Patent Number: 
Section: claims

1. A radiation exposure system having a beam source, the system further comprising:a variable thickness degrader, positioned between the beam source and an object to be exposed, for providing varying degrees of degradation to a radiation beam emitted from the beam source onto the object; anda set of detectors, positioned between the variable thickness degrader and the object, for receiving and measuring only a portion of the radiation beam remaining after the degradation of the radiation beam by the variable thickness degrader,wherein the variable thickness degrader is formed to include a plurality of sections, and wherein each of the plurality of sections comprises a respective aperture for enabling an un-degraded portion of the radiation beam to pass there through onto the object. 2. The radiation exposure system of claim 1, wherein each of the plurality of sections has a respective one of a plurality of different thicknesses to provide a respective one of the varying degrees of degradation. 3. The radiation exposure system of claim 1, wherein each of the plurality of sections is formed from a respective one of a plurality of different materials to provide a respective one of the varying degrees of degradation. 4. The radiation exposure system of claim 1, wherein the variable thickness degrader is formed from one or more metals. 5. The radiation exposure system of claim 1, wherein the variable thickness degrader is arranged to reduce an amount of radiation exposure applied to the set of detectors to below a threshold amount. 6. The radiation exposure system of claim 1, wherein the set of detectors comprise a set of diodes. 7. The radiation exposure system of claim 1, further comprising a processor for calculating an amount of radiation exposure emitted by the radiation beam based on a current amount in the set of diodes. 8. The radiation exposure system of claim 1, wherein the set of detectors comprise a set of photomultiplier tubes. 9. The radiation exposure system of claim 1, wherein the degrader is formed to have at least a semi-circular shape. 10. The radiation exposure system of claim 9, further comprising a motor for varying a position of a portion of the variable thickness degrader that is exposed to the radiation beam from among a set of predetermined positions corresponding to the varying degrees of degradation. 11. The radiation exposure system of claim 1, wherein the set of detectors are connected to a printed circuit board and arranged symmetrically around an aperture of the printed circuit board. 12. The radiation exposure system of claim 11, wherein the set of detectors comprise four detectors arranged ninety degrees apart. 13. The radiation exposure system of claim 1, further comprising a detection circuit that includes the set of detectors, the detection circuit being configured to detect and record a flux of the radiation beam over time. 14. The radiation exposure system of claim 1, wherein the variable thickness degrader has stepped levels for modulating the degradation of the radiation beam by predetermined amounts. 15. The radiation exposure system of claim 1, wherein the variable thickness degrader is formed from various plates of stackable metal such that different plate combinations formed from the various plates provide different levels of degradation to the radiation beam. 16. The radiation exposure system of claim 1, further comprising a motor for controlling a position of the variable thickness degrader to obtain a particular one of the different levels of degradation. 17. A computer program product for radiation beam control, the computer program product comprising a non-transitory computer readable storage medium having program instructions embodied therewith, the program instructions executable by a computer to cause the computer to perform a method comprising:forming a variable thickness degrader to include a plurality of sections;providing, by the variable thickness degrader positioned between the beam source and an object to be exposed, varying degrees of degradation to a radiation beam emitted from the beam source onto the object; andreceiving and measuring, by a set of detectors positioned between the variable thickness degrader and the object, only a portion of the radiation beam remaining after the degradation of the radiation beam by the variable thickness degrader,wherein said forming step forms each of the plurality of sections so as to include a respective aperture for enabling an un-degraded portion of the radiation beam to pass there through onto the object.