EGT-A sensitive time-of-flight mass spectrometer for multielement isotope gas analysis

Riedo, Andreas; Rout, Surya Snata; Wiesendanger, Reto; Wurz, Peter; Leya, Ingo (2018). EGT-A sensitive time-of-flight mass spectrometer for multielement isotope gas analysis. Journal of mass spectrometry, 53(11), pp. 1036-1045. Wiley 10.1002/jms.4275

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The principles of operation and figures of merit of a novel, compact (324 mm × Ø 114 mm; volume approximately 1000 cm³) reflectron‐type time‐of‐flight mass spectrometer designed for simultaneous multielement isotope gas analysis is presented. The system, which consists of a pulsed electron impact ion source, is designed either to directly analyse gas samples collected and stored in a compartment or samples extracted from solids using a CW laser system (fibre‐coupled diode laser, <75 W, λ = 808 ± 10 nm). In latter case, laser pulses are focussed onto the sample surface to spot sizes of approximately 400 μm in diameter that allows for direct ablation and vaporisation of solid sample material and releasing of trapped gases. A cleaning and trapping system that consists of various cold stages and getters is used before the gas enters the mass analyser. Measurements on various gases were conducted for performance evaluation, ranging from standard gases (Ar, Kr, and Xe) to trapped gases extracted from a sample of the Millbillillie meteorite. At optimised instrument settings, mass spectrometric measurements can be conducted with a mass resolution m/∆m of up to approximately 1200 (¹⁶O and CH₄ can be resolved), with a dynamic range of approximately 6 orders of magnitude and a mass calibration accuracy of approximately 100 ppm. The high detection sensitivity of the system allows the detection of gas species at partial pressures down to the low 10⁻¹⁶ mbar level (corresponding to <10 particles/cm³ at standard temperature and pressure, including an ion transmission of approximately 80%). Measurements using standard gases demonstrated that the isotope ratios for a given element can be measured with an accuracy at the per mill level (relative to terrestrial values). Measurements of Ar extracted from the meteorite Millbillillie gave a ³⁶Ar/³⁸Ar ratio of approximately 1.6, which is in good agreement with literature values.

Item Type:

Journal Article (Original Article)

Division/Institute:

08 Faculty of Science > Physics Institute > Space Research and Planetary Sciences
08 Faculty of Science > Physics Institute
08 Faculty of Science > Physics Institute > NCCR PlanetS

UniBE Contributor:

Riedo, Andreas; Rout, Surya Snata; Wiesendanger, Reto; Wurz, Peter and Leya, Ingo

Subjects:

500 Science > 520 Astronomy
600 Technology > 620 Engineering
500 Science > 530 Physics

ISSN:

1076-5174

Publisher:

Wiley

Language:

English

Submitter:

Dora Ursula Zimmerer

Date Deposited:

08 Feb 2019 09:55

Last Modified:

22 Mar 2019 13:34

Publisher DOI:

10.1002/jms.4275

BORIS DOI:

10.7892/boris.122696

URI:

https://boris.unibe.ch/id/eprint/122696

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