I’ve done some measurements on a white tritium implant (neither xGLO nor Firefly, but is encased in soda lime glass like xGLO) and found there is still definitely still some radiation produced, but it’s around .9-1.5 CPS above background - I can actually do graphs of spectrum and maybe oneday I’ll get my hands on an xGLO and Firefly (V1 or V2) to compare
Implant stored in plastic vial, funnily enough I don’t have a tritium vial to measure, working on doing some more measurements has been on the backburner for a while
The inner layer holds the tritium gas and is coated with phosphor.
The next layer holds the lead foil shield.
The outer layer is in contact with your skin. Both outer layers are made from borosilicate, as far as I know.