Control of transverse motion caused by chromatic aberration and misalignments in linear accelerators

Chen, Yu‐Jiuan

doi:10.1016/s0168-9002(97)00738-9

Cited by 24 publications

(12 citation statements)

References 5 publications

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“…Beam energy variations coupling with focusing magnet misalignments is the source of the ''corkscrew'' motion [17] observed in the ETA-II LIA [18][19][20][21]. Moreover, suppression of this energy-dependent motion by using steering dipoles throughout the LIA in a procedure known as a ''tuning V'' has been demonstrated [18][19][20][21].…”

Section: B Suppression Of Low-frequency Beam Sweepmentioning

confidence: 99%

“…Moreover, suppression of this energy-dependent motion by using steering dipoles throughout the LIA in a procedure known as a ''tuning V'' has been demonstrated [18][19][20][21]. However, the procedures employed on ETA-II used between 12 and 60 dipole pairs, and required between one hour and one day at the 1-pulse=s repetition rate of ETA-II [19][20][21].…”

Section: B Suppression Of Low-frequency Beam Sweepmentioning

confidence: 99%

See 1 more Smart Citation

Suppressing beam-centroid motion in a long-pulse linear induction accelerator

Ekdahl

Abeyta

Archuleta

et al. 2011

Phys. Rev. ST Accel. Beams

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The second axis of the dual-axis radiography of hydrodynamic testing (DARHT) facility produces up to four radiographs within an interval of 1:6 s. It does this by slicing four micropulses out of a 2-s long electron beam pulse and focusing them onto a bremsstrahlung converter target. The 1.8-kA beam pulse is created by a dispenser cathode diode and accelerated to more than 16 MeV by the unique DARHT Axis-II linear induction accelerator (LIA). Beam motion in the accelerator would be a problem for multipulse flash radiography. High-frequency motion, such as from beam-breakup (BBU) instability, would blur the individual spots. Low-frequency motion, such as produced by pulsed-power variation, would produce spot-to-spot differences. In this article, we describe these sources of beam motion, and the measures we have taken to minimize it. Using the methods discussed, we have reduced beam motion at the accelerator exit to less than 2% of the beam envelope radius for the high-frequency BBU, and less than 1=3 of the envelope radius for the low-frequency sweep.

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Section: B Suppression Of Low-frequency Beam Sweepmentioning

confidence: 99%

Section: B Suppression Of Low-frequency Beam Sweepmentioning

confidence: 99%

Suppressing beam-centroid motion in a long-pulse linear induction accelerator

Ekdahl

Abeyta

Archuleta

et al. 2011

Phys. Rev. ST Accel. Beams

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show abstract

“…Some of the effects seen in the results are due to causes which are not easily controlled in the laboratory. grows axially along a focusing lattice if each additional solenoid is misaligned [35,36].…”

Section: Adverse Effects On the Transverse Beam Dynamicsmentioning

confidence: 99%

“…Precise alignment of the axial magnetic field in a solenoid lattice is critical to the beam dynamics. Slight misalignment of the solenoids in a focusing lattice causes the beam centroid to carry out a corkscrew orbit and this motion can grow along a focusing lattice if each additional solenoid is misaligned [35,36]. This excitation can also lead to emittance growth and halo formation [37].…”

Section: Centroid Motionmentioning

confidence: 99%

Intense Ion Beam for Warm Dense Matter Physics

Coleman¹

2008

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“…Such applications typically require precise control of the beam centroid to: control the placement of the beam spot on target, maintain alignment of the beam with the field in cooling applications, and control a variety of deleterious processes that are enhanced with increasing amplitude of centroid oscillations in the machine. Effects enhanced include nonlinear image charges and currents, applied field nonlinearities, and corkscrew effects [5,6].…”

Section: Introductionmentioning

confidence: 99%

Transverse centroid oscillations in solenoidially focused beam transport lattices

Lund

Wootton

Lee

2009

Nuclear Instruments and Methods in Physics Research Section A:

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Linear equations of motion are derived that describe small-amplitude centroid oscillations induced by displacement and rotational misalignments of the focusing solenoids in the transport lattice, dipole steering elements, and initial centroid offset errors. These equations are analyzed in a local rotating Larmor frame to derive complex-variable "alignment functions" and "bending functions" that efficiently describe the characteristics of the centroid oscillations induced by mechanical misalignments of the solenoids and dipole steering elements. The alignment and bending functions depend only on properties of the ideal lattice in the absence of errors and steering and have associated expansion amplitudes set by the misalignments and steering fields. Applications of this formulation are presented for statistical analysis of centroid deviations, calculation of actual lattice misalignments from centroid measurements, and optimal beam steering.

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Control of transverse motion caused by chromatic aberration and misalignments in linear accelerators

Cited by 24 publications

References 5 publications

Suppressing beam-centroid motion in a long-pulse linear induction accelerator

Suppressing beam-centroid motion in a long-pulse linear induction accelerator

Intense Ion Beam for Warm Dense Matter Physics

Transverse centroid oscillations in solenoidially focused beam transport lattices

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