CERN Accelerating science

Article
Title	DARHT-II Long-Pulse Beam-Dynamics Experiments
Author(s)	Ekdahl, Carl ; Abeyta, E O ; Bartsch, Richard ; Bender, Howard ; Briggs, Richard J ; Broste, William ; Carlson, Carl ; Caudill, Larry ; Chan, Kwok-Chi D ; Chen Yu Jiuan ; Dalmas, Dale ; Durtschi, Grant ; Eversole, Steven ; Eylon, Shmuel ; Fawley, William M ; Frayer, Daniel ; Gallegos, Robert J ; Harrison, James ; Henestroza, Enrique ; Holzscheiter, M H ; Houck, Timothy L ; Hughes, Thomas P ; Jacquez, Edward ; Johnson, Douglas ; Johnson, Jeffrey ; Jones, Kenneth ; McCuistian, Brian T ; Meidinger, Alfred ; Montoya, Nicholas ; Mostrom, Chris ; Moy, Kenneth ; Nath, Subrata ; Nielsen, Kurt ; Oro, David ; Rodriguez, Leroy ; Rodriguez, Patrick ; Rowton, Larry J ; Sanchez, Manolito ; Scarpetti, Raymond ; Schauer, Martin ; Schulze, Martin E ; Simmons, David ; Studebaker, Jan ; Sturgess, Ronald ; Sullivan, Gary ; Swinney, Charles ; Tang, Yan ; Temple, Rodney ; Tipton, Angela ; Tom, C Y ; Vernon Smith, H ; Yu, Simon
Affiliation	(ATK-MR, Albuquerque, New Mexico) ; (Bechtel Nevada, Los Alamos, New Mexico) ; (GA, San Diego, California) ; (LANL, Los Alamos, New Mexico) ; (LBNL, Berkeley) ; (LLNL, Livermore, California) ; (SAIC, Alamo, California)
Publication	2005
In:	21st IEEE Particle Accelerator Conference, Knoxville, TN, USA, 16 - 20 May 2005, pp.19
Subject category	Accelerators and Storage Rings
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 than1.2-kA, 12.5-MeV peak current and energy. Experiments are now underway with a  2000-ns pulse length, but 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 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  2000-ns pulse length beam.