The operating principles of the two duoplasmatron ion sources and the PIG source available for the Van de Graaff accelerator have been determined qualitatively, mainly by studying the extensive literature on ion sourc...The operating principles of the two duoplasmatron ion sources and the PIG source available for the Van de Graaff accelerator have been determined qualitatively, mainly by studying the extensive literature on ion sources. The main characteristics of the three sources have therefore been determined experimentally on an ion source test bench. Important parameters of the sources such as the pressure and temperature in different regions of the sources not measured, because of space limitations. However, in spite of these limitations in quantitative understanding of the sources, sufficient information to continue with the study of the beam transport through the Van de Graaff accelerator and its beamlines could be obtained from these measurements. With regard to beam intensity, lifetime and gas consumption the measurements showed that the hotcathode duoplasmatron is at present by far the most suitable source for the van de Graaff accelerator. The emittance of the ion source was measured with two slits, 90 mm apart, and a Faraday cup in the ion source test bench at an arc voltage of 83 V, an arc current of 1 Amp, a filament voltage of 24 V and an extraction voltage of 5 kV. The measured emittance for 90% of the beam intensity is 48π mm mrad. This figure will be used to calculate the beam transmission through the Van de Graaf accelerator. Different computer programs have been used for these calculations from the ion source through the terminal section, the accelerator and beam line up to the Nuclear Microprobe (NMP) for beam quality.展开更多
This study deals with an overview of the biomedical projects performed at iThemba LABS, particularly in relation to the spatial distribution of trace metals in hard human tissues from disadvantaged Sudanese communitie...This study deals with an overview of the biomedical projects performed at iThemba LABS, particularly in relation to the spatial distribution of trace metals in hard human tissues from disadvantaged Sudanese communities, such as kidney stone concretions, teeth and hair, undertaken at the iThemba LABS Nuclear Microprobe (NMP) facility. Relevant information about the ion beam techniques used for material characterization was discussed. The Particle Induced X-ray Emission (PIXE) technique was used to investigate the elemental composition of human hard tissues on a microscopic scale with the elemental mapping;complementary ion beam techniques are used to provide information on the major and minor components. Analysis of teeth sections by μ-PIXE showed that the levels of trace elements were enriched and/or depleted, this may associated with leaching and/or erosive processes. On the other hand the characterization of kidney stone concretions by μ-PIXE showed a marked difference of individuals from different region within Sudan.展开更多
文摘The operating principles of the two duoplasmatron ion sources and the PIG source available for the Van de Graaff accelerator have been determined qualitatively, mainly by studying the extensive literature on ion sources. The main characteristics of the three sources have therefore been determined experimentally on an ion source test bench. Important parameters of the sources such as the pressure and temperature in different regions of the sources not measured, because of space limitations. However, in spite of these limitations in quantitative understanding of the sources, sufficient information to continue with the study of the beam transport through the Van de Graaff accelerator and its beamlines could be obtained from these measurements. With regard to beam intensity, lifetime and gas consumption the measurements showed that the hotcathode duoplasmatron is at present by far the most suitable source for the van de Graaff accelerator. The emittance of the ion source was measured with two slits, 90 mm apart, and a Faraday cup in the ion source test bench at an arc voltage of 83 V, an arc current of 1 Amp, a filament voltage of 24 V and an extraction voltage of 5 kV. The measured emittance for 90% of the beam intensity is 48π mm mrad. This figure will be used to calculate the beam transmission through the Van de Graaf accelerator. Different computer programs have been used for these calculations from the ion source through the terminal section, the accelerator and beam line up to the Nuclear Microprobe (NMP) for beam quality.
文摘This study deals with an overview of the biomedical projects performed at iThemba LABS, particularly in relation to the spatial distribution of trace metals in hard human tissues from disadvantaged Sudanese communities, such as kidney stone concretions, teeth and hair, undertaken at the iThemba LABS Nuclear Microprobe (NMP) facility. Relevant information about the ion beam techniques used for material characterization was discussed. The Particle Induced X-ray Emission (PIXE) technique was used to investigate the elemental composition of human hard tissues on a microscopic scale with the elemental mapping;complementary ion beam techniques are used to provide information on the major and minor components. Analysis of teeth sections by μ-PIXE showed that the levels of trace elements were enriched and/or depleted, this may associated with leaching and/or erosive processes. On the other hand the characterization of kidney stone concretions by μ-PIXE showed a marked difference of individuals from different region within Sudan.
