Wilhelm Röntgen

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Wilhelm Röntgen
Wilhelm Conrad Röntgen

(1845-03-27)27 March 1845
Died10 February 1923(1923-02-10) (aged 77)
Nationality German [1]
Alma mater
Known forDiscovery of X-rays
Awards Matteucci Medal (1896)
Rumford Medal (1896)
Elliott Cresson Medal (1897)
Barnard Medal (1900)
Nobel Prize in Physics (1901)
Scientific career
Fields Physics
X-ray astronomy
Doctoral advisor August Kundt
Doctoral students
Other notable students Franz S. Exner
Wilhelm Rontgen signature.svg

Wilhelm Conrad Röntgen ( /ˈrɛntɡən, -ən, ˈrʌnt-/ ; [2] German: [ˈvɪlhɛlm ˈʁœntɡən] ; 27 March 1845 – 10 February 1923) was a German [1] mechanical engineer and physicist, who, on 8 November 1895, produced and detected electromagnetic radiation in a wavelength range known as X-rays or Röntgen rays, an achievement that earned him the first Nobel Prize in Physics in 1901. [3] In honour of his accomplishments, in 2004 the International Union of Pure and Applied Chemistry (IUPAC) named element 111, roentgenium, a radioactive element with multiple unstable isotopes, after him.

Mechanical engineering engineering discipline and economic branch

Mechanical engineering is the discipline that applies engineering, physics, engineering mathematics, and materials science principles to design, analyze, manufacture, and maintain mechanical systems. It is one of the oldest and broadest of the engineering disciplines.

Physics Study of the fundamental properties of matter and energy

Physics is the natural science that studies matter, its motion, and behavior through space and time, and that studies the related entities of energy and force. Physics is one of the most fundamental scientific disciplines, and its main goal is to understand how the universe behaves.

Electromagnetic radiation form of energy emitted and absorbed by charged particles, which exhibits wave-like behavior as it travels through space

In physics, electromagnetic radiation refers to the waves of the electromagnetic field, propagating (radiating) through space, carrying electromagnetic radiant energy. It includes radio waves, microwaves, infrared, (visible) light, ultraviolet, X-rays, and gamma rays.




Born to a German father and a Dutch mother, Röntgen attended high school in Utrecht, Netherlands. In 1865, he was unfairly expelled from high school when one of his teachers intercepted a caricature of one of the teachers, which was in fact done by someone else. Without a high school diploma, Röntgen could only attend university in the Netherlands as a visitor. In 1865, he tried to attend Utrecht University without having the necessary credentials required for a regular student. Upon hearing that he could enter the Federal Polytechnic Institute in Zurich (today known as the ETH Zurich), he passed its examinations, and began studies there as a student of mechanical engineering. In 1869, he graduated with a Ph.D. from the University of Zurich; once there, he became a favorite student of Professor August Kundt, whom he followed to the University of Strasbourg. [4]

Utrecht City and municipality in the province of Utrecht, Netherlands

Utrecht is the fourth-largest city and a municipality of the Netherlands, capital and most populous city of the province of Utrecht. It is located in the eastern corner of the Randstad conurbation, and in the very centre of mainland Netherlands, and had a population of 345,080 in 2017.

Netherlands Constituent country of the Kingdom of the Netherlands in Europe

The Netherlands is a country located mainly in Northwestern Europe. The European portion of the Netherlands consists of twelve separate provinces that border Germany to the east, Belgium to the south, and the North Sea to the northwest, with maritime borders in the North Sea with Belgium, Germany and the United Kingdom. Together with three island territories in the Caribbean Sea—Bonaire, Sint Eustatius and Saba—it forms a constituent country of the Kingdom of the Netherlands. The official language is Dutch, but a secondary official language in the province of Friesland is West Frisian.

Caricature rendered image showing the features of its subject in a simplified or exaggerated way through sketching, pencil strokes, or through other artistic drawings

A caricature is a rendered image showing the features of its subject in a simplified or exaggerated way through sketching, pencil strokes, or through other artistic drawings.

Birthplace of Roentgen in Remscheid-Lennep House-of birth of Wilhelm Conrad Roentgen.jpg
Birthplace of Roentgen in Remscheid-Lennep


In 1874, Röntgen became a lecturer at the University of Strasbourg. In 1875, he became a professor at the Academy of Agriculture at Hohenheim, Württemberg. He returned to Strasbourg as a professor of physics in 1876, and in 1879, he was appointed to the chair of physics at the University of Giessen. In 1888, he obtained the physics chair at the University of Würzburg, and in 1900 at the University of Munich, by special request of the Bavarian government.

Professor academic title at universities and other post-secondary education and research institutions in most countries

Professor is an academic rank at universities and other post-secondary education and research institutions in most countries. Literally, professor derives from Latin as a "person who professes" being usually an expert in arts or sciences, a teacher of the highest rank.

University of Hohenheim university

The University of Hohenheim is a campus university located in the south of Stuttgart, Germany. Founded in 1818, it is Stuttgart's oldest university. Its primary areas of specialisation had traditionally been agricultural and natural sciences. Today, however, the majority of its students are enrolled in one of the many study programs offered by the faculty of business, economics and social sciences. The faculty has regularly been ranked among the best in the country, making the University of Hohenheim one of Germany's top-tier universities in these fields. The university maintains academic alliances with a number of partner universities and is involved in numerous joint research projects.

Hohenheim Quarter of Stuttgart in Baden-Württemberg, Germany

Hohenheim is one of 18 outer districts of the city of Stuttgart in the borough of Plieningen that sits on the Filder in central Baden-Württemberg. The Municipality was founded in 1782.

Röntgen had family in Iowa in the United States and planned to emigrate. He accepted an appointment at Columbia University in New York City and bought transatlantic tickets, before the outbreak of World War I changed his plans. He remained in Munich for the rest of his career.

Iowa State of the United States of America

Iowa is a state in the Midwestern United States, bordered by the Mississippi River to the east and the Missouri River and Big Sioux River to the west. It is bordered by six states; Wisconsin to the northeast, Illinois to the east, Missouri to the south, Nebraska to the west, South Dakota to the northwest, and Minnesota to the north.

Columbia University Private Ivy League research university in New York City

Columbia University is a private Ivy League research university in Upper Manhattan, New York City. Established in 1754, Columbia is the oldest institution of higher education in New York and the fifth-oldest institution of higher learning in the United States. It is one of nine colonial colleges founded prior to the Declaration of Independence, seven of which belong to the Ivy League. It has been ranked by numerous major education publications as among the top ten universities in the world.

New York City Largest city in the United States

The City of New York, usually called either New York City (NYC) or simply New York (NY), is the most populous city in the United States. With an estimated 2018 population of 8,398,748 distributed over a land area of about 302.6 square miles (784 km2), New York is also the most densely populated major city in the United States. Located at the southern tip of the state of New York, the city is the center of the New York metropolitan area, the largest metropolitan area in the world by urban landmass and one of the world's most populous megacities, with an estimated 19,979,477 people in its 2018 Metropolitan Statistical Area and 22,679,948 residents in its Combined Statistical Area. A global power city, New York City has been described as the cultural, financial, and media capital of the world, and exerts a significant impact upon commerce, entertainment, research, technology, education, politics, tourism, art, fashion, and sports. The city's fast pace has inspired the term New York minute. Home to the headquarters of the United Nations, New York is an important center for international diplomacy.

During 1895, Röntgen was investigating the external effects from the various types of vacuum tube equipment — apparatuses from Heinrich Hertz, Johann Hittorf, William Crookes, Nikola Tesla and Philipp von Lenard — when an electrical discharge is passed through them. [5] [6] In early November, he was repeating an experiment with one of Lenard's tubes in which a thin aluminium window had been added to permit the cathode rays to exit the tube but a cardboard covering was added to protect the aluminium from damage by the strong electrostatic field that produces the cathode rays. He knew the cardboard covering prevented light from escaping, yet Röntgen observed that the invisible cathode rays caused a fluorescent effect on a small cardboard screen painted with barium platinocyanide when it was placed close to the aluminium window. It occurred to Röntgen that the Crookes–Hittorf tube, which had a much thicker glass wall than the Lenard tube, might also cause this fluorescent effect.

Heinrich Hertz German physicist

Heinrich Rudolf Hertz was a German physicist who first conclusively proved the existence of the electromagnetic waves theorized by James Clerk Maxwell's electromagnetic theory of light. The unit of frequency, cycle per second, was named the "Hertz" in his honor.

William Crookes 19th and 20th-century British chemist and physicist

Sir William Crookes was a British chemist and physicist who attended the Royal College of Chemistry in London, and worked on spectroscopy. He was a pioneer of vacuum tubes, inventing the Crookes tube which was made in 1875. In 1913, Crookes invented 100% ultraviolet blocking sunglass lens. Crookes was the inventor of the Crookes radiometer, which today is made and sold as a novelty item. Late in life, he became interested in spiritualism, and became the president of the Society for Psychical Research.

Nikola Tesla Serbian American inventor

Nikola Tesla was a Serbian-American inventor, electrical engineer, mechanical engineer, and futurist who is best known for his contributions to the design of the modern alternating current (AC) electricity supply system.

In the late afternoon of 8 November 1895, Röntgen was determined to test his idea. He carefully constructed a black cardboard covering similar to the one he had used on the Lenard tube. He covered the Crookes–Hittorf tube with the cardboard and attached electrodes to a Ruhmkorff coil to generate an electrostatic charge. Before setting up the barium platinocyanide screen to test his idea, Röntgen darkened the room to test the opacity of his cardboard cover. As he passed the Ruhmkorff coil charge through the tube, he determined that the cover was light-tight and turned to prepare the next step of the experiment. It was at this point that Röntgen noticed a faint shimmering from a bench a few feet away from the tube. To be sure, he tried several more discharges and saw the same shimmering each time. Striking a match, he discovered the shimmering had come from the location of the barium platinocyanide screen he had been intending to use next.

Opacity is the measure of impenetrability to electromagnetic or other kinds of radiation, especially visible light. In radiative transfer, it describes the absorption and scattering of radiation in a medium, such as a plasma, dielectric, shielding material, glass, etc. An opaque object is neither transparent nor translucent. When light strikes an interface between two substances, in general some may be reflected, some absorbed, some scattered, and the rest transmitted. Reflection can be diffuse, for example light reflecting off a white wall, or specular, for example light reflecting off a mirror. An opaque substance transmits no light, and therefore reflects, scatters, or absorbs all of it. Both mirrors and carbon black are opaque. Opacity depends on the frequency of the light being considered. For instance, some kinds of glass, while transparent in the visual range, are largely opaque to ultraviolet light. More extreme frequency-dependence is visible in the absorption lines of cold gases. Opacity can be quantified in many ways; for example, see the article mathematical descriptions of opacity.

Röntgen speculated that a new kind of ray might be responsible. 8 November was a Friday, so he took advantage of the weekend to repeat his experiments and made his first notes. In the following weeks he ate and slept in his laboratory as he investigated many properties of the new rays he temporarily termed "X-rays", using the mathematical designation ("X") for something unknown. The new rays came to bear his name in many languages as "Röntgen rays" (and the associated X-ray radiograms as "Röntgenograms").

At one point while he was investigating the ability of various materials to stop the rays, Röntgen brought a small piece of lead into position while a discharge was occurring. Röntgen thus saw the first radiographic image, his own flickering ghostly skeleton on the barium platinocyanide screen. He later reported that it was at this point that he determined to continue his experiments in secrecy, because he feared for his professional reputation if his observations were in error.

Nearly two weeks after his discovery, he took the very first picture using X-rays of his wife Anna Bertha's hand. When she saw her skeleton she exclaimed "I have seen my death!" [7] He later made a better picture of his friend Albert von Kölliker's hand at a public lecture.

Röntgen's original paper, "On A New Kind Of Rays" (Ueber eine neue Art von Strahlen), was published on 28 December 1895. On 5 January 1896, an Austrian newspaper reported Röntgen's discovery of a new type of radiation. Röntgen was awarded an honorary Doctor of Medicine degree from the University of Würzburg after his discovery. He published a total of three papers on X-rays between 1895 and 1897. [8] Today, Röntgen is considered the father of diagnostic radiology, the medical speciality which uses imaging to diagnose disease.

A collection of his papers is held at the National Library of Medicine in Bethesda, Maryland. [9]

Personal life

Grave of Wilhelm Rontgen at Alter Friedhof (old cemetery) in Giessen Roentgen family-grave-Giessen-Alter Friedhof-2011-07.jpg
Grave of Wilhelm Röntgen at Alter Friedhof (old cemetery) in Gießen

Röntgen was married to Anna Bertha Ludwig (m. 1872, d. 1919). They raised one child, Josephine Bertha Ludwig, whom they adopted at age 6 from Anna's brother in 1887. [10] Röntgen died on 10 February 1923 from carcinoma of the intestine. [11]

First medical X-ray by Wilhelm Rontgen of his wife Anna Bertha Ludwig's hand First medical X-ray by Wilhelm Rontgen of his wife Anna Bertha Ludwig's hand - 18951222.gif
First medical X-ray by Wilhelm Röntgen of his wife Anna Bertha Ludwig's hand
X-ray of Albert von Kolliker's hand X-ray by Wilhelm Rontgen of Albert von Kolliker's hand - 18960123-02.jpg
X-ray of Albert von Kölliker's hand

He inherited two Million Reichsmarks after his father's death. [12] With the inflation following World War I, Röntgen fell into bankruptcy later in life, spending his final years at his country home at Weilheim, near Munich. [5] In keeping with his will, all his personal and scientific correspondence was destroyed upon his death.[ citation needed ][ dubious ] [13]

Honours and awards

In 1901, Röntgen was awarded the first Nobel Prize in Physics. The award was officially "in recognition of the extraordinary services he has rendered by the discovery of the remarkable rays subsequently named after him". Röntgen donated the monetary reward from his Nobel Prize to his university.[ clarification needed ] Like Pierre Curie, Röntgen refused to take out patents related to his discovery of X-rays, as he wanted society as a whole to benefit from practical applications of the phenomenon. Röntgen was also awarded Barnard Medal for Meritorious Service to Science in 1900. [14]

His honors include:

In 1907 he became a foreign member of the Royal Netherlands Academy of Arts and Sciences. [15]


Today, in Remscheid-Lennep, 40 kilometres east of Düsseldorf, the town in which Röntgen was born in 1845 is the Deutsches Röntgen-Museum. [16]
In Würzburg, where he discovered the X-rays, a non-profit organization maintains his laboratory and provides guided tours to the Röntgen Memorial Site. [17]

World Radiology Day: The International Day of Radiology is an annual event promoting the role of medical imaging in modern healthcare. It is celebrated on November 8 each year, coincides with the anniversary of the discovery of X-rays by Wilhelm Roentgen in 1895. It was first introduced in 2012, as a joint initiative, by the European Society of Radiology (ESR), the Radiological Society of North America (RSNA), and the American College of Radiology (ACR).

Röntgen Peak in Antarctica is named after Wilhelm Röntgen. [18]

See also

Related Research Articles

Cathode ray stream of electrons observed in vacuum tubes

Cathode rays are streams of electrons observed in vacuum tubes. If an evacuated glass tube is equipped with two electrodes and a voltage is applied, glass behind the positive electrode is observed to glow, due to electrons emitted from the cathode. They were first observed in 1869 by German physicist Julius Plücker and Johann Wilhelm Hittorf, and were named in 1876 by Eugen Goldstein Kathodenstrahlen, or cathode rays. In 1897, British physicist J. J. Thomson showed that cathode rays were composed of a previously unknown negatively charged particle, which was later named the electron. Cathode ray tubes (CRTs) use a focused beam of electrons deflected by electric or magnetic fields to render an image on a screen.

X-ray form of electromagnetic radiation

X-rays make up X-radiation, a form of high-energy electromagnetic radiation. Most X-rays have a wavelength ranging from 0.01 to 10 nanometers, corresponding to frequencies in the range 30 petahertz to 30 exahertz (3×1016 Hz to 3×1019 Hz) and energies in the range 100 eV to 100 keV. X-ray wavelengths are shorter than those of UV rays and typically longer than those of gamma rays. In many languages, X-radiation is referred to as Röntgen radiation, after the German scientist Wilhelm Röntgen who discovered these on November 8, 1895, and who named it X-radiation to signify an unknown type of radiation. Spelling of X-ray(s) in the English language includes the variants x-ray(s), xray(s), and X ray(s).

Henri Becquerel French physicist

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Radiography imaging technique

Radiography is an imaging technique using X-rays, gamma rays, or similar ionizing radiation and non-ionizing radiation to view the internal form of an object. Applications of radiography include medical radiography and industrial radiography. Similar techniques are used in airport security . To create an image in Conventional Radiography, a beam of X-rays is produced by an X-ray generator and is projected toward the object. A certain amount of the X-rays or other radiation is absorbed by the object, dependent on the object's density and structural composition. The X-rays that pass through the object are captured behind the object by a detector. The generation of flat two dimensional images by this technique is called projectional radiography. In computed tomography an X-ray source and its associated detectors rotate around the subject which itself moves through the conical X-ray beam produced. Any given point within the subject is crossed from many directions by many different beams at different times. Information regarding attenuation of these beams is collated and subjected to computation to generate two dimensional images in three planes which can be further processed to produce a three dimensional image.

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Philipp Lenard German physicist

Philipp Eduard Anton von Lenard was a German physicist and the winner of the Nobel Prize for Physics in 1905 for his research on cathode rays and the discovery of many of their properties. Lenard was a nationalist and anti-Semite; as an active proponent of the Nazi ideology, he supported Adolf Hitler in the 1920s and was an important role model for the "Deutsche Physik" movement during the Nazi period. Notably, he labeled Albert Einstein's contributions to science as "Jewish physics".

University of Würzburg university in Germany

The Julius Maximilian University of Würzburg is a public research university in Würzburg, Germany. The University of Würzburg is one of the oldest institutions of higher learning in Germany, having been founded in 1402. The university initially had a brief run and was closed in 1415. It was reopened in 1582 on the initiative of Julius Echter von Mespelbrunn. Today, the university is named for Julius Echter von Mespelbrunn and Maximilian Joseph.

Albert von Kölliker Swiss anatomist, physiologist

Albert von Kölliker was a Swiss anatomist, physiologist, and histologist.

Ivan Puluj Ukrainian physicist

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Crookes tube

A Crookes tube is an early experimental electrical discharge tube, with partial vacuum, invented by English physicist William Crookes and others around 1869-1875, in which cathode rays, streams of electrons, were discovered.

Johann Wilhelm Hittorf German physicist

Johann Wilhelm Hittorf was a German physicist who was born in Bonn and died in Münster, Germany.

John Macintyre British doctor

John Macintyre or Mcintyre FRSE was a Scottish doctor who set up the world's first radiology department at the Glasgow Royal Infirmary, in Glasgow.

Radiographer specialist in the imaging of human anatomy for diagnosis and treatment of pathology

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Clarence Madison Dally (1865–1904) was an American glassblower, noted as an assistant to Thomas Edison in his work on X-rays and as an early victim of radiation dermatitis and its complications.

The Institute of Martinus Herman van Doorn is a private boarding school in Apeldoorn, Netherlands.

The International Day of Radiology (IDoR) is an annual event promoting the role of medical imaging in modern healthcare. It is celebrated on November 8 each year, and coincides with the anniversary of the discovery of x-rays. It was first introduced in 2012, as a joint initiative, by the European Society of Radiology (ESR), the Radiological Society of North America (RSNA), and the American College of Radiology (ACR). The International Society of Radiographers and Radiological Technologists have celebrated 8 November as World Radiography Day.

Röntgen Memorial Site

The Röntgen Memorial Site in Würzburg, Germany is dedicated to the work of the German physicist Wilhelm Conrad Röntgen (1845–1923) and his discovery of X-rays, for which he was granted the Nobel Prize in physics. It contains an exhibition of historical instruments, machines and documents.

Charles Thurstan Holland British physician and pioneer radiologist

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Father Joseph Patrick Slattery, CM physicist, radiologist, Catholic priest, pioneer in the field of radiography in Australia and credited with the first use of fluoroscopy in Australia. In 1866, born in Waterford, Ireland. Traveled to Australia as a deacon in 1888. Ordained as a priest by Cardinal Moran. As a member of the Vincentian Congregation, he and several of his confreres took over the running of St Stanislaus' at Bathurst from the diocesan clergy. Appointed to the position of professor and taught science, including physics and chemistry. Slattery had a keen interest in the new technology of wireless radio and was the first to install a wireless set west of the Blue Mountains. He was an early pioneer of radio in Australia and found delight in building radio sets. Slattery built an X-ray practice at Bathurst and local doctors benefited greatly from this convenience. He performed mission work for the Vincentian fathers and toured Australia and New Zealand to serve the faithful. Slattery was superior of the Vincentian novitiate at Eastwood. He was appointed vice-rector of St. John's College at the University of Sydney. At Springwood and Manly, he was spiritual director of the seminaries for 6 years. Slattery performed parish work for the last 3 years of his life. In 1931 he died and was buried in Rookwood Cemetery at Sydney, New South Wales, Australia.

Dawson Turner (radiologist) radiology pioneer from Great Britain

Dr Dawson Fyers Duckworth Turner FRSE, FRCPE (1857-1928) was a British pioneer of radiology and patron of the arts, who died of radiation related cancer.


  1. 1 2 "Wilhelm Röntgen (1845-1923) – Ontdekker röntgenstraling". historiek.net.
  2. "Röntgen". Random House Webster's Unabridged Dictionary .
  3. Novelize, Robert. Squire's Fundamentals of Radiology. Harvard University Press. 5th edition. 1997. ISBN   0-674-83339-2 p. 1.
  4. Trevert, Edward (1988). Something About X-Rays for Everybody. Madison, WI: Medical Physics Publishing Corporation. p. 4. ISBN   0-944838-05-7.
  5. 1 2 Nitske, Robert W., The Life of W. C. Röntgen, Discoverer of the X-Ray, University of Arizona Press, 1971.
  6. Agar, Jon (2012). Science in the Twentieth Century and Beyond. Cambridge: Polity Press. p. 18. ISBN   978-0-7456-3469-2.
  7. Landwehr, Gottfried (1997). Hasse, A (ed.). Röntgen centennial: X-rays in Natural and Life Sciences. Singapore: World Scientific. pp. 7–8. ISBN   981-02-3085-0.
  8. Wilhelm Röntgen, "Ueber eine neue Art von Strahlen. Vorläufige Mitteilung", in: Aus den Sitzungsberichten der Würzburger Physik.-medic. Gesellschaft Würzburg, pp. 137–147, 1895; Wilhelm Röntgen, "Eine neue Art von Strahlen. 2. Mitteilung", in: Aus den Sitzungsberichten der Würzburger Physik.-medic. Gesellschaft Würzburg, pp. 11–17, 1896; Wilhelm Röntgen, "Weitere Beobachtungen über die Eigenschaften der X-Strahlen", in: Mathematische und Naturwissenschaftliche Mitteilungen aus den Sitzungsberichten der Königlich Preußischen Akademie der Wissenschaften zu Berlin, pp. 392–406, 1897.
  9. "Fundamental contributions to the X-ray: the three original communications on a new kind of ray / Wilhelm Conrad Röentgen, 1972". National Library of Medicine.
  10. Glasser (1933: 63)
  11. Glasser, Otto (1933). Wilhelm Conrad Röntgen and the Early History of the Roentgen Rays. London: John Bale, Sons and Danielsson, Ltd. p. 305. OCLC   220696336.
  12. Hans-Erhard Lessing: Eminence thanks to fluorescence - Wilhelm Röntgen. German Life (Grantsville MD) Oct/Nov 1995 pp. 40-42
  13. https://upscgk.com/Online-gk/5852/wilhelm-conrad-r%C3%B6ntgen-was-born-on-march-27-1845
  14. "Award of Bernard Medal". Columbia Daily Spectator . XLIII (57). New York City. 23 May 1900. Retrieved 22 March 2018.
  15. "W.C. Röntgen (1845 - 1923)". Royal Netherlands Academy of Arts and Sciences. Retrieved 20 July 2015.
  16. Deutsches Röntgen-Museum at roentgen-museum.de
  17. Röntgen Memorial Site at wilhelmconradroentgen.de
  18. Röntgen Peak. SCAR Composite Antarctic Gazetteer