Device for varying the energy of a particle beam extracted from an accelerator
AssigneeIon Beam Applications S.A.
InventorsYves Jongen, Vincent Poreye
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Abstract
A device for varying the energy of a particle beam extracted from a fixed-energy particle accelerator includes a block of energy degrading material positioned in the path of the particle beam. The block of energy degrading material is preferably in the form of a ring arranged on a wheel. The ring is of a staircase configuration, having discrete steps defining a thickness between parallel entry and exit faces. According to one aspect of the invention, the block is configured so that the particle beam energy variation reaches a maximum at the edges of each step. This upper limit is also the lower limit of the next step. Thus, continuous energy variation is possible despite the fact that the thickness of the block varies in discrete steps.
Claims13
Device for varying the energy of a particle beam extracted from a particle accelerator, comprising an energy degrader substantially consisting of a block of material, the thickness of which (E1+E2) is discretely variable by steps, characterized in that the energy difference between the steps is variable and is determined such that the variation in the intensity of the beam reaches, at the limit between two consecutive steps, a maximum of 15%, and preferably a maximum of 10%, of the maximum intensity obtained at the exit of each of the two adjacent steps under consideration.
A method for producing substantially continuous variation of the energy of a particle beam extracted from a fixed energy particle accelerator comprising the steps of:
- positioning a block of energy degrading material in the path of the particle beam, said block having a thickness between parallel entry and exit faces which is variable in discrete steps to define a staircase configuration in which each step imparts a variable energy difference to the particle beam and said variable energy difference reaches a maximum energy difference at a limit of each step, so that the maximum energy difference of a step is approximately equal to a minimum energy difference of a succeeding step;
- and
- rotating said block to position successive steps in the path of the particle beam.
Dependencies are inferred from the claim text.