Mevion Medical Systems, Inc.

Jan Van Der Laan

Kenneth P Gall

Gerrit Townsend Zwart

Ken Yoshiki Franzen

Charles D O'Neal, Iii

Stanley J Rosenthal

Michael Busky

James Cooley

Adam C Molzahn

Thomas C Sobczynski

Stanislaw P Sobczynski

Charles D O'NEAL Iii

Charles D Iii O'NEAL

An example particle accelerator includes the following: a voltage source to provide a radio frequency (RF) voltage to a cavity to accelerate particles from a plasma column, where the cavity has a magnetic field causing particles accelerated from the plasma column to move orbitally within the cavity; an extraction channel to receive the particles accelerated from the plasma column and to output the received particles from the cavity; and a regenerator to provide a magnetic field bump within the cavity to thereby change successive orbits of the particles accelerated from the plasma column so that, eventually, particles output to the extraction channel. The magnetic field is at least 6 Tesla and the magnetic field bump is at most 2 Tesla.

Magnetic field regenerator

In an example, a synchrocyclotron includes a particle source to provide pulses of ionized plasma to a cavity; a voltage source to provide a radio frequency (RF) voltage to the cavity to accelerate particles from the plasma column outwardly; and an extraction channel to receive a beam of particles from the cavity for output from the particle accelerator. The particle source is configured to control pulse widths of the ionized plasma in order to control an intensity of the beam of particles. This example synchrocyclotron may include one or more of the following features, either alone or in combination.

Controlling intensity of a particle beam

An example particle accelerator includes a coil to provide a magnetic field to a cavity; a particle source to provide a plasma column to the cavity; a voltage source to provide a radio frequency (RF) voltage to the cavity to accelerate particles from the plasma column, where the magnetic field causes particles accelerated from the plasma column to move orbitally within the cavity; an enclosure containing an extraction channel to receive the particles accelerated from the plasma column and to output the received particles from the cavity; and a structure arranged proximate to the extraction channel to change an energy level of the received particles.

Adjusting energy of a particle beam

An example particle accelerator includes a coil to provide a magnetic field to a cavity; a cryostat comprising a chamber for holding the coil, where the coil is arranged in the chamber to define an interior region of the coil and an exterior region of the coil; magnetic structures adjacent to the cryostat, where the magnetic structures have one or more slots at least part-way therethrough; and one or more magnetic shims in one or more corresponding slots. The one or more magnetic shims are movable to adjust a position of the coil by changing a magnetic field produced by the magnetic structures.

Magnetic shims to alter magnetic fields

An example particle accelerator may include the following: a voltage source to sweep a radio frequency (RF) voltage in a cavity to accelerate particles from a plasma column, where the cavity has a magnetic field causing particles accelerated from the plasma column to move orbitally within the cavity, and where the magnetic field has flux that bows at edges of the cavity; a regenerator to provide a magnetic field bump within the cavity to thereby change successive orbits of the particles accelerated from the plasma column so that, eventually, particles output to an extraction point, where the regenerator is located at a radius in the cavity relative to the plasma column; and ferromagnetic arrangements located in the cavity proximate to the radius, where each ferromagnetic arrangement provides a magnetic field bump, and where ferromagnetic arrangements adjacent to the regenerator are separated from the regenerator by a space.

Focusing a particle beam using magnetic field flutter

An example particle accelerator includes the following: a resonant cavity in which particles are accelerated, where the resonant cavity has a background magnetic field having a first shape; and an extraction channel for receiving particles output from the resonant cavity. The extraction channel comprises a series of focusing regions to focus a beam of received particles. At least one of the focusing regions is a focusing element configured to alter a shape of the background magnetic field to a second shape that is substantially opposite to the first shape in the presence of a magnetic field gradient resulting from reduction of the background magnetic field from the resonant cavity to the extraction channel.

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Danvers, MA, United States of America

Jan Van Der Laan