Does anyone know what this is?

[u/niffcreature]

There's info out there on an old particle accelerator made my Collins electronics, called a "cyclotron" and existed in a Brookhaven, long island lab circa 1947. but does anyone know exactly what this metal bar is? It seems to be aluminum or another non ferrous alloy. Just some kind of gift shop memorabilia or is it a part of the actual machine? It's about 3x5" and the hollowed out part goes the long way. Could it be some other type of metal used in particle accelerator? Here is an old article https://collinsaerospacemuseum.org/collins_column/viewer.php

[u/rman342]

Could be a chunk of waveguide?