A 13 cm tall, shaped, AECL-patented, ceramic component that was used with the THERAC 25 accelerator to provide irradiation of tumours in the bremsstrahlung mode. The THERAC 25 was an electron accelerator with a beam that was typically only several mm in diameter. This beam would be magnetically scanned across a near-surface tumour for treatments. Deep-seated tumours required operation in the super-X-ray or bremsstrahlung mode whereby the electron beam strikes a material that converts the electron beam energy into energetic photons. This device, with the pointed end towards the electron beam, served to convert the energy and also to scatter the generated photon radiation uniformly so that a typical 20 cm by 20 cm treatment area would be treated with a uniform or flat radiation dose. The ceramic material, often aluminum-based, was adequately-efficient in generating the bremsstrahlung radiation while minimizing the production of neutrons. High Z materials like tantalum are more efficient but also contaminate the beam with a greater flux of neutrons.
