An apparatus and method for the production of radioisotopes utilizing an energy recovery linac. The ERL system is composed of an electron beam source, multiple superconducting radio frequency cavities operating at 4.5 K, a thin radiator, a target material, and a beam dump. The accompanying method discloses the use of the ERL system to generate desired radioisotopes via target interaction with bremsstrahlung photons while allowing recovery of a substantial portion of the electron beam energy before the beam is extracted to the beam dump.

A radio-frequency (RF) cavity apparatus for accelerating charged particles includes first and second cavity arms. The first and second cavity arms have respective first and second axes of rotational symmetry and each cavity arm includes at least one cell. The first and second cavity arms are connected by a resonance coupler. The cell(s) of the first cavity arm have an axial dimensional parameter that is equal to a corresponding axial dimensional parameter of the cell(s) of the second cavity arm, and the cell(s) of the first cavity arm have at least one non-axial dimensional parameter that differs from corresponding non-axial dimensional parameter(s) of the cell(s) of the second cavity arm.

A radio-frequency (RF) cavity apparatus for accelerating charged particles includes first and second cavity arms. The first and second cavity arms have respective first and second axes of rotational symmetry and each cavity arm includes at least one cell. The first and second cavity arms are connected by a resonance coupler. The cell(s) of the first cavity arm have an axial dimensional parameter that is equal to a corresponding axial dimensional parameter of the cell(s) of the second cavity arm, and the cell(s) of the first cavity arm have at least one non-axial dimensional parameter that differs from corresponding non-axial dimensional parameter(s) of the cell(s) of the second cavity arm.

As the ion beam is accelerated, the radii of the closed orbits gradually increase, and the centers thereof move in a direction approaching the peripheral edge portion along a predetermined radial direction of the cavity, and upon reversing the direction of movement, move further toward the center of the cavity. The intensity distribution in the orbital plane of the main magnetic field is designed to realize the foregoing feature. Thus, an accelerator is provided that is compact and that enables the energy of an extracted beam to be changed, that enhances the efficiency of beam injection into the accelerator from an external ion source, and that improves a dose rate of the resulting extracted ion beam.

As the ion beam is accelerated, the radii of the closed orbits gradually increase, and the centers thereof move in a direction approaching the peripheral edge portion along a predetermined radial direction of the cavity, and upon reversing the direction of movement, move further toward the center of the cavity. The intensity distribution in the orbital plane of the main magnetic field is designed to realize the foregoing feature. Thus, an accelerator is provided that is compact and that enables the energy of an extracted beam to be changed, that enhances the efficiency of beam injection into the accelerator from an external ion source, and that improves a dose rate of the resulting extracted ion beam.

An electron accelerator is provided. The electron accelerator comprises a resonant cavity comprising a hollow closed conductor, an electron source configured to inject a beam of electrons, and an RF system. The electron accelerator further comprises a magnet unit, comprising a deflecting magnet. The deflecting magnet is configured to generate a magnetic field in a deflecting chamber in fluid communication with the resonant cavity by a deflecting window. The magnetic field is configured to deflect an electron beam emerging out of the resonant cavity through the deflecting window along a first radial trajectory in the mid-plane (Pm) and to redirect the electron beam into the resonant cavity through the deflecting window towards the central axis along a second radial trajectory. The deflecting magnet is composed of first and second permanent magnets positioned on either side of the mid-plane (Pm).

An electron accelerator comprising a resonant cavity, an electron source, an RF system, and at least one magnet unit is provided. The resonant cavity further comprises a hollow closed conductor and the electron source is configured to radially inject a beam of electrons into the cavity. The RF system is configured to generate an electric field to accelerate the electrons along radial trajectories. The at least one magnet unit further comprises a deflecting magnet configured to generate a magnetic field that deflects an electron beam emerging out of the resonant cavity along a first radial trajectory and redirects the electron beam into the resonant cavity along a second radial trajectory. The resonant cavity further comprises a first half shell, a second half shell, and a central ring element.

The present disclosure relates to compact isochronous sector-focused cyclotrons having reduced dimensions and weight compared with state of the art cyclotrons of same energies. In one implementation, a cyclotron may include two pole magnets facing each other in a chamber defined by a yoke having base plates and flux return yokes forming a lateral wall of the chamber. The magnet poles may include between three and eight hill sectors alternating with a same number of valley sectors distributed about a central axis. The lip of the abyssal opening may be positioned at a distance from the corresponding valley peripheral edge. The flux return yoke may have a thickness in the portions facing valley sectors, such that the ratio of the product of the distance times the thickness to the square of the distance of the peripheral edge to the central axis is less than 5%.

A method and electron linac system for production of radioisotopes is provided. The electron linac is an energy recovery linac (ERL) with an electron beam transmitted through a thin bremsstrahlung radiator. Isotopes are produced through bremsstrahlung photon interactions in an isotope production target that is spatially separated from the bremsstrahlung radiator. The electron beam does not pass through the isotope production target. The electron beam energy is recollected and reinjected into the linac accelerating structure. The reduction of material in the beam by removing the isotope production target and making the radiator thin is the essential aspect of the invention because large spreads in energy and transverse scattering angles caused by material in the beam preclude efficient energy recovery. The method described here can reduce the cost of energy to produce a quantity of radioisotope by more than a factor of 3 compared to a non-ERL bremsstrahlung method.

As the ion beam is accelerated, the radii of the closed orbits gradually increase, and the centers thereof move in a direction approaching the peripheral edge portion along a predetermined radial direction of the cavity, and upon reversing the direction of movement, move further toward the center of the cavity. The intensity distribution in the orbital plane of the main magnetic field is designed to realize the foregoing feature. Thus, an accelerator is provided that is compact and that enables the energy of an extracted beam to be changed, that enhances the efficiency of beam injection into the accelerator from an external ion source, and that improves a dose rate of the resulting extracted ion beam.