Accelerator mass spectrometry: revealing subtle signals in ice sheets

dc.contributor.authorSmith, AMen_AU
dc.date.accessioned2015-12-16T00:06:15Zen_AU
dc.date.available2015-12-16T00:06:15Zen_AU
dc.date.issued2013-02-13en_AU
dc.date.statistics2015-11-18en_AU
dc.description.abstractAccelerator Mass Spectrometry (AMS) determines the ratio of a rare isotope, normally radioactive and of intermediate half-life, to a stable isotope. AMS permits the detection of individual atoms in a sample and so is an inherently sensitive analytical technique. A well-known example is radiocarbon dating (14C, t1/2 = 5730 a), where measurement of the 14C/12C ratio permits determination of the age of an artifact. Such AMS measurements can be performed rapidly (~ 20 min), at good precision (~ 0.3 ‰), with high sensitivity (< 10-15) and on very small samples (as little a few μg of carbon). Radiometric measurements, by contrast, require much larger sample masses and much longer measurement times in order to obtain good precision. Besides its use as a chronometer, 14C is increasingly used as a tracer in geophysical studies as the amount of carbon required for a measurement has decreased.At ANSTO we routinely measure 14C, 10Be, 26Al and the Actinides by AMS and in 2010 we added 7Be to the list. Here I give some examples from the ice sheets in Greenland and Antarctica of palaeoclimate research I have been involved in. In each case AMS has provided the unique key to unlock these important climate archives. I will discuss 14C studies of atmospheric gases from firn air and ice core bubbles, with the objective of learning more about the natural and anthropogenic sources of the important greenhouse gas methane. Additionally, I will discuss studies of the beryllium isotopes, 7Be (t1/2 = 53 d) and 10Be (t1/2 = 1.4 _ 106 a) in snow and ice, with the objective of improving the use of 10Be as a proxy for Solar variability.en_AU
dc.identifier.citationSmith, A.(2013). Accelerator mass spectrometry: revealing subtle signals in ice sheets. Paper presented the Past Global Changes 4th Open Science Meeting, Goa, India 13-16 February 2013.en_AU
dc.identifier.conferenceenddate16 February 2013en_AU
dc.identifier.conferencenamePast Global Changes 4th Open Science Meetingen_AU
dc.identifier.conferenceplaceGoa, Indiaen_AU
dc.identifier.conferencestartdate13 February 2013en_AU
dc.identifier.govdoc6296en_AU
dc.identifier.urihttp://apo.ansto.gov.au/dspace/handle/10238/6459en_AU
dc.language.isoenen_AU
dc.publisherPast Global Changesen_AU
dc.subjectAcceleratorsen_AU
dc.subjectMass spectroscopyen_AU
dc.subjectIsotopesen_AU
dc.subjectIsotope datingen_AU
dc.subjectANSTOen_AU
dc.subjectAntarcticaen_AU
dc.titleAccelerator mass spectrometry: revealing subtle signals in ice sheetsen_AU
dc.typeConference Abstracten_AU
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