Early results from the ANSTO/NIWA 14C of atmospheric methane program

Simple item page
dc.contributor.authorSmith, AMen_AU
dc.contributor.authorBrailsford, Gen_AU
dc.contributor.authorYang, Ben_AU
dc.contributor.authorBromley, Ten_AU
dc.contributor.authorMartin, Ren_AU
dc.date.accessioned2012-06-27T05:47:26Zen_AU
dc.date.available2012-06-27T05:47:26Zen_AU
dc.date.issued2011-03-24en_AU
dc.date.statistics2012-06-27en_AU
dc.description.abstractdevelopment and proving of the laser heated microfurnace we have used it to prepare 45 samples of ~ 16 μg of carbon. These comprised CO2, derived from atmospheric methane, frozen back into glass breakseals following measurement for δ13C at NIWA. There were three sample sets: 15 from Baring Head, NZ (BHD), collected each ~ 15 days between March and September 2009, 9 from Arrival Heights, Antarctica (SCT), collected each ~ 41 days between February 2008 and January 2009, plus 21 samples taken along a Pacific Ocean voyage from Nelson (NZ) – Osaka (Japan) in December 2005 (FTW). All samples were measured to better than 1% precision, sufficient to reveal a 14CH4 signal. The BHD set shows significant temporal variation in 14C for baseline air passing over the Southern Ocean, whereas the SCT set shows a lesser variation for Antarctic air. The FTW set covers a S-N transect across the Pacific Ocean, showing the influence of the ITCZ (5°-10° N) and different meteorological conditions on the concentration, δ13C and Δ14C of CH4 and demonstrates that CH4 is not well mixed. Graphitisation reactions averaged 32 min with 0.7 mg of Fe, reduced from Fe2O3, as the catalyst. The samples, blanks and standards were measured in two 10 minute blocks; some were measured again to improve statistics. Average 13C4+ currents per microgram of carbon were 13, 4 and 2 nA/μg for each 10 min block. Similarly-sized targets prepared in the conventional furnace with Fe2O3 gave 8, 5 and 2 nA/μg for each 10 min block. Graphitisation efficiencies were typically 90-100% for microfurnace samples, compared with 37-84% for conventional furnace samples. Subsequent examination by microscope showed that the cesium beam was well-centred on the 1 mm diameter recess and that effectively all C/Fe was sputtered, leading to a (minimum) estimation of ~4% overall AMS measurement efficiency. Copyright (c) 2011 AMS12 en_AU
dc.identifier.citationSmith, A., Brailsford, G., Yang, B., Bromley, T., Martin, R. (2011). Early results from the ANSTO/NIWA 14C of atmospheric methane program. Paper presented to the 12th International Conference on Accelerator Mass Spectrometry (AMS 12), 20th - 25th March 2011. Museum of New Zealand: Te Papa Tongarewa, Wellington, New Zealand.en_AU
dc.identifier.conferenceenddate25 March 2011en_AU
dc.identifier.conferencename12th International Conference on Accelerator Mass Spectrometry (AMS 12)en_AU
dc.identifier.conferenceplaceWellington, New Zealanden_AU
dc.identifier.conferencestartdate20 March 2011en_AU
dc.identifier.govdoc4441en_AU
dc.identifier.urihttp://www.gns.cri.nz/ams12/en_AU
dc.identifier.urihttp://apo.ansto.gov.au/dspace/handle/10238/4373en_AU
dc.language.isoenen_AU
dc.publisher12th International Conference on Accelerator Mass Spectrometry (AMS-12)en_AU
dc.subjectMethaneen_AU
dc.subjectSample preparationen_AU
dc.subjectMeteorologyen_AU
dc.subjectGraphitizationen_AU
dc.subjectFurnacesen_AU
dc.subjectCesiumen_AU
dc.titleEarly results from the ANSTO/NIWA 14C of atmospheric methane programen_AU
dc.typeConference Presentationen_AU
Files
Original bundle
Now showing 1 - 1 of 1
Thumbnail Image
Name:
AMS-12_Abstracts_Book_Final(3).pdf
Size:
5.14 MB
Format:
Adobe Portable Document Format
Description:
Download
License bundle
Now showing 1 - 1 of 1
Thumbnail Image
Name:
license.txt
Size:
1.71 KB
Format:
Item-specific license agreed upon to submission
Description:
Download
Collections
Conference Publications