Kiirgusfüüsika

Kiirgusfüüsika, known in English as radiation physics, is the branch of physics that studies the generation, propagation, interaction, and effects of ionizing and non‑ionizing radiation. It encompasses both theoretical and experimental aspects, focusing on the properties of photons, electrons, neutrons, alpha and beta particles, and other charged or neutral particles that carry energy.

The field emerged in the early 20th century with discoveries such as X‑rays by Wilhelm Roentgen, radioactivity by Henri Becquerel, and radio waves by Heinrich Hertz. Subsequent development of quantum mechanics and special relativity provided the theoretical underpinnings necessary to describe photon interactions and particle decay processes. Key concepts include attenuation coefficients, cross‑sections, dose measurements, and the distinction between deterministic and stochastic biological effects.

Applications of kiirgusfüüsika are widespread. In medicine, it informs diagnostic imaging, radiotherapy, and radiation safety protocols. In industry, it supports non‑destructive testing, sterilization, and material analysis. Environmental science uses radiation physics to monitor natural background radiation and assess contamination. Space missions rely on it to understand cosmic radiation and protect astronauts. The energy of radiation and its interaction with matter also guide the design of shielding, detectors, and energy‑harvesting devices.

Prominent contributors to kiirgusfüüsika include Enrico Fermi, who demonstrated nuclear fission, John von Neumann, who helped model neutron transport, and P.T. Pütuma, who led early Estonian research in radiation shielding. The discipline remains integral to advancing nuclear technology, ensuring public safety, and improving diagnostic and therapeutic techniques.