Velocity distribution measurements in atomic beams generated using laser induced back-ablation

TL;DR

This paper measures the velocity distribution of calcium atoms in a laser back-ablation generated atomic beam, finding it to be Boltzmann-like with temperatures above calcium's melting point, and refutes previous claims of sub-thermal beams.

Contribution

It provides the first detailed velocity distribution measurements for calcium atomic beams from laser back-ablation, challenging prior reports of sub-thermal velocities.

Findings

Velocity distributions are Boltzmann-like.

Atomic beam temperatures are above calcium's melting point.

No sub-thermal atomic beam observed.

Abstract

We present measurements of the velocity distribution of calcium atoms in an atomic beam generated using a dual-stage laser back-ablation apparatus. Distributions are measured using a velocity selective Doppler time-of-flight technique. They are Boltzmann-like with rms velocities corresponding to temperatures above the melting point for calcium. Contrary to a recent report in the literature, this method does not generate a sub-thermal atomic beam.