Talk:Magnetic lens

I changed the order of $$H_R$$ and $$H_Z$$ in the sentence "$$H_R$$ causes the particle to spiral through the lens, and this spiraling expose the electron to $$H_Z$$ which in turn focus the electron". This can not be true, since $$\mathbf{F} = q\mathbf{v} \times \mathbf{B_R} = 0$$ for a particle traveling in z-direction. The other way round it makes sense, see http://www.umsl.edu/~fraundorfp/nanowrld/newlive/maglens.html. The mistake is also in the source. — Preceding unsigned comment added by 81.223.138.18 (talk) 13:47, 7 March 2017 (UTC)