A novel mass spectrometry system for helium-4 measurement

Abstract

Here we report a novel mass spectrometry measurement system (MSHE4) developed at State Key Laboratory of Isotope Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences for quantifying helium-4 contents of geological mineral samples. The MSHE4 system consists of seven units, a high vacuum level generating unit, a gas purified unit, a laser heating unit, a pneumatic valve unit, an automatic control unit, a gas standard unit and a quadropole mass spectrometer unit. The unique software package, developed using LabVIEW for embedded system, allows users to control the full measurement sequences. Results from a test of the Durango apatite sample are used to illustrate the performance of the new MSHE4. We show that the constructed MSHE4 system is able to accurately measure helium-4 contents of apatite mineral, which in turn can be used to quantify the low temperature thermochronology of geological minerals in combination with measurements of uranium and thorium by LA-ICP-MS. The configuration of the MSHE4 system has following advantages: smaller volume of pipeline for gas purification, easier operation of graphic user interface for measurements, and more compact design of sample holder for single grain measurements. The separate step-heating unit can be mounted to the system smoothly. The MSHE4 system can be used for measurement of noble gases from minerals, and in turn thermochronology applications for geochemists.

Keywords

helium-4 / thermochronology / apatite / mass spectrometry

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