Reinhold Rudenberg
Encyclopedia
Reinhold Rudenberg was a German-American electrical engineer and inventor, credited with many innovations in the electric power
Electric power
Electric power is the rate at which electric energy is transferred by an electric circuit. The SI unit of power is the watt.-Circuits:Electric power, like mechanical power, is represented by the letter P in electrical equations...

 and related fields. Aside from improvements in electric power equipment, especially large alternating current generator
Electrical generator
In electricity generation, an electric generator is a device that converts mechanical energy to electrical energy. A generator forces electric charge to flow through an external electrical circuit. It is analogous to a water pump, which causes water to flow...

s, among others were the electrostatic-lens electron microscope
Electron microscope
An electron microscope is a type of microscope that uses a beam of electrons to illuminate the specimen and produce a magnified image. Electron microscopes have a greater resolving power than a light-powered optical microscope, because electrons have wavelengths about 100,000 times shorter than...

, carrier-current communications
Power line communication
Power line communication or power line carrier , also known as power line digital subscriber line , mains communication, power line telecom , power line networking , or broadband over power lines are systems for carrying data on a conductor also used for electric power transmission.A wide range...

 on power lines, a form of phased array radar, an explanation of power blackouts, preferred number
Preferred number
In industrial design, preferred numbers are standard guidelines for choosing exact product dimensions within a given set of constraints....

 series, and the number prefix "Giga-".

Early Life and education

Reinhold Rudenberg was born in Hanover, Germany to a family of Jewish descent. His father Georg was a manufacturer, who operated a plant for preparing, cleaning feathers and down goods. His mother was a daughter of the Chief Rabbi of the county of Braunschweig
Braunschweig
Braunschweig , is a city of 247,400 people, located in the federal-state of Lower Saxony, Germany. It is located north of the Harz mountains at the farthest navigable point of the Oker river, which connects to the North Sea via the rivers Aller and Weser....

. He attended the Technical University Hanover (then Technische Hochschule
Technische Hochschule
Technische Hochschule is what an Institute of Technology used to be called in German-speaking countries, as well as in the Netherlands, before most of them changed their name to Technische Universität or Technische Universiteit in the 1970s and in the...

), and after receiving his electrical engineering degrees (Dipl. Ing.) and doctorate (Dr. Ing.), both in 1906, he worked for Professor Ludwig Prandtl as a teaching assistant at the Institute for Applied Physics and Mechanics at Göttingen University. There he also attended courses in physics and the celebrated Advanced Electrodynamics course by Emil Wiechert
Emil Wiechert
Emil Johann Wiechert was a German geophysicist who presented the first verifiable model of a layered structure of the Earth.-Life:...

, who only ten years earlier had been one of the discoverers of the electron.

In 1919 Rudenberg married Lily Minkowski, daughter of the Göttingen mathematician Hermann Minkowski and Auguste née Adler.

Work and research

Rudenberg taught at Göttingen, Berlin
Berlin
Berlin is the capital city of Germany and is one of the 16 states of Germany. With a population of 3.45 million people, Berlin is Germany's largest city. It is the second most populous city proper and the seventh most populous urban area in the European Union...

, London
London
London is the capital city of :England and the :United Kingdom, the largest metropolitan area in the United Kingdom, and the largest urban zone in the European Union by most measures. Located on the River Thames, London has been a major settlement for two millennia, its history going back to its...

, and in the U.S. at MIT and Harvard University
Harvard University
Harvard University is a private Ivy League university located in Cambridge, Massachusetts, United States, established in 1636 by the Massachusetts legislature. Harvard is the oldest institution of higher learning in the United States and the first corporation chartered in the country...

. At Harvard he was head of the Department of Electrical Engineering at the Graduate School of Engineering from 1939-1952, when he retired.

After leaving Göttingen in 1908 he started at the manufacturer of electrical machinery Siemens-Schuckertwerke (SSW), part of the Siemens group of companies, in Berlin. He entered as a machine design engineer, and quickly advanced to head this department. His work soon broadened to include transmission lines, distribution systems, and protective relay
Protective relay
In electrical engineering, a protective relay is a complex electromechanical apparatus, often with more than one coil, designed to calculate operating conditions on an electrical circuit and trip circuit breakers when a fault is detected...

s and switches. In 1923 he was appointed Director of the Scientific Department (Wissenschaftliche Abteilung) of SSW responsible for the research on and development of machinery and systems for the firm. Simultaneously he was named Chief Electrical Engineer (Chef-Elektriker) of the firm.

In 1916, Rudenberg designed the electric generator for the main power station in Cologne, then the largest known.

He had a keen and agile mind, published much and became a prolific inventor. His books, especially on electrical transients, were widely read and used as college texts. Among his contributions were:
  • Carrier current communications (patent)
  • Hollow conductors for overhead high voltage power transmission
  • Electron microscope with electrostatic lenses (patent)
  • Reversing or Backing of Ships and Propellers
  • Phased array radar “geoscope” (patent)
  • First analysis of explosives blast overpressure versus energy of charge
  • Hyperbolic field lenses for focusing electron beams
  • Electric power directly from atomic radiation (patent)
  • Explaining the contributing cause of electric power systems blackout

Electron microscope and patents

In 1930, just after returning home from a summer vacation on the Dutch seaside, his 2 ¾-year-old son became ill with leg paralysis. This was soon diagnosed as poliomyelitis
Poliomyelitis
Poliomyelitis, often called polio or infantile paralysis, is an acute viral infectious disease spread from person to person, primarily via the fecal-oral route...

, which at that time was a frightening disease with a death rate of 10-25% as the disease progressed to the lungs. Polio was then known to be caused by a virus
Virus
A virus is a small infectious agent that can replicate only inside the living cells of organisms. Viruses infect all types of organisms, from animals and plants to bacteria and archaea...

, too small to be visible under an optical microscope
Optical microscope
The optical microscope, often referred to as the "light microscope", is a type of microscope which uses visible light and a system of lenses to magnify images of small samples. Optical microscopes are the oldest design of microscope and were possibly designed in their present compound form in the...

. From that time Rudenberg was determined to find or invent a way to make such a small virus particle visible. He thought that electrons, because of their subatomic size, as he had learned in Göttingen from Wiechert, would be able to resolve such small virus particles, and he investigated ways to focus these to create their enlarged image.

Already in 1927 Hans Busch
Hans Busch
Hans Konrad Busch was a highly decorated Major in the Wehrmacht during World War II and an Oberstleutnant in the Bundeswehr. He was also a recipient of the Knight's Cross of the Iron Cross. The Knight's Cross of the Iron Cross was awarded to recognise extreme battlefield bravery or successful...

, his friend since Göttingen, had published an analysis of a magnetic coil acting as a lens
Lens (optics)
A lens is an optical device with perfect or approximate axial symmetry which transmits and refracts light, converging or diverging the beam. A simple lens consists of a single optical element...

. Rudenberg reasoned that an electron beam leaving a point on an object in an axially symmetric electrostatic system could be focused back to an image point if the radial electric field was proportional to the electron distance from the axis. Thus he believed that real magnified images could be obtained under these conditions. As the date of a public lecture on electron optics was approaching Siemens applied for a patent on Rudenberg’s electrostatic-lens instrument and his general electron microscope principles on May 30, 1931. Siemens also obtained patents in six other countries. In Germany this, or patents derived therefrom, were granted at various later times from 1938-1954. Some competitors voiced complaints against the Rudenberg patents, but ignored or did not notice the earlier year that Rudenberg began his invention (1930) nor the difference of the stimulus that initiated it, nor would they recognize the technical differences between his electrostatic electron lenses and the magnetic lenses used by others.

Honors

  • 1911 - Montefiori Prize, Institut Montefiore, Liege, Belgium
  • 1921 - Dr.Ing. h.c. T.U. Karlsruhe
  • 1946 - Stevens Institute Honor Award and Medal "For notable achievement in the Field of Electron Optics as the inventor of the electron microscope."
  • 1949 - Cedergren Medal, Sweden
  • 1954 - Eta Kappa Nu
    Eta Kappa Nu
    Eta Kappa Nu is the electrical and computer engineering honor society of the IEEE, founded in October 1904 by Maurice L. Carr at the University of Illinois at Urbana-Champaign. The organization currently has around 200 student chapters and about 3,000,000 members and is headquartered in Chicago,...

     Eminent Member
  • 1956 - TU Berlin Honorary Senator
  • 1957 - Grand Cross of Meritorious Service of the Federal German Republic, Germany’s GVK medal “Pour le Merite” (Große Verdienstkreuz des Verdienstordens der Bundesrepublik)
  • 1961 - Elliott Cresson Medal
    Elliott Cresson Medal
    The Elliott Cresson Medal, also known as the Elliott Cresson Gold Medal, was the highest award given by the Franklin Institute. The award was established by Elliott Cresson, life member of the Franklin Institute, with $1,000 granted in 1848...

    , Franklin Institute
    Franklin Institute
    The Franklin Institute is a museum in Philadelphia, Pennsylvania, and one of the oldest centers of science education and development in the United States, dating to 1824. The Institute also houses the Benjamin Franklin National Memorial.-History:On February 5, 1824, Samuel Vaughn Merrick and...

    , Philadelphia

Works

  • Rüdenberg, Reinhold (1916) Artilleristische Monatshefte, No. 113/114, 237-265, 285-316 (in which Rudenberg analyzes the mechanism and the propagation of shock waves from heavy explossions and determines the laws of destruction at a distance).
  • Rüdenberg, R. (1932) Elektronenmikroskop (Electron microscope). Naturwissenschaften 20, 522
  • Rüdenberg,Reinhold (1943) The frequencies of natural power oscillations in interconnected generating and distribution systems. Trans. Amer. Inst. Elec. Engineers 62, 791-803 (In which Rudenberg shows the fundamental period of power surge and sag after a major transient, that may trigger a total blackout).
  • Rüdenberg, Reinhold (1943) "The Early History of the Electron Microscope", J Appl. Physics 14, 434-436, (in which Rudenberg describes stimulus to begin his work, also patent excerpts showing his electrostatic aperture electron lenses).
  • Rüdenberg, Reinhold (1945) J. Franklin Inst. 240, p. 193ff & 347ff (in which Rudenberg investigates the reversal and the transient behaviour of propellers and ships during maneuvering for controlled rapid action and the prevention of loss of control from propeller "cavitation").

See also

  • Rudenberg, H. Gunther and Rudenberg, F. Hermann (1994), "Reinhold Rudenberg as a physicist – his contributions and patents on the electron microscope, traced back to the 'Göttingen Electron Group'", MSA Bulletin, 24, No. 4, 572-578.
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