ACCELERATION OF NITROGEN IONS WITH A l-MeV MEQALAC

kcelerator) multiple N+ ion beams are accelerated in a number of gaps which carry a rfvnlrage. The trunsversefocrrsing of the intense ion beams is achieved by means of sets of miniaturized electrostatic quadrupnles Results are presented which sho~f that the ion beams are accelerated to I MeV uith an energy spread of less than 8 o/o. The maximum heam current measured so fk in a single channel is ZOO M. This is considerably less than the theoretically predicted current. It is shown that the smaller transmission is due mainly to misalign-ment of the quadrupnle lenses. Jntroduction At the FOM-Institute in Amsterdam a MEQALAC for the accel-eration of four intense NC ion beams has been built and is now in operation. In this type of rf accelerator, which is originally proposed by Maschke [I]. the ions are accelerated in rf gaps, while the trans-versely-directed space charge forces of the intense ion beams are op