PILGRIM and MLLTRAP: opportunities with ion-traps at the low energy beam lines of S3, DESIR and ALTO

Combining the 3 facilities ALTO, SPIRAL1 and S3 will allow to produce most of the exotic nuclei known so far. Especially, S3 is expected to produce the most intense beams in the N=Z=50 and superheavy regions, and the “clean” photo-fission at ALTO allows to create neutron-rich beams of superior purity. These unique beams, combined with a new generation of state-of-the-art equipments, open physics niches in our accelerators. The mass excess is one of the most fundamental properties of the nucleus as it accounts for the sum of all nuclear interactions within. High-precision mass measurement using ion traps are thus a powerful tool for testing nuclear models, and can highlight regions of increased shell effects or deformation.

PILGRIM and MLLTRAP will be respectively the first MR-ToF-MS and the first Penning trap operating in France. PILGRIM, will be part of S3-LEB and will be used to purify the beam from isobaric contaminants and for mass measurement with uncertainties down to a few 10^-7. MLLTRAP is currently installed at ALTO and will ultimately be moved to DESIR. Two alternate double trap assemblies can be inserted in MLLTRAP’s 7T magnet. The first is dedicated to high-precision mass measurement with a proven 3X10^-8 uncertainty. The second is dedicated to in-trap decay spectroscopy and nuclear level lifetime measurement of heavy to superheavy alpha emitters.