First Glimpse of the N = 82 Shell Closure below Z = 50 from Masses of Neutron-Rich Cadmium Isotopes and Isomers

Masses of neutron-rich cadmium isotopes and isomers from ¹²⁴Cd to ¹³²Cd, giving the first value of the N=82 two-neutron shell gap below tin.

ISOLDE fission beams, RILIS laser ionization, then every ISOLTRAP tool: MR-ToF for ¹³¹,¹³²Cd, ToF-ICR, and PI-ICR to order the 11/2⁻ and 3/2⁺ isomers in ¹²⁹Cd.

The ¹³²Cd mass shows a sharp drop in the N=82 gap below Z=50 and confirms mutually enhanced magicity at ¹³²Sn. PI-ICR also inverted the ¹²⁹Cd isomer ordering, which models had not settled.