Beam transport system and method, accelerator including beam transport system, and ion source including the accelerator
A beam transport system for transporting a charged particle beam, includes a magnetic field generation device that is provided in a transport line that transports the charged particle beam and generates a magnetic field parallel to a center orbit of the charged particle beam, and a beam shielding device that is provided in a region through which the charged particle beam in the magnetic field generation device passes, causes a charged particle beam in a predetermined range of the charged particle beam to pass through, and stops other charged particle beams.
1 . A beam transport system for transporting a charged particle beam, the beam transport system comprising:
a magnetic field generation device that is provided in a transport line that transports the charged particle beam and generates a magnetic field parallel to a center orbit of the charged particle beam;
a beam shielding device, that is provided in a region through which the charged particle beam in the magnetic field generation device passes, is configured to cause a portion of the charged particle beam in a predetermined range of the charged particle beam to pass through, and stop another portion of the charged particle beam; and
a control system configured to adjust an angular momentum of the charged particle beam to ≠0 and adjust the Twiss parameter α to be close to 0 at at-least one point on the central orbit of the charged particle beam in the beam shielding device.
2 . The beam transport system according to claim 1 ,
wherein the magnetic field generation device is a solenoid electromagnet that generates the magnetic field parallel to the center orbit of the charged particle beam, and
wherein the beam shielding device is a collimator that is provided in the solenoid electromagnet and the collimator is configured to stop a charged particle deviated from the center orbit of the charged particle beam by a predetermined value or more.
3 . The beam transport system according to claim 2 ,
wherein the control system controls energization of the solenoid electromagnet.
4 . The beam transport system according to claim 1 ,
wherein the control system controls the energization of the solenoid electromagnet based on temperature of the collimator to adjust the Twiss parameter α to be near 0 at at-least one point of the center orbit of the charged particle beam in the collimator.
5 . The beam transport system according to claim 4 ,
wherein the collimator is provided in a range from an axial center in the solenoid electromagnet to an outlet from which a charged particle beam is extracted.
6 . The beam transport system according to claim 1 ,
wherein another solenoid electromagnet different from the solenoid electromagnet is provided on a downstream side of the solenoid electromagnet in a traveling direction of the charged particle beam.
7 . An accelerator comprising the beam transport system according to claim 1 .
8 . An ion source connected to the beam transport system according to claim 1 .
9 . A beam transport method for transporting a charged particle beam by a beam transport system, the beam transport method comprising:
disposing a collimator in a solenoid electromagnet provided in the middle of a transport line that transports the charged particle beam, and
setting an angular momentum of the charged particle beam not to be 0 and a Twiss parameter α to be near 0 at at least one point of a center orbit of the charged particle beam in the collimator.