GB484281A - Method of and means for preventing overloading of roentgen tubes - Google Patents

Abstract

484,281. Photo - electric control of R÷ntgen - ray apparatus. SIEMENS - REINIGER-WERKE AKT.-GES. Oct. 19, 1937, Nos. 28488, 28489, and 28490. Convention dates, Oct. 19, 1936, Oct. 31, 1936, and Aug. 5, 1937. [Class 40 (iii)] [Also in Group XXXV] A photo-electric cell or other light-sensitive device is subjected to the light from the focus of a R÷ntgen tube to control the tube to prevent its overloading. For example, a mirror 13, Fig. 11, is mounted in the diaphragm housing 29 of the earthed casing 27 of a R÷ntgen tube 1 so as to reflect the light coming through aperture 28 from focus of tube to an optical system 5, which throws the light on a photo-electric cell 6. The current from the cell may control a relay to switch the R÷ntgen tube off when the light exceeds a predetermined value. In a modification, Fig. 2, the current from the cell 6 flows through a resistance 11 causing discharge of a tube 10 through a resistance 12, which in turn causes interruption of discharge of a tube 9, whereby the R÷ntgen tube 1 is switched off. In another modification, the R÷ntgen tube is switched on and off by a valve connected to a discharge tube device or a trigger circuit operated by an amplifying valve controlled by the cell. In the form shown in Fig. 5, the cell controls the bias of a grid 20 in the R÷ntgen tube and thereby maintains its emission substantially constant. In another form, Fig. 9, the cell controls the alternating current heating circuit of the R÷ntgen tube ; and in a modification of this the heating is performed by direct current from a valve controlled by the cell.