Influence of an electron-beam injection on ion charge state distribution in an ECR source at 2.45 GHz
The single stage multicharged ion ECR source supplimented with a La-B electron gun is investigated. The magnetic system of the source consists of Sm-Co hexapole and two solenoids which create mirror configuration. The argon plasma production chamber is a TE111 mode cavity fed with a 600-W oscillator of 2.45 GHz. The source performance was found to be independent of the gun bias potential if the gun was located in a magnetic throat. It was observed that the injection of the cold electron beam (15 mA) at the pressure of 0.008 mTorr shifted the mean ion charge from 1.3 to 1.8 and increased the currents of ions in states Z=3 and Z=4 by a factor of 2.5-3.0. For a low-frequency source, the application of an electron gun allows for the generation of middle charged ions.