eprintid: 1464571
rev_number: 32
eprint_status: archive
userid: 608
dir: disk0/01/46/45/71
datestamp: 2015-11-26 11:41:50
lastmod: 2020-02-12 18:05:08
status_changed: 2015-11-26 11:41:50
type: article
metadata_visibility: show
item_issues_count: 0
creators_name: Schwanethal, J
title: Minimising 12 C 3+ interference on 4 He + measurements in a noble gas mass spectrometer
ispublished: pub
divisions: UCL
divisions: A01
divisions: B04
divisions: C06
divisions: F57
note: This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
abstract: Measurements of helium isotopes used for geochronological studies are subject to interferences from 12C3+ and HD+. The 12C3+ interference was studied on a Nu Instruments Noblesse mass spectrometer which has sufficient mass resolution to measure the interference on the 4He+ peak due to 12C3+ directly, by setting the magnet at the relevant peak shoulders. Helium sensitivity varies with source trap current. Increasing the source trap current increases the electron fluence, and hence the probability of ionisation, within the source. The source trap current on the Noblesse is typically held at ∼400 μA. Increasing the trap current to 550 μA increases sensitivity to 4He+ approximately two-fold, but 12C3+ increases approximately 17 times. The 4He+ and 12C3+ peak shoulders at m/z = 4 are narrow, despite the high mass resolution, and consequently any instrument drift can cause the peak positions to be lost. However, it is shown that measurement of 12C2+ at m/z = 6 can be used to correct for this interference, allowing the intensity of the broad flat top of m/z = 4 to be used.
date: 2015-02-13
date_type: published
official_url: http://dx.doi.org/10.1039/C4JA00422A
vfaculties: VMPS
oa_status: green
full_text_type: pub
language: eng
primo: open
primo_central: open_green
verified: verified_manual
elements_source: crossref
elements_id: 1024556
doi: 10.1039/C4JA00422A
lyricists_name: Schwanethal, James
lyricists_id: JSCHW50
actors_name: Schwanethal, James
actors_name: Gibson, Alice
actors_id: JSCHW50
actors_id: AGIBS47
actors_role: owner
actors_role: impersonator
full_text_status: public
publication: Journal of Analytical Atomic Spectrometry
volume: 30
number: 6
pagerange: 1400-1404
issn: 1364-5544
citation:        Schwanethal, J;      (2015)    Minimising 12 C 3+ interference on 4 He + measurements in a noble gas mass spectrometer.                   Journal of Analytical Atomic Spectrometry , 30  (6)   pp. 1400-1404.    10.1039/C4JA00422A <https://doi.org/10.1039/C4JA00422A>.       Green open access   
 
document_url: https://discovery.ucl.ac.uk/id/eprint/1464571/11/Minimising%2012%20C%203%2B%20interference%20on%204%20He%20%2B%20measurements%20in%20a%20noble%20gas%20mass%20spectrometerGold.pdf