High precision isotopic determination of archaeological materials using laser ablation ICP-MS rem... more High precision isotopic determination of archaeological materials using laser ablation ICP-MS remains an elusive goal. Practical, nearly non-destructive, rapid and cost effective, isotope ratio measures using LA-ICP-MS suffer from transient effects, laser-induced fractionation, and generally lower precision than other methods of sample introduction. However, in contrast to high precision measurement requirements in biological systems, lower levels of analytical precision may still meet threshold levels for isotopic discrimination in archaeological materials, depending on the specificity of the research questions. We here report on our efforts to reduce the spread of replicate isotopic measurements of archaeological materials using pre and post-laser sample treatment, and evaluate the degree to which lower levels of precision affect group attribution in specific cases.
A reconstruction technique to calculate accurate tomograms of a sample, at a voxel scale, from to... more A reconstruction technique to calculate accurate tomograms of a sample, at a voxel scale, from tomographic experiments that involve probe - sample interactions of any degree of complexity is proposed. The properties of the reconstruction technique that accomplish this are outlined. The first guess to the solution is calculated directly from the reconstructed experimental projection data. To improve the accuracy
This article will demonstrate the production and application of {open_quote}{open_quote}mixed{clo... more This article will demonstrate the production and application of {open_quote}{open_quote}mixed{close_quote}{close_quote} beams for a magnetically focused nuclear microprobe. A {open_quote}{open_quote}mixed{close_quote}{close_quote} beam is defined as any two beams of ions of different species, or energy, or both that can be quickly and easily made to have the same magnetic rigidity ({ital R}{sub {ital m}}) so that they transport, focus, and scan the
Nuclear Instruments & Methods in Physics Research Section B-beam Interactions With Materials and Atoms, 1997
This paper presents some recent results in the investigation of MeV ion microprobe imaging techni... more This paper presents some recent results in the investigation of MeV ion microprobe imaging techniques at the Micro-Analytical Research Centre MARC in Melbourne, Australia. In the first section we investigate the use of molecular hydrogen beams as tools for scattering contrast STIM imaging. The second section deals with the use of post-specimen scanning as a means of quantitatively imaging transmission
Nuclear Instruments & Methods in Physics Research Section B-beam Interactions With Materials and Atoms, 1997
The aim of this project is to develop a new system for single ion irradiation of cells for geneti... more The aim of this project is to develop a new system for single ion irradiation of cells for genetic and cell biology studies. This charged particle focused microbeam system will provide a fully computer controlled irradiation facility with submicron (subcellular) resolution and will open many new avenues into studies of radiobiological mechanisms. In the first stage of this project a
Nuclear Instruments & Methods in Physics Research Section B-beam Interactions With Materials and Atoms, 1991
Scanning Transmission Ion Microscopy (STIM) has been combined with Channeling Contrast Microscopy... more Scanning Transmission Ion Microscopy (STIM) has been combined with Channeling Contrast Microscopy (CCM) to examine damage in a thin crystal (4 mum thick Si) with high spatial resolution (200 nm). Such measurements require very low beam currents (<1 fA), whereas the crystal was damaged only by relatively large currents (nA).
Nuclear Instruments & Methods in Physics Research Section B-beam Interactions With Materials and Atoms, 1993
Channeling scanning transmission ion muscopy (CSTIM) has been used to explore transmission channe... more Channeling scanning transmission ion muscopy (CSTIM) has been used to explore transmission channeling in thin Si and SiC crystals. The CSTIM technique was applied to the investigation of the quality of sim 30 mum thick SiC crystal. In this work the results from channeling contrast muscopy (CCM) were combined with CSTIM. The channeling STIM (CSTIM) technique is almost 100% efficient,
... Ratio Determination of Archaeological Materials Using Laser Ablation-Time-of-Flight-Inductive... more ... Ratio Determination of Archaeological Materials Using Laser Ablation-Time-of-Flight-Inductively Coupled Plasma-Mass Spectrometry Increasing Ratio Precision John V. Dudgeon1,4, Hector Neff2,4, Andrew &quot;Flynn&quot; Saint3, and William Balsanek3 ...
... It was observed both at the ablation stage (in the case of femtosecond laser ablation) due to... more ... It was observed both at the ablation stage (in the case of femtosecond laser ablation) due to separation of ions in electromagnetic fields,12 ... of TOF-oa-MS, we reveal new aspects of the critical influence of particulate formation on fractionation of different elements in LA-ICP-MS. ...
High precision isotopic determination of archaeological materials using laser ablation ICP-MS rem... more High precision isotopic determination of archaeological materials using laser ablation ICP-MS remains an elusive goal. Practical, nearly non-destructive, rapid and cost effective, isotope ratio measures using LA-ICP-MS suffer from transient effects, laser-induced fractionation, and generally lower precision than other methods of sample introduction. However, in contrast to high precision measurement requirements in biological systems, lower levels of analytical precision may still meet threshold levels for isotopic discrimination in archaeological materials, depending on the specificity of the research questions. We here report on our efforts to reduce the spread of replicate isotopic measurements of archaeological materials using pre and post-laser sample treatment, and evaluate the degree to which lower levels of precision affect group attribution in specific cases.
A reconstruction technique to calculate accurate tomograms of a sample, at a voxel scale, from to... more A reconstruction technique to calculate accurate tomograms of a sample, at a voxel scale, from tomographic experiments that involve probe - sample interactions of any degree of complexity is proposed. The properties of the reconstruction technique that accomplish this are outlined. The first guess to the solution is calculated directly from the reconstructed experimental projection data. To improve the accuracy
This article will demonstrate the production and application of {open_quote}{open_quote}mixed{clo... more This article will demonstrate the production and application of {open_quote}{open_quote}mixed{close_quote}{close_quote} beams for a magnetically focused nuclear microprobe. A {open_quote}{open_quote}mixed{close_quote}{close_quote} beam is defined as any two beams of ions of different species, or energy, or both that can be quickly and easily made to have the same magnetic rigidity ({ital R}{sub {ital m}}) so that they transport, focus, and scan the
Nuclear Instruments & Methods in Physics Research Section B-beam Interactions With Materials and Atoms, 1997
This paper presents some recent results in the investigation of MeV ion microprobe imaging techni... more This paper presents some recent results in the investigation of MeV ion microprobe imaging techniques at the Micro-Analytical Research Centre MARC in Melbourne, Australia. In the first section we investigate the use of molecular hydrogen beams as tools for scattering contrast STIM imaging. The second section deals with the use of post-specimen scanning as a means of quantitatively imaging transmission
Nuclear Instruments & Methods in Physics Research Section B-beam Interactions With Materials and Atoms, 1997
The aim of this project is to develop a new system for single ion irradiation of cells for geneti... more The aim of this project is to develop a new system for single ion irradiation of cells for genetic and cell biology studies. This charged particle focused microbeam system will provide a fully computer controlled irradiation facility with submicron (subcellular) resolution and will open many new avenues into studies of radiobiological mechanisms. In the first stage of this project a
Nuclear Instruments & Methods in Physics Research Section B-beam Interactions With Materials and Atoms, 1991
Scanning Transmission Ion Microscopy (STIM) has been combined with Channeling Contrast Microscopy... more Scanning Transmission Ion Microscopy (STIM) has been combined with Channeling Contrast Microscopy (CCM) to examine damage in a thin crystal (4 mum thick Si) with high spatial resolution (200 nm). Such measurements require very low beam currents (<1 fA), whereas the crystal was damaged only by relatively large currents (nA).
Nuclear Instruments & Methods in Physics Research Section B-beam Interactions With Materials and Atoms, 1993
Channeling scanning transmission ion muscopy (CSTIM) has been used to explore transmission channe... more Channeling scanning transmission ion muscopy (CSTIM) has been used to explore transmission channeling in thin Si and SiC crystals. The CSTIM technique was applied to the investigation of the quality of sim 30 mum thick SiC crystal. In this work the results from channeling contrast muscopy (CCM) were combined with CSTIM. The channeling STIM (CSTIM) technique is almost 100% efficient,
... Ratio Determination of Archaeological Materials Using Laser Ablation-Time-of-Flight-Inductive... more ... Ratio Determination of Archaeological Materials Using Laser Ablation-Time-of-Flight-Inductively Coupled Plasma-Mass Spectrometry Increasing Ratio Precision John V. Dudgeon1,4, Hector Neff2,4, Andrew &quot;Flynn&quot; Saint3, and William Balsanek3 ...
... It was observed both at the ablation stage (in the case of femtosecond laser ablation) due to... more ... It was observed both at the ablation stage (in the case of femtosecond laser ablation) due to separation of ions in electromagnetic fields,12 ... of TOF-oa-MS, we reveal new aspects of the critical influence of particulate formation on fractionation of different elements in LA-ICP-MS. ...
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Papers by Andrew Saint