Conformity Magazine - June 2008 - (Page 16)

of elements from sodium (Na) to uranium (U) in a variety of sample forms such as metals, resins, powders, ceramics, rubber, plastics and liquids. Detection Made Simple EDX spectroscopy examines samples through interactions between electromagnetic radiation and matter, analyzing the X-rays emitted by the matter. A sample is irradiated with X-rays emitted by an X-ray tube, and the resulting characteristic X-rays generated in the sample (fluorescent X-rays) are detected. In particular, X-ray fluorescence spectrometers that use semiconductor detectors are called “energy dispersive” (Figure 2). A strong advantage is that the systems can perform simultaneous measurement for many different elements. Systems are also compact because the distance between the sample and detector is very small. Using these systems, attenuation of fluorescent X-rays is small and thus it is possible to measure samples in air. Furthermore, these systems do not require time-consuming pretreatment and a wide variety of samples can be measured. After analysis, the sample is not radioactive or altered in any way. EDX’s characterization capabilities are associated with the fundamental principle that each element of the periodic table has a unique atomic structure. This allows X-rays that are distinctive of an element’s atomic structure to be distinguished from each other. Conventional analysis methods can only achieve about 50ppm. EDX can achieve lower limits of detection (LLD) below 10ppm. For example, lead (82Pb) can be detected at 5.3 ppm using a nickel (Ni) filter. One important thing to note is the large effect matrix has on the intensity of an emitted X-ray. The intensity of the characteristic X-ray decreases with the density of the matrix. In Figure 3, three different matrices were chosen based on the popularity of use in common consumer product components: paint, resin and metal. Different amounts of lead contamination in each matrix are used to establish a linear relationship between the lead and the matrix. Integrating an EDX System for Testing The functionality of an EDX system that meets JIS, ANSI and DIN standards allows it to be easily integrated into any stage of a product’s production, from the individual components to the final assembly, in any manufacturing process worldwide. Complex sample preparation is unnecessary, and rapid analyses are possible. EDX is ideal for quality control on the manufacturing side and distribution/reseller side. This type of double checking can prevent a catastrophe, similar to the recent recall of millions of toys, from happening in the future. Figure 1: Diagram of a WDX spectrometer Figure 2: Diagram of an EDX spectrometer 16 Conformity JUnE 2008

Table of Contents Feed for the Digital Edition of Conformity - June 2008

Conformity - June 2008 Contents Editor's Note 700 MHz Auction Raises a Record $20 Billion FCC Modifies PCS and AWS Power Limit Rules for Broadband Wireless Commission Designates Spectrum Test Bed FCC Releases Report on Wireless Competition Commission Proposes $5 Million Fine for Slamming Using EDX for Non-Destructive Detection of Lead in Consumer Products ESD Open Forum Challenges in Testing - Improving Election Security and Accuracy Part 1 Challenges in Testing - Human Body Model: The Hidden Challenges High-Speed Signal Integrity Considerations for ESD Components Focus On...EMC Components Buyer's Guide FCC Levies $2.6 Million Fine for Junk Faxes FDA Updates Guidance on its Product Review Process EU Issues Updated Energy Star Regulations EU Repeals Directive on Veterinary Electro-Medical Equipment New Product Announcements Updated Standards List for the EU's PPE Directive CPSC Announces New Effort to Keep Out Hazardous Products CPSC Actions in the News IEC Standards Update UL Standards Update Product Reviews Telcordia Standards Update From Our "You Can't Make This Stuff Up" Department Looking Back: Items from Past Issues of Conformity Advertisers

Conformity - June 2008

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