Producing and quantifying enriched para-$H2$ Available to Purchase

The production of enriched para-$H2$ is useful for many scientific applications, but the technology for producing and measuring para-$H2$ is not yet widespread. In this note and in the accompanying auxiliary material, we describe the design, construction, and use of a versatile standalone converter that is capable of producing para-$H2$ enrichments of up to $≥99.99%$ at continuous flow rates of up to 0.4 SLM. We also discuss para-$H2$ storage and back conversion rates, and improvements to three techniques (thermal conductance, NMR, and solid hydrogen impurity spectroscopy) used to quantify the para-$H2$ enrichment.