Abstract: The novel radiation source system of this invention includes a pair of electrodes which are coaxially mounted at each end of a single cylindrical transparent arc chamber. A liquid, such as water, is circulated through the arc chamber with a tangential velocity so as to form a vortexing liquid wall. The main functions of the liquid wall are to cool the periphery of the arc discharge between the electrodes thus constricting the arc diameter, and to absorb ultraviolet and infrared radiation which would otherwise be absorbed by the outer solid wall. This liquid wall produces a positive dynamic impedance for the arc discharge. In addition, a vortexing column of inert gas, injected through the length of the chamber, stabilizes the arc discharge between the electrodes.

Abstract: This invention is directed to an electro-optical apparatus for determining the position of an opaque surface without contact with the surface. It includes a light beam system which projects a well defined beam having a rectangular cross-section, obliquely onto the surface such that any movement of the surface in the perpendicular direction will result in a displacement of the illuminated area on the surface, and a detector which converts this displacement into a proportional light intensity. The detector has a field stop with an aperture of specific shape onto which the illuminated area is imaged such that only a portion of the image will pass through the aperture depending on the displacement of the illuminated area. A photosensitive device is used to measure the light intensity passing through the aperture.