Negative ionisation efficiencies for 10Be, 26Al and Pu with MCSNICS at ANSTO

dc.contributor.authorWilcken, KMen_AU
dc.contributor.authorChild, DPen_AU
dc.contributor.authorHotchkis, MACen_AU
dc.contributor.authorMann, Men_AU
dc.contributor.authorSimon, KJen_AU
dc.contributor.authorKoll, Den_AU
dc.contributor.authorWallner, Aen_AU
dc.contributor.authorHauser, Ten_AU
dc.contributor.authorKitchen, Ren_AU
dc.date.accessioned2023-01-20T03:29:02Zen_AU
dc.date.available2023-01-20T03:29:02Zen_AU
dc.date.issued2021-11-17en_AU
dc.date.statistics2022-07-01en_AU
dc.description.abstractLow overall detection efficiency for actinides and cosmogenic isotopes (Al, Be) is the limiting factor affecting precision and sensitivity for applications where the amount of available sample material is small and/or rare isotope concentration is low. Due to low ionisation efficiencies for these isotopes it is not uncommon that more than 99% of the rare isotopes in the sample do not contribute to the statistical precision of the measurement. Optimising ion transmission and detection efficiency in the AMS measurement offers some room for improvement but these avenues are already close to their theoretical limits. On the other hand, optimising the performance and operation of the negative ion Cs-sputter sources has significant scope for improvement but is challenging. One often needs to compromise between competing requirements, for example, maintaining high sputtering rate to allow expedient consumption of the sample material but at the same time keeping the source insulators clean for longevity. The lack of a well-understood theoretical model for the negative ionisation process adds to the engineering challenges. Negative ionisation efficiencies above 30% have been demonstrated for radiocarbon [1] but remain often more than an order of magnitude lower for Be, Al and actinides. This is sometimes taken to be an inherent limitation of the technique, rather than a challenge to be addressed. Here we present details of the modified MC-SNICS sources at ANSTO, including engineering modifications that have improved longevity and stability. With attention to a combination of ion source running conditions, sample masses and sample binders the total efficiency for Pu measurements was increased up to 1.5%, corresponding to a negative ionisation yield of 4%. For Aland BeO- negative ion source yields are 0.2% and 3%, respectively.en_AU
dc.identifier.citationWilcken, K., Child, D., Hotchkis. M., Mann, M., Simon, K., Kill, D., Wallner, A., Hauser, T., & Kitchen, R. (2021). Negative ionisation efficiencies for 10Be, 26Al and Pu with MCSNICS at ANSTO. Poster plus presentation to the 15th International Conference on Accelerator Mass Spectrometry. ANSTO Sydney, Australia. November 15th – 19th, 2021, (pp. 210). Retrieved from: https://ams15sydney.com/wp-content/uploads/2021/11/AMS-15-Full-Program-and-Abstract-Book-R-1.pdfen_AU
dc.identifier.conferenceenddate19 November 2021en_AU
dc.identifier.conferencename15th International Conference on Accelerator Mass Spectrometryen_AU
dc.identifier.conferenceplaceSydney, Australiaen_AU
dc.identifier.conferencestartdate15 November 2021en_AU
dc.identifier.pagination210en_AU
dc.identifier.urihttps://ams15sydney.com/wp-content/uploads/2021/11/AMS-15-Full-Program-and-Abstract-Book-R-1.pdfen_AU
dc.identifier.urihttps://apo.ansto.gov.au/dspace/handle/10238/14445en_AU
dc.language.isoenen_AU
dc.publisherAustralian Nuclear Science and Technology Organisationen_AU
dc.subjectIonsen_AU
dc.subjectBeryllium 10en_AU
dc.subjectAluminium 26en_AU
dc.subjectPlutoniumen_AU
dc.subjectANSTOen_AU
dc.subjectActinidesen_AU
dc.subjectIsotopesen_AU
dc.subjectMass spectroscopyen_AU
dc.titleNegative ionisation efficiencies for 10Be, 26Al and Pu with MCSNICS at ANSTOen_AU
dc.typeConference Abstracten_AU
Files
Original bundle
Now showing 1 - 1 of 1
Loading...
Thumbnail Image
Name:
AMS-15-Full-Program-and-Abstract-Book-R-1.pdf
Size:
4.92 MB
Format:
Adobe Portable Document Format
Description:
License bundle
Now showing 1 - 1 of 1
Loading...
Thumbnail Image
Name:
license.txt
Size:
1.63 KB
Format:
Item-specific license agreed upon to submission
Description: