Accelerator mass spectrometry facility

In order to provide AMS analyses to the broad ocean sciences research community, the National Ocean Sciences Accelerator Mass Spectrometry Facility (NOSAMS) was established at Woods Hole Oceanographic Institution (Massachusetts) in 1989. Studies performed there include identification of sources of carbon-bearing materials in the water column and sediment, dating of sedimentary samples, investigations of paleocirculation patterns (e.g., from observations of differences in 14C relative abundances in planktonic and benthic foraminifera, and coral cores and cross sections), as well as studies of modern oceanic carbon cycling and circulation. In fact, much that is known about advective and diffusive processes in the ocean comes from measurements of chemical tracers, such as 14C, rather than from direct measurements of water mass flow. 

Ann McNichol is a Research Specialist at the National Ocean Sciences Accelerator Mass Spectrometry Facility at the Woods Hole Oceanographic Institution, which produces high-precision 14C measurements from small-volume samples. Dr. McNichol s research interests include the study and use of carbon, nitrogen, and oxygen isotope techniques to quantify bio-geochemical processes, the study of the fate of organic matter (both natu-... 

National Ocean Sciences Accelerator Mass Spectrometry Facility and Department of Geology and Geophysics Woods Hole Oceanographic Institution Woods Hole, Massachusetts 02543... 

A multi-wire counter was used by Libby to measure the radiocarbon content in archeological artifacts. The first sample he dated was a piece of acacia wood from furniture in Pharaoh Zoser s tomb at Saqqara, Egypt. About 20 g were used, and the date determined was 2,030 350 years BC. The technique developed rapidly, and only 10 mg of the same sample were dated in 1992 in the new National Ocean Sciences Accelerator mass spectrometry facility at Woods Hole Oceanographic Institution and gave an age of 4,115 34 years, i.e., within one cr error of the first (Libby) analysis. The Oeschger Counter is another indispensable tool on... 

Accelerator mass spectrometry (AMS) extends the capabilities of atom-counting using conventional mass spectrometry, by removing whole-mass molecular interferences without the need for a mass resolution very much better than the mass difference between the atom and its molecular isobar. This technique has been used with great success for the routine measurement of C, Be, " Al, C1 and, recently, (see Table 5.15). Analysis of " C by AMS can, for example, generate dates with a precision that is at least equal to the best conventional beta-particle-counting facility. In many cases, where small sample analysis is required, the AMS method has proved superior (Benkens, 1990). A complete description of AMS can be found in review articles (Litherland et al., 1987 Elmore and Philips, 1978) or recent conference publications. The application of AMS to measurement has been discussed in detail in Kilins et al. (1992). 

Because use of mass spectrometry by chemists has increased greatly, most U.S. chemists have access to mass spectrometry facilities at their own institutions to confirm synthesis and support structure elucidations. Heavily used national centers provide more expensive instrumentation and more complex experiments. Most notably, a section of the National High Magnetic Field Laboratory at Florida State University provides state-of-the-art Fourier transform ion cyclotron resonance mass spectrometry. The NSF Arizona Accelerator Mass Spectrometry Laboratory is used primarily to provide radiocarbon measurements. NIH funds a number of national mass spectrometry centers to support biomedical research, including those at Boston University and the Pacific Northwest National Laboratory. 

For several interesting descriptions of AMS facilities, do a Google search on accelerator mass spectrometry."... 

Method B Accelerator mass spectrometry (AMS) and isotope ratio mass spectrometry (IRMS) techniques to quantify the biobased content of a given product. Sample preparation methods are identical to Method A. Stored CO2 is sent to an AMS facility for final processing and analysis. The maximum error is 1-2% for AMS and 0.1-0.5% for IRMS. 

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