How do X-rays display images


Shortly after its discovery, X-rays were used in medicine. Even today it is an important pillar of medical diagnostics and provides valuable services in areas such as archeology and art. As the radiation sources of the future, powerful X-ray lasers open up completely new research opportunities.

X-ray of a lung

X-rays have wavelengths between 10 billionths of a meter (10 nanometers) and 0.01 nanometers. It occurs when the inner electrons in an atom change their orbit around the nucleus and release energy in the process, or when fast electrons fly around a curve or are suddenly braked.

Wilhelm Conrad Röntgen accidentally discovered a new type of radiation in 1895. He didn't know what nature it was and called it X-rays. The special thing about it was that it could penetrate matter. So it was possible to take pictures of the inside of the body. In the German-speaking world, this radiation is called X-rays in honor of the discoverer. In English, the word X-rays used.

It was not until 1912 that Max von Laue proved that X-rays are electromagnetic waves similar to those of light.

Light that gets under the skin

X-rays in medicine

X-rays can partially penetrate matter, which enables deep insights into the interior of the human body, for example. This property was discovered just a few weeks after the radiation itself and has led to important applications in medical diagnostics.

The danger of uncontrolled dosing of X-rays was not known at the time, and some doctors and scientists died as a result of early research with X-rays. Over the years, ever more sophisticated and safer X-ray machines were built that offered a multitude of examination options, from taking full-body images to filming processes in the body.

Applications in archeology and art

It's one of those things with mummies: on the one hand, the preserved corpses offer a fantastic opportunity to gain insight into the past, on the other hand, these historically valuable dead bodies can turn to dust when they are unpacked.

X-rays make it possible to look behind the mummification without damaging the mummies. A large number of findings can be obtained, for example about the causes of death of the wrapped people and their diseases. X-rays also indicate the type of mummification, the status of medical healing methods and surgical interventions. The age of death can also be found using this technique.

X-rays can also play an important role when examining works of art. After the discovery of radiation in 1895, only two years passed when its penetrating properties were first used to examine a painting. Its origin was unknown. But the use of X-rays brought the painter's signature and a year to light. The advantage of the X-ray examination: the work of art remains completely undamaged during the analysis.

X-rays can also be used to distinguish the works of old masters from the attempts at painting by their students or - much more importantly - from professional forgeries. While two paintings may look like eggs when viewed with the naked eye, it is unlikely that the same painting technique was used to create the forgery as the original. It can be typical for a painter in which order and in which layers he applies the colors. An X-ray examination can reveal these differences between the original and a forgery.

Radiation sources of the future: X-ray lasers

The development of sources for X-rays

More than 100 years after Röntgen's discovery, X-ray lasers such as the European XFEL X-ray laser planned in Hamburg are producing radiation sources that will deliver a billion times higher peak output than the most modern X-ray sources. This will open up fields of experimentation that scientists have previously only been able to dream of.

For example, the X-ray laser flashes from the European XFEL X-ray laser are so short that they can be used to film chemical reactions. Exposure times in the range of billiardths of a second guarantee that nothing is blurred. Such recordings can be used, for example, to better understand the processes in fuel and solar cells. The researchers can also watch biomolecules at work or examine in detail how atoms and molecules form into materials. Whether chemists, biologists, materials researchers or physicists - there is something for everyone with the possible applications of X-ray laser flashes. The industry will also open up completely new opportunities.