Title :
A high-current density contact ionization source for heavy-ion fusion
Author :
MacLaren, S. ; Beck, D. ; Faltens, A. ; Ghiorso, W. ; Henestroza, E. ; Seidl, P.
Author_Institution :
Lawrence Berkeley Nat. Lab., CA, USA
Abstract :
Heavy ion fusion (HIF) sources will be low-emittance, high current (0.5-1 A), and suitable for injection into a multiple beam induction linac, where the diameter of each beam aperture at the beginning of the accelerator is 3-6 cm. Practical transport limits involved in matching the beam to the accelerator aperture in a reasonably-sized structure correspond to several mA/cm2 of space charge limited flow with an injector extraction voltage of 1-2.5 MV. We have built a J≈8 mA/cm2 Cs+ contact ionization source for a 160 kV diode; this represents a factor of four increase in the Cs+ current density over previous sources for HIF. The emitter is sintered iridium, operating at 950<T<1150°C. We are experimenting with several methods of alkali feeding capable of maintaining a fraction (<5%) of a monolayer coverage on the iridium surface
Keywords :
caesium; collective accelerators; heavy ion fusion reactions; ion accelerators; ion sources; linear accelerators; particle beam extraction; particle beam fusion accelerators; particle beam injection; positive ions; space charge; 0.5 to 1 A; 1 to 2.5 MV; 160 kV; 3 to 6 cm; 950 to 1150 C; Cs; Cs+ high-current density contact ionization source; Ir; alkali feeding; beam matching; extraction voltage; heavy-ion fusion; high current; injection; low-emittance; monolayer coverage; multiple beam induction linac; space charge limited flow; transport limits; Apertures; Current density; Indium; Ion accelerators; Ion sources; Ionization; Laboratories; Linear particle accelerator; Optical refraction; Particle beams;
Conference_Titel :
Particle Accelerator Conference, 1999. Proceedings of the 1999
Conference_Location :
New York, NY
Print_ISBN :
0-7803-5573-3
DOI :
10.1109/PAC.1999.792959
