techniques

The pepper-pot method and two slit-and-collector type techniques are tested for their applicability to measure the emittance of low energy ion beams. The exposure of Kapton foil, used here as the detector in the pepper-pot method, has been found to show a nonlinear behavior of the image contrast with the local power density of He+ beam for energy less than 10 keV. Therefore, the emittance measurement with the pepper-pot method must be made with the calibration of the contrast of the Kapton film in advance. The measured values of emittance, obtained by the different diagnostic schemes, are similar. From the view point of the negative ion beam measurement, the pepper-pot type system using Kapton film and the multislit-and-Faraday-cup system are proved to be promising.