Method for the electrochemical etching of macropores in n-type silicon wafers, using illumination of the wafer reverse sides and using an aqueous electrolyte, characterized in that the electrolyte is an aqueous acetic acid solution with the composition of H2O:CH3COOH in the range between 2:1 and 7:3, with an addition of at least 9 percent by weight hydrofluoric acid. The band stop filter includes a capacitor in parallel with an inductor. The charged particle orbit control device includes multiple bending magnets that bend the charged particle.