individual research laboratories. System layout At a minimum, an atom probe will consist of several key pieces of equipment. A vacuum system for maintaining the low pressures (~10−8 to 10−10 Pa) required, typically a classic 3 chambered UHV design. A system for the manipulation of samples inside the vacuum, including sample viewing systems. A cooling system to reduce atomic motion, such as a helium refrigeration circuit - providing sample temperatures as low as 15K. A high voltage system to raise the sample standing voltage near the threshold for field evaporation. A high voltage pulsing system, use to create timed field evaporation events A counter electrode that can be a simple disk shape (like the EIKOS™, or earlier generation atom probes), or a cone-shaped Local Electrode, like on a LEAP® system. The voltage pulse (negative) is typically applied to the counter electrode. A detection system for single energetic ions that includes XY position and TOF information. Optionally, an atom probe may also include laser-optical systems for laser beam targeting and pulsing, if using laser-evaporation methods. In-situ reaction systems, heaters, or plasma treatment may also be employed for some studies as well as a pure noble gas introduction for FIM. Performance Collectable ion volumes were previously limited to several thousand, or tens of thousands of ionic events. Subsequent electronics and instrumentation development has increased the rate of data accumulation, with datasets of hundreds of million atoms (dataset volumes of 107 nm3). Data collection times vary considerably depending upon the experimental conditions and the number of ions collected. Experiments take from a few minutes, to many hours to complete. Applications Metallurgy Atom probe has typically been employed in the chemical analysis of alloy systems at the atomic level. This has arisen as a result of voltage pulsed atom probes providing good chemical and sufficient spatial information in these materials. Metal samples from large grained alloys may be simple to fabricate, particularly from wire samples, with hand-electropolishing techniques giving good results. Subsequently, atom probe has been used in the analysis of the chemical composition of a wide range of alloys. Such data is critical in determining the effect of alloy constituents in a bulk material, identification of solid-state reaction features, such as solid phase precipitates. Such information may not be amenable to analysis by other means (e.g. TEM) owing to the difficulty in generating a three-dimensional dataset with composition. Semiconductors Semi-conductor materials are often