ION-BEAM NOISE-REDUCTION METHOD FOR THE MEVVA ION-SOURCE

The beam extracted from the MEVVA ion source tends to be of a relatively high noise level, particularly for the higher charge states, making beam transport difficult in accelerator application. This paper presents experimental results which show that the use of grids within the ion source in combination with a solenoidal magnetic field can decrease the noise of the extracted beam considerably. The noise reduction can be explained by an increase in plasma density due to the applied magnetic field and space charge limitation of the extracted ion beam current.