Patent Number: 
Section: claims

1. An X-ray inspection system, comprising the following elements disposed sequentially along a central axis: an X-ray source capable of projecting a beam of radiation along said central axis;  a first collimator disposed coaxially with said central axis at a first location along said central axis, said first collimator having a first slit-shaped aperture having a first dimension in a first direction perpendicular to said central axis;  a second collimator disposed coaxially with said central axis at a second location along said central axis, said second collimator having a second slit-shaped aperture having a second dimension in said first direction; and  means for causing said central axis to pass through a selected inspection zone of a target, wherein said second location of said second collimator and said second dimension of said second aperture are selected such that the portion of said target actually illuminated by said beam measured in said first direction is substantially equal to the size of said selected inspection zone measured in said first direction. 2. The X-ray inspection system of  claim 1  further comprising: claim 1 an X-ray detector disposed adjacent said target and opposite said second collimator; and  a third collimator disposed between said target and said detector. 3. The X-ray inspection system of  claim 2  wherein said third collimator has a third aperture, said third aperture being oriented perpendicular to said central axis and to said first direction. claim 2 4. The X-ray inspection system of  claim 1  wherein said second dimension of said second aperture is adjustable. claim 1 5. A X-ray inspection method, comprising: providing an X-ray source capable of projecting a beam of radiation along a central axis;  providing a first collimator disposed coaxially with said central axis at a first location along said central axis, said first collimator having a first slit-shaped aperture having a first dimension in a first direction perpendicular to said central axis;  providing a second collimator disposed coaxially with said central axis at a second location along said central axis, said second collimator having a second slit-shaped aperture having a second dimension in said first direction;  providing means for causing said central axis to pass through a selected inspection zone of a target,  wherein said step of providing said second collimator includes selecting said second location and said second dimension of said second aperture such that the portion of said target actually illuminated by said beam measured in said first direction is substantially equal to the size of said selected inspection zone measured in said first direction. 6. The X-ray inspection method of  claim 5  further comprising: claim 5 providing an X-ray detector disposed adjacent said target and opposite said second collimator; and  providing a third collimator disposed between said target and said detector. 7. The X-ray inspection method of  claim 6  wherein said third collimator has a third aperture, said third aperture being oriented perpendicular to said central axis and to said first direction. claim 6 8. An X-ray inspection system, comprising the following elements disposed sequentially along a central axis: an X-ray source capable of projecting a beam of radiation along said central axis;  a first collimator disposed coaxially with said central axis at a first location along said central axis, said first collimator having a first slit-shaped aperture oriented in a first direction;  a second collimator disposed coaxially with said central axis at a second location along said central axis, said second collimator having a second slit-shaped aperture oriented in said first direction; and  means for supporting a target, wherein said second collimator is positioned as close as possible to said means for supporting said target without interfering with said target. 9. The X-ray inspection system of  claim 8  further comprising: claim 8 an X-ray detector disposed adjacent said target and opposite said second collimator; and  a third collimator disposed between said target and said detector. 10. The X-ray inspection system of  claim 9  wherein said third collimator is oriented perpendicular to said first direction. claim 9 11. The X-ray inspection system of  claim 8  wherein said second aperture is adjustable is said first direction. claim 8