X-ray tube comprising two successive layers of anode material
First Claim
1. An X-ray tube comprising an anode target for emitting X-rays when struck by electrons, a cathode disposed opposite the anode target for emitting target striking electrons when an accelerating potential difference is applied between the cathode and the anode target, and an evacuated envelope containing the cathode and the anode target and having an X-ray permeable window for passing the X-rays emitted by the target;
- characterized in that said anode target comprises, in order from the window;
(a) a first layer consisting essentially of a material having a maximum atomic number of approximately 30, for emitting long wavelength X-rays when a first predetermined accelerating potential difference is applied; and
(b) a second layer consisting essentially of a material having a minimum atomic number of approximately 40, for emitting short wavelength X-rays when a second predetermined accelerating potential difference is applied;
said first layer having a thickness which is sufficiently small to facilitate passage therethrough of X-rays emitted by the second layer.
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Accused Products
Abstract
An anode of an X-ray tube, particularly for X-ray analysis, comprises at least two successive layers (7, 8 or 11, 10 or 13, 12) of anode material. A first layer (7, 11, 12) thereof consists mainly of an element having a comparatively low atomic number, such as scandium or chromium, while a second layer (8, 10, 13) consists mainly of an element having a comparatively high atomic number, such as molybdenum, tungsten or uranium. For the selection of a desired radiation spectrum, the tube voltage is selectively adjusted such that either or both layers are activated.
40 Citations
13 Claims
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1. An X-ray tube comprising an anode target for emitting X-rays when struck by electrons, a cathode disposed opposite the anode target for emitting target striking electrons when an accelerating potential difference is applied between the cathode and the anode target, and an evacuated envelope containing the cathode and the anode target and having an X-ray permeable window for passing the X-rays emitted by the target;
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characterized in that said anode target comprises, in order from the window; (a) a first layer consisting essentially of a material having a maximum atomic number of approximately 30, for emitting long wavelength X-rays when a first predetermined accelerating potential difference is applied; and (b) a second layer consisting essentially of a material having a minimum atomic number of approximately 40, for emitting short wavelength X-rays when a second predetermined accelerating potential difference is applied; said first layer having a thickness which is sufficiently small to facilitate passage therethrough of X-rays emitted by the second layer. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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Specification