Overview

High-energy, rare-isotope beams are produced by FRIB. These beams are purified using the FRIB fragment separator prior to being sent to the Gas Stopping Facility where the fast, relativistic beams are stopped and extracted as low-energy beams, which is a necessary step for high-precision mass measurements.  

Next the rare-isotope beams are delivered to LEBIT where the beam is first cooled and bunched in a three-stage radiofrequency ion trap filled with a helium buffer gas. The rare isotopes are delivered in bunches to one of two Penning trap mass spectrometers where the mass measurements are performed. One Penning trap mass spectrometer with a 9.4T superconducting solenoid is extremely versatile, using Time-of-Flight Ion Cyclotron Resonance (TOF-ICR) detection. A new Single-Ion Penning Trap (SIPT), in a separate 7T superconducting solenoid, has been developed to enable high-precision mass measurements using a single detected rare isotope ion, employing Fourier Transform Ion Cyclotron Resonance (FT-ICR) detection.

Funding acknowledgement: The construction of LEBIT was funded by Michigan State University.  The construction of SIPT was funded by an NSF Major Research Instrumentation (MRI) grant (PHY-1126282).

Reference

• doi.org/10.1016/j.ijms.2013.04.001
• doi.org/10.1016/j.nima.2016.01.078
• doi.org/10.1016/j.nima.2009.03.207