초록 |
A technique for indirectly measuring the degree of alignment of a beam in an electron-optical system including aligning means, focusing means and deflection means. To carry out the measurements, a simple sensor may be used, even a single-element sensor, provided it has a well-defined spatial extent. When practiced in connection with an X-ray source which is operable to produce an X-ray target, further, a technique for determining and controlling a width of an electron-beam at its intersection point with the target. |