The multi-reflection time-of-flight mass separator/spectrometer (MR-ToF MS) [1, 2] installed at the ISOLTRAP experiment  at ISOLDE at CERN has proven to be a valuable asset, allowing fast identification of the incoming ion beams  and selection and transfer of only a certain species to either the Penning-trap section , or to other experimental components . The time-of-flight information can also be used to determine the masses of the beam constituents with sufficient precision for many physics topics, such as nuclear structure [7,8,9,10] and astrophysics [5, 11]. In addition to mass spectrometry, the MR-ToF can also provide purified samples for decay spectroscopy  or, in combination with the Resonant Ionization Laser Ion Source (RILIS) of ISOLDE, for measurements of nuclear moments and charge radii with background suppression [12, 13]. The fast-identification capabilities also make the MR-ToF a very attractive tool for target and ion source optimization and ion yield determination .
The ISOLTRAP MR-ToF MS will be discussed in detail and the idea of a future 30-kV general-purpose MR-ToF MS at ISOLDE will be presented.
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