Increasing the intensity of an induction accelerator and reduction of the beam breakup instability

Coleman, J. E.; Moir, D.C.; Ekdahl, C.A.; Johnson, J. B.; McCuistian, B.T.; Sullivan, G. W.; Crawford, M.

doi:10.1103/physrevstab.17.030101

Cited by 23 publications

(25 citation statements)

References 11 publications

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“…[22], BBU manifests itself as a transverse magnetic coupling to destroy the beam quality. The BBU growth along the accelerator is characterized by the equation below [30]:…”

Section: Beam Misalignments and Bbu Instabilitymentioning

confidence: 99%

“…A summary of these previous BBU studies and recent increased intensity and vacuum transport on an induction accelerator with 64 cells is described in Ref. [22].…”

Section: Introductionmentioning

confidence: 99%

“…The first axis of the Dual-Axis Radiography for Hydrodynamic Testing (DARHT) facility [22] is exploring the limitations of increasing the intensity of the electron beam for future radiographic capabilities. After increasing the current by 70% on DARHT Axis-I it was determined that the beam centroid was substantially offset and needed to be corrected for transport of the beam to the target.…”

Section: Introductionmentioning

confidence: 99%

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Correcting the beam centroid motion in an induction accelerator and reducing the beam breakup instability

Coleman

Ekdahl

Moir

et al. 2014

Phys. Rev. ST Accel. Beams

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Axial beam centroid and beam breakup (BBU) measurements were conducted on an 80 ns FWHM, intense relativistic electron bunch with an injected energy of 3.8 MV and current of 2.9 kA. The intense relativistic electron bunch is accelerated and transported through a nested solenoid and ferrite induction core lattice consisting of 64 elements, exiting the accelerator with a nominal energy of 19.8 MeV. The principal objective of these experiments is to quantify the coupling of the beam centroid motion to the BBU instability and validate the theory of this coupling for the first time. Time resolved centroid measurements indicate a reduction in the BBU amplitude, hξi, of 19% and a reduction in the BBU growth rate (Γ) of 4% by reducing beam centroid misalignments ∼50% throughout the accelerator. An investigation into the contribution of the misaligned elements is made. An alignment algorithm is presented in addition to a qualitative comparison of experimental and calculated results which include axial beam centroid oscillations, BBU amplitude, and growth with different dipole steering.

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“…[22], BBU manifests itself as a transverse magnetic coupling to destroy the beam quality. The BBU growth along the accelerator is characterized by the equation below [30]:…”

Section: Beam Misalignments and Bbu Instabilitymentioning

confidence: 99%

“…A summary of these previous BBU studies and recent increased intensity and vacuum transport on an induction accelerator with 64 cells is described in Ref. [22].…”

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Correcting the beam centroid motion in an induction accelerator and reducing the beam breakup instability

Coleman

Ekdahl

Moir

et al. 2014

Phys. Rev. ST Accel. Beams

Self Cite

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“…CsI doped carbon velvet has also been examined at low resolution indicating 3 x 10 4 pulses were required to measure H [16]. The first axis of the Dual-Axis Radiography for Hydrodynamic Testing (DARHT) facility [25,26] is characterizing the photon spectrum generated in the diode in motivation to gain a better understanding of the electron beam generation through the use of a cold cathode, including the beam and plasma dynamics, and beam emittance. In addition there is a motivation to use of this cathode technology for longer (~ s) pulsed and multi-pulsed operations and continue to develop improved high brightness (B = J/ ) cold cathodes.…”

Section: Introductionmentioning

confidence: 99%

Characterizing the photon spectrum in the DARHT Axis-I diode

Coleman¹,

Johnson²,

McCuistian³

et al. 2014

2014 IEEE 41st International Conference on Plasma Sciences (ICOPS) Held With 2014 IEEE International Conference on High-Power P

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An array of photon diagnostics have been deployed on a high power relativistic electron beam diode. Surface flashover of a carbon fiber velvet cathode generates a discharge from which electrons are accelerated through a 17.8 cm diode. This discharge is assumed to be a hydrocarbon mixture. A small portion of the off energy electrons (1-3 MeV) accelerated during the rise and fall of the 80 ns FWHM pulse impact the beam pipe and generate a Bremsstrahlung spectrum of 0.1-3 MeV photons. The principal objective of these experiments is to quantify the dynamics of the hard X-ray and -ray flux generated in the diode region, in addition to quantifying dynamics of the visible photons generated, and the ion species of the surface discharge on the velvet cathode. A qualitative comparison of different diagnostic results are presented, which include time resolved measurements with X-ray PIN diodes, a PMT, and CCD images. In addition initial visible spectroscopy measurements will also be presented.

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“…X-ray flash radiography is a powerful diagnostic used worldwide [1][2][3][4][5][6] for investigating the structural response of matter under impulsive loading during hydrodynamic experiments. Intense pulsed x-ray sources are required for capturing target motion during these experiments and, hence, obtaining good quality images.…”

Section: Introductionmentioning

confidence: 99%

High power electron diode for linear induction accelerator at a flash radiographic facility

Plewa

Bernigaud

Barnes

et al. 2018

Phys. Rev. Accel. Beams

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We investigated a new cathode design and beam transport with the EPURE axis-1 injector in order to increase the beam characteristics at 3.8 MeV, 80 ns FWHM from the 2.0 kA nominal current to 2.6 kA corresponding to an average current density of 82 A=cm 2 . Such current increase is highly desirable for improving the x-ray dose and hence radiographic performances. To achieve this, a time-dependent model based on the particle-in-cell method was developed in order to simulate the injector. Using results from calculations based on this model, a 17.2 cm AK gap diode with a larger radius cathode (3.175 cm) was designed, manufactured and tested. Experimental and calculated currents and emittances are qualitatively compared. The study provides a detailed understanding of the beam dynamics inside this type of high current, high energy injector.

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Increasing the intensity of an induction accelerator and reduction of the beam breakup instability

Cited by 23 publications

References 11 publications

Correcting the beam centroid motion in an induction accelerator and reducing the beam breakup instability

Correcting the beam centroid motion in an induction accelerator and reducing the beam breakup instability

Characterizing the photon spectrum in the DARHT Axis-I diode

High power electron diode for linear induction accelerator at a flash radiographic facility

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