Analysis of Heavy-Ion Beam Images and Comparison to RetardingPotential Analyzer Measurements

Rosenberg, Beth Ellen

Lawrence Berkeley National Laboratory

关键词: Thermonuclear Reactors;    Energy Demand;    Energy Sources;    Electrostatics;    Energy Spectra;   

DOI  :  10.2172/878114
RP-ID  :  LBNL--58759
RP-ID  :  DE-AC02-05CH11231
RP-ID  :  878114

美国|英语

来源: UNT Digital Library

【 摘 要 】

It has been predicted that world energy demand will soon put enormous pressure on the currently available energy sources. Fusion energy is a potential solution to this problem if it can be controlled and converted into electricity in an economically feasible manner. One type of potential fusion energy plant uses heavy-ion beam drivers for inertial fusion energy. As part of the High Current Experiment (HCX), we seek to understand the injection, transport and focusing of high-current ion beams, by investigating the interactions of background gas and electrons (which can deteriorate the beam quality) with the primary K{sup +} beam. We present here a method of analyzing the electrostatic potential distribution due to the beam space charge within the grounded conducting vacuum pipe. This method enables tracking of ions arising from the ionization of background gas atoms by the incident K{sup +} beam. The beam intensity distribution is obtained from images gathered using a scintillator placed in the beam path. These data are used to calculate the expelled ion energy distribution, which is then compared to data collected from a Retarding Potential Analyzer (RPA). The comparison of the image analysis with RPA measurements is in fair agreement, given model and experimental uncertainties. Some remaining issues to be explored include the apparent correlation of maximum beam potential with RMS beam size, the systematic effect of background subtraction in the images, as well as possible 3D effects. The new method offers an improved capability to investigate and understand the physics of intense beams, furthering the development of a viable heavy-ion driver for an inertial fusion power plant, which is intended to make fusion energy an affordable and environmentally attractive source of electric power.