Abstract: A system for stabilizing an irradiated mask for use in lithographic set-ups, the mask including formations which are permeable to electromagnetic or corpuscular radiations, especially ion beams, the system having one or more cooling surfaces that surround the beam axis, are disposed in the field of view of the mask, and are located between the mask and the radiation source and/or behind the mask. The cooling surfaces preferably are in the form of surfaces of revolutions, are comprised of metal, have grooves that produce multiple reflections of the thermal radiation and are spaced equal distances apart from the axis of the optical path. The distances from the cooling surfaces to the axis of the optical path preferably exceed the distance from the edge of the mask sheet to the axis of the optical path. The mask is disposed in a chamber which is maintained by automatic control at a constant temperature, particularly at room temperature, e.g. by heating of the walls.

Abstract: An operating structure of an electrical switch is an assembly comprising a contact arm part, a fixed contact part and an insulating part preferably sandwiched therebetween. The contact arm part and the fixed contact arm are made of electrically conducting material. The insulating part is preferably of a thermoplastic material. The contact arm part and the fixed contact part are provided each with two securing holes. To assemble the three parts, the material of the insulating part in its portions associated with the securing holes is locally brought into a plastic state and bulged out through the securing holes. Then, the bulges are flattened, clinched or the like, at the other side to form a structure which is joined by quasi-rivets of plastic. The manufacture of this structure takes place in a timed sequence with suitable stamping and forming tools.