A high-performance multiple-reflection time-of-flight mass spectrometer and isobar separator for the research with exotic nuclei

摘要

A novel multiple-reflection time-of-flight mass spectrometer (MR-TOF-MS) and isobar separator for the research with exotic nuclides at low-energy rare isotope beam facilities has been developed, commissioned and characterized. It can be used (ⅰ) as broadband mass spectrometer with medium resolution, (ⅱ) as highly accurate mass spectrometer for direct mass measurements and (ⅲ) as high-resolution mass separator. The device features a worldwide unique combination of performance characteristics: a mass resolving power of 600,000 (FWHM), a mass measurement accuracy of ～ 10~(-7), large ion capacities in excess of 10~6 ions per second, a transmission efficiency of up to 70%, single-ion sensitivity, and cycle frequencies of up to 400 Hz have been achieved. The spatial separation of close-lying isobars with an intensity ratio of 200:1 and a binding energy difference as small as 4 MeV has been demonstrated. The MR-TOF-MS is ideally suited for experiments with rare and very short-lived nuclei at present and future in-flight, ISOL or IGISOL facilities, such as the FRS Ion-Catcher and SHIP/SHIPTRAP at GSI, TITAN at TRIUMF, IGISOL at the University of Jyvaeskylae and the Low-Energy Branch of the Super-FRS at FAIR.