Experiment List

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{
    "count": 3,
    "next": null,
    "previous": null,
    "results": [
        {
            "id": 1,
            "name": "ClusTOF",
            "doi": "10.1002/mas.21699",
            "comments": "Helium droplets represent a cold inert matrix, free of walls with outstanding properties to grow complexes and clusters at conditions that are perfect to simulate cold and dense regions of the interstellar medium. At sub‐Kelvin temperatures, barrierless reactions triggered by radicals or ions have been observed and studied by optical spectroscopy and mass spectrometry. The present review summarizes developments of experimental techniques and methods and recent results they enabled."
        },
        {
            "id": 2,
            "name": "SurfTOF",
            "doi": "10.1063/1.5145170",
            "comments": "The device described is the combination of two mass spectrometers, with a surface sample placed between them. Its aim is to allow for detailed research on low-energy ion-surface interactions, involving and triggering surface chemistry. This task is fulfilled by a carefully chosen geometry: Projectile ions from an electron impact source are mass-per-charge selected using a quadrupole. Such continuous bombardment allows for good control of the surface condition. Species emerging from the collisions are focused onto a beam and analyzed using a purpose-built orthogonal pulsing time-of-flight mass spectrometer. Neutral species can be post-ionized using a second electron impact source. Neutral gases can be adsorbed to the surface from the gas phase in a controlled manner, using a feedback-controlled pressure regulator. In order to minimize the discrimination of secondary ions, the distance from the surface to the analyzing mass spectrometer system was kept as short as possible and the acceptance angle of the lens system as large as possible. This increased the sensitivity five orders of magnitude compared to its predecessor. The rigorous use of computer aided design software is responsible for the successful commissioning of the new device. This article describes first which parameters can be measured or controlled. Then, these are linked to the physical processes that occur in reactive ion-surface interactions. Next, the design goal and the design implementation are presented. In the end, a performance comparison, measurements of hydrogen surface chemistry with extensive use of isotope labeling, and measurements of post-ionized beryllium are presented."
        },
        {
            "id": 3,
            "name": "Toffy",
            "doi": "10.1063/1.5133112",
            "comments": "The demand for nanoscale materials of ultra-high purity and narrow size distribution is addressed. Clusters of Au, C60, H2O, and serine are produced inside helium nanodroplets using a combination of ionization, mass filtering, collisions with atomic or molecular vapor, and electrostatic extraction, in a specific and novel sequence. The helium droplets are produced in an expansion of cold helium gas through a nozzle into vacuum. The droplets are ionized by electron bombardment and subjected to a mass filter. The ionic and mass-selected helium droplets are then guided through a vacuum chamber filled with atomic or molecular vapor where they collide and “pick up” the vapor. The dopants then agglomerate inside the helium droplets around charge centers to singly charged clusters. Evaporation of the helium droplets is induced by collisions in a helium-filled radio frequency (RF)-hexapole, which liberates the cluster ions from the host droplets. The clusters are analyzed with a time-of-flight mass spectrometer. It is demonstrated that using this sequence, the size distribution of the dopant cluster ions is distinctly narrower compared to ionization after pickup. Likewise, the ion cluster beam is more intense. The mass spectra show, as well, that ion clusters of the dopants can be produced with only few helium atoms attached, which will be important for messenger spectroscopy. All these findings are important for the scientific research of clusters and nanoscale materials in general."
        }
    ]
}