- Project: Development of the first 4He/3He thermochronology facility in Europe.
Establish a world-leading 4He/3He laboratory.
- Project date: 01 January, 2021 – 31 December, 2022
- Lab manager: Julien Amalberti
- Helix SFT Mass spctrometer with focus on 4He/3He high precision measurement.
- 75K Diode Laser with step heating capability.
- Thermo Prepline couple with Janis 10K cryotrap for He cryo-separation.
OverviewThe Potsdam 4He/3He Thermochronology Laboratory at the University of Potsdam, Germany is dedicated to high-precision measurement of 4He and 3He noble gas abundances and isotopic ratios (i.e. 4He3He) in U-bearing accessory minerals such as apatite.
The laboratory is equipped with a Helix SFT Thermo Scientific mass spectrometer recently acquired and funded by the European Research Council (ERC). The Helix SFT is connected to a Thermo extraction and purification Prepline dedicated to mineral samples for routine analysis with a single-head cryotrap (planned to be installed at the end of May 2021). The Prepline is equipped with an inlet cell for Diode Laser fusion and/or step heating. The upcoming cryotrap (planned in May) will allow the separation of He from other noble gases (i.e. Ne, Ar, Kr and Xe). The purification system includes 4 NP10 getters.
The Helix SFT is specifically designed to analyze 4He and 3He in multi-collection mode with 1 CDDs and 1 Faradays cups.
Once the gases have been extracted from a sample, all clean-up and cryogenic separation procedures will be fully automated by a computer controlled system. The computer that controls the automation and the extraction benches runs under LabView, which allows the user to also fully manually control the system. The entire system will be designed by multi-threaded control software from the LabView computer, which allows for communication between Labview and Teledyne (Diode Laser) software with the Thermo Helix SFT (Qtegra).
Developing a world-leading 4He and 3He thermochronology facility in Europe: Project Detail
We are building a 4He and 3He thermochronology facility in Potsdam by acquiring a high-resolution noble-gas mass-spectrometer. The Helix SFT from ThermoFisher Intrument provides a sensitivity >2×104 Amps / Torr required to measure extremely small amounts of 4He and 3He. The split-flight tube design allows measuring both isotopes simultaneously in multi-collection mode (low mass on a multiplier, high mass on a Faraday detector) or by peak jumping in single collector mode (in case of very low 4He abundances). A noble-gas preparation line is acquired together with the mass spectrometer, ensuring optimum effi-ciency in the setup. The line includes a diode-laser heated sample cell for precise step-heating, and a cryogenic cold-trap for separating He from Ne, while at the same time concentrating He before expansion into the mass spectrometer to enhance detection. Collaborations with European-based facilities for proton irradiations are curently being set up. Our ambitious project is to ensure that proton irradiation facilities can be performed at the fluences required for successful 4He and 3He analyses (1015–1016protons / cm 2, corresponding to ~5-10 hours irradiation per sample batch). U-Th(-Sm) measurements required fordating will be carried out on aninductively-coupled plasma mass spectrometer (ICP-MS) already installed at Potsdam. The development of this unique 4He and 3He thermochronology facility constitutes the core of the COOLER project. This will be the first purpose-built 4He and 3He thermochronology facility worldwide and it is expected to set a new level in sensitivity, resolution and efficiency of the technique (in particular through the possibility of measuring samples in multi-collector mode). We will experiment with new proton-irradiation routines designed to solve the challenge of limited capacity that has hindered the development of 4He and 3He thermochronology in the last years, as well as with routine electron-microscope scanning of samples to map out U-Th distributions.
Current statusThe Laboratory is equipped with an operating Diode laser, a 10K cryotrap connected to a Thermo Prep-line and a Helix SFT.
Our Janis 10K cryotrap is now operational and calibrated and the line have been calibrated. Consequently, our current state is running pipette and standard in order to determine the best approach to run multiple apatite samples.
Our current LabVIEW software is under development but provide a user-friendly interface and partial automation.
The facility is expected to be fully operational by the end of 2021.