Simulations of a proof-of-principle experiment for collinear laser spectroscopy within a multi-reflection time-of-flight device

Abstract

For nearly four decades Collinear Laser Spectroscopy (CLS) has been employed to determine ground-state properties of short-lived radionuclides. To extend its reach to the most exotic radionuclides with very low production yields, the novel Multi Ion Reflection Apparatus for CLS (MIRACLS) is currently under development at ISOLDE/CERN. In this setup, 30-keV ion bunches will be trapped between two electrostatic mirrors of a multi-reflection time-of-flight (MR-ToF) device such that the laser beam will probe the ions during each revolution. Thus, the observation time will be extended and the experimental sensitivity will be increased significantly while maintaining the high resolution of conventional CLS. A proof-of-principle experiment is currently being performed to demonstrate the potential of CLS within a low-energy MR-ToF device. Its first experimental results benchmark the validity of ion-optical simulations from the CLS perspective, which will also be applied to MIRACLS' 30-keV apparatus.

First steps in the development of the Multi Ion Reflection Apparatus for Collinear Laser Spectroscopy

“…SIMION [33] simulations of the ion transport from the RFQ to the MR-ToF device show that Doppler broadening is the main contributing process to the total linewidth of the measured spectrum at energies of 1.3 keV [25] as the natural line width is only 42 MHz [34]. A total broadening of ≈ 370 MHz is expected, in accordance with the experimental observation of about 400 MHz as depicted in Fig.…”

“…Each mirror consists of 4 cylindrical electrodes to which electric potentials are applied. These are optimized with respect to ion trapping and focusing, while keeping the central drift region of the instrument free of fringe fields [25]. This central drift section is fully surrounded by a mesh electrode that defines the electrical potential.…”

“…In the current, first stage of the project, a proof-of-principle (PoP) setup has been assembled by adapting a low-energy MR-ToF device [22][23][24] for preliminary CLS tests. This PoP setup will be utilized to experimentally demonstrate the MIRACLS concept, further develop the technique, and benchmark simulations [25] that are employed to design the future 30-keV apparatus.…”

Fluorescence detection as a new diagnostics tool for electrostatic ion beam traps

“…In order to investigate the importance of self-bunching in the present setup, SIMION [30] simulations of ion trajectories inside the EIBT are carried out, which follow closely the procedure described in [31]. An ion bunch is thermalized in the Paul trap and then transferred into the EIBT.…”

“…An ion bunch is thermalized in the Paul trap and then transferred into the EIBT. The storage in the EIBT over typically 300 revolutions is simulated separately at the highest computationally feasible geometrical resolution [31]. The mirror potentials, as shown in Fig.…”