Patent Number: 
Section: claims

1. A target assembly for an isotope production system, the target assembly comprising:a target body having a production chamber and a beam passage, the production chamber being positioned to receive a particle beam directed through the beam passage, the production chamber configured to hold a target material;a first grid section and a second grid section of the target body disposed in the beam passage, each of the first and second grid sections having a front side and a back side, the back side of the first grid section and the front side of the second grid section abutting each other with an interface therebetween, the back side of the second grid section facing the production chamber; anda foil positioned between the first and second grid sections at the interface, each of the first and second grid sections having interior walls disposed within the beam passage, at least some of the interior walls of the first grid section extend radially inward in the beam passage, the interior walls defining multiple grid channels through each of the first and second grid sections, respectively, the particle beam configured to pass through the grid channels of the first and second grid sections toward the production chamber, the interior walls of the first and second grid sections engaging opposite sides of the foil. 2. The target assembly of claim 1, wherein the second grid section has a radial surface that surrounds the beam passage and defines a profile of a portion of the beam passage, the radial surface being devoid of ports that are fluidically coupled to cooling channels of the target body. 3. The target assembly of claim 1, further comprising a cooling channel extending through the target body, the cooling channel configured to have a cooling medium flow therethrough that absorbs thermal energy from the second grid section and transfers the thermal energy away from the second grid section. 4. The target assembly of claim 1, wherein the foil is a first foil and the target assembly comprises a second foil that engages the back side of the second grid section and faces the production chamber. 5. The target assembly of claim 4, wherein the second foil forming a chamber wall that defines the production chamber. 6. The target assembly of claim 4, wherein the interior walls of the second grid section engage the first foil and the second foil. 7. The target assembly of claim 4, wherein the first foil is at least 5× thicker than the second foil. 8. The target assembly of claim 4, wherein the first foil is configured to reduce the beam energy of the particle beam by at least 10%. 9. The target assembly of claim 1, wherein interior walls extend across the beam passage. 10. The target assembly of claim 1, wherein the first grid section has a radial surface that surrounds the portion of the beam passage defined by the first grid section and at least some of the interior walls of the first grid section are connected to the radial surface and extend from the radial surface into the beam passage. 11. The target assembly of claim 1, wherein each grid channel of the first grid section is formed by a plurality of the interior walls of the first grid section, and each grid channel of the second grid section is formed by a plurality of the interior walls of the second grid section. 12. The target assembly of claim 1, wherein the grid channels of the first grid section are aligned with corresponding grid channels of the second grid section to define multiple flow paths through the beam passage, wherein the foil extends across and interrupts the flow paths. 13. An isotope production system comprising:a particle accelerator configured to generate a particle beam; anda target assembly having a production chamber and a beam passage that is aligned with the production chamber, the production chamber configured to hold a target material, the beam passage configured to receive a particle beam that is directed toward the production chamber, the target assembly also including:a first grid section and a second grid section disposed in the beam passage, each of the first and second grid sections having a front side and a back side, the back side of the first grid section and the front side of the second grid section abutting each other with an interface therebetween, the back side of the second grid section facing the production chamber; anda foil positioned between the first and second grid sections along the interface, each of the first and second grid sections having interior walls disposed within the beam passage, inward in the beam passage, the interior walls defining multiple grid channels through each of the first and second grid sections, the particle beam configured to pass through the grid channels of the first and second grid sections toward the production chamber, the interior walls of the first and second grid sections engaging the foil. 14. The isotope production system of claim 13, wherein the second grid section has a radial surface that surrounds the beam passage and defines a profile of a portion of the beam passage, the radial surface being devoid of ports that are fluidically coupled to cooling channels of the target assembly. 15. The isotope production system of claim 13, further comprising a cooling channel extending through the target body, the cooling channel configured to have a cooling medium flow therethrough that absorbs thermal energy from the first and second grid sections and transfers the thermal energy away from the first and second grid sections. 16. The isotope production system of claim 13, wherein the foil is a first foil and the target assembly comprises a second foil that engages the back side of the second grid section and faces the production chamber. 17. The isotope production system of claim 16, wherein the second foil forms an interior surface that defines the production chamber. 18. The isotope production system of claim 16, wherein the interior walls of the second grid section engage the first foil and the second foil. 19. The isotope production system of claim 16, wherein the first foil is at least 5× thicker than the second foil. 20. The isotope production system of claim 16, wherein the first foil is configured to reduce the beam energy of the particle beam by at least 10%.