Reprocessing of 10B-contaminated 10Be AMS targets

Simple item page
dc.contributor.authorSimon, KJen_AU
dc.contributor.authorPedro, JBen_AU
dc.contributor.authorSmith, AMen_AU
dc.contributor.authorChild, DPen_AU
dc.contributor.authorFink, Den_AU
dc.date.accessioned2011-07-28T01:43:25Zen_AU
dc.date.available2011-07-28T01:43:25Zen_AU
dc.date.issued2011-03-24en_AU
dc.date.statistics2011-07-28en_AU
dc.description.abstractForty 10Be samples of Antarctic ice (DSS0506-pit) along with associated procedural blanks, measured at the ANTARES AMS facility at ANSTO were found to have 10-100 times the 10B levels of routine BeO samples and blanks (full procedural blanks with this beryl carrier are typically 10Be/9Be <5 x 10-15). These exceptionally high boron rates (measured via an active absorber cell filled with argon gas), coupled with the relatively low 10Be/9Be ratios of ice samples, made any correction to the raw 10Be detector count rate highly unreliable and uncertain. As this was a unique sample set, a method for reprocessing the targets to remove the boron was developed and tested. For measurement on ANTARES ~0.5mg BeO is mixed with 2.0mg of niobium powder and rearpressed into an aluminium target holder with a 1.6mm diameter recess at 120 kPa. To reprocess the samples, this BeO/Nb mixture was physically removed from the target holders by pushing the sample loading pin forward with a hand press. The beryllium was separated from the niobium by dissolving the BeO in concentrated H2SO4. This solution was then heated with HF to remove the boron as BF3. The beryllium was then re-precipitated as Be(OH)2 and calcined to BeO, which was then mixed with new niobium powder before being rear-pressed into a detachable cap target holder with a smaller (1 mm) diameter recess. Overall yields for this process averaged 40%. Boron levels for all the original samples and blanks returned to acceptable levels, with 10Be/9Be blanks of ~10 x 10-15. Extensive testing of the equipment, reagents and laboratory failed to determine the source of the boron. As a precautionary measure, a similar H2SO4/HF step has been subsequently added to the standard ice processing method, resulting in consistently low boron levels without any decrease in processing yields. Copyright (c) 2011 AMS12en_AU
dc.identifier.citationSimon K., Pedro J., Smith A.M., Child D., Fink D., (2011). Reprocessing of 10B-contaminated 10Be AMS targets. 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.govdoc3228en_AU
dc.identifier.urihttp://www.gns.cri.nz/ams12/en_AU
dc.identifier.urihttp://apo.ansto.gov.au/dspace/handle/10238/3628en_AU
dc.language.isoenen_AU
dc.publisherGNS Scienceen_AU
dc.subjectANTARES Tandem Acceleratoren_AU
dc.subjectBeryllium 10 targeten_AU
dc.subjectReprocessingen_AU
dc.subjectAntarcticaen_AU
dc.subjectArgonen_AU
dc.subjectBerylliumen_AU
dc.titleReprocessing of 10B-contaminated 10Be AMS targetsen_AU
dc.typeConference Presentationen_AU
Files
Original bundle
Now showing 1 - 1 of 1
Thumbnail Image
Name:
AMS-12_Abstracts_Book_Final(5).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