SPI Standards for Microanalysis, 44 Metals, Mounted on 3 mounts, each 4x12.5 mm diam.

This mount contains 40 metallic element standard materials, and four compounds for hard-to-polish metals, giving all together 49 different elements suitable for use with either WDS or EDS systems or on free standing microprobe instruments. Originally this standard had 44 pure metals, but problems with the preparation and stability of boron, gallium, indium and thallium led us to switch to simple compounds of these metals. Rather than cut down the number of items in the mount we decided to preserve the "44 Metals" characterization as this has been well known and well received in the microanalysis community for many years.

Purities are is no less than 99% while most are better than "99.99%". Of cours4e a listing of individual purities is supplied with purchase.

The light elements, which can be resolved in modern "windowless" EDS systems, and which are usually excluded from sets of standards for microanalysis are all included in this product. All 44 items are mounted on one 25mm diameter, 6mm thick stainless steel mount and includes a removable Faraday cup.

The set is also available split between three stainless steel mounts, each of which is 12.5mm diameter, 4mm high, and is suitable for attaching to an SEM stub. Each 12.5mm diameter mount also has a Faraday cup permanently built-in, not removable.

We are sometimes asked about the level of radioactivity present as a result of the U and Th present in this particular standard product, since in most countries special licensing is required if the levels exceed some threshold levels. Because both the U and Th are fabricated metals, all accumulated radioactive daughter products have been removed and what is left is only the very long lived, low activity isotopes (U-238 half-life 4.5 billion years and Th-232 half-life 14 billion years). We have made measurements of this radioactivity and have determined that the radioactivity present is less than 0.1MBq. This level is far below the level of concern in any country in the world. For comparison purposes only, for some countries in the far east, the level of concern (e.g. where licensing is required) is 3.7 MBq. Should you in fact have some personal concern about the radioactivity coming from U and Th, we would be very happy to supply the mount without these two elements being present. 

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