X-RAY SPECTROMETRY APPARATUS HAVING A CONTROLLED X-RAY SOURCE

1329264 Automatic current and X-ray control SOC NATIONALE DES PETROLES D'AQUITAINE 11 Sept 1970 [12 Sept 1969] 43648/70 Heading G3R [Also in Division H1] The gas pressure within an X-ray tube is controlled automatically in response to the electrons collected or reflected from the anode, or in response to X-rays emitted from the anode or from a sample irradiated by X-rays from the tube. In Fig. 1 a capillary tube 14 supplies gas such as argon, nitrogen, or dry air at a pressure of 10-2 - 10-3 mm. in the vicinity of apertures 13 and 13a which allow X-rays and electrons to emerge from the anode 12 which pass to a collector 20 feeding a vibrating condenser amplifier 21 and comparator 22 which controls the motor 23 actuating the needle of a valve 15 adjusting the flow of gas through the capillary tube 14. The cathode support 2 is provided with cooling fins 3 and is surrounded by a tube 1 one end of which forms a socket adapted to provide electrical connection to the cathode In the spectrometer shown in Fig. 2 an X-ray tube 32 as described above irradiates a sample 33 which produces X-rays which pass through collimating slits 34 to a crystal 35 and detector 36. A detector 37 receives X-rays from the sample and its output is used to control the valve 31 which admits gas to the X-ray tube 32.