Variable energy constant current accelerator structure

Patent · Mon Jan 01 00:00:00 EST 1990

OSTI ID:867316

Anderson, Oscar A ^[1]

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1. Berkeley, CA

A variable energy, constant current ion beam accelerator structure is disclosed comprising an ion source capable of providing the desired ions, a pre-accelerator for establishing an initial energy level, a matching/pumping module having means for focusing means for maintaining the beam current, and at least one main accelerator module for continuing beam focus, with means capable of variably imparting acceleration to the beam so that a constant beam output current is maintained independent of the variable output energy. In a preferred embodiment, quadrupole electrodes are provided in both the matching/pumping module and the one or more accelerator modules, and are formed using four opposing cylinder electrodes which extend parallel to the beam axis and are spaced around the beam at 90.degree. intervals with opposing electrodes maintained at the same potential. Adjacent cylinder electrodes of the quadrupole structure are maintained at different potentials to thereby reshape the cross section of the charged particle beam to an ellipse in cross section at the mid point along each quadrupole electrode unit in the accelerator modules. The beam is maintained in focus by alternating the major axis of the ellipse along the x and y axis respectively at adjacent quadrupoles. In another embodiment, electrostatic ring electrodes may be utilized instead of the quadrupole electrodes.

• Research Organization: Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States)
• DOE Contract Number: AC03-76SF00098
• Assignee: United States of America as represented by United States (Washington, DC)
• Patent Number(s): US 4912421
• OSTI ID: 867316
• Country of Publication: United States
• Language: English

Related Subjects

variable
energy
constant
current
accelerator
structure
beam
disclosed
comprising
source
capable
providing
desired
pre-accelerator
establishing
initial
level
matching
pumping
module
means
focusing
maintaining
main
continuing
focus
variably
imparting
acceleration
output
maintained
independent
preferred
embodiment
quadrupole
electrodes
provided
modules
formed
opposing
cylinder
extend
parallel
axis
spaced
90
degree
intervals
potential
adjacent
potentials
reshape
section
charged
particle
ellipse
mid
electrode
unit
alternating
major
respectively
quadrupoles
electrostatic
utilized
beam output
accelerator module
beam current
constant current
disclosed comprising
output current
major axis
beam accelerator
energy level
particle beam
preferred embodiment
charged particle
beam axis
source capable
variable energy
accelerator structure
output energy
beam focus
accelerator modules
means capable
focusing means
initial energy
extend parallel
variable output
constant beam
/315/313/