Analytical emission model for the design of primary effusive sources

TL;DR

This paper introduces an analytical emission model for effusive sources with long collimation tubes, accurately predicting molecular flow properties from transparent to opaque regimes, aiding efficient source design.

Contribution

It improves a secondary-emission-surface model to accurately predict angular flux distribution in effusive sources across flow regimes.

Findings

Accurately predicts angular intensity distribution in molecular flow regime.

Captures full range of molecular flow from transparent to opaque regimes.

Provides analytical guidance for designing primary effusive sources.

Abstract

We present an analytical emission model that accurately predicts the properties of effusive sources formed by long collimation tubes. By construction, it captures the full range of molecular flow, from the transparent flux regime, which occurs in highly rarefied gases, to the opaque regime, which arises as the flux increases and interparticle collisions become non-negligible. The model is based on a previously developed secondary-emission-surface approach, improved here to overcome its internal limitations and recover the well-established axial flux intensity. It provides accurate analytical predictions of the angular intensity distribution in the molecular flow regime, offering valuable guidance for the design of efficient primary sources across a broad range of experiments in atomic and molecular physics