Kinetic-beam-energy determination via collinear laser spectroscopy

TL;DR

This paper introduces a highly precise method using collinear laser spectroscopy to determine the kinetic energy of ion beams with an accuracy exceeding previous techniques, requiring only standard equipment.

Contribution

It presents a novel approach for kinetic beam energy measurement at the 10^-5 level, significantly improving precision without additional specialized tools.

Findings

Achieved over an order of magnitude improvement in energy measurement accuracy.

Demonstrated the method with a proof-of-principle experiment on a nickel beam.

Identified specific transition frequencies in neutral nickel isotopes.

Abstract

An approach to determine the kinetic beam energy at the $10^{-5}$ level is presented, which corresponds to an improvement by more than one order of magnitude compared to conventional methods. Particularly, collinear fluorescence and resonance ionization spectroscopy measurements on rare isotope beams, where the beam energy is a major contribution to the uncertainty, can benefit from this method. The approach is based on collinear spectroscopy and requires no special equipment besides a wavelength meter, which is commonly available. Its advent is demonstrated in a proof-of-principle experiment on a Ni beam. In preparation for the energy measurement, the rest-frame transition frequencies of the $3d^9 4s\;^3\mathrm{D}_3 \rightarrow 3d^9 4p\;^3\mathrm{P}_2$ transitions in neutral nickel isotopes have been identified to be $\nu_0(^{58}\mathrm{Ni})=850\,343\,678\,(20)$ MHz and $\nu_0(^{60}\mathrm{Ni})=850\,344\,183\,(20)$ MHz.