Isotope Separator for External Ion Injection into EBIS

An advanced Electron Beam Ion Source (RhicEBIS) was successfully used over the last several years at Brookhaven National Laboratory to supply highly charged ion beams of various elements to the Relativistic Heavy Ion Collider (RHIC) and to the NASA Space Radiation Laboratory (NSRL). It is advantageous to inject isotopically pure beams of singly charged ions into the EBIS, in order to increase the relative abundance of ions of the desired charge to mass ratio, and thereby enhance the RHIC luminosity. For this purpose we are developing an isotope separator based on a 900 double focusing dipole magnet, and presently coupled to a hollow cathode ion source (HCIS). This source is able to generate 1+ ion beams of different elements for external injection into EBIS with intensities high enough to fully fill the capacity of the EBIS ion trap in the slow injection mode. A quadruplet of electrostatic quadrupole lenses has been installed in front of the dipole magnet to separate different isotopes in the plane of the magnet output slit. A CsI (Tl) scintillator placed near this plane has been used to optimize mass resolution of the separator. The main challenge was to simultaneously achieve both the required resolution and high transmission from the ion source to the output of the separator. The results of measurements for charged xenon isotopes, injected into the HCIS as gas with natural abundance are presented and discussed.