Universal angulometer

Abstract

An angulometer for recording on film at the time of exposure, both the direction of an incident radiation beam and the angle which the beam makes with the normal to the plane of the film, the angulometer consisting of a radiation transparent plate within which is fixedly mounted perpendicularly to the plane of the plate a radiation opaque small diameter cylindrical rod which has its lower end coincident with the bottom surface of the plate. A set of concentric radiation opaque angulation indicator circles having a center common with the center of the rod are formed in the bottom surface of the plate, each successive circle of larger radius corresponding to a successively larger number of degrees of inclination of a radiation beam to the axis of the rod. In use, the device is placed on the X-ray film adjacent to the part to be X-rayed and left there during exposure. When the film is developed, the shadows of the radiation opaque concentric circles and rod appear. The length of the shadow to the outermost circle to which it extends gives the angle of the X-ray beam to the rod, and the direction of the shadow gives the direction of the beam with regard to the part photographed. If the shadow falls between two circles the angle can be readily interpolated.

Dependencies are inferred from the claim text.