| 摘要 |
PROBLEM TO BE SOLVED: To provide a beam shaping assembly for neutron capture therapy that is invented for improving radiation flux and quality of a neutron source.SOLUTION: In a beam shaping assembly 10, neutrons are produced by nuclear reaction between a target 12 and an incident proton beam from a beam inlet 11, the neutrons form a neutron beam defining one main axis X. A moderator 13 moderates the neutrons from the target to epithermal neutron energies. A gap channel 18 is arranged between the moderator and a reflector 14 so as to improve an epithermal neutron flux. The reflector leads the neutrons deviated from the main axis to the main axis so as to enhance epithermal neutron beam intensity. A thermal neutron filter 15 is used for absorbing thermal neutrons so as to avoid overdosing in a superficial normal tissue during therapy. A radiation shield 16 is used for shielding leaking neutrons and photons so as to reduce dose of the normal tissue in a non-radiation region.SELECTED DRAWING: Figure 3 |
