Abstract: An electron-optical system directs an electron beam which emanates, for example from a line-shaped or annular emissive cathode element, onto an anode target face in a collimated fashion so that a large part of reflected electrons is incident on the target face again, thus contributing to the generating of X-rays. The construction of the electron-optical system and the high degree of re-incidence of scattered electrons allows for a minimum distance between the anode target face and the exit window. A filament of the cathode may be constructed so as to achieve an optimally uniform operating temperature over a comparatively large part of its length.

Abstract: The connector comprises two coupling elements (1) in each of which end parts of light conducting fibres (9) are secured mutually in parallel beside each other in such a manner that the centers of their end faces (15) are situated on one line (17) in an end face (19) of the coupling element (1). The connector further comprises a connector housing (25) for receiving the two coupling elements (1). Each coupling element (1) has a cylindrical outer surface (20) the axis of which coincides with the axis of the light conducting core of one of the fibre end parts (9) secured therein (preferably the central one) and which is capable of cooperating with a centring member (27) of the connector housing (25). Each coupling element furthermore has an orientation element (23) which is capable of cooperating with an orientation member (29) of the connector housing (25).