Sunday, June 28, 2009

Handheld xrf and archaeology

I'll have a unit on loan from Bruker this summer to try on ceramics and maybe soils at the Etruscan site of Poggio Colla where I've been working. Cool - thanks, Bruker!

Here's what another vendor, Niton, has to see about the possibilities of handheld xrf:

With new advancements in technology, archaeometry – or the collection of quantitative data from archaeological samples – is quickly becoming one of the most trusted methods in archaeological study. As the longtime industry leader in portable XRF analysis, Thermo Fisher Scientific is uniquely capable of providing handheld nondestructive testing solutions for art and artifacts in the field, in the lab, or on the museum wall.
NITON analyzers are ideal tools to aid in a variety of applications in art and archaeology, including:
Archaeological reconnaissance survey – obtain geochemical data instantaneously
Provenance – compare sources and artifacts, build databases, and much more
Restoration – match pigments and other materials for restoration quickly and accurately
Conservation – help identify how objects have been preserved in the past, and how to better conserve them for the future by looking at elemental composition data Cultural Resource Management – identify areas of historic human activity quickly and easily
NAGPRA Compliance – ensure that traces of toxic preservatives have been removed from artifacts prior to repatriation
Dating – glean important clues to the age of petroglyphs, alloys, and other materials through elemental analysis
Authentication – help authenticate a variety of art and artifacts using elemental data

Any success stories or warnings from my many readers?

3 comments:

  1. I discussed my findings at GSA a few years ago:

    http://gsa.confex.com/gsa/responses/2007AM/250.pdf
    http://gsa.confex.com/gsa/2007AM/finalprogram/abstract_123895.htm

    The XRF "ray guns" are currently the best option for fieldwork due to their extreme portibility, but they're no replacement for lab instruments. I think they're best suited as "first sort" tools in the field for choosing samples to be sent back to the lab.

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  2. I also cringe a bit when I see these instruments touted as "non-destructive," and the product literature shows them aimed at museum paintings:

    http://www.niton.com/images/products/all/_044_lg.jpg

    XRF is fairly efficient, but one is still putting 50-keV X-rays from a 2-watt source into the paint -- there will be heat produced. Museum conservators would never let anyone do that with a laser, but I suspect that the invisible X-rays make it seem "safer" to them. No one knows yet what the long-term effects on paint and canvas will be.

    Also, Rob, don't analyze the soils through plastic bags, like one can see on the NITON website and in product literature:

    http://www.niton.com/images/products/all/823_lg.jpg

    The plastic bags absorb lower-energy X-rays more readily than higher-energy one, so it will screw up your element ratios, even block lighter elements completely. We tested that here too, but that didn't make it into my GSA talk.

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  3. In the absence of readily available standards, the SpectroStandard® XRF Reference Materials Preparation Kit offers an alternate choice in accommodating infrequent or "out of the ordinary" sample unknowns. The unique assemblage of assorted compounds contains 50 elements to prepare "in-lab" reference materials for single or multiple elemental analyses.

    XRF Supplies

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