A new beamline for Resonant Excitation of Beams with Electromagnetic fields and Lasers (REBEL) and Stopping and Trapping of Radioactive Isotopes for Precision Experiments (STRIPE)

TL;DR

This paper introduces two integrated experimental setups, REBEL and STRIPE, at KU Leuven for high-precision laser spectroscopy and ion trapping of radioactive isotopes, enabling advanced research in nuclear physics.

Contribution

The paper presents the design, construction, and initial results of a novel dual-beamline platform combining laser spectroscopy and ion trapping for radioactive isotopes.

Findings

Mass-resolving power of R ≈ 12900 achieved in REBEL

Successful ion trapping and laser cooling at 10 keV in STRIPE

Enhanced performance with frequency-modulated cooling laser

Abstract

We present two newly constructed experimental setups - REBEL (Resonant Excitation of Beams with Electromagnetic fields and Lasers) and STRIPE (Stopping and Trapping of Radioactive Isotopes for Precision Experiments) - integrated into a single offline beamline at KU Leuven. REBEL is designed for collinear laser spectroscopy of ion bunches following isobaric separation with a multireflection time-of-flight mass spectrometer, enabling high-sensitivity measurements of mass-selected fast-ion beams. In contrast, STRIPE focuses on the deceleration, trapping, and laser cooling of ions in a segmented linear Paul trap, optimized for long interrogation times and precision spectroscopy. The shared infrastructure features stable high-voltage operation ($<10$ ppm), modular vacuum sections, and a fast-beam switchyard to route ions to either experiment. Initial results include a mass-resolving power of $R \approx 12900$ in REBEL and successful ion trapping and laser cooling of ions with a kinetic energy of 10 keV in STRIPE, with improved performance achieved using a frequency-modulated cooling laser. This dual-system platform enables the development and benchmarking of advanced spectroscopy and trapping techniques and is compatible with future operation at radioactive ion beam facilities.