Atomic nuclei are few-body systems mainly governed by the strong force and quantum mechanical laws. They are composed of nucleons interacting through the in-medium nuclear forces. Ina shell model picture, the nuclear shell gaps represent the backbone of nuclear structure and are a direct fingerprint of the nuclear interactions. Magic numbers of nucleons are well established for stable nuclei: 2, 8, 20, 28, 50, 82, 126 but are known not to be universal over the nuclear chart. Indeed, the nuclear shell structure is known to change, sometimes drastically, with the number of protons and neutrons, revealing how delicate the arrangement of interacting nucleons is.
Strong shell reordering may occur in several new regions of the nuclear chart at reach with current setups and beam intensities.
To achieve sufficient statistics and resolution for the spectroscopy of these rare isotopes produced at very low yields, we focus on in-beam gamma spectroscopy with the combination of gamma detectors and the MINOS liquid hydrogen and vertex tracker device [1,2]. Selected examples of our recent experiments at the RIBF are given as references [2-5]. We are also investigating new techniques for high-resolutions spectroscopy of these isotopes.
MINOS belongs to CEA Science Matter Department and was initiated and developed under the ERC Grant MINOS (PI: A. Obertelli). It is currently hosted by the Spin-Isospin laboratory (Chief Scientist: T. Uesaka) of the RIKEN Nishina Center.
 ERC Starting Grant, MINOS, A. Obertelli (2010-2015).
 A. Obertelli et al., European Physics Journal A 50, 8 (2014)
 C. Santamaria et al., Physical Review Letter 115, 192501 (2016)
 N. Paul et al., Physical Review Letter 118, 032501 (2017)
 F. Flavigny et al., Physical Review Letter 118, 242501 (2017)
 L. Olivier et al., Physical Review Letter 119, 192501 (2017)