The eleventh Accelerator Mass Spectrometry (AMS 11) Conference took place in September 2008, the Thirtieth Anniversary of the first Conference. That occurred in 1978 after discoveries with nuclear physics accelerators in 1977. Since the first Conference there have now been ten further conferences on the development and applications of what has become known as AMS. This is the accepted acronym for the use of accelerators, together with nuclear and atomic physics techniques, to enhance the performance of mass spectrometers for the detection and measurement of rare long-lived radioactive elements such as radiocarbon. This paper gives an outline of the events that led to the first conference together with a brief account of the first four conferences before the introduction of the second generation of accelerator mass spectrometers at AMS 5.

The diffusion of implanted chlorine in silicon wafers is studied with neutron activation/accelerator mass spectroscopy (NA/AMS). Depth profiles are obtained from as-implanted and annealed samples. While there is a marked difference between the annealed and as-implanted profiles for the lowest implant dose studied, 1013/cm2, the chlorine from the higher dose implants is virtually immobile. The diffusion of implanted chlorine in silicon is characterized by the apparent absence of indiffusion for the experimental conditions studied. However, outdiffusion is rapid at low concentrations for anneal temperatures of 1100°C and above. This behavior is qualitatively similar to that reported for fluorine in silicon at lower temperatures.

Radioactive chlorine-36 (half-life = 301,000 years) is produced by cosmic-ray induced spallation reactions in the Earth`s atmosphere and in surface rocks and through thermal neutron activation of stable chlorine-35 in the Earth`s crust. A large amount of chlorine-36 was introduced into the atmosphere and hydrosphere during nuclear weapon tests in the 1950`s and 1960`s (the so called {open_quotes}bomb pulse{close_quotes}). Additional sources of anthropogenic Cl-36 in the environment are activities associated with the nuclear power cycle. Results of three recent applications of chlorine-36 will be presented and discussed: (1) study of the dynamics of water movement and radioactive contaminants from nuclear fuel reprocessing plants at Savannah River Site, South Carolina and Idaho National Engineering Laboratory, Idaho Falls, Idaho, (2) investigation of potential water movement through the unsaturated zone at Yucca Mountain (a possible site for high level radioactive waste disposal), and (3) deciphering past variations in cosmic radiation using ancient packrat urine from Nevada.

Initial measurements of the cosmogenic radionuclide, Cl-36, in the lower stratosphere were made by accelerator mass spectrometry. Samples were obtained using the large volume LASL air sampling pods on a NASA WB-57F aircraft. Untreated (for collection of particulates only) and tetrabutyl ammonium hydroxide treated (for collection of particulates and HCl) IPC-1478 filters were flown on three flights in the lower stratosphere. Chlorine (Cl) and Cl compounds are important trace constituents for stratospheric chemistry, in particular with respect to O3 destruction. Stratospheric Cl chemistry has recently received increased attention with the observation of strong O3 depletion in the Antarctic winter vortex and in the weaker and more complex Arctic winter vortices. Cosmogenic (Cl-36) is produced by spallation reactions from Ar mainly in the stratosphere, and has had several applications as a geochemical tracer. The large amounts of Cl-36 introduced by nuclear weapon testing have been removed from the stratosphere by now, and measurements in the stratosphere to obtain cosmogenic production rates and concentration distributions is now possible. The use of cosmogenic Cl-36 as a tracer for stratospheric Cl chemistry and for stratospheric/tropospheric exchange processes is investigated. A first attempt to determine stratospheric and tropospheric production rates, the partitioning of Cl-36 among particulate and gaseous Cl compounds, and the respective inventories and removal rates is being made. Results from a flight at 13.7 km, 30-33 degrees N, 97-107 degrees W, and from a second flight at 17.7 km, 43-45-36 degrees N, 92-94 degrees W, for the untreated and treated filters respectively are presented.

ArchaeometryVolume 31, Issue 2 p. 235-237 LETTER TO THE EDITOR: THE TURIN SHROUD H. E. GOVE, H. E. GOVE Nuclear Structure Research Laboratory, Rochester University, Rochester, New, York 14627, U.S.A.Search for more papers by this author H. E. GOVE, H. E. GOVE Nuclear Structure Research Laboratory, Rochester University, Rochester, New, York 14627, U.S.A.Search for more papers by this author First published: August 1989 https://doi.org/10.1111/j.1475-4754.1989.tb01016.xCitations: 2AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat Citing Literature Volume31, Issue2August 1989Pages 235-237 RelatedInformation

We report here results of recent determinations of osmium isotope ratios and rhenium/osmium ratios measured with AMS. Because Re forms negative atomic ions with a considerably lower efficiency than Os, Os isotopes can be determined with minimal isobaric interference at mass 187. Detection limits for AMS measurements of osmium are 20 ppb in chemically untreated samples and 0.01 ppb in samples where Os has been preconcentrated with a nickel sulfide method. The fact that Re and Os each form negative ions as oxides at a comparable rate has been used to determine Re Os ratios in untreated meteorite samples.

The measurement of Ca-41 and I-129 utilizing the Rochester Tanden Accelerator Mass Spectrometer (TAMS) is discussed. Ca-41, having a half-life of 100,000 yrs., is of potential use for the dating of ground water as well as of bones in the age range between 50,000 and 1 million yrs. A major problem for the measurement of Ca-41 with TAMS is the fact that calcium does not readily form negative atomic ions. It does, however, form negative molecular ions. The production of CaO ions from compounds such as CaO and CaCO3 and from free Ca molecules sprayed with oxygen gas was studied. A project to utilize I-129 as a tracer for hydrothermal convection in sediment-covered oceanic crust is also briefly described. Finally, plans to use the Os-187/Os-186 ratio for the determination of extraterrestrial material in the Ries crater in Germany are summarized.