Dual energy power supply

In a CT system including an X-ray tube having a cathode and anode, a detector system for detecting X-rays emitted from said tube, means for rotating at least the tube about a rotation axis, and a power supply for use in alternately powering the X-ray tube at high and low voltage levels at a predetermined rate so that the tube generates a dual energy X-ray beam, the power supply comprising:

• at least one high DC voltage supply for providing a stable, high DC voltage to the X-ray tube;
• means, including at least one waveform generator, for providing a periodic time varying waveform;
• and
• coupling means, including a transformer, for coupling the waveform generator to said DC voltage supply so that the total voltage across the cathode and anode of the tube is periodically changed between the high and low voltage levels at the predetermined rate in response to the periodic time varying waveform provided by the waveform generator.

A scanning system for scanning objects comprising a CT scanner having an X-ray tube having a cathode and anode, a detector system for detecting X-rays emitted from said tube, a conveyance system for successively moving said objects through the scanner, means for rotating at least the tube about a rotation axis around the objects as they are moved through the scanner, and a power supply for use in alternately powering the X-ray tube at high and low voltage levels at a predetermined rate so that the tube generates a dual energy X-ray beam, the power supply comprising:

• at least one high DC voltage supply for providing a stable, high DC voltage to the X-ray tube;
• means, including at least one waveform generator, for providing a periodic time varying waveform;
• and
• coupling means, including a transformer, for coupling the waveform generator to said DC voltage supply so that the total voltage across the cathode and anode of the tube is periodically changed between the high and low voltage levels at the predetermined rate in response to the periodic time varying waveform provided by the waveform generator.