Abstract: He--Ne gas discharge tube having a cylindrical tube body with an inside cathode cylinder and end walls which are inserted into ends of the tube body and which have for two capillary tubes, outside ends of which are closed by means of Brewster windows, exhaust pipe and connecting pin for the cathode cylinder. The tube, the end walls and the capillary tubes consist of calcium alkalisilicate glass or calcium alumosilicate glass. The end walls are sealingly connected by means of glass solder to the tube body, the capillary tubes, the exhaust pipe and the cathode connecting pin. The He--Ne gas discharge tube is characterized by a high helium tightness.

Abstract: The rotational vibration drive consists of a first plate attachable to a ed baseplate and a second plate attachable to a clamping plate for the ring laser block. The first and second plates are arranged side by side in the same plane. A torsionally stiff rotational spring linkage joins the first and second plates and has a rotational axis perpendicular to the plane of the beam path of the ring laser. The first and the second plates together with the rotational spring linkage are of unitary construction. Two slots originating from the rotational spring linkage extend between the first and the second plates. A piezoceramic stack drive is arranged in mutually-aligned holes in the first and second plates and acts between the said first and second plates, the axis of the piezoceramic stack drive being positioned centrally in height between surfaces of the first and second plates.