US2015223315A1PendingUtilityA1
Methods and systems for confining charged particles to a compact orbit during acceleration using a non-scaling fixed field alternating gradient magnetic field
Est. expiryFeb 25, 2030(~3.6 yrs left)· nominal 20-yr term from priority
H05H 13/08H05H 2007/043G06F 17/10H05H 11/00G06F 30/00H05H 7/04G06F 17/50
51
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Claims
Abstract
A method is described wherein a beam of charged particles is confined to an orbit within a compact region of space as it is accelerated across a wide range of energies. This confinement is achieved using a non-scaling magnetic field based on the Fixed Alternating Gradient principle where the field strength includes non-linear components. Examples of magnet configurations designed using this method are disclosed.
Claims
exact text as granted — not AI-modified1 . A non-scaling fixed field alternating-gradient particle accelerator, comprising
a) an induction core; and b) a plurality of substantially-identical cells, each cell comprising an F-magnet configured to focus a charged particle beam horizontally and defocus said beam vertically and a D-magnet configured to defocus said beam horizontally and focus said beam vertically, wherein said cells are arranged in a ring such that the F- and D-magnets alternate, and such that the charged particle beam circulates in said ring and is stable after being injected and until being extracted; wherein the cells are symmetrically arranged; and wherein the F-magnets and D-magnets have linear edges; and wherein the F-magnets and D-magnets are configured to generate a guide magnetic field which varies non-linearly with radius and to determine reference orbits which close geometrically.
2 . The accelerator of claim 1 , wherein, for each D-magnet and for each F-magnet, an edge angle of that magnet at an extraction radius and an edge angle of that magnet at an injection radius are equal to each other.
3 . The accelerator of claim 1 , wherein, for each D-magnet and for each F-magnet, a magnet length is greater than or equal to 0.01 m.
4 . The accelerator of claim 1 , wherein, for each D-magnet and for each F-magnet, an absolute magnetic field strength is less than or equal to 5 kG.
5 . The accelerator of claim 1 , wherein, for each pair of adjoining magnets, a magnet spacing between said magnets at an extraction energy is greater than or equal to 0.05 m.
6 . The accelerator of claim 1 , wherein, for each pair of adjoining magnets, a drift length at injection and a drift length at an energy intermediate between injection and extraction is greater than 0.01 m.
7 . The accelerator of claim 1 , wherein:
a beam energy is about 0.05 MeV at injection and about 3 MeV at extraction, an average radius is about 0.198 m. at injection and about 0.417 m at extraction, a peak field in the F-magnets is about 0.088 kG at injection and about 1.002 kG at extraction, a peak field in the D-magnets is about −0.177 kG at injection and about −0.491 kG at extraction, a magnet length for the F-magnets is about 0.0877 m at injection and about 0.1348 m at extraction, a magnet length for the D-magnets is about 0.0094 m. at injection and about 0.0976 at extraction, an aperture in the F-magnet is about 0.218 m, an aperture in the D-magnets is about 0.179 m, there are 8 cells, and a sextupole field is sufficient to contain tune variation and permit beam stability.
8 . The accelerator of claim 1 , wherein:
a beam energy is about 0.05 MeV at injection and about 4 MeV at extraction, an average radius is about 0.162 m. at injection and about 0.350 m at extraction, a peak field in the F-magnets is about 0.082 kG at injection and about 1.105 kG at extraction, a peak field in the D-magnets is about −0.110 kG at injection and about −1.488 kG at extraction, a magnet length for the F-magnets is about 0.0949 m at injection and about 0.1458 m at extraction, a magnet length for the D-magnets is about 0.0134 m. at injection and about 0.0294 at extraction, an aperture in the F-magnet is about 0.190 m, an aperture in the D-magnets is about 0.162 m, and there are 8 cells.
9 . The accelerator of claim 1 , wherein:
a beam energy is about 0.05 MeV at injection and about 3.5 MeV at extraction, an average radius is about 0.104 m. at injection and about 0.274 m at extraction, a peak field in the F-magnets is about 0.500 kG at injection and about 2.034 kG at extraction, a peak field in the D-magnets is about −0.000 kG at injection and about −0.209 kG at extraction, a magnet length for the F-magnets is about 0.0112 m at injection and about 0.061 m at extraction, a magnet length for the D-magnets is about 0.0390 m. at injection and about 0.0598 at extraction, an aperture in the F-magnet is about 0.190 m, an aperture in the D-magnets is about 0.161 m, and there are 8 cells.
10 . The accelerator of claim 1 , wherein
a beam energy is about 0.05 MeV at injection and about 9 MeV at extraction, an average radius is about 0.206 m. at injection and about 0.437 m at extraction, a peak field in the F-magnets is about 0.114 kG at injection and about 1.986 kG at extraction, a peak field in the D-magnets is about −0.107 kG at injection and about −2.811 kG at extraction, a magnet length for the F-magnets is about 0.0670 m at injection and about 0.1650 m at extraction, a magnet length for the D-magnets is about 0.0208 m. at injection and about 0.0398 at extraction, an aperture in the F-magnet is about 0.230 m, an aperture in the D-magnets is about 0.199 m, and there are 9 cells.
11 . A method of designing a non-scaling fixed field alternating-gradient particle accelerator, wherein there is a non-linear magnetic field variation with radius, the method comprising
a) selecting a first plurality of design parameters for the accelerator; b) selecting a second plurality of equations relating the selected design parameters; c) selecting a third plurality of constraints on at least some of the selected design parameters; d) selecting a fourth plurality of constraint equations; e) specifying an intermediate energy; f) selecting a fifth plurality of equations relating to the intermediate energy; g) carrying out an optimizer search to determine at least one potential design for the accelerator; h) verifying at least one potential design by calculating exact orbits and checking tunes for stability over a desired energy range; i) if no potential design has a stable tune, repeating the optimizer search; and j) if at least one potential design has a stable tune, completing the design of the accelerator based upon said potential design.
12 . The method of claim 11 , wherein at least some of the second plurality of equations comprise thick lens linear matrix traces.
13 . The method of claim 11 , wherein the first plurality of design parameters comprises:
D e , a drift distance between an F magnet and a D magnet at extraction; L if , L ef , L id , L ed , F magnet and D magnet half-lengths at injection and extraction; B if , B ef , B id , B ed , F magnet and D magnet fields at injection and extraction; δx if, , a distance from an injection orbit to an extraction orbit in an F magnet; and η f , and η d , linear edge angles for F magnets and D-magnets.
14 . The method of claim 11 , wherein the second plurality of equations comprises:
1
)
k
if
L
if
+
θ
if
ρ
if
+
(
(
θ
ef
-
θ
if
)
+
η
if
)
ρ
if
=
1
f
if
;
2
)
?
3
)
k
ef
L
ef
+
θ
ef
ρ
ef
+
η
ef
ρ
ef
=
1
f
ef
;
4
)
?
5
)
θ
halfcell
=
θ
if
+
θ
id
=
θ
ef
+
θ
ed
;
6
)
L
if
[
cos
(
θ
if
)
+
sin
(
θ
if
)
tan
(
θ
ef
+
η
ef
)
]
=
L
ef
cos
(
θ
ef
)
-
[
δ
x
if
-
L
ef
sin
(
θ
ef
)
]
tan
(
θ
ef
+
η
ef
)
7
)
L
ed
cos
(
θ
ef
)
=
L
id
cos
(
θ
if
)
+
δ
x
id
sin
(
θ
id
+
θ
if
)
+
[
δ
x
if
+
(
L
if
+
D
i
)
sin
(
θ
if
)
-
(
L
ef
+
D
e
)
sin
(
θ
ef
)
]
tan
(
η
ed
)
?
indicates text missing or illegible when filed
15 . The method of claim 11 , wherein the third plurality of constraints comprises:
1) magnet lengths less than 0.01 m are excluded; 2) absolute magnetic field strengths greater than 5 kG are excluded; 3) magnet spacings at an extraction energy less than 0.05 m are excluded; and 4) drifts at injection and intermediate energies less than 0.01 m are excluded.
16 . The method of claim 11 , wherein the fourth plurality of constraint equations comprises:
1
)
Inj
Radius
=
Radi
=
NSector
Lihalf
/
π
2
)
Ext
Radius
=
Rade
=
NSector
Lehalf
/
π
3
)
π
NSector
=
0
id
+
θ
if
4
)
δ
x
id
cos
(
θ
id
+
θ
if
)
=
δ
x
if
+
Lihalf
sin
(
θ
if
)
-
Lehalf
sin
(
θ
ef
)
5
)
D
i
[
cos
(
θ
if
)
-
sin
(
θ
if
)
tan
(
η
ed
)
]
=
(
L
ef
+
D
e
)
cos
(
θ
ef
)
-
L
if
cos
(
θ
if
)
+
[
δ
x
if
+
L
if
sin
(
θ
if
)
-
(
L
ef
+
D
e
)
sin
(
θ
ef
)
]
tan
(
η
ed
)
17 . The method of claim 11 , wherein the fifth plurality of equations comprises:
1
)
k
3
f
L
3
f
+
θ
3
f
ρ
3
f
+
(
(
θ
ef
-
θ
3
f
)
+
η
if
)
ρ
3
f
=
1
f
3
f
;
2
)
k
3
d
L
3
d
+
θ
3
f
+
η
3
d
ρ
3
d
=
1
f
3
d
;
3
)
θ
halfcell
=
θ
if
+
θ
id
=
θ
3
f
+
θ
3
d
4
)
L
3
f
[
cos
(
θ
3
f
)
+
sin
(
θ
3
f
)
tan
(
θ
ef
+
η
ef
)
]
=
L
ef
cos
(
θ
ef
)
-
[
δ
x
3
f
-
L
ef
sin
(
θ
ef
)
]
tan
(
θ
ef
+
η
ef
)
;
5
)
L
ed
cos
(
θ
ef
)
=
L
3
d
cos
(
θ
3
f
)
+
δ
x
3
d
sin
(
θ
3
d
+
θ
3
f
)
+
[
δ
x
3
f
+
(
L
3
f
+
D
3
)
sin
(
θ
3
if
)
-
(
L
ef
+
D
e
)
sin
(
θ
ef
)
]
tan
(
η
ed
)
6
)
δ
x
3
d
cos
(
θ
3
d
+
θ
3
f
)
=
δ
x
3
f
+
L
3
half
sin
(
θ
3
f
)
-
Lehalf
sin
(
θ
ef
)
7
)
D
3
[
cos
(
θ
3
f
)
-
sin
(
θ
3
f
)
tan
(
η
ed
)
]
=
(
L
ef
+
D
e
)
cos
(
θ
ef
)
-
L
3
f
cos
(
θ
3
f
)
+
[
δ
x
3
f
+
L
3
f
sin
(
θ
3
f
)
-
(
L
ef
+
D
e
)
sin
(
θ
ef
)
]
tan
(
η
ed
)
8
)
Rad
3
=
N
sector
L
3
half
/
π
[
δ
x
3
f
+
(
l
ef
+
D
e
)
18 . The method of claim 11 , wherein a least squares merit function is used in the optimization.
19 . The method of claim 11 , wherein the number of sectors is between 6 and 11.
20 . A method of designing a non-scaling fixed field alternating-gradient particle accelerator, wherein there is a non-linear magnetic field variation with radius, the method comprising
a) selecting a first plurality of design parameters for the accelerator, a second plurality of equations relating the selected design parameters, a third plurality of constraints on at least some of the selected design parameters, and a fourth plurality of equations relating to an intermediate energy; b) carrying out an optimizer search to determine at least one potential design for the accelerator; c) verifying at least one potential design by checking tunes for stability over a desired energy range; and d) for at least one potential design with a stable tune, completing the design of the accelerator based upon said potential design.Join the waitlist — get patent alerts
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