Abstract: A method for producing durable optical baffling materials comprising poling to a mirror finish the surface of a starting material, preferably having a very fine-grained structure, and then bombarding the surface of the starting material with low energy (0 to 50 keV) pulsed electrodes at a pulse length of about 0.1 microseconds. A fluence of 0.5 cal/cm.sup.2 renders the surface completely black in appearance, retaining none of its initial mirror-like properties.

Abstract: A method and an apparatus for controlling the angle of incidence of low-egy, high current density electron beams are disclosed. The apparatus includes a current generating diode arrangement with a mesh anode for producing a drifting electron beam. An auxiliary grounded screen electrode is placed between the anode and a target for controlling the average angle of incidence of electrons in the drifting electron beam. According to the method of the present invention, movement of the auxiliary screen electrode relative to the target and the anode permits reliable and reproducible adjustment of the average angle of incidence of the electrons in low energy, high current density relativistic electron beams.