Iron shielding made of the hull plating of a battleship from 1st world war.

Our Pelletron accelerator is equipped with a beamline for hydrogen depth profilung using the ¹H(¹⁵ N,ag)12C nuclear reaction, in which 4.x MeV Gamma radiation is emitted.
The high sensitivity of the technique required shielding of the large NaI Scintillattion gamma detector from the natural radiation background. This shielding is achieved by large 20 cm thick iron plates cut out from the hull plating of a battleship from 1st world war. The iron from this ship is free of radioactive Co-60 contaminants and is therefore an ideal shielding of the detector.