Biographical Memoirs: Volume 54 (1983)

Below is the uncorrected machine-read text of this chapter, intended to provide our own search engines and external engines with highly rich, chapter-representative searchable text of each book. Because it is UNCORRECTED material, please consider the following text as a useful but insufficient proxy for the authoritative book pages.

:: :~ :~ i::: ~ ~ ::: ~ I: ::: ~ i: i: ~ ~ it: i: ~ ~~ ~~:~ ~ ~~ ~ ~~ ~ ~ ~ ~ ~ ~ ~ T ::~ : :::::::::: :::: ::: ::::: ~ :: :::::::: ~ :: i::: ~ T~::::~:::~: i: :: ~~:~:~:~:~:~:~:~ ::: ~ i:: i: : : ~ ma: ~ ~ ~ i: :: ~ ~~ ~~ ~ ~ i::: ~ it:: i::: ~ ~ ~~ i: ~ it: :~: i: :: i:: ~ i: :: ~ ~ ::::: :::::: i. ~ ~y Hi :?. - -I . ~ ~ ~ ~ ~~ ~ ~~ :: ~ ~ ~ ~~ ~ ~ ~~ ~ ~ if: ~~::~:. ::,: :.,'', i:: : :-': A..' ~: ~~'~ ~2:~'~'~: :::- : :-.''' : :: .::: :~ :: i: ~ ~ :: : :~ V ~:~ ~ :: ::: o U) o S" o C) AL o o

RUDOLF KOMPFNER May 16, 1909-December 3, 1977 BY T. R. PI ERCE THE SUCCESSFUL PURSUIT of science and technology is something of a mystery. The way of endeavor is con- spicuously marked by sterile studies and lucky flukes. Yet, ~ believe there are ways conducive to winning. These are il- lustrated in the work of Rudolf Kompfner. In writing about him, ~ hope that it will not be taken amiss if ~ refer to him consistently as Rudi. Few knew him as Kompfner or as Dr. Kompfner, and none as Rudolf. Rudi's success in a field that he himself chose is inclubi- table; it is attested by numerous honors. In 1955 the Physical Society awardecI him its Duciclell Medal for his invention of the traveling-wave tube. This lee! him to give a lecture and later to write a book on The Invention of the Trave1!ing-Wave Tube. He was made a fellow of the Institute of Electrical and Electronics Engineers anc! given its David Sarnoff Award in 1960 ant! its highest award, the Mecial of Honor, in 1973. He received the Stuart Ballantine Mecial of the Franklin Institute in 1960; the John Scott Award from the City of Philadelphia in 1974; the Sylvanus Thompson Medal of the Rontgen Society, incorporated with the British Institute of Radiology, in 1974; anc! the National Medal of Science in 1975. He was awarded an honorary doctor of technical science by the Tech- nische Hochschule of Vienna in 1964 and the honorary de- 157

158 BIOGRAPHICAL MEMOIRS gree of doctor of science from Oxford University in ~ 969. He was a fellow of the American Association for the Advance- ment of Science and a member of the National Academy of Engineering and the National Academy of Sciences. He served well on important committees of these organizations. He also server! as a member of the Board of Trustees of Associated Universities, Inc. Rudi succeecled—despite very real difficulties—through hard work and a constellation of qualities so various that they might be thought inconsistent. He had a driving purpose ant! intense application in his chosen field. Yet this clid not ex- clucle a wicle range of interests and enthusiasms. He loved all good things except poetry, yet he could and did live simply. Nothing dauntec! him, and few things seemed beyonc! his range. He was warm and open and quickly became what seemec! like a lifelong friend. Felix Bloch regarcled Rudi as a close friencl, though they met only two years before Rudi's (leash, when neither was young. People were attracted to Rudi, and Rucli was attracted to those whom he felt worthy of his in- terest. Others, he must have ignored. ~ remember a lunch with Ructi and a foreign visitor. ~ solicited the visitor's opin- ions, listened intently, ant! commented politely. After lunch, Rudi seemed almost annoyed! with me. He asked why T hacI bothered with such a man he was nothing. And of course, Rudi was right. To discuss Rudi ant] his career and its significance is no easy matter. He lived in many places, clid many things, and interacted with many people. He was born in Vienna, Austria on May 16, 1909, the son of Bernharcit and Paula Kompfner. His father was an accountant and a composer of Viennese songs ant! waltzes who played the piano in a Heurigen in the outskirts of Vienna. Rucli hac! a book, published in 1913, that included several of his father's compositions.

RUDOLF KOMPFNER 159 Rudi himself exhibited an early musical talent, picking out tunes on the keyboard and learning which notes went pleas- ingly together by trial with, apparently, little error. Piano lessons failed to teach him to react music; he memorized instantly the pieces he was told to stucly. Rudi seems to have Earned to cope with difficulties of life as he learned music through exposure anc! talent. Toward the end of World War I, through the armistice, and for some time thereafter, Viennese children starved because of a total AlliecT blockade. Rudi survived because he was put on a train by the Red Cross and sent without his parents knowing exactly where he was going—to Sweden. The months there, cluring which he recoverer} from boils and other ills of mal- nutrition, were spent with a deeply religious family. Their attitudes impressed him and remained fresh in his memory, though they had little long-term influence on his own beliefs. Early reading, and particularly the works of Arago, enamored Rudi of physics. This was his lifelong love, but he was not allowed to pursue his chosen career immediately or directly. Through the influence of his uncle, Fritz Keller, an architect, he studied architecture at the Technische Hoch- schule in Vienna, becoming a Diplom-Tngenier in 1933. This was a difficult time for Jews in Austria. An English- man, Roy Franey, who had married Rudi's cousin Mowgli ~onasz, was helpful in Rucli's coming to Englanc! in 1934. Franey later succeeded in getting Rudi's parents and sister out of Austria in 1938. After Rudi had servect an architec- tural apprenticeship with P. D. Hepworth in London from 1934 to 1936, he became managing director of Franey's firm, AImoncl Franey and Son, LtcI., Estate Managers and BuiTclers, Lonclon, from ~ 936 to ~ 94 ~ . Here we have a man who had sufferer! starvation during a terrible war, had been shipped off to one foreign land as a chiTct, had been compellec! to pursue a career not of his own

160 BIOGRAPHICAL MEMOIRS choosing, and then had to go to another strange lancT ant! make his way as an architect. We might imagine him as dis- illusioned, bitter, slighting his own work or forever cut off from that which he valued most. Not Ructi. Indeed, ~ believe that he Earned a good clear from archi- tecture that was valuable in his later endeavors. One thing was an appreciation of the practical aspects of any art, inclucl- ing that of the builcler. Another was that in order to accom- plish something, one must make a start. Rucli told of staring at a blank piece of paper on his drawing board after having been instructed to clesign a house. A senior ciraftsman came, leaned over his shoulder, ant] saw that he was having trouble. The ciraftsman drew a square on the paper and told him, "The secret of getting started is to start." Rucli hacI his start and proceeclecl with the design. Audi became an architect of some accomplishment. Ac- cording to Rucli's recollection, cluring a civil service examina- tion, C. P. Snow walkecl in, glancecl through Rudi's dossier, and said: "Mr. Kompfner, I see you are an Austrian and an architect." Rudi agreed. "Mr. Kompfner, Adolf Hitler was an Austrian and an architect. Tell me which is the better architect, you or Hitler?" "What I built still stands," Rudi replied. ~ncleecI it does. Among his works is a house in south London, described and pictured inSmalIHouses, £500-£2500 (editect by H. Myles Wright, London: The Architectural Press, 1937~. It is an admirable building for a narrow (30-foot wide), ciark site. Rucli also designed a number of artisan's flats in the Bermonctsey District. Rucli's experience in architecture had various influences in his life. He was acutely aware of buildings, their beauties

RUDOLF KOMPFNER 16 and their failings. I remember his telling me that of two builclings neighboring St. Mark's in Venice: one is marvelous; the other, trash. He insisted! that the south facade of the Parliament building in Vienna is a masterpiece far superior to the front. He speculated that this was the work of some junior architect and had escaped attention and ruination. Of lesser note, driving past a house in Summit, New Jersey, that we both acimired, he said that the second-story windows were too close to the roof, which was certainly so. Another influence of architecture was that it enhanced Ru(li's natural talent for drawing. In his Viennese days, Ru(li procluced some striking prints in a then-current style. Later, he proviclec] twenty-three illustrations for a book, 3 jungen Ziehen durch Kleinasien, in Veriag Das Bergland-Buch, pub- lishec! in ~ 936 and written by Rudi's closest and lifelong Vien- nese friend, Theo Eder. Ructi's talent for illustration was a joy throughout his life; he recorded home, family, and a one-time pet raccoon. It served a different purpose in illustrating his technical thoughts clearly. At the blackboard, most of us fumble in trying to convey our ideas; Rucli was never unclear, never at a loss. He insisted that his students picture things accurately. One student toIcl me that he continually clemande~l, "draw it to scale." That can make a real difference. While Rudi was practicing architecture ant! learning through it, he began to make his way in his chosen field of physics. How cloes one turn from a practicing architect to a physi- cist? Rucli's approach was phenomenally original. He went to the excellent Patent Office Library in Chancery Lane and read journals and books in the evening. Sometimes Peggy Mason accompanies! him. He had met her at the Westminster swimming club in 1935; they were married at Caxton Hall, Westminster on April 29, 1939.

162 BIOGRAPHICAL MEMOIRS Beginning in 1935, Rudi recordect in a series of notebooks those things that interested him most. These incluclect the television camera tubes of Zworykin and Farnsworth, and later the microwave tubes of Heil and Varian. Soon, original ideas and inventions appeared in the note- books. Among these is the "Relayoscope," in which a pattern of light (an image) impinging on a nonconducting photo- electric grit! was to be user] to control the flow of an electron beam. This lecT to a triple-barrelecl British patent, number 476,31 I, applies] for on June 4, July 27, and August IS, 1936 and accepted on December 6, 1937. The patent covers the functions of a television pickup tube and the reproduction of infrared, ultraviolet, or X-ray images as light images. Ruth triecI vainly to market this invention. As his reading progressed, Rudi's interests definitely turned towarc! microwave tubes. He hac! original ideas for explaining the Hei! tube and the klystron. What course Rucli's activities might have taken but for the coming of World War Al in September of 1939 is an unan- swerable question. In June of 1940 Peggy returned from work one evening to filch that he had been taken to the Brixton Police Station for internment as an enemy alien. He was interned on the Isle of Man from June to December 1940. In some way, through the intervention of Peggy, rela- tives, friends, and people who knew of his work, including Hugh Pocock, the editor of the Wireless Engineer, and by declaring himself a stateless person, Rudi was releasecI. During internment, Rucli never lost his balance of judg- ment and was always considerate and charming. He met a number of German internees, with whom he studied and discussed physics. He shared quarters with Wolfgang Fuchs, a mathematician from Cambridge who is now a professor at Cornell. They became close ant] affectionate friends as well as collaborators in science. Together they wrote a paper on

RUDOLF KOMPFNER 163 space charge effects in velocity moclulatec! electron beams. This was eventually published in the Proceedings of the Physical Society. W. E. Benham, a somewhat eccentric expert on vacuum tubes with whom Rudi began to correspond on July 9, 1941, was helpful in this connection. Prior to his internment, Rucli had submitted a paper on magnetrons to the Wireless Engineer. Hugh Pocock had taken this to the Acimiralty, and it was cleemed unpublishable in wartime. The Acimiralty wrote to Peggy, asking for cletails of Rudi's qualifications. She went to the Acimiralty in late 1940 to see if they might have use for Rucli. Frederick Brundrett saicT that Rudi shouIc! see them when he was released. Rucli was released, anct, though Brunctrett saicT that he was "neither fish nor fowl" to them, in September of 1941 he was sent to the Physics Department of Birmingham Univer- sity to work uncler Professor M. L. Oliphant. The work he found there on high-power magnetrons, the heart of wartime racier, was a revelation. Characteristically, however, Rucli soon turned his own endeavors in a novel direction. The fruitful outcome was the invention of the traveling-wave tube, while trying to make a better klystron amplifier for radar receivers. His funcla- mental idea—the continuous interaction of an electron stream and an electromagnetic wave of the same velocity traveling along a helix was ingenious, ant] the realization worked! The invention of the traveling-wave tube is characteristic of Rudi's career in several ways. The big thing of the day was the magnetron. Rudi hac! already written a paper on the magnetron. But at Birmingham, the heart of magnetron re- search, he turned his attention to something else, anti, almost singlehan(lecl, he succeedecl. He succeeded in the face of contrary acivice. "Experts" told him that a collect wire, or helix, wouIct not transmit

164 BIOGRAPHICAL MEMOIRS microwaves. Rucli clidn't believe them. He wound a helix himself anc! made measurements. He didn't just think and argue, he clicI something with his own hands, and it suc- ceeded. Then he built a traveling-wave tube. This was important, because what he found went beyond what he hac! expected. Initially, he had thought only of a strong action of the electric field of the electromagnetic wave on electrons traveling at the same velocity. He fount] that as the current of electrons was increased, the tube broke into microwave oscillation. Not only did the electromagnetic wave act to bunch the electrons, the bunched electron beam acted to strengthen the electro- magnetic wave. The helix anc! beam together constitutes! an amplifier that gave a very high gain over a very broad band of frequencies. Rudi analyzed this phenomenon by means of a series cal- culation: the effect of the field on the beam, the effect of the beam on the field, and so on, back and forth. He thus ex- plained the "Kompfner clip" a reduction of transmission at a particular electron velocity or accelerating voltage. Joseph Hatton, a young research student who had begun to work with Rudi, pusher] the analysis further. When T react of Kompfner's work through CVD (Com- mittee on Valve Development) reports, ~ was astonished. quickly worked out a wave analysis that explained the be- havior of traveling-wave tubes more to my satisfaction, and, ~ believe, to Rucli's. ~ tract been considering the effect of traveling waves on electron beams. But because T cticin't think of that wonderfully simple circuit, the helix, and because T only calculated an(l didn't builcl anything, ~ missed the most important point the mutual interaction between the elec- tromagnetic wave an(l electrons that results in a very great amplification.

RUDOLF KOMPFNER 165 In 1944 Rudi, deep in work on his traveling-wave tube, was transferred, still as an employee of the Admiralty, to the CIarendon Laboratory at Oxford. While there, he met Neville Robinson, who was working at the Services Electronic Research Laboratory at BaIdock. It was characteristic that when Robinson, pursuing some ideas of his own that were only vaguely related to Rudi's interest, modified the design of the helix in order to make a narrow-band amplifier, Rudi realized that while it might not work as Robinson intended, it might possibly work as a low-noise amplifier. It did. Beyond his work on traveling-wave tubes, Rudi became haunted with the idea of a voltage-tunable traveling-wave oscillator. His interest persisted throughout the period dur- ing which he studied for his D.Phil. in physics, which he obtained in 1951. He made some theoretical and experi- mental progress toward this end, partly in collaboration with Neville Robinson. In 1950 Rudi left the Admiralty and became associated with the Atomic Energy Research Establishment, but he con- tinued to work at the CIarendon Laboratory on microwave tubes. ~ had hoped that Rudi might come to work at Bell Laboratories, and we had approached him shortly after the close of World War IT. At that time he applied for a visa, which was long in coming. It was granted in 1951, and he came to the Bell Laboratories at Murray Hill, New Jersey on December 27, 1951. There he found the facilities necessary to continue his work on tunable traveling-wave oscillators, and in a short time he had demonstrated electronic tuning over an unprecedented range of ~ 0,000 megahertz a wave- length range from 6.00 to 7.50 millimeters. Rudi's interest in microwave tubes extended over many years, and his contributions were various, including the use of coupled helices, novel means of focusing (Slalom focus-

66 BIOGRAPHICAL MEMOIRS in"), understanding of noise, and the effects of nonreciprocal loss. Eventually, he assumed greater responsibilities, becom- ing director of electronics research in 1955, director of elec- tronics and radio research in 1957, and associate executive director, research, Communication Sciences Division in 1962. In 1958 Rucli and ~ became interested! in communication satellites. He was full of enthusiasm in pushing and augment- ing an idea that hac! originally been mine. We published a paper in 1959 outlining the potentialities of such satellites. Rudi brushed up his spherical trigonometry, a subject of which T was utterly innocent, in order to calculate earth coverage areas. We traveled here and there, trying to get someone to do something. Finally, NASA Aim. The Bell Labora- tories work on the Echo satellite, which was launcher! on August 12, 1960, was carried out in Rudi's department and under his inspiration and direction. He was also deeply in- volved in the Telstar experiment—the launching by AT&T in 1962 of a satellite that carriect live television across the Atian- tic for the first time. But Rucli's influence at Bell Laboratories was wide ant] pervasive. He loved to hear and talk about novel things. He proposed new ideas without any concern for personal creclit. Drafts of technical memoranda were typed on pink paper in those clays. Nothing delighted Rudi more than to send out pink drafts for comment in order to stir up the reader. He said that pink was his favorite color. When what he proposer! proved wrong, he was not afraid to change his mincl. The 20-foot horn-reflector antenna built to receive sig- nals from the Echo satellite was equipped with a low-noise ruby maser amplifier built for Rucli by Derek Scovil. Charles Townes had invented the first maser in 1953, and one of Townes's students and coworkers, Jim Gordon, was aireacly at work at Bell Laboratories. Early in 1960, when the horn reflector antenna was partially completed, Rudi invited

RUDOLF KOMPFNER 167 Townes and his students out to see it. Among the students was Arno Penzias, who was doing a thesis on radio astron- omy. Penzias saw the potential of the antenna for work in this field, and Rudi was fascinated. In 1961 Penzias came to work at Holmclel, ant! two years later Robert Wilson, a radio as- tronomer from Caltech, joiner! him. In using the horn- reflector antenna and the ruby maser amplifier they dis- covered a sky background noise temperature of about 3K. This project to be most significant; it demonstrated the exis- tence of black body radiation left over from the big bang of creation, and in 1978 Penzias and Wilson shared the Nobel Prize for physics. While he was interested in masers in connection with the Echo satellite, Ruth heard a talk at MIT on the superconduc- tivity of niobium at comparatively high temperatures. This led him to think of a superconducting magnetic shield for masers. On his return to Bell Laboratories, he consulted Tec! Geballe and Bernd Matthias, who were interested in these superconducting phenomena. He found that they had been unable to get the metallurgists to make the required alloys. Rudi excited the interest of Earie Schumacher and Morris Tanenbaum of the metallurgy group. This intervention led to a great deal of fruitful work, including the discovery by J. E. Kunzler of the niobium-3 tin alloy that had an unprece- clented property of remaining superconducting in a mag- netic field! of .~8 kilogauss. This work led to today's remark- able superconducting magnets. As a part of his interest in communication satellites, Ructi wonderect whether the advantages of a directive antenna on a satellite couIcl be attained with an electronically controller] array, so that the attitude of the satellite wouldn't have to be controlled. He starter] with the Van Atta array, which could only send a signal back in the direction from which it had come. Working with C. C. Cutler and L. C. Tillotson, the Star

168 BIOGRAPHICAL MEMOIRS array was devisect. This makes it possible to guicle a micro- wave beam down by means of a signal sent from the ground. The laser, which can produce and amplify coherent light, is an optical maser. When T. H. Maiman first used a ruby laser to produce coherent light in 1960, Rucli became con- vince(1 that light waves wouIcl play an important part in com- munication. A complex program was initiatecl, involving many people and many icleas: sequences of lenses in large tubes buries! underground, combinations of mirrors in place of lenses, and gas lenses that macle use of the variation of refractive index of air with temperature. Somewhat later, Rudi playecl a part in shifting the whole course of work in optical communication at Bell Laboratories. Neville Robinson remembers Rudi telling him of work at the British post office laboratories on highly transparent fibers— it was typical that Audi went around looking for icleas. Stewart Miller, a leacler in Bell Laboratories optical research, remembers that a paper written by K. C. Kao came to the attention of Rudi anc! himself. Kao had made measurements that suggested that fibers made of glass or quartz much purer than any then in exis- tence might transmit light waves over long distances with very little loss. Together, Rudi and Miller wrote a memorandum that stimulated Bell Laboratories materials people to work toward such super-transparent fibers. Such fibers have in- deed come into being and into use. After Ructi left Bell Labo- ratories, they played an important part in his work at Oxford. Advances in the held of light-wave communication have in- volved many people, but Rucli playecI a very special role in proposing, arguing, and encouraging that all those con- cernec! valued anc} appreciated. In June of 1973 Rudi retiree! from Bell Laboratories and clivided the rest of his years between Stanford University in

RUDOLF KOMPFNER 169 the winter, where he became professor of applied physics and professor emeritus in 1974, and Oxford, where he was pro- fessor of engineering ant! a professorial fellow of All Souls from 1973 to 1976 anc! an associate member of the college from 1977 onward. At Oxford he did important work on scanning optical microscopes, on the metal coating of optical wires to make them stronger and more durable, and on holo- graphic means for interconnecting single-mode fibers. Colin Shepparc! carried things on while Rudi was away, anal, as everywhere, Rudi was in close and inspirational touch with many, including Don Walsh and Hanz Motz, and also with his students, }. N. Gannaway, T. Wilson, and Peter Hale. Ructi inspired others to have good icleas and never sought creclit for these—or sometimes even for his own. The work at Oxford on scanning optical microscopes, in which the specimen is examined by means of a fine laser spot, was particularly productive. The device exhibited improve- ments in resolution, contrast, and depth of focus and proved particularly valuable in biological studies and in studies of integrated circuits. He hoped to gain further advantages through observing harmonics of the illumination light. At Stanford Ru(li's activities were various. Long before he went there, on April 5, 1966, he had written to Peggy of a Sunday evening meeting with Cal Quate, Marvin Chorlorow, and Joe Pick, and had said that "the project of an acoustical microscope is now under way." On coming to Stanford, he was delighted by the marvelous acoustic microscope work under Quate ant! contributed consiclerably in this area, par- ticularly concerning depth of focus. The work of three graduate students whom RucTi super- visec! shows something of his interest: Celia Yeack worked on a nonlinear acoustic microscope in which the information- bearing signal is a harmonic of the frequency of illumination;

170 BIOGRAPHICAL MEMOIRS Steve Newton worked on a lenseless scanning optical micro- scope in which the sharp definition depends on holographic effects involving light from a pinhole aperture; and Heungsup Park worked on optical picosecond racier using dye lasers a project intenclecl to make it possible to examine the tissue under a person's skin. To his students, Rudi gave encIless time and sage advice and counsel. He insistecT that they try the simplest way thoroughly before trying more complex solutions. He coun- seled them rather than dominating them. He was at once their friend and their hero. His explanations of other faculty members gave the students a deeper and wider unclerstancI- ing of different men anct different approaches. Beyond the work of his students, Rudi took a keen interest in the work of other Stanford faculty members, including Cal Quate, Marvin Chodorow, Tony Siegman, Gordon Kino, and Steve Harris. All welcomed his profitable discussions. He approached problems from a fresh and indiviclual point of view. He wasn't always right, but often enough his fresh approach lee! somewhere. And it was an extraordinary qual- ity of Ructi that, no matter how many projects he had in hand, he always hac! time to discuss and criticize a new one; no one ever found him too busy to listen. Rucli was a member of the committee for Bill Colson's doctor's oral examination on free electron lasers. This was an idea that had originated with John Macley, who had given a complicated quantum mechanical explanation. During Col- son's doctoral examination, Rucli insisted that there must be a classical explanation of the operation of the device. Rudi's last seminar at Stanford was devoted to a simple classical analysis of the original free-electron laser and relater! crevices, some of them much earlier. Anti, at the end of a paper on the same subject written by W. B. Colson and S. K. Ride, the authors stated: "We are particularly grateful for the friend-

RUDOLF KOMPFNER 171 ship and guidance offered by Peggy and Rudi Kompfner, who will remain an inspiration." ' Rudi invited students, faculty, and friends to his home and discussed technical matters—and other things. At a point of great success, he celebrated with the secretary and the technicians as well as the students and faculty. For three years, Rudi conductecl in his garage and home a freshman seminar on how to do research. The students and he proposer! projects. One among these was chosen by vote. Analyses and experiments were then made and moctels were constructed. The three years' projects were: a new form of windmill, an earthquake-resistant builcting on rollers, and a wheelchair capable of mounting a curb. Rudi was clisappointed that in the last year a favorite proposal of his lost by one vote. That was a very small swim- ming pool in which one could swim Tong distances against a current of water, without moving at all with respect to the pool. Rudi's versatility and originality lect to a number of in- genious icleas and contraptions. When a Picturephone terminal was installed in his office, he put an excellent like- ness of himself in front of the camera tube, so that those who called him fount! him remarkably quiet and attentive. In his home, Rucli built a set of swinging cat doors. When he found that a raccoon got in and stole the cat's foot! he arranged a complicated linkage of strings, pulleys, and hooks by means of which an intruder could be exclu(lecl or trapped. Later, Rucli feel an abandoned baby raccoon, which became a pet, and built a marvelous house for it and arranged an aerial tramway to carry food to it on winter clays. For several years, Ructi devotect a great clear of time and ingenuity toward producing four-legged chairs and tables 1. W. B. Colson and S. K. Ride, "A Laser Accelerator," Applied Physics, 20( 1979):65.

172 B IOGRAPH I CAL MEMOI RS that would rest steadily on an uneven surface. Alas, a search revealed a number of patents. Nonetheless, Rucli finally did construct a table and a chair of his own design—operable, but not objects of great beauty, and perhaps of marginal utility. A different invention, a sort of mat or coaster to make the port and Madeira decanters at All Souls slide more easily on the table top, has been an unqualified success. Rudi's analysis of the noise level in the clining room of the faculty club at Stanford was sound. He arguer! that cliners talk loudly enough to be heart! across the table against the voices of other speakers. He worked out a quantitative theory. The Stanford dining room was so noisy, he showed, because diners shouted vainly across very wide tables in an effort to make themselves heard amid the din of the futile efforts of others to converse at nearby tables. Eventually, the tables were maple narrower, the diners at the same table could hear one another, and the hubbub sub- sided. ~ have not been able to trace the change clirectly to Rudi's insightful work. Rudi's life was cut short in the full exercise of his powers and in full enjoyment of his family, his friends, anct his world. He must have seen something of himself and of Peggy in his children, who acquirer! their qualities more by gooc! example than in any other way. He liver! to see his claughter married and to wheel his son's son around Palo Alto. As he enjoyed all good things, ~ am sure that Rudi must nave valued the many honors that came his way, but he was a modest man. His students told me that before leaving on a trip, Rucli usually told them where he was going. When he didn't, they felt that he must be going to receive some new honor, and so it prover] to be. Ru~li's moclesty a(ldecl to the real joy that all his friends felt for him in his successes. ~ am grateful to have had this

RUDOLF KOMPFNER 173 opportunity to write good and true things about him that he would not have said himself. But I wish to tell in words that Rudi himself wrote the true reward that his career brought him: THE FEELING ONE EXPERIENCES when he obtains a new and important insight, when a crucial experiment works, when an idea begins to grow and bear fruit, these mental states are indescribably beautiful and exciting. No material rewards can produce effects even dis- tantly approaching them. Yet another benefit is that an inventor can never be bored. There is no time when I cannot think of a variety of problems, all waiting to be speculated about, perhaps tackled, perhaps solved. All one has to do is to ask questions, why? how?, and not be content with the easy, the superficial answer.

174 BIOGRAPHICAL MEMOIRS BIBLIOGRAPHY 1940 Velocity modulation: Results of further considerations. Wireless Eng., 17:478- 89. 1941 Method of correcting the spherical error of electron lenses, es- pecially of those employed with the electron microscope. Philos. Mag., 32:410-16. 1942 Transit-time phenomena in electronic tubes. Wireless Eng., 19:2-6. Current induced in an external circuit by electrons moving between two plane electrodes. Wireless Eng., 19:52-55. With W. H. l. Fuchso. Space-charge effects in velocity-modulated electron beams. Proc. Phys. Soc. (London), 54: 135-50. Velocity-modulating grids: an investigation of their action by means of analysis and graphical methods. Wireless Eng., 19: 158-61. 1946 The traveling-wave valve. New amplifier for centimeter wave- lengths. Wireless World, 52:369-72. With J. Hatton, E. E. Schneider, and L. A. G. Dresel. The transmis- sion line diode as noise source at centimeter wavelengths. I. Inst. Elect. Eng., 93 Part 3A: 1436-42. 1947 The traveling-wave tube as amplifier at microwaves. Proc. IRE, 35: 124-27. The traveling-wave tube. Wireless Eng., 24:255-66. 1949 With D. K. C. MacDonald. Fluctuation phenomena arising in the quantum interaction of electrons with high-frequency fields. Proc. IRE, 37: 1424-26.

RUDOLF KOMPFNER 175 1950 On the operation of the traveling-wave tube at low level. I. Br. Inst. Radio Eng., 10:283-89. 1951 With A. Leemans. Heating in vacua by an external radiation source. Vacuum, 1:203-4. With F. N. H. Robinson. Noise in traveling-wave tubes. Proc. IRE, 39:918-26. 1952 Traveling-wave tubes. Rep. Prog. Phys., 15:275-327. . 1953 Backward-wave oscillator. Bell Lab. Rec., 31 :281-85. With N. T. Williams. Backward-wave tubes. Proc. IRE,41: 1602-11. 1954 Nonreciprocal loss in traveling-wave tubes using ferrite attenua- tors. Proc. IRE, 42:1188-89. 1956 Ferrite attenuators for traveling-wave amplifiers. Bell Lab. Rec., 34:361-65. With I. S. Cook and C. F. Quate. Coupled helices. Bell Syst. Tech. J., 35:127-78. Some recollections of the early history of the traveling-wave tube. Yearb. Phys. Soc. (London):30-33. 1957 With i. S. Cook and W. H. Yocom. Slalom focusing. Proc. IRE, 45: 1517-22. 1958 With C. F. Quate and D. A. Chisholm. The reflex klystron as a negative resistance type amplifier. IRE Trans. Electron Devices, ED-5: 173- 79.

176 BIOGRAPHICAL MEMOIRS 1959 With I. R. Pierce. Transoceanic communication by means of satel- lites. Proc. IRE, 47:372-80. 1961 With A. Yariv. Noise temperature in distributed amplifiers. IRE Trans. Electron Devices, ED-8:207-11. The sources of noise in the cyclotron-wave amplifier. Nachrichten- technische Fach., 22:403-5. 1962 With I. P. Kaminow and W. H. Louisell. Improvements in light modulation of the traveling-wave type. IRE Trans. Microwave Theory Tech., MTT- 10:311- 13. 1963 With A. B. Crawford, C. C. Cutler, and L. C. Tillotson. The re- search background of the Telstar experiment. Bell Syst. Tech. J., 42:747-64. With C. C. Cutler and L. C. Tillotson. A self-steering array re- peater. Bell Syst. Tech. I., 42:2013-32. 1964 The invention of the traveling-wave tube. San Francisco: San Fran- cisco Press. Off-axis paths in spherical mirror interferometers. Appl. Opt., 3:523. 1965 The development of the traveling-wave tube. Endeavour, 24~921: 106-10. Optical communications. Science, 150~3693~: 149- 55. 1966 Beitrage zur Erforschung und Nutzbarmachung von Weltraum- phanomenen. Elektrotech. Maschinenbau, 83~9~:495-500.

RUDOLF KOMPFNER 177 1967 Windows to space (from 10~° hz up). In: Commercial Utilization of Space (13th Annual Meeting of the American Astronautical Society), p. 160. Electron devices in science and technology past and future. IEEE Spectrum, 4:47-52. Foreword. In: J F. Gittens, Power Traveling Wave Tubes, p. v. New York: American Elsevier. Foreword. In: Peter Lindsay, An Introduction to Quantum Mechanics for Electrical Engineers. New York and Great Britain: McGraw- Hill. 1972 Optics at Bell Laboratories optical communications. Appl. Opt., 11(11):2412-25. 1975 Recent advances in acoustical microscopy. Br. T. Radiol., 48:615. 1976 With R. A. Lemons. Nonlinear acoustic microscopy. Appl. Phys. Lett., 28:295. The invention of traveling-wave tubes. IEEE Trans. Electron De- vices, 23:730. With H. Park. High-resolution heterodyne coincidence detection of optical pulse streams. Int. I. Electron., 41:317.

178 BIOGRAPHICAL MEMOIRS PATENTS 1957 2,804,511. Traveling Wave Tube Amplifier. (Issued 8/27/57.) 2,811,673. Traveling Wave Tube. (Issued 10 / 29 / 57.) 2,812,467. Electron Beam System. (Issued 11 / 5 / 57.) 1958 2,834,908. Traveling Wave Tube. (Issued 5 / 13 / 58.) 2,857,548. Electron Beam System. (Issued 10/ 21 / 58.) 2,860,278. Non-reciprocal Wave Transmission. (Issued 11/ 11/ 58.) 1959 2,867,744. Traveling Wave Tube. (Issued 1 /6/ 59.) 2,879,442. Direct View Storage Tube. (Issued 3/24/59.) 2,891,191. Backward Wave Tube. (Issued 6/ 16/59.) 2,895,071. Traveling Wave Tube. (Issued 7/ 14/ 59.) 2,899,597. Apparatus Utilizing Slalom Focusing. (Issued 8/ 11/ 59.) 2,911,544. Non-reciprocal Wave Transmission Device. (Issued 11/3/59.) 2,916,657. Backward Wave Amplifier. (Issued 12/8/59.) 1960 2,922,917. Non-reciprocal Elements in Microwave Tubes. (Issued 1 /26/60.) 2,925,565. Coaxial Couplers. (Issued 2/ 16/60.) 2,933,640. Pulse Coincidence Detecting Tube. (Issued 4/ 19/60.) 2,939,034. Electron Gun for Slalom Focusing Systems. (Issued 5/31 /60.) 2,949,558. High Efficiency Velocity Modulation Devices. (Issued 8/ 16/60.) 2,955,223. Traveling Wave Tube. (Issued 10/ 4/ 60.) 1961 2,972,081. Low Noise Amplifier. (Issued 2 / 14/ 61.) 2,972,702. High Frequency Amplifier. (Issued 2 / 21 / 61.) 2,985,790. Backward Wave Tube. (Issued 5/23/61.) 3,012,204. Elastic Wave Parametric Amplifier. (Issued 12 / 5 / 61.)

RUDOLF KOMPFNER 179 1962 3,021,490. Parallel High Frequency Amplifier Circuits. (Issued 2/ 13/62.) 3,021,524. Scanning Horn-Reflector Antenna. (Issued 2 / 13 / 62.) 3,041,559. Microwave Filter. (Issued 6/ 26/ 62.) 3,051,911. Broadband Cyclotron Wave Parametric Amplifier. (Issued 8/ 28/ 62.) 3,067,379. High Frequency Generator. (Issued 12 / 4 / 62.) 1964 3,133,198. Traveling Wave Light Modulator. (Issued 5 / 12 / 64.) 3,151,325. Artificial Scattering Elements for Use as Reflectors in Space Communication Systems. (Issued 9129164.) 3,154,748. Detector for Optical Communication System. (Issued 10/27/64.) 1965 3,188,155. Beam Collector with Auxiliary Collector for Repelled or Secondarily-Emitted Electrons. (Issued 618165.) 3,196,438. Antenna System. (Issued 7 / 20/ 65.) 3,224,331. Sinusoidal-Shaped Lens for Light Wave Communica- tion. (Issued 12/21 / 65.) 3,224,330. Transmission of Light Waves. (Issued 12/21 / 65.) 1966 3,253,226. Optical Maser Amplifier. (Issued 5124166.) 3,273,151. Antenna System. (Issued 9/ 13 / 66.) 3,285,129. Triple Element S-Lens Focusing System. (Issued 11/ 15/66.) 1967 3,317,861. Spherical Reflector Elastic Wave Delay Device with Planar Transducers. (Issued 512167.) 1969 3,454,768. Intracavity Image Converter. (Issued 7/8/ 69.)

180 BIOGRAPHICAL MEMOIRS 1970 3,490,021. Receiving Antenna Apparatus Compensated for An- tenna Surface Irregularities. (Issued 1 / 13 / 70.) 3,503,070. Anti-Doppler Shift Antenna for Mobile Radio. (Issued 3/24/70.) 3,503,671. Multiple-Pass Light-Deflecting Modulator. (Issued 3/31/70.) 3,503,671. Multiple-Pass Light-Deflecting Modulator. (Issued 3/31 /70.) 3,506,331. Optical Waveguide. (Issued 4/ 14/ 70.) 3,506,834. Time Division Multiplex Optical Transmission System. (Issued 4/ 14/ 70.) 3,515,455. Digital Light Deflecting Systems. (Issued 6/2/70.) 3,520,584. Method and Apparatus for Obtaining 3-Dimensional Images from Recorded Standing Patterns. (Issued a 7/ 14/70.) 3,530,298. Optical Heterodyne Receiver with Pulse Widening or ~ , Stretching. (Issued 9/22/70.) 3,532,889. Light Communication System with Improved Signal- to-Noise Ratio. (Issued 10/ 6/ 70.) 1977 4,012,950. Method of and Apparatus for Acoustic Imaging. (Issued 3/ 15/ 77.)