Displaced-ray CT inspection

1. A computed tomography scanner comprising:

a housing;

a conveyor disposed at least partially within the housing and configured to move an object to be scanned through the housing along a direction of travel;

a gantry connected to the housing and configured to receive the object to be scanned;

an x-ray source attached to the gantry and configured to provide an x-ray beam that extends along a length in the direction of travel;

a plurality of detector arrays attached to the gantry and configured and disposed to receive and detect x-rays from the x-ray source, the detector arrays being displaced relative to each other, in the direction of travel, by an array spacing distance such that a geometric efficiency of the arrays is less than about 80%; and

a processor coupled to the conveyor and the gantry to control the conveyor and move the object through the housing at a first speed, and to control the rotation of the gantry at a second speed, such that the object will move a distance substantially equal to the array spacing distance during a time the gantry rotates an angle approximately equal to 180° divided by a quantity of detector arrays.

2. The scanner of claim 1 wherein the array spacing distance is such that a geometric efficiency of the arrays is less than about 70%.

3. The scanner of claim 1 wherein the array spacing distance is such that a geometric efficiency of the arrays is less than about 60%.

4. The scanner of claim 1 wherein the array spacing distance is such that a geometric efficiency of the arrays is less than about 50%.

5. The scanner of claim 1 wherein the array spacing distance is such that a geometric efficiency of the arrays is less than about 40%.

6. The scanner of claim 1 wherein the array spacing distance is such that a geometric efficiency of the arrays is less than about 30%.

7. The scanner of claim 1 wherein the array spacing distance is such that a geometric efficiency of the arrays is less than about 20%.

8. The scanner of claim 1 wherein the processor is further configured to knit data received from the plurality of detector arrays into one effective array.

9. A computed tomography scanner comprising:

a housing;

a conveyor disposed at least partially within the housing and configured to move an object to be scanned through the housing along a direction of travel;

an x-ray transmission and detection system connected to the housing and configured and disposed to transmit a plurality of x-ray fan beams through the object on the conveyor with x-rays displaced along the length of travel passing through the object, the x-ray transmission and detection system being further configured to detect x-rays in the plurality of fan beams after passing through the object, the detected x-rays being displaced along the direction of travel when passing through the object; and

a processor configured to excite the plurality of fan beams sequentially;

wherein the detected x-rays passing through the object are displaced relative to each other in the direction of travel to provide an effective geometric efficiency of the detected x-rays that is less than about 80%.

10. The scanner of claim 9 wherein the transmission and detection system comprises at least two sources and at least one detector array.

11. The scanner of claim 9 wherein the transmission and detection system comprises at least one detector array with detectors disposed substantially completely 360° around the conveyor.

12. The scanner of claim 9 wherein the transmission and detection system comprises a plurality of x-ray sources disposed substantially completely 360° around the conveyor.

13. The scanner of claim 9 wherein the transmission and detection system comprises detectors having detector widths and a plurality of pairs of x-ray sources with sources in the pairs being displaced relative to each other approximately one-half of the detector width in a direction substantially perpendicular to the direction of travel.

14. The scanner of claim 9 wherein the transmission and detection system is configured such that the effective geometric efficiency is less than about 60%.

15. The scanner of claim 9 wherein the transmission and detection system is configured such that the effective geometric efficiency is less than about 40%.

16. The scanner of claim 9 wherein the transmission and detection system is configured such that the effective geometric efficiency is less than about 20%.

17. The scanner of claim 9 wherein the x-ray transmission and detection system includes a plurality of x-ray sources and the x-ray transmission and detection system is configured to trigger the sources at a plurality of different energies to capture multi-energy data for atomic number calculations.

18. A method of CT scanning an object, the method comprising:

moving the object along a direction of travel;

transmitting displaced x-rays through the object substantially perpendicular to the direction of travel;

detecting the displaced x-rays with an effective geometric efficiency at the object of about 80% or less, wherein the speed at which the object is moved is dependent upon the geometric efficiency and the rate at which the displaced x-rays are detected;

combining information indicative of detected intensities of the displaced x-rays to group information from different x-rays for common slices together;

analyzing the combined information for slices of the object; and

outputting at least one result based on the combined information.