Properties of Quantum Beams and Their Applications

A conceptual formulation of quantum beams and their basic properties are presented. The present status and outlook of their industrial applications are also discussed. Quantum beams are highly directional energy beams consisting of quantum-mechanical particles characterized by wave-particle duality. They are a concept developed out of need in industry, and, together with quantum mechanics developed during the turn of the century, have been applied to semiconductor and medical industries. The quantum beams can be classified by penetrating or ionizing power. X-rays and neutron beams are classified into those with high penetrating power, and the beams of alpha particles are classified into those with high ionizing power. Electron beams fall in between, giving rise to their unique intermediate property. Their chemical and biological effects are used in modifying the properties of materials or sterilizing food and beverage containers. Finally, we discuss the importance of developing further advanced accelerator technologies which can produce high-energy quantum beams, which will be necessary to chart our future research in yet unknown areas of science. In doing so, profit should not be the only goal; contribution to a sustainable society should be considered as well.