Transverse Emittance Measurements of the REX-ISOLDE Beams in Preparation for the HIE-ISOLDE Commissioning

The transverse emittance at the output of the REX-ISOLDE normal conducting linac has been measured at different energies in order to characterise the beam at injection to the future HIE-ISOLDE superconducting linac. The measurements were done with low intensity stable beams (~0.5 enA) in order to avoid compensation effects in the EBIS ion source and obtain representative measurements of the radioactive ion beam emittance. Emittances were measured using a slit-grid emittance meter and compared with results obtained with a quadrupole-scan (three-gradient) method. An analysis of the background suppression is presented and possible source of errors for both type of measurements are discussed.