Cavendish Laboratory : Annular magnet used by Rutherford and his colleagues.

Cavendish Laboratory

<p style='text-align: justify;'>This annular electromagnet was used by Rutherford and his colleagues in 1933 to investigate the spectrum of α-rays emitted by radium C' (https://doi.org/10.1098/rspa.1933.0043). The particles were bent along the circumference of the magnet and specific velocities could be selected by adjusting the strength of the magnetic field. They were detected in an ionization chamber placed on the opposite side of the magnet and connected to a scale-of-two counter. The magnet was designed by J. Cockcroft and produced by the Metropolitan-Vickers company.</p>