An electrostatic sweep plate device for emittance measurement of ion beams to 2 MeV

Electrostatic sweep plate devices have been used previously for the measurement of ion beam emittance. These devices may be routinely designed with an ultimate angle resolution of /spl plusmn/0.25 mrad or less. We have used a similar device for measuring the emittance of H/sup -/ and H/sup +/ beams exiting an RFQ at 1 MeV. This scanner will be used to characterize the beam exiting a low-power DTL at energies up to 2 MeV. The physics design changes consist primarily of increasing the length of the deflection plates and decreasing their separation to obtain high electric field at low deflection plate voltage. The front face of the scanner was made thicker and designed for water cooling to withstand the beam power at up to 2 MeV. The design of the scanner is discussed. This includes the device angular resolution and maximum acceptable angle. The thermal analysis that led to the design of the water-cooled front face is shown. Data showing the performance of the device and resulting emittance measurements at 1 MeV are presented.<
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