I work in this exact field. Yes. It's essentially a thermos. There's several cans nested within each other. Each can hangs from a different refrigeration stage.

I work in this exact field. Yes. It's essentially a thermos. There's several cans nested within each other. Each can hangs from a different refrigeration stage. Typically you go from 300 K (the outer vacuum can), to 77 K (first pulse tube stage), to 4K (second pulse tube stage), then to 300 mK (still of dilution unit), then to base at 10 mK, though the 10 mK stage doesn't have it's own can. Everything is copper or gold plated copper where you want heat to flow, or G-10 (fiberglass) or stainless steel where you don't. There's mechanisms for thermally shorting stages together... sometimes it's a mechanical gripper that pinches an extension from a colder stage, other times it's stainless steel tubing that gets filled with gas (the heat conducting material) when you want to transfer heat, and then evacuated when you don't.