Single-Source, Collinear Merged-Beam Experiment for the Study of Reactive Neutral-Neutral Collisions

TL;DR

This paper introduces two innovative collinear merged-beam methods for studying reactive neutral-neutral collisions, utilizing laser cooling and deceleration, with experimental feasibility demonstrated through pulse production tests.

Contribution

The paper presents novel merged-beam and intrabeam-scattering techniques for collision studies, including detailed experimental implementation and feasibility analysis.

Findings

Estimated detection efficiency and collision-energy resolution from numerical calculations.

Experimental demonstration of producing two gas pulses at short intervals.

Feasibility of studying autoionizing collisions with the proposed methods.

Abstract

We present two methods for studying reactive collisions between two atomic or molecular species: a collinear merged-beam method, in which two gas pulses from a single supersonic beam source are coalesced, and an intrabeam-scattering technique, in which a single gas pulse is used. Both approaches, which rely on the laser cooling and deceleration of a laser-coolable species inside a Zeeman slower, can be used for a wide range of scattering studies. Possible experimental implementations of the proposed methods are outlined for autoionizing collisions between helium atoms in the metastable $2^3\mathrm{S}_1$ state and a second, atomic or molecular species. Using numerical trajectory calculations, we provide estimates of the expected on-axis detection efficiency, collision-energy range and collision-energy resolution of the approach. We have experimentally tested the feasibility of such an experiment by producing two gas pulses at very short time intervals, and the results of these measurements are detailed as well.