1–200 amu tunable Pretzel magnet notch-mass-filter and injector for trace element accelerator mass spectrometry

Abstract

A novel recombinator and injector has been designed for the trace element accelerator mass spectrometer (TEAMS) at the Naval Research Laboratory. It will allow parallel analysis of a broad range of impurities in electronic, biological, and geological materials. The recombinator consists of a tunable Pretzel magnet that serves as a notch mass filter [1]. The mass filter has near-amu mass resolution over the range of 1–200 amu for 40 keV ions. Masks positioned along the Pretzel's symmetry axis block intense matrix-related beams, (e.g. Si, SiO, Si3, etc.) while passing beams of interest into the accelerator. The primary and secondary columns of a Physical Electronics model 6300 quadrupole secondary ion mass spectrometer (SIMS) form the key components of the ion source for the injector. This commercially proven instrument facilitates depth profiling, imaging, and the analysis of both conducting and insulating substrates at pressures as low as 10−10 Torr.