Particle measurement issues play a prominent role as they arise in industrial, environmental, and processing environments. Providing appropriate measurement tools for different particle analysis issues is the focus of this project. CSTL researchers direct efforts to:

• Identify samples, contaminants, or analyze particles in advanced materials.
• Apply infrastructure measurement capabilities to characterize actinides and other materials.
• Develop standards, data, and measurement protocols for quality assurance.
• Transfer measurement capabilities to user communities, e.g., DoD, DoE, DHS and IAEA.
• Characterize individual particles and populations of particles.
• Automate particle measurement methods, while developing or extending software for data collection, visualization, and interpretation.

• Production of Uniform Particle Standards Using the Vibrating Orifice Particle Generator and Quantification by Optical Particle Sensor: CSTL researchers are developing a method to produce accurate and precise particle standards of known composition, size, and number for testing ion mobility spectrometers, trace analysis, particle testing, and for pharmaceutical research. We found that the Vibrating Orifice Aerosol Generator (VOAG) is reproducible and that each particle contains the same amount of desired test compound that can be controlled by the solute concentration in solution. The ability to make trace particle standard test materials in a custom fashion for many materials is a valuable addition to our capabilities. Instruments that detect trace explosives and trace drug quantities can be tested and their performance quantified.
• NIST Trace Explosive Vapor Preconcentrator (EVAP) Test Facility: CSTL researchers improve the sensitivity of trace explosive detection by establishing standards for testing chemical processing technologies that preconcentrate the vapors of RDX, HMX, PETN, TNT, and other explosives. The major technical challenge involved the design and fabrication of a robust system that integrated the ability to monitor multiple aspects of performance, allowed flexibility of configuration, and was fairly easy to operate. Demonstration of capabilities involved determining the collection efficiency of the EVAP with respect to explosive type, heating rate, and airstream velocity and humidity. These four variables all proved to be significant.
• Portal Filter Particle Collection Efficiency Using Mondispersed Aerosol: A CSTL research team along with the Transportation Security Administration and the Department of Homeland Security, have characterized the collection efficiency of the metal-fiber filter material used by the manufacturers of portal systems.
• A new Monte Carlo application for complex sample geometries: Assigning particles to a descriptive class through quantitative microanalysis is hampered by morphologically induced particle-to-particle variance. This research involves modeling the shape of the particle to reduce particle-to-particle variance and thereby improve the ability to differentiate particles of similar but different materials.
• Quantitative analysis of submicrometer particles in the Scanning Electron Microscope (SEM) utilizing the ? factor approach: Traditionally ultrafine particles have been analyzed in analytical electron microscopes, which often require large capital investments in excess of $1M and have difficult sample preparation procedures. The SEM method developed here could potentially offer a more economical approach.
• XML for Microanalysis: CSTL researcher creates new microanalysis technique schemas for AnIML covering spectroscopies and electron optical scanning techniques (STEM, SEM, Spectrum Imaging).
• Rapid searching of spectrum image databases for rare events, or finding the needle in the haystack when you don't even know you're looking for a needle!: CSTL researchers have developed the Maximum Pixel Spectrum , a software tool that enables rapid searching of SEM x-ray spectrum image databases to detect rare features, even if the analyst does not know in advance which elements are present. Maximum Pixel Spectrum software tool is available free at http://www.nist.gov/lispix/
• Advanced InkJet Printing Technology for Trace Explosives Standards: CSTL researchers are exploring drop-on-demand inkjet printing as a low cost, flexible, and reproducible method for preparation of explosive standards over a wide range of concentrations on almost any substrate. The NIST printer system has been used to prepare prototype calibration standards by drop-on-demand printing of RDX, PETN, and TNT from isobutanol solutions onto various substrates. The concentration of explosives delivered in individual inkjet droplets is determined by GC-MS analysis or by determination of droplet diameter using digital camera imaging with high-frequency strobe illumination.

• Jablonksi, F. Salvat, C. J. Powell NIST Electron Elastic-Scattering Cross-Section Database – Version 3.1. National Institute of Standards and Technology, Gaithersburg , MD (2003)