Due to the importance of controlling the X- ray (package) beam in the diagnostic field, and the high prices of the control kids and devices for both engineer and the medical physicist, and due to the importance of recognizing the presence or absence of an X-ray beam, the researcher found it necessary to search for tools not to measure but to work as indications of the presence of X-ray beam and to know whether or not the X-ray tube has generated the X-ray. The designed device was very simple in its construction. It is composed of a wooden box lined from inside with phosphoric plates in all sides except two sides which are lined with two plane mirrors, in order to increase reflection of light inside the wooden box. The light emitted from the phosphoric plates affects a photo resistance, which works as an electric switch, and can be in connection state when there is light or in disconnection state when there is no light (Dark). This photo cell is connected to an electronic warning circuit which makes a sound when there is light from the phosphoric plate, which indicates the presence of X-ray beam,The design unit called CMRS. .