| 摘要 |
A beam emittance measuring apparatus suitable for use with small diameter beams of the type commonly found in accelerators and beam transport systems. The apparatus includes a U-shaped frame that supports four thin wires that traverse the particle beam to create and detect thin particle shadows in the particle distribution. Two of the wires are shadow wires and are supported on one side of the U-shaped frame. Two of the wires are detection wires and are supported on the other side of the U-shaped frame, downstream from the shadow wires. One shadow wire and its corresponding detection wire are positioned to detect emittance data at a given point in a first emittance plane. The other shadow wire and its corresponding detection wire are positioned to detect emittance data at a given point in a second emittance plane. A given shadow wire and its corresponding detection wire are generally at right angles to each other so that the point of insertion defines the point at which the emittance measurement is made, much as the cross-hairs on a sighting device define a point being sighted. The location of the particle shadow on the detection wire provides a measure of the emittance angle of the particular beam particle whose shadow is cast by the shadow wire. The location of the particle shadow on the detection wire is detected optically using a concave mirror mounted in one side of the U-shaped frame that collects the image of the detection wire and focuses it on a segmented detector mounted in the other side of the U-shaped frame.
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