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Radiochemical Processing Laboratory

Radiological Surface Science Laboratory

The Radiological Surface Science Laboratory (RSSL) is a unique facility that provides an array of surface analysis instruments for the examination of radioactive samples. Surface and interface analysis tools have been used extensively and with great success over the past 35 years in corrosion, geochemistry, catalysis, electronics, tribology, and many other areas. The RSSL now combines these powerful research tools with the ability to examine radiological samples, creating new opportunities for basic through applied research. The RSSL's location gives it direct access to radiological labs and hot cells, where highly active and dispersible samples may be received, tested and prepared for surface analysis.

Surface Analysis Capabilities

Auger Electron Spectroscopy (AES) provides elemental composition of the top 5 - 20 atomic layers of a sample. Spatial resolution is currently as high as 0.1 µm. Analysis modes include: spot analysis; larger area average (up to about 0.5 cm); line scan; and elemental mapping of an approximately 0.5 cm square area.

The Physical Electronics 560 Surface Analysis System, one of the Radiological Surface Science Laboratory’s four surface analysis systems, may be used for AES, XPS and SIMS experiments on radiological samples.
The Physical Electronics 560 Surface Analysis System, one of the Radiological Surface Science Laboratory’s four surface analysis systems, may be used for AES, XPS and SIMS experiments on radiological samples. (Enlarge image)

X-ray Photoelectron Spectroscopy (XPS) provides elemental composition and also oxidation state information of the top 5 - 20 atomic layers. The highest spatial resolution is currently 150 µm - 250 µm. Three different anodes are available: magnesium (1253.6 eV x-rays); aluminum (1486.7 eV x-rays); and chromium (5417 eV x-rays).

Secondary Ion Mass Spectroscopy (SIMS) uses a rastered beam of mono-energetic ions (argon, krypton, xenon, or other) to create and eject ions from the surface. These ions are mass analyzed with a quadrupole mass spectrometer, giving an isotopic composition of the surface. This is extremely useful in the analysis of actinides in a sample, particularly when combined with the elemental and oxidation state information from XPS.

Depth profiles, or plots of how the concentrations of different elements vary with depth, can be collected using any of these techniques, allowing investigation of buried interfaces. SIMS inherently creates a depth profile as the probe ions remove material from the surface; AES and XPS depth profiles may be collected by sputtering (bombarding with ions) between measurements.

Systems for Examination of Radioactive and Non-Radioactive Samples

The Physical Electronics 660 Scanning Auger Microprobe provides scanning AES, SIMS, and secondary-electron and absorbed-current imaging systems. Spatial resolution of the AES and imaging systems in the surface plane is 0.1 µm. All instruments are focused on one point. This allows visual inspection, selection of a region of interest, sample analysis with either the AES or SIMS, and follow-up visual inspection, with no major sample movement or re-alignment. The system has an in situ fracture unit and a separate sputtering chamber for high-activity samples. A radiological containment box over the sample introduction port, plus a sample introduction airlock, allow high throughput of radiological samples.

The Physical Electronics 590 provides scanning AES, SIMS, and secondary-electron and absorbed-current imaging systems. The capabilities of this system are very similar to the 660 system, but the spatial resolution of the AES and imaging systems in the surface plane is nominally 2 µm. Samples can be heated before or during analysis. A radiological containment box over the sample introduction port and sample introduction airlock allow high throughput of radiological samples without breaking vacuum.

The Physical Electronics 560 provides scanning AES, XPS, and SIMS, in addition to secondary-electron and absorbed-current imaging. The AES and imaging instruments have a spatial resolution of approximately 50 µm. As with the Physical Electronics 660 and 590 systems, all instruments are focused on the same point inside the chamber, allowing analysis by all methods with minimal sample movement. Samples can be heated before or during analysis. A radiological containment box over the sample introduction port and a sample introduction airlock allow high throughput of radiological samples.

An elemental map produced using Auger Electron Spectroscopy shows strontium deposited on a concrete sample.
An elemental map produced using Auger Electron Spectroscopy shows strontium deposited on a concrete sample. Strontium is colored blue, calcium is white, silicon is red, and sodium is yellow. The association of strontium and silicon suggests that strontium is bound more strongly to the silicate minerals in the concrete than to the other concrete components. (Enlarge image)

With the 560 system, various reaction chambers can be used, including one that allows reaction of samples with gases, an electrochemical reaction cell, and a dipping chamber that allows immersion of a sample in a liquid. These ancillary chambers are sealed to the 560 system, allowing a sample to be cleaned and examined in the main vacuum chamber, transferred to one of the small chambers for reaction under controlled conditions, then returned to the main chamber for examination to determine the effects on the surface. The transfer chambers are backfilled with an inert gas to avoid contamination/reaction of the sample with constituents in air.

The Physical Electronics 545 provides a Low Energy Electron Diffraction instrument (LEED) and an XPS system in addition to the original AES system. The LEED allows researchers to determine ordered structures on a surface. A sample transfer system allows rapid introduction of samples from a 4-ft radiological fume hood.

All AES, XPS and SIMS systems are controlled with standard PC computer systems, allowing rapid data acquisition and ease of file manipulation. Secure (Limited Area) laboratories and offices are available for classified data collection and analysis.

Current Applications

Areas in which RSSL capabilities may be applied include:

  • Energy: Understanding the properties and behavior of advanced fuels, such as migration and segregation of fission and activation products in spent fuel; investigating corrosion and degradation of plant and pipeline components; and examination and diagnostic testing of materials.
  • National and Homeland Security: Attribution; forensics; interaction of radionuclides with urban surfaces; and analysis of materials for weapons production, maintenance, and disassembly.
  • Environmental: Interactions of actinides and other radionuclides with mineral and engineering barrier surfaces; analysis of waste forms; and speciation of high-level-waste solids components.
  • Biological: Interactions of actinides and other radionuclides with biological materials, such as bone and tissues.

A printer-friendly copy of our brochure is available here.

Point of Contact:
David L. Blanchard, Ph.D., Irradiated Materials Team
Phone: (509) 375-5376

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