Ion beam probe for measurement of wiggler errors

Precise characterization of wiggler field errors is needed in order to perform compensations. The traditional method, which relies solely on Hall probe data acquired from a field map, suffers due to cumulative noise effects and is inadequate for long wigglers. The proposed instrument avoids this problem by directly measuring an equivalent trajectory of a low energy ion beam which is momentum and emittance matched to the electron beam. The ion beam is injected into the wiggler where it is imaged onto the screen of a miniature CCD camera which travels through the wiggler bore. By combining data from the camera and the Hall probe, the instrument achieves a resolution superior to that of a Hall probe alone.<>