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From: "RADIOLOGICAL PHYSICISTS" by J.A. del Regato,M.D.,D,Sc Special publication of the American Association of Medical Physicists Published by the American Institute of Physics,1985.

[edit] Wilhelm Conrad Röntgen

Wilhelm Conrad Röntgen (in English: "William Conrad Roentgen") was a German physicist, of the University of Würzburg, who, on November 8, 1895, produced and detected electromagnetic radiation in a wavelength range today known as x-rays or Röntgen Rays, an achievement that earned him the first Nobel Prize in Physics in 1901. Wilhelm Conrad Röntgen was born March 27, 1845, in the lower Rhine town of Lennep, the only child of Friedrich Conrad Röntgen, a well-to-do textile merchant, and his Dutch wife and cousin, Charlotte Constance Frowein. When Wilhelm was three years of age, he moved with his parents parents to Apeldoorn in Holland, the home of his maternal grandparents, where he became a Dutch citizen. He attended primary school in Apeldoorn and boarding school at Middelaan. At age 17, he registered at a private Technical School in Utrecht. He lodged in the home of one of his professors, Jan Willem Gunning, a fine scholar who became his tutor, guide and mentor; Wilhelm was to remain loyal and affectionately devoted to him ("...your place in my heart never became empty"). Wilhelm served as instructor in chemistry and wrote a section in the professor's textbook. Towards the end of his studies at the technical school, a disparaging caricature of one of the teachers appeared on a blackboard. Because Wilhelm refused to reveal the name of the mischievous artist, he was expelled from the school as an accomplice. As the only alternative, he audited courses and was privately tutored, but he failed to gain admission at the University of Utrecht. His lofty dream of higher education had vanished. (Figs. I-1 and I-2.) In 1865, Röntgen learned that the Zürich Polytechnikum was accepting students without the customary credentials, provided they passed a stiff entrance examination. He applied for admission and upon consideration of his documents and letters, the examination was waived. Röntgen was a tall, slender and broad-shouldered young man with distinguished facial features: ample forehead, deep-set brown eyes, thick and wavy black hair and well-groomed sideburns. He dressed impeccably wearing a soft wing collar with a large bow cravat and a gold chain across his vest. He was reserved and rather shy but gay and friendly; his eyes betrayed both his determination and his kindness. Röentgen was born in the Rhineland town of Lennep on 27 March 1845. His German father Friedrich and Dutch mother Charlotte were cousins, coming from a well known family of merchants.1 When Wilhelm was three, the family moved to Apeldoorn in the Netherlands and, at the age of 16 he attended the Utrecht Technical School. Expelled because of a prank, he then entered the Polytechnic School in Zurich in 1865, where three years later he acquired a diploma in engineering. The following year, under the direction of A E E Kundt, he obtained a PhD for studies on the properties of gases. He then entered the University of Utrecht in 1.865 (20) to study physics. Not having attained the credentials required for a regular student, and hearing that he could enter the Polytechnic at Zurich by passing its examination, he passed this and began studies there as a student of mechanical engineering. He attended the lectures given by Clausius and also worked in the laboratory of Kundt. Both Kundt and Clausius exerted great influence on his development. In 1.869 (24) he graduated Ph.D. at the University of Zurich, was appointed assistant to Kundt and went with him to Würzburg in the same year, and three years later to Strasbourg. In 1.874 (29) he qualified as Lecturer at Strasbourg University and in 1.875 (30) he was appointed Professor in the Academy of Agriculture at Hohenheim in Wurtemberg. In 1.876 (31) he returned to Strasbourg as Professor of Physics, but three years later he accepted the invitation to the Chair of Physics in the University of Giessen. After having declined invitations to similar positions in the Universities of Jena (1886) and Utrecht (1888), he accepted it from the University of Würzburg (1888), where he succeeded Kohlrausch und found among his colleagues Helmholtz and Lorenz. In 1899 he declined an offer to the Chair of Physics in the University of Leipzig, but in 1900 he accepted it in the University of Munich, by special request of the Bavarian government, as successor of E. Lommel. Here he remained for the rest of his life, although he was offered, but declined, the Presidency of the Physikalisch-Technische Reichsanstalt at Berlin and the Chair of Physics of the Berlin Academy. Röntgen's first work was published in 1870, dealing with the specific heats of gases, followed a few years later by a paper on the thermal conductivity of crystals. Among other problems he studied were the electrical and other characteristics of quartz; the influence of pressure on the refractive indices of various fluids; the modification of the planes of polarised light by electromagnetic influences; the variations in the functions of the temperature and the compressibility of water and other fluids; the phenomena accompanying the spreading of oil drops on water. Röntgen's name, however, is chiefly associated with his discovery of the rays that he called X-rays. In 1895 he was studying the phenomena accompanying the passage of an electric current through a gas of extremely low pressure. Previous work in this field had already been carried out by J. Plucker (1801-1868), J. W. Hittorf (1824-1914), C. F. Varley (1828-1883), E. Goldstein (1850-1931), Sir William Crookes (1832-1919), H. Hertz (1857-1894) and Ph. von Lenard (1862-1947), and by the work of these scientists the properties of cathode rays - the name given by Goldstein to the electric current established in highly rarefied gases by the very high tension electricity generated by Ruhmkorff's induction coil-had become well known. Röntgen's work on cathode rays led him, however, to the discovery of a new and different kind of rays. On the evening of November 8, 1895, he found that, if the discharge tube is enclosed in a sealed, thick black carton to exclude all light, and if he worked in a dark room, a paper plate covered on one side with barium platinocyanide placed in the path of the rays became fluorescent even when it was as far as two metres from the discharge tube. During subsequent experiments he found that objects of different thicknesses interposed in the path of the rays showed variable transparency to them when recorded on a photographic plate. When he immobilised for some moments the hand of his wife in the path of the rays over a photographic plate, he observed after development of the plate an image of his wife's hand which showed the shadows thrown by the bones of her hand and that of a ring she was wearing, surrounded by the penumbra of the flesh, which was more permeable to the rays and therefore threw a fainter shadow. This was the first "röntgenogram" ever taken. In further experiments, Röntgen showed that the new rays are produced by the impact of cathode rays on a material object. Because their nature was then unknown, he gave them the name X-rays. Later, Max von Laue and his pupils showed that they are of the same electromagnetic nature as light, but differ from it only in the higher frequency of their vibration. Numerous honours were showered upon him. In several cities, streets were named after him, and a complete list of Prizes, Medals, honorary doctorates, honorary and corresponding memberships of learned societies in Germany as well as abroad, and other honours would fill a whole page of this book. In spite of all this, Röntgen retained the characteristic of a strikingly modest and reticent man. Throughout his life he retained his love of nature and outdoor occupations. Many vacations were spent at his summer home at Weilheim, at the foot of the Bavarian Alps, where he entertained his friends and went on many expeditions into the mountains. He was a great mountaineer and more than once got into dangerous situations. Amiable and courteous by nature, he was always understanding the views and difficulties of others. He was always shy of having an assistant, and preferred to work alone. Much of the apparatus he used was built by himself with great ingenuity and experimental skill. Röntgen married Anna Bertha Ludwig of Zürich, whom he had met in the café run by her father. She was a niece of the poet Otto Ludwig. They married in 1872 in Apeldoorn, The Netherlands. They had no children, but in 1887 adopted Josephine Bertha Ludwig, then aged 6, daughter of Mrs. Röntgen's only brother. Four years after his wife, Röntgen died at Munich on February 10, 1923, from carcinoma of the intestine.

Wilhelm Conrad Röntgen

In English it would be: William Conrad Roentgen. He was a German physicist, of the University of Würzburg, who, on November 8, 1.895, produced and detected electromagnetic radiation in a wavelength range today known as x-rays or Röntgent Rays, an achievement that earned him the first Nobel Prize in Physics in 1.901. Röntgent was born on March 27, 1.845 in the lower Rhine town of Lennep (duderdoff, Germany). He was an only child, his parents were: Friederich Conrad Röntgent, a well-to-do textile merchant, (he was his father) and Charlotte Constance Frowein, a Dutch homemaker that was his mother. Friederich and Charlote besides being married, they were cousins. When Wilhelm was three years old, he moved with his parents to Apeldoorn in Holland, the home of his maternal grandparents, where he became a Dutch citizen. He attended primary school in Apeldoorn and boarding school at Middelaan. When he was 17, he registered at a private Technical School in Utrecht. He lodged in the home of one of his professors, Jan Willem Gunning, a fine scholar who became his tutor, guide and mentor; Wilhelm was to remain loyal and affectionately devoted to him ("...your place in my heart never became empty"). Wilhelm served as instructor in chemistry and wrote a section in the professor's textbook. Towards the end of his studies at the technical school, a disparaging caricature of one of the teachers appeared on a blackboard. Because Wilhelm refused to reveal the name of the mischievous artist, he was expelled from the school as an accomplice. As the only alternative, he audited courses and was privately tutored, but he failed to gain admission at the University of Utrecht. His lofty dream of higher education had vanished.

On the evening of November 8, he was working in a dark room with several tubes and a paper plate covered on one side with barium, so, he applied electricity and rays became fluorescents. During subsequent experiments he found that objects of different thicknesses interposed in the path of the rays showed variable transparency to them when recorded on a photographic plate. When he immobilised for some moments the hand of his wife in the path of the rays over a photographic plate, he observed after development of the plate an image of his wife's hand which showed the shadows thrown by the bones of her hand and that of a ring she was wearing, surrounded by the penumbra of the flesh, which was more permeable to the rays and therefore threw a fainter shadow. This was the first "röntgenogram" ever taken. In further experiments, Röntgen showed that the new rays are produced by the impact of cathode rays on a material object. Because their nature was then unknown, he gave them the name X-rays. Later, Max von Laue and his pupils showed that they are of the same electromagnetic nature as light, but differ from it only in the higher frequency of their vibration. Röntgen died in 1923 of carcinoma of the bowel. It is not believed his carcinoma was a result of his work with ionizing radiation because his investigations were only for a short time and he was one of the few pioneers in the field who used protective lead shields routinely.

Wilhelm Conrad Röntgen (in English: "William Conrad Roentgen") (March 27, 1845 – February 10, 1923) was a German physicist, of the University of Würzburg, who, on November 8, 1895, produced and detected electromagnetic radiation in a wavelength range today known as x-rays or Röntgen Rays, an achievement that earned him the first Nobel Prize in Physics in 1901. Career In 1874 Röntgen became a lecturer at Strasbourg University and in 1875 became a professor at the Academy of Agriculture at Hohenheim, Württemberg. In 1876, he returned to Strasbourg as a professor of Physics 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. Röntgen had family in the United States (in Iowa) and at one time he planned to emigrate. Although he accepted an appointment at Columbia University in New York City and had actually purchased transatlantic tickets, the outbreak of World War I changed his plans and he remained in Munich for the rest of his career. Röntgen died in 1923 of carcinoma of the bowel. It is not believed his carcinoma was a result of his work with ionizing radiation because his investigations were only for a short time and he was one of the few pioneers in the field who used protective lead shields routinely. Discovery of X-rays During 1895 Röntgen was using equipment developed by his colleagues (reputedly, Ivan Pulyui personally presented one (the 'Pulyui lamp') to Röntgen, but Röntgen went on to be credited as the major developer of the technology), Hertz, Hittorf, Crookes, Tesla, and Lenard to explore the effects of high tension electrical discharges in evacuated glass tubes. By late 1895 these investigators were beginning to explore the properties of cathode rays outside the tubes. In early November Röntgen was repeating an experiment with one of Lenard's tubes in which a thin aluminium window had been added tout a cardboard covering was added to protect the aluminium from damage by the strong electrostatic field that is necessary to produce 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 Hittorf-Crookes tube, which had a much thicker glass wall than the Lenard tube, might also cause this fluorescent effect. In the late afternoon of November 8, 1895, Röntgen 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 Hittorf-Crookes 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 meter 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. Röntgen speculated that a new kind of ray might be responsible. November 8 was a Friday, so he took advantage of the weekend to repeat his experiments and make 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 for something unknown. Although the new rays would eventually come to bear his name when they became known as Röntgen Rays, he always preferred the term X-rays. Röntgen's discovery of X-rays was not an accident, nor was he working alone. With the investigations he and his colleagues in various countries were pursuing, the discovery was imminent. In fact, X-rays were produced and a film image recorded at the University of Pennsylvania two years earlier, and the articles by Professor Ivan Pulyui published in the Notes of the Austrian Imperial Academy of Sciences even as early as 1880-1883 explain the nature and the effects of the invisible light, unlike Roengen's own short and contradicting articles. Ivan Pulyui, unlike Röntgen, experimented with gas discharge lamps for over a decade by the time of Röntgen's publication and excelled in the construction of lamps. He obtained first images of a hand and a frog as early as 1890. He was the first to produce the image of the full human skeleton, which was a 7-months still-born baby. It is the perk of the history that the Austrian mass media drew attention to the German scientist and thus the discovery was associated with Röntgen since then. (Ternopil State Ivan Puluj Technical University, A brief translation of the previous reference) The idea that Röntgen happened to notice the barium platinocyanide screen misrepresents his investigative powers; he had planned to use the screen in the next step of his experiment and would therefore have made the discovery a few moments later. An X-ray picture (radiograph) taken by Röntgen of Albert von Kölliker's hand 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. Röntgen's original paper, "On A New Kind Of Rays" (Über eine neue Art von Strahlen), was published 50 days later on December 28, 1895. On January 5, 1896, an Austrian newspaper reported Röntgen's discovery of a new type of radiation. Röntgen was awarded an honorary degree of Doctor of Medicine from University of Würzburg after his discovery. He published a total of 3 papers on X-rays between 1895 and 1897. None of his conclusions have yet been proven false. Today, Röntgen is considered the father of Diagnostic Radiology, the medical specialty which uses imaging to diagnose disease. In 1901 Röntgen was awarded the very 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 the prize to his university. Like Pierre Curie would do several years later he refused to take out any patents related to his discovery on moral grounds. He did not even want the rays to be named after him. According to his will all his personal and scientific correspondence had been destroyed upon his death. (On November 2004 IUPAC named the element Roentgenium after him as well.) • Spouse: Anna Bertha Ludwig (m. 1872, d. 1919) • Children: Josephine Bertha Ludwig (adopted at age 6, in 1887, daughter of Anna's brother)