ERNST RUSKA: BIOGRAPHY, CONTRIBUTIONS AND ACKNOWLEDGMENTS - ARTE - 2024

Ernst Ruska (1906-1988) was a prominent German physicist who managed to obtain the 1986 Nobel Prize in physics, due to the work carried out in the area of ​​electronic optics, as well as for his contribution in the design of the first electron microscope. His studies of electronic lenses with short focal lengths were a determining and key factor in the subsequent innovation and invention of the electron microscope.

He dealt with the experimental and mathematical proof of Busch's theory on the effect of the magnetic field of a coil of wire, through which an electric current passes and which is then used as an electron lens. Thanks to this discovery, he designed the polschuh lens, which has since been incorporated into all high-resolution magnetic electron microscopes.

Ernst Ruska. Image via: biografiasyvidas.com

Later work, carried out together with Max Knoll, led him in 1931 to invent the first electron microscope. With this instrument two of the most important processes for the reproduction of images were introduced: the principles of emission and radiation.

In 1933, he was able to put into use an electron microscope of his own construction, which for the first time gave better definition than a light microscope. During his life, Ruska was awarded several recognitions, such as being named honorary doctorates from the universities of Berlin, Kiel, Toronto and Modena.

Biography

Personal life

Ernst August Friedrich Ruska was born in the city of Heidelberg, Germany, on December 25, 1906. His parents were Julius Ferdinand Ruska and Elisabeth Merx. This marriage had five more children in addition to Ernst.

His father was a professor and orientalist, renowned for his work on the history of science during the Islamic period. In the period of the First World War, Ernst suffered the loss of Hans, his older brother.

In 1937, Ruska married Irmela Ruth Geigis and had three children. At the end of the Second World War he had two more children, but the fruit of a relationship he had with a Siemens worker. The wife finally accepted it, and on Ernst's birthdays he would reunite with the two families.

He was a man completely dedicated to his work. He died on May 27, 1988 in Berlin.

Studies

Ernst studied at the same school where his father taught. This period of study was crucial for his later achievements, since it was at this stage that he began to show interest in electronic inventions.

After leaving secondary school, he continued his studies at the Technical School in Munich, where he began studying electronics between 1925 and 1927. He then continued studying at the University of Munich until 1931, where he managed to obtain a degree in electronic engineering.

He did his internships at Mannheim, Brown-Boveri & Co and Siemens & Halske Ltda in Berlin. While studying at the University of Berlin, he began working at the High Voltage Institute, whose director was Professor Adolf Matthias. There he became familiar with high voltage and vacuum technology.

Together with other doctoral students and his colleague Max Knoll, he developed a high-performance cathode ray oscilloscope. His interest was focused on the development of materials for the construction of vacuum instruments according to construction principles.

On the other hand, he focused on continuing theoretical lectures and practical experiments on the optical behavior of electron beams.

In 1934, Ernst Ruska continued his studies at the University of Berlin, where he was awarded the academic title of doctor, after doing work on electronic lenses with short focal lengths, which were later key to inventing the electron microscope.

Contributions to science

Between 1928 and 1929 he carried out his first theoretical and experimental study on Busch's work on the effect of the magnetic field through a coil of wire. This passes the electric current and can be used as an electron lens.

Thanks to the completion of this work, Ruska was able to verify that the waves could be shortened through an iron cover due to the focal length. From that moment, the lens appeared that would be incorporated in future high-resolution magnetic microscopes, which had the ability to detect electrons.

The first electron microscope

In the late 1930s, together with Max Knoll, he designed the first electron microscope, based on earlier work by Louis-Victor De Broglie on the properties of electrons.

In the electron microscope, he succeeded in making the magnetic and electric fields give the electronic beams changes similar to the refraction of optical lenses on light waves.

For the operation of the electron microscope, the light source was replaced by an electron source. This was caused by a tungsten cannon and by the use of electrostatic and magnetic devices. They managed to deflect electrons in the same way that lenses did with light rays.

The electron gun produces a beam of electrons accelerated by high voltage and focused through an absolute vacuum and magnetic lenses. The beam then crosses the sample, which has been previously dehydrated and in some cases covered by a thin metallic layer.

Finally, magnification is achieved by means of a group of magnetic lenses and the image is formed on a photographic plate with ultra-fine grain emulsion, perfect for large enlargements. It was also feasible by transferring the image to a computer and impacting the electrons on a sensitive screen.

Recognitions

Ernst was awarded an honorary doctorate from the universities of Kiel, Berlin, Toronto and Modena. Likewise, he belonged to several scientific associations, such as the English, French and Japanese electron microscopy associations. During his life he received the following awards and recognitions:

- The Senckenberg Prize in 1939 by the University of Frankfurt.

- The Silberne medal of the Berlin Academy of Sciences, in 1941.

- The Albert-Lasker Award from the American Public Health Association, San Francisco in 1960.

- The Diesel Gold medal in 1969

- The Duddel Medal from the London Institute of Physics in 1975.

- The Albert von Gräfe medal in 1983.

- The Robert Koch Medal in 1986.

In 1986, Ernst Ruska shared the Nobel Prize in Physics with Gerd Binnig and Heinrich Rohrer. He obtained fifty percent of the economic prize, precisely for the design of the first electron microscope and for his contributions in electronic optics.

Unfortunately, Reinhold Rüdenberg, who belonged to Siemens, was ahead of him with the filing of the patent. Ruska, realizing this, claimed and finally got priority. However, Rüdenberg got the electron microscope patent for the United States.

References

1. Deutsche Biographie - Ruska, Ernst. (2019). Taken from deutsche-biographie.de
2. Ernst Ruska (1906-1988). (2019). Taken from historiadelamedicina.org
3. Ernst Ruska - German engineer. (2019). Taken from britannica.com
4. The Nobel Prize in Physics 1986. (2019). Taken from nobelprize.org
5. Ernst Ruska - The Inventor of Electron Microscope. (2019). Taken from leo-em.co.uk