Experimental results on MEIRA characteristics and some typical operational problems

Various types of factors affect the deflection radius of a separator and consequently its mass calibration versus the magnetic field setting. In particular, the effects of the source magnetic field and of the shift of the effective boundaries with increasing field values are described in detail. Results of accurate measurements of the deflection radius for MEIRA are reported and interpreted. Measurements of the third order aperture aberrations are in good agreement with the expected curve. The image curvatures for trajectories with the same α were found to be practically independent of the value of α, thus achieving the main objective of the MEIRA optical design. Three typical operational problems encountered during the trial runs of MEIRA and their solutions are described: lack of space-charge neutralization of the ion beam, frequent high-voltage breakdown in the source region, permanent short-circuits between the source and the electrode under certain conditions. (Auth.)