Effect of magnetic filter on volume production type negative ion source

Density of negative hydrogen ion H- produced by volume process is calculated in the tandem multicusp chamber with a ''magnetic filter'' and compared with the density in the single multicusp chamber without a magnetic filter. Balance equations for the negative hydrogen ion H- and for the excited hydrogen molecule H2* are solved in the stationary state. The calculated results confirm that the tandem chamber with magnetic filter is effective for producing more H- ions than the single chamber, and the negative ion density can achieve about 10 times larger value than that obtained with no filter. (author)