Isochronous cyclotron
First Claim
1. In an isochronous cyclotron of frequency Ω
- of the type in which ions are injected at an initial energy at radius rin and non-relativistic velocity V.sub.θ
in in the orbital plane, focused in a curvilinear orbit by a magnetic field, and accelerated to a final energy and a relativistic velocity V.sub.θ
out at radius rout, the combination comprising;
means for providing a magnetic field having an absolute minimum intensity at a circle radius r°
greater than rin in the orbital plane, said means comprising an electric solenoid having a central radius rC in the orbital plane where rC is less than rin and having end radii rM equidistant from rC where rM is greater than rC ; and
means for accelerating said ions comprising means for producing an electric field directed tangentially to the orbit of said ions, and at least one radially-directed resonator horn coupled to said electric-field-producing means, said resonator horn confining said tangentially-directed electric field within said horn, said horn having means for allowing the orbiting ions to pass through said electric field within said horn.
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Abstract
A solenoid comprising several, discrete, coaxial, circular, superconducting coils provides a magnetic field which decreases radially to an absolute minimum intensity to focus the ions as they are accelerated to the end of the non-relativistic velocity range. As the ions are further accelerated to relativistic velocities, the magnetic field increases radially from the absolute minimum intensity to compensate for the relativistic increase in mass. The revolving ions are accelerated by repeated passage through an electric field which is established in radially-directed resonator horns. The accelerating structure and the associated electric field reinforce the focusing provided by the radially-increasing magnetic field.
60 Citations
7 Claims
-
1. In an isochronous cyclotron of frequency Ω
- of the type in which ions are injected at an initial energy at radius rin and non-relativistic velocity V.sub.θ
in in the orbital plane, focused in a curvilinear orbit by a magnetic field, and accelerated to a final energy and a relativistic velocity V.sub.θ
out at radius rout, the combination comprising;means for providing a magnetic field having an absolute minimum intensity at a circle radius r°
greater than rin in the orbital plane, said means comprising an electric solenoid having a central radius rC in the orbital plane where rC is less than rin and having end radii rM equidistant from rC where rM is greater than rC ; andmeans for accelerating said ions comprising means for producing an electric field directed tangentially to the orbit of said ions, and at least one radially-directed resonator horn coupled to said electric-field-producing means, said resonator horn confining said tangentially-directed electric field within said horn, said horn having means for allowing the orbiting ions to pass through said electric field within said horn. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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4. The combination as recited in claim 1 wherein said electric-field-producing means means coupled to said resonator horn is a magnetron coupled to the inner end of said radially-directed horn.
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5. The combination as recited in claim 1 wherein said electric-field-producing means means is a Klystron amplifier coupled to the outer end of said radially-directed horn.
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6. The combination as recited in claim 1 wherein the resonator horn is shaped to provide a radially-increasing electric-field intensity within said horn between r°
- and rout.
- 7. The combination as recited in claim 1 wherein the intensity as a function of time of the electric field at radius r varies outwardly from the circle of absolute-minimum field intensity according to the expression
- space="preserve" listing-type="equation">E.sub.θ
.sup.P (r°
,t)[1-(r°
/r.sub.M).sup.2 ][1-(r/r.sub.M).sup.2 ].sup.-1
where E.sub.θ
P (r°
, t) is the electric field intensity at radius r°
as a function of time, rM is c/Ω
, and c is the velocity of light. - space="preserve" listing-type="equation">E.sub.θ
- of the type in which ions are injected at an initial energy at radius rin and non-relativistic velocity V.sub.θ
Specification