Pushing the boundaries: Next-Generation MR-ToF devices for the study of rare isotopes
Dr. Franziska Maria Maier
Facility for Rare Isotope Beams
Michigan State University
Over the last 15 years, Multi-Reflection Time-of-Flight (MR-ToF) devices have established themselves as indispensable instruments for mass measurements and mass separation of short- lived radionuclides at radioactive ion beam (RIB) facilities. Very recently, the application field of MR-ToF devices has been extended to access electromagnetic properties of scarcely produced isotopes via the novel MIRACLS technique at ISOLDE/CERN [1,2]. By trapping ions between the two electrostatic mirrors of an MR-ToF device, the same ion bunch is probed by a spectroscopic laser for thousands of times compared to a single passage in traditional collinear laser spectroscopy. The resulting increase in experimental sensitivity is beneficial for the measurement of nuclear properties via fluorescence-based laser spectroscopy of very rare, positively-charged radionuclides as well as for electron-affinity measurements of negatively- charged ions via laser-photodetachment-threshold spectroscopy.
Furthermore, development work is ongoing for a next-generation MR-ToF setup at FRIB expanding FRIB’s mass measurement and separation capabilities. Simulations based on previous work at MIRACLS [3] show that a mass resolving power of 1e6 is reachable within 8 ms of processing time even when >10,000 ions/s are injected into the MR-ToF device. Beyond high-precision mass measurements, this MR-ToF device will hence also serve as a highly selective, high-throughput mass separator, providing isobaric and isomeric purified ion beams to subsequent experiments in the stopped and reaccelerated beam areas at FRIB.
In this seminar, I will give an overview of these MR-ToF developments and discuss recent highlights, including the first laser spectroscopic studies of 33,34Mg ever performed as well as the electron affinity measurements of 35Cl, where we achieved at MIRACLS a similar precision to the literature value despite employing a factor 150,000 times lower ion samples.
[1] S.Sels et al, NIMB 463, 310-314 (2020)
[2] F.M.Maier et al, NIMA 1048, 167927 (2023)
[3] F.M.Maier et al, NIMA 1056, 168545 (2023)
Hosted by Prof. Brodeur