There's also a fantastic Youtube video in a neutron beam facility of a Moka pot, in which you can see the full process of brewing. The water and plastic handle appear 'black' as hydrogen scatters neutrons so strongly.
However, if you have a neutron imaging beamline you probably are motivated to make a cool demo.
Found the video: https://www.youtube.com/watch?v=c7FoqR9oCfI
You might want some blast protection if you use a completely transparent one due to the explosion risk and flying glass pieces.
You knew it was working when the glass fogged up.