Low-β acceleration with a MEQALAC

In a Multiple Electrostatic Quadrupole Array Linear Accelerator (MEQALAC) a number of parallel beams is accelerated simultaneously. This devise is useful for exit energies up to 1 MeV per nucleon. Radial stability is provided by electrostatic quadrupole lenses placed between successive acceleration gaps. The proof-of-principle MEQALAC presently available at FOM features four He+ ion beams which are accelerated to an energy of 120 keV. The resonator cavity has a modified Interdigital-H-structure and contains 20 acceleration gaps. Its resonance frequency is 40 MHz. Transmission measurements on injected beams with currents ranging from 1 to 15 mA are presented. The transverse phase advance per cell of the quadrupole channels is varied between 430 and 1140. A maximum current of 2.2 mA per channel has been accelerated. A design for a MEQALAC which will be used for acceleration of N+ ions to 1 MeV is presented. This accelerator will be operated at various frequencies to allow for a variation of the exit energy