Tesla Valve: A Fast Signal Smoothing Device for Rapid Laser Ablation Quadrupole-ICP-MS

Abstract

Laser ablation with quadrupole ICP-MS has become a crucial tool that is widely used in geochronology and geochemistry. The growing demand for a large number of ablation spots, e.g., large-n detrital zircon U-Pb geochronology, raises experimental costs and requires substantial time. To address this, a rapid aerosol transport system, ARIS (Teledyne Technologies Inc.) is being utilised. Although developed to enhance 2D mapping via faster repetition rates, the system has also demonstrated suitability for large-n ablation. However, insufficient sampling of the periodic signal (especially with low repetition rate) can lead to signal aliasing, resulting in high uncertainty. In our study, a 3D-printed Tesla valve was designed and integrated into the ARIS to smooth the signal fluctuations during the rapid U-Pb analysis. When operated at a 10 Hz repetition rate and 2 J cm^-2 laser fluence, with a duty cycle of 40 ms on each mass, the Tesla valve can reduce signal oscillations by more than tenfold, achieve a signal wash-in time of ~ 0.7 s, and completes 98% signal decay within 0.8 s during the wash-out. Spot analyses of zircon reference materials (GJ-1, Plešovice, Qinghu and Mud Tank) with 15 s ablation durations yielded ²⁰⁶Pb/²³⁸U ages consistent with their recommended values (< 1.5% deviation). Furthermore, a re-analysed detrital zircon sample demonstrated that the short ablation durations (15 s per spot) could produce large-n age spectra statistically indistinguishable from those obtained with conventional long ablation durations (> 30 s per spot). Therefore, the Tesla valve-based smoothing device offers a cost-effective and easily implementable solution that is particularly well suited for fast aerosol transport systems (e.g., ARIS) and low-repetition-rate laser ablation applications.