Simulation Study of a Hyperbolic Linear Ion Trap with Asymmetric Curvature Radii.

Linear ion traps (LITs) with simplified geometries have shown potential for miniaturized mass spectrometry systems, though structural simplifications often introduce nonlinear higher-order fields that compromise performance. This study investigates asymmetric hyperbolic electrode modifications to address the inherent 50% detection efficiency limitation in miniaturized LITs caused by bidirectional ion ejection. The research employed numerical simulations to evaluate a geometrically modified LIT design. Electrode asymmetry was introduced through independent adjustments of vertex curvature radii and bending angles in opposing x-direction electrodes, creating an asymmetric trapping field. Structural optimization involved initial x-axis elongation of a centrosymmetric ion trap followed by controlled geometric modifications. Field analysis confirmed the incorporation of odd-order multipole components through these adjustments. Experimental results demonstrated approximately 90% ion ejection efficiency from a single trap side when combining higher-order odd and even multipole fields. This work provides valuable insights into the design of asymmetric ion traps, offering a practical solution for high-performance portable MS development.