Development of a compact cryogenic Penning trap with permanent magnets: An intermediate step toward the Shanghai Penning Trap.

Penning traps, renowned for their unparalleled precision in determining fundamental properties, such as mass and magnetic moments, are cornerstone instruments in modern physics. Their applications span from nuclear structure studies to stringent tests of quantum electrodynamics and CPT invariance. Although Penning traps have been demonstrated for fundamental studies, often employing superconducting magnets, their high cost and operational complexity remain challenges. In this work, we report the development of a compact cryogenic Penning trap that utilizes a permanent magnet to provide a confining magnetic field, offering a more economical and flexible alternative. We have successfully demonstrated all core functionalities of this system, including ion generation, transport, confinement, manipulation, and signal detection. This compact trap not only serves as a vital technical testbed for the development of the Shanghai Penning Trap but also establishes a cryogenic Penning-trap experiment platform for ion trapping and cooling applications and envisaged spectroscopic studies applications.