Crystals of $^{\mathrm{40}}$Ca$^{\mathrm{+}}$ and $^{\mathrm{9}}$Be$^{\mathrm{+}}$ in a Compact Penning Trap*

Penning ion traps are useful experimental platforms for quantum simulation, mass spectrometry, precision metrology, molecular spectroscopy, and measurements of fundamental constants. We recently developed a compact, permanent-magnet based Penning trap that is compatible with cold ion physics experiments at 0.6 T [1]. We will describe the results of trap magnetic field characterization (both stability and uniformity) using confined, laser-cooled $^{\mathrm{40}}$Ca$^{\mathrm{+}}$ and $^{\mathrm{9}}$Be$^{\mathrm{+}}$ as probes. We have also demonstrated a laser cooling technique for $^{\mathrm{40}}$Ca$^{\mathrm{+}}$ at high magnetic field that allows for spin state detection without the need for shelving to metastable D levels. This cooling and detection scheme reduces the laser requirements for Penning trap experiments with atomic ions possessing low-lying D states. [1] B. J. McMahon, C. Volin, W. G. Rellergert, and B. C. Sawyer, Phys. Rev. A \textbf{101}, 013408 (2020)