Enhancing the mass resolving power of FRIB's proposed high-voltage MR-ToF mass separator and spectrometer: addressing non-ideal conditions

Abstract

Multi-reflection time-of-flight mass separators and spectrometers (MR-ToF MSs) are indispensable tools at radioactive ion beam (RIB) facilities. These electrostatic ion beam traps act as highly selective mass separators and high-precision mass spectrometers for rare and exotic nuclei. When well-tuned and designed to minimize higher-order flight-time aberrations, state-of-the-art MR-ToF MSs approach, and slightly exceed, mass resolving powers of \( m / Δm = 10^6 \). Achieving \( m / Δm > 3 \cdot 10^6 \) would provide the ability to resolve \( >90\% \) of all known isomeric states with half-lives above 10~\text{ms}. However, the ability to mass separate in all practical setups is limited by non-ideal conditions which place such resolving powers out of reach. To this end, we present a simulated analysis of these conditions in the newly proposed high-voltage MR-ToF MS for the Facility for Rare Isotope Beams (FRIB). It is expected to store ions at 30~\text{keV} beam energy and increase ion throughput by two orders of magnitude compared to current devices. Existing efforts to mitigate the effects of non-ideal conditions employed for current MR-ToF devices storing ions at \( <3~\text{keV} \) beam energy will already enable mass resolving powers approaching \( 10^6 \) for FRIB's high-voltage MR-ToF device. Simulations of newly proposed mitigation strategies show that even mass resolving powers approaching \( 10^7 \) might become feasible.