Development of beam position monitors for heavy ion recirculators
Work is underway at the Lawrence Livermore National Laboratory to design and build a small-scale, heavy ion recirculating induction accelerator. An essential part of this design work is the development of small non-intercepting diagnostics to measure beam current and position. This paper describes some of this work, with particular emphasis on the development of a small capacitive probe beam position monitor to resolve beam position to the 100 /spl mu/m level in a 6 cm diameter beam pipe. Initial measured results with an 80 keV potassium ion beam are presented.
Steering algorithms for a small recirculating heavy-ion accelerator 1 1 Work performed under the auspices of the US Department of Energy by Lawrence Livermore National Laboratory under contract W-7405-ENG-48.
Beam-steering algorithms are proposed for a small recirculating induction accelerator being built at the Lawrence Livermore National Laboratory. The principal problem is that the transverse position and velocity of the beam must be inferred from capacitive position monitors, and this determination is complicated by the limited probe resolution and by the lattice errors within steering modules. The fluid/envelope code CIRCE is used to evaluate these algorithms.
A FET-SWITCHED INDUCTION ACCELERATOR CELL
Abstract : An array of 24 field-effect transistors (FETs) is being used to switch a nominal4-kV, 1-microsecond pulse onto a Metglas induction core at pulse rates exceeding 100kHz. Each transistor receives isolated gate power from a dc/dc converter and analog pulse control via an optical fiber. The array is part of a specialized circuit architecture that generates bursts of pulses while providing for core reset between pulses. The circuit will accommodate variations in pulse width, repetition frequency (prf), pulse amplitude, burst length and reset interval. The various circuit elements are assembled directly onto the core structure to yield a compact, low-impedance package. Two prototype machines are presently under development. A 24- FET machine is in operation and capable of 4.2-kV, 1-microsecond pulses (max.) at a 120-kHz prf for short bursts. Pulse rise and fall times are 25 ns and 65 ns respectively. A 128-FET machine is under construction which should be capable of 6-kV, 1-microsecond pulses (max.) at a 150-kHz prf for long bursts.