-
Carl Ekdahl,
E. O. Abeyta,
P. Aragon,
R. Archuleta,
G. Cook, D. Dalmas,
K. Esquibel,
R. Gallegos,
R. Garnett,
J. Harrison, [......],
C. Carlson,
D. Frayer,
D. Johnson,
C. Y. Tom,
C. Trainham,
R. Temple,
H. Bender,
J. Williams,
B. Prichard,
M. Schulze
linac 2008, Victoria, BC, Canada; 09/2008
-
Martin Schulze,
R. Archuleta,
J. Barazza, D. Dalmas,
C. Ekdahl,
W. Gregory,
J. Harrison,
J. Johnson,
E. Jacquez,
P. Marroquin, [......],
C. Carlson,
D. Frayer,
D. Johnson,
C. Thoma,
E. O. Abeyta,
R. Anaya,
J. Weir,
H. Bender,
C. Y. Tom,
T. P. Hughes
linac 2008, Victoria, BC, Canada; 09/2008
-
C. Ekdahl,
E.O. Abeyta,
P. Aragon,
R. Archuleta,
R. Bartsch, D. Dalmas,
S. Eversole,
R. Gallegos,
J. Harrison,
J. Johnson, [......],
M. Schauer,
G. Seitz,
H. Bender,
W. Broste,
C. Carlson,
D. Frayer,
D. Johnson,
A. Tipton,
C.Y. Tom,
M. Schulze
[show abstract]
[hide abstract]
ABSTRACT: When completed, the DARHT-II accelerator will produce a 2-kA, 17-MeV beam in a 1600-ns pulse. After exiting the accelerator, the long pulse will be sliced into four short pulses by a kicker and quadrupole septum and then transported for several meters to a tantalum target for conversion to bremsstrahlung for radiography. In order to provide early tests of the kicker, septum, transport, and multi-pulse converter target we assembled a short accelerator from the first available refurbished cells, which are now capable of operating of operating at over 200 kV. This scaled accelerator was operated at ~8 MeV and ~1 kA, which provides a beam with approximately the same beam dynamics in the downstream transport as the final 17-MeV, 2-kA beam.
Particle Accelerator Conference, 2007. PAC. IEEE; 07/2007
-
M. Schulze,
E.O. Abeyta,
P. Aragon,
R. Archuleta,
J. Barraza, D. Dalmas,
C. Ekdahl,
K. Esquibel,
S. Eversole,
R. Gallegos, [......],
H. Bender,
W. Broste,
C. Carlson,
D. Frayer,
D. Johnson,
A. Tipton,
C.Y. Tom,
T.C. Genoni,
T.P. Hughes,
C. Thoma
[show abstract]
[hide abstract]
ABSTRACT: The DARHT-II accelerator will produce a 2-kA, 17-MeV beam in a 1600-ns pulse when completed mid-2007. After exiting the accelerator, the pulse is sliced into four short pulses by a kicker and quadrupole septum and then transported for several meters to a tantalum target for conversion to X-rays for radiography. We describe tests of the kicker, septum, transport, and multi-pulse converter target using a short accelerator assembled from the first available refurbished cells. This scaled accelerator was operated at ~8 MeV and ~1 kA, providing a beam with approximately the same v/gamma as the final 18-MeV, 2-kA beam, and therefore the same beam dynamics in the downstream transport. The results of beam measurements made during the commissioning of this scaled accelerator downstream transport are described.
Particle Accelerator Conference, 2007. PAC. IEEE; 07/2007
-
C. Ekdahl,
E.O. Abeyta,
P. Aragon,
R. Archuleta,
R. Bartsch,
H. Bender,
R. Briggs,
W. Broste,
C. Carlson,
K.C.D. Chan, [......],
S. Nath,
D. Oro,
L. Rowton,
M. Sanchez,
R. Scarpetti,
M. Schauer,
M. Schulze,
Y. Tang,
A. Tipton,
C.Y. Tom
[show abstract]
[hide abstract]
ABSTRACT: When completed, the DARHT-II linear induction accelerator (LIA) will produce a 2-kA, 17-MeV electron beam in a 1600-ns flat-top pulse. In initial tests, DARHT-II accelerated beams with current pulse lengths from 500 to 1200 ns full-width at half-maximum (FWHM) with more than 1.2-kA, 12.5-MeV peak current and energy. Experiments have now been done with a ∼1600-ns pulse length. These pulse lengths are all significantly longer than any other multimegaelectronvolt LIA, and they define a novel regime for high-current beam dynamics, especially with regard to beam stability. Although the initial tests demonstrated insignificant beam-breakup instability (BBU), the pulse length was too short to determine whether ion-hose instability would be present toward the end of a long, 1600-ns pulse. The 1600-ns pulse experiments reported here resolved these issues for the long-pulse DARHT-II LIA.
IEEE Transactions on Plasma Science 05/2006; · 1.17 Impact Factor
-
C. Ekdahl,
P. Aragon,
E.O. Abeyta,
R. Bartsch,
L. Caudill,
K.C.D. Chan, D. Dalmas,
S. Eversole,
R. Gallegos,
J. Harrison, [......],
A. Meidinger,
K. Moy,
R. Sturgess,
A. Tipton,
C.Y. Tom,
M. Schulze,
T. Hughes,
C. Mostrom,
Y. Tang,
R. Briggs
[show abstract]
[hide abstract]
ABSTRACT: When completed, the DARHT-II linear induction accelerator (LIA) will produce a 2-kA, 18-MeV electron beam with more than 1500-ns current/energy "flat-top." In initial tests DARHT-II has already accelerated beams with current pulse lengths from 500-ns to 1200-ns full- width at half maximum (FWHM) with more than 1.2- kA, 12.5-MeV peak current and energy. New experiments are planned with a ~1600-ns pulse length but with reduced current and energy. These pulse lengths are all significantly longer than any other multi-MeV LIA, and they define a novel regime for high-current beam dynamics, especially with regard to beam stability. Although the initial tests demonstrated absence of BBU, the pulse length was too short to determine whether ion- hose instability would be present toward the end of a pulse longer than 1500-ns. The 1600-ns pulse experiments are designed to resolve these and other beam-dynamics issues with a long-pulse beam.
Pulsed Power Conference, 2005 IEEE; 07/2005
-
C. Ekdahl,
E.O. Abeyta,
R. Bartsch,
L. Caudill,
K.C.D. Chan, D. Dalmas,
S. Eversole,
R. Gallegos,
J. Harrison,
M. Holzscheiter, [......],
A. Meidinger,
K. Moy,
R. Sturgess,
A. Tipton,
C.Y. Tom,
M. Schulze,
T. Hughes,
C. Mostrom,
Y. Tang,
R. Briggs
[show abstract]
[hide abstract]
ABSTRACT: When completed, the DARHT-II linear induction accelerator (LIA) will produce a 2 kA, 18 MeV electron beam with more than 1500 ns current/energy “flat-top.” In initial tests DARHT-II has already accelerated beams with current pulse lengths from 500 ns to 1200 ns full-width at half maximum (FWHM) with more than 1.2 kA peak current and 12.5 MeV peak energy. Experiments will soon begin with a ∼ 1600 ns flat-top pulse, but with reduced current and energy. These pulse lengths are all significantly longer than any other multi-MeV LIA, and they define a novel regime for high-current beam dynamics, especially with regard to beam stability. Although the initial tests demonstrated the robustness of the DARHT-II LIA to BBU, the < 1200 ns FWHM pulse lengths were too short to test the predicted protection against ion-hose instability. The present experiments are designed to resolve these and other beam-dynamics issues with a ∼ 1600 ns pulse length beam.
Particle Accelerator Conference, 2005. PAC 2005. Proceedings of the; 06/2005
-
C. Ekdahl,
E.O. Abeyta,
H. Bender,
W. Broste,
C. Carlson,
L. Caudill,
K.C.D. Chan,
Y.J. Chen, D. Dalmas,
G. Durtschi, [......],
M. Schauer,
D. Simmons,
H.V. Smith,
J. Studebaker,
R. Sturgess,
G. Sullivan,
C. Swinney,
R. Temple,
C.Y. Tom,
S.S. Yu
[show abstract]
[hide abstract]
ABSTRACT: The DARHT-II linear-induction accelerator has been successfully operated at 1.2-1.3 kA and 12.5-12.7 MeV to demonstrate the production and acceleration of an electron beam. Beam pulse lengths for these experiments were varied from 0.5 μs to 1.2 μs full-width half-maximum. A low-frequency inductance-capacitance (LC) oscillation of diode voltage and current resulted in an oscillation of the beam position through interaction with an accidental (static) magnetic dipole in the diode region. There was no growth in the amplitude of this oscillation after propagating more than 44 m through the accelerator, and there was no loss of beam current that could be measured. The results of these initial experiments are presented in this paper.
IEEE Transactions on Plasma Science 05/2005; · 1.17 Impact Factor
-
C. Ekdahl,
E.O. Abeyta,
L. Caudill,
K.C.D. Chan, D. Dalmas,
S. Eversole,
R. Gallegos,
J. Harrison,
M. Holzscheiter,
J. Johnson, [......],
G. Durtschi,
D. Frayer,
D. Johnson,
K. Jones,
A. Meidinger,
K. Moy,
R. Sturgess,
C.Y. Tom,
T. Hughes,
C. Mostrom
[show abstract]
[hide abstract]
ABSTRACT: The second axis of the Dual Axis Radiographic HydroTest (DARHT) facility will provide up to four short (< 150 ns) radiation pulses for flash radiography of high-explosive driven implosion experiments. To accomplish this the DARHT-II linear induction accelerator (LIA) will produce a 2-kA electron beam with 18-MeV kinetic energy, constant to within ± 0.5% for 2-μs. A fast kicker will cleave four short pulses out of the 2-μs flattop, with the bulk of the beam diverted into a dump. The short pulses will then be transported to the final-focus magnet, and focused onto a tantalum target for conversion to bremsstrahlung pulses for radiography. DARHT-II is a collaborative effort between the Los Alamos, Lawrence Livermore, and Lawrence Berkeley National Laboratories of the University of California.
Particle Accelerator Conference, 2003. PAC 2003. Proceedings of the; 06/2003
