Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
9845486 | Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment | 2005 | 5 Pages |
Abstract
Highly ionized plasmas are being employed as a medium for charge neutralizing heavy ion beams in order to focus to a small spot size. Calculations suggest that plasma at a density of 1-100 times the ion beam density and at a length â¼0.1-1Â m would be suitable for achieving a high level of charge neutralization. A radio frequency (RF) source was constructed at the Princeton Plasma Physics Laboratory (PPPL) in support of the joint Neutralized Transport Experiment (NTX) at the Lawrence Berkeley National Laboratory (LBNL) to study ion beam neutralization. Pulsing the source enabled operation at pressures â¼10â6Â Torr with plasma densities of 1011Â cmâ3. Near 100% ionization was achieved. The plasma was 10Â cm in length, but future experiments require a source 1Â m long. The RF source does not easily scale to the length. Consequently, large-volume plasma sources based upon ferroelectric ceramics are being considered. These sources have the advantage of being able to increase the length of the plasma and operate at low neutral pressures. The source will utilize the ferroelectric ceramic BaTiO3 to form metal plasma. A 1Â m long section of the drift tube inner surface of NTX will be covered with ceramic. A high voltage (â¼1-5Â kV) is applied between the drift tube and the front surface of the ceramic by placing a wire grid on the front surface. Plasma densities of 1012Â cmâ3 and neutral pressures â¼10â6Â Torr are expected. A test stand to produce 20Â cm long plasma is being constructed and will be tested before a 1Â m long source is developed.
Related Topics
Physical Sciences and Engineering
Physics and Astronomy
Instrumentation
Authors
Philip C. Efthimion, Erik P. Gilson, Larry Grisham, Ronald C. Davidson, Simon Yu, William Waldron, B. Grant Logan,