Author
St. Becker
Other affiliations: Lawrence Livermore National Laboratory
Bio: St. Becker is an academic researcher from University of Mainz. The author has contributed to research in topics: Penning trap & Mass spectrometry. The author has an hindex of 14, co-authored 24 publications receiving 1146 citations. Previous affiliations of St. Becker include Lawrence Livermore National Laboratory.
Papers
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TL;DR: In this paper, a new cooling technique for heavy ions stored in a Penning trap was developed, where axial and cyclotron motions were cooled by buffer gas collisions, and the outward radial diffusion caused by the buffer gas was counteracted by an azimuthal quadrupole rf field.
496 citations
11 Jan 1996-Nuclear Instruments & Methods in Physics Research Section A-accelerators Spectrometers Detectors and Associated Equipment
TL;DR: The tandem Penning trap mass spectrometer ISOLTRAP has been set up at the on-line mass separator ISOLDE at CERN/Geneva for accurate mass measurements of short-lived nuclei with T 1 2 ≥ 1 s.
Abstract: The tandem Penning trap mass spectrometer ISOLTRAP has been set up at the on-line mass separator ISOLDE at CERN/Geneva for accurate mass measurements of short-lived nuclei with T 1 2 ≥ 1 s . The mass measurement is performed via the determination of the cyclotron frequency of an ion in a magnetic field. The design of the spectrometer matches the particular requirements for on-line mass measurements on short-lived isotopes. With the ISOLTRAP spectrometer masses of more than 70 radioactive nuclei have so far been determined with resolving powers exceeding one million and an accuracy of typically 10−7.
208 citations
TL;DR: In this paper, a pulsed ion beam from an external source is injected into a Penning trap and accumulated by repeatedly lowering during ion capture to prevent the ions already captured from escaping.
62 citations
TL;DR: In this paper, a Penning trap system has been set up for storing and investigating cluster ions over time ranges from microseconds up to minutes, which enables studies of cluster reactions with extremely low cross sections and the observation of their time dependence in a new regime.
Abstract: A Penning trap system has been set up for storing and investigating cluster ions over time ranges from microseconds up to minutes. This enables studies of cluster reactions with extremely low cross sections and the observation of their time dependence in a new regime. The ions are created externally by laser vaporization, cooled by adiabatic expansion of a supersonic beam, and injected into the Penning trap. Detection of reaction products is achieved by combining the advantages of two complementary approaches, viz. the high resolution of Fourier transform mass spectrometry and the high sensitivity of single‐ion counting with a time‐of‐flight mass spectrometer. The performance of the apparatus is illustrated by results of recent cluster experiments.
54 citations
TL;DR: In this paper, an overview of experiments with stored metal cluster ions in a Penning trap system is given, which allows axial injection of clusters produced in an external source and a time-of-flight mass analysis of the reaction products after axial ejection.
Abstract: An overview is given of experiments with stored metal cluster ions in a Penning trap system. The setup allows axial injection of clusters produced in an external source and a time-of-flight mass analysis of the reaction products after axial ejection. The system's options include the selection of stored ions, the manipulation of their orbits, addition of reactant and buffer gases and axial optical access for laser spectroscopic studies. As described by various examples, investigations have been made with respect to the development of trapping techniques and the characterization of metal clusters in terms of their physical and chemical properties.
42 citations
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TL;DR: The mass of an atom, and its inherent connection with the atomic and nuclear binding energy is a fundamental property, a unique fingerprint of the atomic nucleus as mentioned in this paper, and the importance of its mass ranges from verification of nuclear models to a test of the Standard Model, in particular with regard to the weak interaction and the unitarity of the Cabibbo-Kobayashi-Maskawa quark mixing matrix.
578 citations
TL;DR: The mass of the nucleus has been of capital importance not only for various aspects of nuclear physics, but also for other branches of physics, notably weak-interaction studies and astrophysics as mentioned in this paper.
Abstract: The mass of the nucleus, through its binding energy, continues to be of capital importance not only for various aspects of nuclear physics, but also for other branches of physics, notably weak-interaction studies and astrophysics. The authors first describe the modern experimental techniques dedicated to the particularly challenging task of measuring the mass of exotic nuclides and make detailed comparisons. Though tremendous progress in these and the associated production techniques has been made, allowing access to nuclides very far from stability, it is still not yet possible to produce many nuclides involved in stellar nucleosynthesis, especially the $r$ process, leaving no choice but to resort to theory. The review thus goes on to describe and critically compare the various modern mass formulas that may be used to extrapolate from the data towards the neutron drip line. Special attention is devoted to the crucial interplay between theory and experiment, showing how new measurements far from stability can considerably reduce the ambiguity in extrapolations to nuclides even further away.
555 citations
465 citations
TL;DR: In this article, a dual octupole ion injection system was proposed for high performance mass analysis at low pressure, which was demonstrated on a mixture of 500 fmol of each of three peptides.
459 citations
TL;DR: In this paper, the authors performed ion mobility measurements on gold cluster cations generated by pulsed laser vaporization and found that they have planar structures for n = 3-7.
Abstract: We have performed ion mobility measurements on gold cluster cations Aun+ generated by pulsed laser vaporization. For clusters with n<14, experimental cross sections are compared with theoretical results from density functional calculations. This comparison allows structural assignment. We find that room temperature gold cluster cations have planar structures for n=3–7. Starting at n=8 they form three dimensional structures with (slightly distorted) fragments of the bulk phase structure being observed for n=8–10.
437 citations