Скачать или смотреть Production of X-rays

This video discusses the production of x-rays in detail. The video starts with a brief introduction to x-rays and their discovery by W.C. Röntgen in 1895. It mentions that medical applications of x-rays were realised within months after their discovery. X-rays were understood to be highly penetrating electromagnetic radiation with interesting properties. The wavelengths of x-rays was too low to be measured using plane optical gratings or similar diffracting equipment. After a struggle for more than a decade, scientists were able to figure out a way to measure the wavelength of x-rays using crystals owing to the discovery of x-ray diffraction by Max Von Laue in 1912. Max Von Laue received the Physics Nobel for the year 1914. The typical x-ray wavelengths are discussed. The x-ray production via the mechanism of 'Bremsstrahlung' which means braking radiation is discussed in some detail. How the rapidly moving electrons lose their kinetic energy to produce x-rays in the x-ray tube is mentioned. The x-ray production process is discussed with a schematic diagram of the set up process. Further, the x-ray spectrum which is a plot of x-ray intensities as a function of wavelengths for varying applied electrode potentials is discussed taking the case of tungsten as an example. It is also discussed briefly why it is important to chose high melting metals as the anode targets in x-ray tubes as well as high atomic number elements. Further, based on the x-ray spectrum, the inverse proportionality of the minimum x-ray wavelength as a function of applied potential between the anode and the cathode is discussed and why quantum mechanics is required to explain this behavior is mentioned. It is also made clear that the production of continuous x-rays via the mechanism of Bremsstrahlung is a classical concept that could be explained based on classical electromagnetic theory and Maxwell's equations. Another plot between x-ray intensity and wavelength for two different metals is compared and it is mentioned for various metals beyond certain applied potential values, how spikes are observed in the continuous x-ray spectrum and how behind this is a quantum mechanical phenomenon related to the structural rearrangement of electrons in various atomic shells. Characteristic x-rays are introduced in this context. It is also made clear in this video how x-ray production process is actually inverse photoelectric effect and how one can use the photoelectric equation to understand this. Towards the end of the video, moving back to the variation of minimum x-ray wavelengths as a function of applied potential between the electrodes, Duane-Hunt rule or the Duane-Hunt formula is derived from the photoelectric equation, tying all the loose ends in the x-ray production story.