Moderators @Qmechanic and @dmckee marked it as a duplicate, but it is not so (see How is angular momentum measured in experiments/in practice? ). Linked questions are restricted to fundamental particles, whereas angular momentum is a concept applicable to any system. I now can’t post an answer about composite particles (currently at How does one experimentally determine chirality, helicity, spin and angular momentum of a fundamental particle? ) into correct thread.
I think the marked duplicates cover well enough the intent of the question you mentioned. They are indeed slightly more focused, but there's nothing in the closed one to indicate the level of generality that's being requested. Opening it up because it sort-of also covers composite particles would mean that the question really asked 'how is angular momentum measured in every conceivable experimental system', and that is really much too broad.
If you have a good answer and you want to find a good home for it, you should note that it is perfectly OK to ask a question and answer it. In fact, many of our best questions were written this way, because this gets past the fact that the questioner often doesn't know enough about the topic to ask the really interesting questions. For some samples see the ≲1k results in Self answers that were self-answered from the start.