Performance of the LBL ECR ion source

Abstract

The LBL Electron Cyclotron Resonance (ECR) ion source in test operation since January 1984 has produced a wide variety of high charge state ion beams suitable for injection into the 88-inch Cyclotron. Two recent developments have dramatically improved the capability of the ECR source. The first development was the production of metallic ions. The intensities of aluminum ions produced were 36, 22, 10, and 0.065 eμA for charge states 6, 7, 8, and 11, respectively. Calcium ion intensities were 36, 31, 4.6, and 0.20 eμA for charge states 8, 9, 12, and 14, respectively. The second development was the replacement of the sextupole magnet used in all other high charge state ECR sources with an octupole structure. This modification resulted in a dramatic improvement in the intensities of the high charge state beams and a significant upward shift in the charge state distribution (CSD). The ECR-octupole or “OCTIGUN” has produced 89, 52, 9, and 2.5 eμA. of Ar 8,9,11,12+ and 21, 10, and 0.34 eμA of Kr 10,14,18+, respectively. For the high charge states of argon and krypton the improvement gained by using the octupole is typically a factor of 5 to 10.