Speaker
Description
The ISOLTRAP mass spectrometer [1], located at ISOLDE/CERN, performs high-precision mass measurements of short-lived, exotic nuclides far from stability. These measurements provide direct access to nuclear binding energies, which reflect the underlying nuclear interactions, thereby enabling studies in nuclear structure and nuclear astrophysics, among others.
For this, the ISOLTRAP mass spectrometer uses various ion traps, including a tandem Penning trap system and a multi-reflection time-of-flight mass spectrometer (MR-ToF MS) [2], where the latter is suitable for both efficient mass separation and fast, precise mass measurements.
Focusing on nuclear structure studies near doubly-magic nuclei, particularly the shell evolution near $^{100}$Sn [3-5], ISOLTRAP recently performed mass measurements of neutron-deficient cadmium isotopes. These include the first mass measurement of the self-conjugate nucleus $^{96}$Cd, located in the immediate vicinity of the doubly-magic nucleus $^{100}$Sn, which will be presented.
In addition, ISOLTRAP advanced in ion purification with the first application of the mass-selective re-trapping technique [6]. This technique, enabled by a newly implemented mini-RFQ following the MR-ToF MS, allowed the mass measurement of the neutron-rich $^{49}$Ar, which will be presented and demonstrates the feasibility of low-yield experiments in the presence of extremely abundant isobaric contamination.
With an overview of the recent technical developments, such as the temperature stabilization of the MR-ToF MS, an improved laser ablation ion source and an additional data acquisition system for ToF measurements, current limitations and future developments planned for the Long Shutdown 3 will be outlined.
[1] Lunney D. et al., J. Phys. G: Nucl. Part. Phys. 44, 064008 (2017)
[2] Wolf R. N. et al., Int. J. Mass Spectrom. 349-350:123–133 (2013)
[3] Mougeot M. et al., Nature Physics 17, p. 1099–1103 (2021)
[4] Nies L. et al., PRL 131, 022502 (2023)
[5] Nies L. et al., PRC 111, 014315 (2025)
[6] Dickel T. et al., J. Am. Soc. Mass Spectrom. 28, 1079-1090 (2017)
