Production of intense pulsed beams of highly charged ions from a superconducting electron cyclotron resonance ion source

Abstract

An experimental study of the afterglow mode was performed with a third generation electron cyclotron resonance ion source, SECRAL-II (Superconducting ECR ion source with Advanced design in Lanzhou No. II), under double frequency heating. The experimental results show that intense pulsed beams of highly charged ions (e.g., 266 eμA of ^{129}Xe^{34+} and 169 eμA of ^{129}Xe^{38+}) could be produced at high frequency (24+18 GHz) and high power (∼8 kW), even compared with the beam intensity records of SECRAL-II obtained in continuous wave (cw) mode at higher microwave frequency (28+18 GHz) and higher power (∼10 kW), the gain factor is also up to ∼3. Meanwhile, it is found that the afterglow decay time in our study is much longer than that obtained with the second generation ECR ion sources typically operating at 10–18 GHz, and the corresponding peak duration is greater than 2 ms. This study provides a viable solution for heavy ion synchrotron accelerator complex such as High Intensity Heavy Ion Accelerator Facility project that requires intense pulsed beams of highly charged ions with long peak duration.