Life and Work of Rolf Wideröe by © Pedro Waloschek,     => Contents

Chronological Survey

Entries emphasized in italics refer directly to the life and work of Rolf Wideröe (RW). I have included events, which could have had relevance for Wideröe's life. They were originally collected as editing aids and I make no claims for completeness. P.W.


1902-07-11 RW born in Oslo.

1905 Nobel prize to Philipp Lenard.

1906 Nobel prize to Joseph J. Thomson (the electron).

1911 Ernest Rutherford discovers the atomic nucleus.

1918 Nobel prize to Max Planck (quanta).

1918 Rutherford: first disintegration of an atomic nucleus.

1920-summer RW's school-laving exams at the Halling School in Oslo.

1920-autumn RW begins studies in electrical engineering at Karlsruhe Technical University.

1921 Nobel prize to Albert Einstein.

1922 Nobel prize to Niels Bohr.

1922-01 1 $ = 192 German Mark.

1922-04-01 J. Slepian (Westinghouse) applies for a US-Patent `XRay Tube' presenting the first rudimental ideas for a betatron [Sl27]; published on Oct. 11, 1927.

1923-03-15 RW's first (preserved) notes in a copy-book including a sketch for a betatron [Wi23]. (More drawings and computations in other copy-books.)

1923 RW's one-month practical work in a factory for electric motors in Strasbourg.

1923? RW asks an agency in Karlsruhe to submit a patent on the betatron. It was probably never submitted. (The agency's building was completely destroyed during the War.)

1923-11-15 1 $ = 4,200,000,000,000 German Mark.

1924-03-12 G. Ising: First known proposal for the acceleration of charged particles with electromagnetic `travelling waves' [Is24].

1924 RW obtains his diploma in electrical engineering at Karlsruhe Technical University. His thesis was on `Voltage Distributions in Chains of Isolators'.

1924 RW's first publication, on `Inflation in Germany' [Wi24].

1925-summer RW's `practical work' in the locomotive factory of the Norwegian State-Railways. He also completes 72 days of military service in Norway.

1925-autumn RW proposes the `ray-transformer' (betatron) as thesis for a doctor-degree in electrical engineering in Karlsruhe. Prof. Schleiermacher (theory) agrees, Prof. Gaede (physics) refuses. Gaede assumes that the achievable vacuum would not be sufficient (residual gas would absorb the circulating particles.

1925-End RW studies Lenard's publications [Le18] on the absorption of electrons in matter and comes to the conclusion that Gaede's assumptions were wrong.

1926-05 RW proposes the construction of the ray-transformer to Prof. Rogowski in Aachen.

1926-06... RW starts working and studying at the Technical University in Aachen (RWTH) under Prof. Rogowski. Tests of the first ray-transformer (betatron) are unsuccessful due to surface charges in the tube and lack of stabilizing forces of the magnetic steering field.

1927-autumn RW changes over to building a small linear accelerator. He succeeds in accelerating ions to 50,000 volts, having only 25,000 volts at his disposal. It is the first drift-tube ever operated, demonstrating the principle of acceleration of charged particles with high frequency alternating voltages.

1927-autumn Steenbeck starts working with Rüdenberg at Siemens Halske company in Berlin.

1927-10-11 Slepian's US-Patent (Westinghouse) `X-Ray Tube' is made public [Sl22].

1927-11-28 RW finishes all examinations and obtains his `Dr.-Ing.'-degree in Aachen. The successful linac with one drift-tube is the main subject of his thesis, the ray-transformer (betatron) is explained in Section IV including the `2:1-ratio' between accelerating and steering fields, which is later called the `Wideröe-relation' for betatrons.

1927 Breit and Tuve (Carnegie Institution USA) perform interesting tests with a simple betatron [Br27]. Their efforts are unsuccessful, but very promising.

1928 RW's dissertation is published in the `Archiv für Elektrotechnik' [Wi28].

1928-03 RW moves to Berlin. He obtains a position at AEG's transformer factory (Berlin Oberschöneweide) following a recommendation from Rogowski. RW develops safety-relays for short circuits in power lines. By the end of 1932 he has applied for 42 German patents and 2 US patents, all for AEG.

1929 Walton reports on tests of a simple betatron and a linac built at Cambridge, following suggestions by Rutherford. None of these devices work. However, Walton includes very important deductions and formulas in his publication, establishing for the first time precise stability conditions for circular orbits in betatrons [Wa29].

1930 Breit, Tuve, Hafstad and Dahl develop several very interesting high voltage generators at the Carnegie Institution in Washington DC.

1930 Lawrence and Edlefsen publish the basic ideas for a `cyclotron' [La30].

1931-01 Lawrence communicates the successful operation of his first cyclotron (13 cm diameter, 80 keV) to the American Physical Society [La31b].

1931 Lawrence and Sloan construct and operate a linac following Wideröe's ideas. It has 15 drift-tubes and reaches 1,26MV [La31a]. Other linacs follow.

1931 Van de Graaff communicates to the American Physical Society the successful operation of his first electrostatic generator using a silk-band [Gr31] with which he achieves about 1,5MV. Several similar installations follow.

1932 Cockroft and Walton [Co32] succeed in obtaining the first nuclear disintegrations using artificially accelerated particles (400 keV cascade generator). Lawrence confirms this results a few months later with a 1.2-MeV-cyclotron.

1932-12 Lawrence successfully operates a 69-cm-cyclotron for 4,8 MeV.

1932-12 RW moves from Berlin to Oslo, scared of the economic crisis in Germany and of Hitler's rise to power.

1933-03-01 Rüdenberg and Steenbeck (Siemens-Schuckert-Werke, Berlin) apply for a German patent [Ru33] which includes a rough stability condition for a betatron (published on Febr. 4, 1938). As is usual at that time, no references to previous work are given. When the patent is submitted Rüdenberg has already emigrated to Great Britain to escape anti-semitism.

1933 Ising publishes an article in the Annual-Report of the Swedish Physical Society [Is33] in which Wideröe is wrongly described as `German' (page 34).

1933-04-01... RW builds protective relays for the company N. Jacobsen in Oslo. By 1937 he has applied for ten Norwegian patents on relays.

1933-autumn RW's driving holiday in a Ford-A. From England (with his friend Torwald Torgersen), to France, Spain and Germany. RW also tries to sell his relays. He has no success and experiences severe health problems.

1934-02 RW meets Ragnhild Christiansen (born Jan. 3, 1913), in Ms. Fearnley's dance academy in Oslo.

1934-11-14 RW and Ragnhild are married.

1935-03-07 Steenbeck (Siemens) applies for a second patent in Germany (also in Austria) for a betatron [St35]. Besides the rough stability condition, this patent also includes (as claim) the 2:1-relation between steering and accelerating field.

1935-Middle Ragnhild Wideröe works for a short time (unofficially) at Jacobsen's and helps RW build and test relays.

1936 Jassinski: interesting paper on betatrons [Ja36].

1936-03-06 Steenbeck (Siemens) applies for a betatron-patent in the USA [St36] (published on Dec. 28, 1937).

1936-06-25 RW's daughter Unn is born in Oslo.

1937 RW's chance discovery of Slepian's US patent [Sl27].

1937 ?? RW's report on relays in Copenhagen (Nordish Engineer's meeting). Ing. Styff (from NEBB) is present.

1937-04... RW starts working for the transformer factory `National Industri', in Oslo, a subsidiary of Westinghous USA. Very boring activity!

1938-12-20 RW's son Arild is born in Oslo.

1937-12-28 Steenbeck's US-Patent on betatrons is published [St35].

1938-autumn The `Physics Association' is founded in Oslo.

1939-summer First edition of the Norwegian review `Fra Fysikkens Verden' published by the Physics Association.

1939-09-01 German troops invade Poland. Great Britain and France declare war against Germany.

1939-10 Lawrence operates his 150-cm-cyclotron for 19MeV deuterons.

1939-11 Nobel prize to Lawrence.

1940-04-09 German troops occupy Norway.

1940-05 Touschek is expelled from Vienna University as `non Aryan'. Takes several jobs. He helps Arnold Sommerfeld revise Vol. 2 of the famous book `Atombau und Spektrallinien'.

1940-06... RW starts working for `Norsk elektrisk og Brown Boveri' (NEBB) in Oslo, planning and building power plants.

1940-10-15 Kerst (Univ. of Illinois) reports on successful tests of a 2MeV betatron [Ke40a]; Wideröe and Walton are quoted, Steenbeck is not.

1940-11-13 Kerst (`on leave at General Electric') applies for a US-patent for a betatron [Ke40b].

1940-11-22 Kerst (`on leave at General Electric') reports on the successful operation of his 2,3-MeV-betatron [Ke40a].

1940-End Touschek goes to Hamburg, R&D at the `Studiengesellschaft für Elektronengeräte' (Philips). He is allowed to hear (illegally) lectures by Professors Lenz und Jensen at the University of Hamburg.

1941? General Electric asks Siemens for a licence to use Steenbeck's betatron patent [Ka47] [St77].

1941-04-18 Kerst (General Electric) submits his famous paper on the operation of the 2,3-MeV-betatron [Ke41a] to Phys. Rev. He reports on gamma rays equivalent to about 1 gr of radium. Wideröe's, Walton's und Jassinski's papers are referred to (according to RW, on a request by the editor), Steenbeck's patent is not. In a subsequent paper Kerst and Serber describe the corresponding theory [Ke41b]. According to Professor W. Paul, this is the last issue of the Phys. Rev. which arrives legally in Germany; it arrives illegally in occupied Norway (Trondheim), mailed as an ordinary letter.

1941-09-03 RW's son Rolf is born in Oslo.

1941-autumn RW hears Roald Tangen's seminar at the `Physics Association' in Oslo, in which he reports on the Kerst-betatron. RW realizes that it is possible to construct a ray-transformer and starts working on the subject again.

1941-12-06 According to Max Steenbeck [St77], Siemens licensed General Electric to use his patents the day before the Japanese attack on Pearl Harbor.

1941 End Konrad Gund (X-ray engineer) begins planning a 6MeV-betatron (550 Hz) for medical purposes at the `Siemens Reiniger Werke' in Erlangen, prompted by Steenbeck.

1942-02 Steenbeck's publication in `Electronics', February issue 1942, pp.2223.

1942-?? RW's brother Viggo (born 1904, a pioneer of Nowegian air transport) is imprisoned in Germany after trying to help resistance members to escape from Norway to England.

1942-07 According to Kaiser [Ka47], Siemens applies for a betatron patent, `Akt. 151 465, VIII c/211g'.

1942 Kerst reports on the operation of a 20-MeV-betatron and introduces the name `betatron' [Ke42].

1942-09-15 RW submits a paper on betatrons to `Archiv für Elektrotechnik' [Wi43b], describing his own and Kerst's work, as well as some new ideas on betatrons from 10 to 1000MeV and a detailed design for a 100MeVbetatron, including cost estimates.

1942-09-29 The US-patent `betatron' of Kerst [Ke40] is published.

1942-End Touschek moves to Berlin, works at `Opta Radio' on the development of Braun-tubes, the predecessors of the klystron-valves used later on for radar applications. He also works for Dr. Egerer, the editor of the `Archiv für Elektrotechnik' and sees Wideröe's proposal for a betatron. He finds a mistake in the relativistic calculations and writes to RW, who asks him to join him (quoted in [Am81] p. 5). (RW can not remember these letters; there seem to be no copies preserved.)

1942-12-15 Steenbeck, Dr. Kurt Bischoff, Dr. J. Patzeld und (Dr.) Konrad Gund: meeting on the new betatron project, following ideas of Jassinski [Ja36], quoted in [Ka47].

1943-01-31 Capitulation of German troops in Stalingrad.

1943-spring Visit of (2 or 3) German Air Force officers to RW at NEBB in Oslo. Two days later RW is taken to Berlin by air. It is implied that they would help get his brother Viggo out of prison. According to RW, this is why he accepts to go to Germany. He is to build first a small betatron for 15MeV in Hamburg and some larger ones later on. This is to be done as `compulsory labour' with the agreement of NEBB Company (BBC).

1943-05-08 Prof. Jensen discusses with Schmellenmeier plans to build a 1,5-MeV-`Rheotron' (Jensen had previously agreed this with Prof. F. Houtermans).

1943 Steenbeck reports in `Naturwissenschaften' on a 1,8MeV betatron (a secret project at Siemens) which had already been in operation in 1935/36 and explains his early ideas and patents on betatrons [St43].

1943-07-12 RW submits a second article on betatrons to `Archiv für Elektrotechnik', which includes ideas for a 200-MeV-machine. It is not published.

1943-07-15 RW applies for his first patent on betatrons in Germany on `Injection' (No. 889659), accepted on Jul. 30, 1953, published on Sept. 14, 1953. RW receives legal advice from his friend Dr. Ernst Sommerfeld (Berlin), the son of Arnold Sommerfeld, for all his German patents .

1943-07-25 (to 1943-08-04) Operation `Gomorrha': Five allied bombings on Hamburg cause great destruction. During these days RW is not in Hamburg.

1943-08-05 The `Reichsforschungsrat' (German Research Council) orders a `Rheotron' (betatron) from Schmellenmeyer (Berlin) [Sw92].

1943-08... RW starts working in Hamburg; rents a room. Back and forth between Hamburg and Oslo. Occasional visits to Berlin. His family remains in Oslo. His salary is paid to his wife in Oslo. RW gets in touch with Hollnack and Richard Seifert (trustees of the German Aviation Ministry) und with physicist Dr. Kollath.

1943-? RW meets Bruno Touschek for the first time at the home of Prof. Lenz. Touschek starts working with RW, makes theoretical calculations for the betatron, i.e. on radiation losses (also for an already envisaged 200-MeV-machine) and orbit studies, using the Hamilton formalism.

1943-08-End RW takes a vacation in Tuddal near Telemarken (Southern Norway) and has the idea for `storage rings' whilst lying on the lown behind his hotel. These are expected to provide higher energy and improved collision rates for nuclear reactions.

1943-09-02 RW applies for a 2nd betatron-patent in Germany on `electrical lenses', No. 927590, published Dec. 5, 1953.

1943-09-02 RW applies for a 3rd betatron-patent in Germany on `premagnetisation', No. 932194, published Aug. 25, 1953.

1943-09-04 RW applies for a 4th betatron-patent in Germany on `opposite magnetisation', No. 925004, published on March 10, 1955.

1943-09-08 RW applies for a German patent on `storage ring collider'; No. 876279 [Wi43a], published on May 11, 1953.

1943-09 RW meets the editor of `Archiv für Elektrotechnik', Dr.Egerer, as well as Dr. Schiebold (the physicist promoting `death-X-rays' for shooting down aeroplanes) at Hollnack's.

1943-10-01 RW's report (unpublished) on the development of betatrons, including many references [Wi43b].

1943-10-05 RW applies for a 5th betatron-patent in Germany, on `magnetic lenses', No. 932081, published Nov. 10, 1955 (addendum to patent No. 927,590)

1943-11 Begin of design and construction of a 15-MeV-betatron at C.H.F.Müller-company (Philips) in Hamburg. Iron plates supplied by Seifert's factory, cathodes by Boersch. There is a detailed report with drawings by `Dr.Müller' at the ETH-Library [Mu43].

1943-11-06 RW proposes (report from Oslo) a `fast schedule' for building betatrons in Germany. It includes: a) a 15-MeV-betatron in Hamburg, b) a 200-MeV-betatron and c) a future test-laboratory in Groß-Ostheim. He mentions that work on the 15-MeV-machine has already been started at C.H.F.Müller company in Hamburg [Wi43c].

1944 RW applies for five further betatron patents in Germany.

1944-04 Gund's 5-MeV-betatron is successfully operated for the first time at Siemens in Erlangen. Machine parameters are measured and first experiments are performed (in Erlangen) by H. Kopfermann and W. Paul (both from Göttingen). RW is apparently unaware of these activities.

1944-04-27 (to 1944-04-29) Visit to BBC in Weinheim. Minutes by RW dated May 1, 1944 [Wi44]: Meyer-Delius (BBC) reports on Bothe and Gentner constructing a betatron with extracted beam. (Gentner perhaps confused with Dänzer, who planned with Bothe a betatron for 10 MeV, as reported by W. Paul [Pa47], p. 51.)

1944-04-29 `Secret' minutes by Meyer-Delius on a BBC-meeting in Heidelberg (present: Seif(f)ert, Wideröe, Meyer-Delius, Kade, Weiss, Kneller) to discuss the construction of a large betatron following the `megavolt procedure' [Me44]. Seif(f)ert had passed a `provisional order' from the German Aviation Ministry for BBC to start R&D for such a machine.

1944-06-13 Start of V1 flying-bomb attacks on London.

1944-summer The 15-MeV-betatron is successfully operated for the first time in Hamburg.

1944-08 According to Kaiser [Ka47], there is a `contract with BBC Heidelberg to built a 200-MeV-betatron' (?). (According to RW there was no BBC representation in Heidelberg at that time. One of the directors lived there, and a few meetings were held in Heidelberg; see [Me44]).

1944... Touschek writes several reports on the theory of betatrons. Some of them are preserved at the ETH-Libr. Zurich.

1944-09-06... German V2-rocket attacks on London and Anvers.

1944-autumn Work on the Hamburg betatron is continued by Kollath and Schumann.

1944-10 Another BBC meeting in Heidelberg to discuss the 200-MeV-betatron (according to Kaiser [Ka47]), present Dr.Meyer-Delius (Dir. BBC), Otto Weiss, Dr. Helmut Boecker plus Wideröe und Kollath representing the `Megavolt-Test-Laboratory' (MVA).

1944-autumn The Rheotron-Laboratory of Schmellenmeier is moved from Berlin to Oberoderwitz in Oberlausitz (near the Czechoslovak border).

1944-autumn RW participates to a meeting at the Kaiser-Wilhelm-Institut in Berlin (chairman Heisenberg), where, among other matters, the betatron is declared useless for war purposes. However, it is recommended that its development for medical applications and research in nuclear physics should continue.

1944-11 RW visits the betatron laboratory at `Siemens-Reiniger-Werke' in Erlangen after which Siemens appear to have switched to 50-Hz-operation of betatrons (the first one was operated at 550 Hz).

1944-End Touschek in Gestapo jail in Hamburg-Fuhlsbüttel, after being discovered reading foreign magazines in the Hamburg Chamber of Commerce. He is, however, allowed to continue working. RW and colleagues provide Touschek with his books, some food and cigarettes, but cannot get him free. In jail Touschek develops a theory of radiative dumping for electrons circulating in betatrons [Am81].

1945-Beg. End of R&D for a 200-MeV-betatron at BBC, according to the Kaiser-report [Ka47] p. 8.

1945-02-13 Allied air attack destroys Dresden.

1945-02 Werner von Braun leaves Peenemünde with 500 engineers and 14 tons of documents. They transfer south [Jo79] and hide the documents in a mine in the Harz.

1945-02(?) Touschek to be transferred from Hamburg jail to Kiel. During the march he falls, is shot by a guard, and left for dead. He recuperates and is again imprisoned in Altona jail [Am81].

1945-02 RW applies for three more German patents on betatrons.

1945-02(?) Following instructions from the German Aviation Ministry the Hamburg-betatron is transferred to Kellinghusen, near Wrist (between Bad Bramstedt and Itzehoe, 40 km north of Hamburg) [Gi93]. It works as well as it did in Hamburg.

1945-03-28 The Rheotron-Laboratory is transported by lorry to Burggrub, a small town in `Kreis Ebermannstadt' (passing close to Dresden in flames) between Bamberg and Bayreuth in High-Franken ([Sw92] p. 122).

1945-03 RW receives a final payment for his work from Hollnack (38.000 RM plus 38.000 NKr) and returns to Oslo by train with several stops caused by sabotage. He had his documents cleared in Copenhagen.

1945-03 RW's brother Viggo is freed by American troops near Darmstadt.

1945-03-27 Last of 2,800 V2 fired [Jo78] [Jo79].

1945-03-29 Last of 10,500 V1 lounched [Jo78] [Jo79].

1945-04-14 US-Troops free Richard Gans and take over the Rheotron-Laboratory of Schmellenmeier in Burggrub.

1945-04-30 Hitler commits suicide in the Führerbunker.

1945-05 German troops retreat from Norway.

1945-05-03 British troops occupy Hamburg without a fight.

1945-05-07 Unconditional surrender; end of the War.

1945-05-09 Quisling surrenders to Norwegian Police.

1945-05 Hollnack makes arrangements with the British troops. Kollath, Schumann and Touschek can continue working with the 15MeVbetatron in Kellinghusen.

1945-05-23 RW is arrested in Oslo (Ilebu jail), accused of having worked on the develoment of V2-rockets. In jail he writes a detailed report on the Hamburg betatron.

1945-06? Touschek is liberated from prison by the British authorities. He goes to Kellinghusen where he writes several additional theoretical reports on the betatron [To45].

1945-07-09 G. Randers visits RW in prison to clarify his activities during the War. On the same day there is a solar eclipse over Europe.

1945-07-09 RW is freed, after 48 days, following an intervention by `a friend of Odd Dahl' (G. Randers?) and probably other prominent scientists [Da81].

1945-07... Until the spring of 1946 RW has no job in Oslo, no money, no passport. NEBB stops paying his salary. RW develops the theory of the gigator (the `synchrotron').

1945-08-06 Atomic bomb dropped on Hiroshima.

1945-09-05 McMillan presents the synchrotron-principle [Mc45].

1945 Veksler presents the synchrotron-principle [Ve45].

1945-11 An ad hoc commission of experts to provide a professional assessment of RW is formed in Oslo.

1945-12-11 Kollath reports on the betatron tests in Wrist [Ko45].

1945-12 Conclusion of betatron-tests in Wrist. The 15-MeV-betatron is then transported to the Woolwich Arsenal near London. Kollath helps to run it there. It is used to X-ray iron plates after which all trace of this machine vanishes, it has probably been dismantled and scrapped.

1946-01-31 RW applies for a Norwegian patent in which the synchrotron principles are described with many details [Wi46]. Privately submitted through an agency (not for BBC), the `Tandbergs Patentkontor' Oslo.

1946-02-14 An experts' report on the activity of RW during the War is presented to the Norwegian Police [Hy46]. It is evidently inspired by the overheated patriotic feelings of the time and includes assumptions (in part incorrect, due to lack of information) which are not taken into account by the Authorities [Wa94].

1946-Beginn. Touschek moves to Göttingen, attracted by the installation of Gund`s 6MeVbetatron and starts his diploma-thesis.

1946-spring RW is given a provisional Norwegian passport for one month.

1946-05-15 RW applies for a Swiss patent on the principles of the synchrotron (253582).

1946-? Goward and Barnes succed testing a first synchrotron.

1946-Easter RW spends approximately two weeks in Baden. Professor Paul Scherrer, a friend of Theodor Boveri, recommends RW for a position at BBC-Basel. RW starts designing a betatron for 31 MeV with H. Hartmann. There is an agreement on future work on betatrons at BBC.

1946-summer Touschek obtains his title of `Diplomphysiker' in Göttingen with a thesis on the theory of the betatron, supervised by R. Becker und H. C. Kopferman [Am81].

1946-08-01... RW starts working for BBC, Baden (CH) and receives a salary as of August 1. In need of money, he later sells the rights for the Norwegian synchrotron patent to BBC (for about 10.000sfr) with the legal advice of Ernst Sommerfeld and Otto Lardelli (BBC).

1946-08-19 RW and his family move from Oslo to Zurich. By boat to Anwers with their car. They initially move into a flat in Zurich.

1946-10 RW is called back to Norway to take part in a judicial hearing. He stays with his parents.

1946-11-02 RW accepts a `forelegg' with minor allegations about his behaviour during the War [Wa94] (it includes a fine and confiscation of most of the last instalment of money received from Hollnack). By doing so he avoids a court trial. He is immediately authorised to return to Zurich, with a passport valid only for Zurich.

1946-11 RW returns to Zurich and continues working on the construction of the BBC-betatron for 31 MeV electrons.

1946-11... Up to 1986 a total of 78 BBC-betatrons are installed worldwide. Their main use is for medical therapy (cancer treatment), but some are used for materials tests.

1947-01 Hermann F. Kaiser from the US Naval Research Lab. Washington DC reports on European developments on induction accelerators [Ka47]: Gund's and Wideröe's work is described. One patent application from Siemens and seven from `C.H.F.Müller, Dr.Müller' are mentioned (1942-1945). Kaiser considers RW's 200 MeV project as the most promising of the time in Europe and provides many details, including cost estimates.

1947... RW and his family live in Zurich until 1948, not very comfortably, freezing... RW is working at BBC in Baden. Ragnhild complains that he works too hard.

1947-03 RW obtains an ordinary Norwegian passport, valid for all countries, and starts travelling. He keeps accurate notes of all trips, conferences attended, visits and meetings.

1947-04-21 RW submits a short comment to `Journ. of Appl. Phys.' correcting some statements contained in the Kaiser-Report [Wi47a].

1947-05-22 Rudolf Kollath and Gerhard Schumann submit their article describing the 15-MeV-betatron and its performance to `Archiv f. Elektrot.' [Ko47]. It includes important information and many details.

1947-08 Gund's 5-MeV-betatron is successfully operated in Göttingen. Up to 70% of the electron beam is extracted following a `scattering' procedure [Gu49].

1948 The Radiumspital in Oslo orders a 6-MeV-betatron from Siemens Erlangen.

1948 RW starts the 31-MeV-betatron project for the Kantonsspital Zurich.

1948-11-09 RW's applies for a German patent (now BBC) on the principles of the synchrotron. It is published on Aug.21, 1952 (847318) and gives recognition to the Norwegian patent 76696 submitted on Jan.31, 1946.

1949 RW's family moves from Zurich to Baden.

1949-autumn Installation of the first BBC-betatron (31 MeV) at the Kantonsspital Zurich.

1949-autumn Olav Netteland from Oslo's Radiumspital visits Erlangen and finds no significant progress on the 6-MeV-betatron. Siemens working on a larger one.

1950 Radiologists Congress in London.

1951-04 Inauguration and start of operation of the first BBC 31MeVbetatron at the Kantonsspital Zurich. First patients are irradiated.

1951-09 Netteland and Dr. Steen from the Radiumspital in Oslo visit the Kantonsspital Zurich and see the 31-MeV-betatron in operation.

1951-autumn Dr. Eker orders a betatron from BBC for the Radiumspital in Oslo.

1952 The Cosmotron accelerator in Brookhaven reaches a particle energy of 3,000 MeV (= 3 GeV).

1952-05-05 (to 1952-50-08) First meeting of the Council of the future CERN in Paris. A provisional CERN-PS-Group is formed to plan a 10-GeV proton-synchrotron; members are: Odd Dahl (chairman), H. Alfven, W. Gentner, F. Goward, F. Regenstreif. RW is appointed as part-time adviser (he is not present).

1952 A 31-MeV-betatron from BBC is installed in the Inselspital in Berne.

1952-summer A 31-MeV-betatron from BBC is installed in the Radiumspital in Oslo. Six months later it is operational.

1952-06-03 (to 1952-06-19) International Conference in Copenhagen to discuss future projects on nuclear and particle physics for Europe. RW joins on 1952-06-17; he does not meet Odd Dahl there.

1952-06-20 (to 1952-06-23) Second meeting of the provisional CERN-Council in Copenhagen. The PS-Group welcomes new members D. W. Fry, K. Johnsen und Chr. Schmelzer.

1952-08-04 Returning from Australia via the USA, RW meets (for the first time) Odd Dahl in Brookhaven. Until Aug. 10, 1952 the three CERN `delegates' (RW, Dahl and Goward) discuss with Courant, Livingston, J.Blewett and Snyder on their newly developed principle of `strong focusing'.

1952-10-04 (to 1952-10-07) Third meeting of CERN-Council in Amsterdam. A 30-GeV-synchrotron with modern `strong focusing' is proposed for CERN.

1952-11-04 RW applies for German and Swiss patents on the extraction of electrons from betatrons. German No. 954814, made public on Dec. 1956 [Wi52].

1952-12-18 RW, Citron und Gentner visit the future site of CERN in Meyrin, north of Geneva.

1953-03-26 RW's German patent on `storage rings' (1943) is retrospectively approved and published.

1953-12-12 Inaugural lecture of RW at ETH in Zurich.

1954-05-17 Start of works for CERN in Meyrin.

1954-07-15 RW becomes head of the department `Electric Accelerators' (EA) at BBC.

1954-10-18 RW to Mannheim and Karlsruhe to negociate a deal on users rights for Steenbeck's patents at a German Federal Court. BBC eventually has to pay 100,000 DM to Siemens. BBC is represented by lawyer Otto Lardelli. According to RW, the historical facts are not correctly taken into account.

1954 In the BEVATRON accelerator in Berkeley, protons reach an energy of 6,1 GeV.

1955 Kollath publishes the first edition of his book on particle accelerators, Vieweg Publishers, Braunschweig [Ko55].

1955 RW's family moves from Baden to Nussbaumen

1955-06-10 Corner-stone laying for the European CERN-Laboratory in Meyrin, north of Geneva.

1956-01-23 Kerst et al. [Ke56] propose synchrotrons with strong focusing to be used as storage rings.

1956 At the `CERN Symposium on High Energy Accelerators and Pion-Physics' Gerry O'Neill proposes `The Storage-Ring-Synchrotron' [O´N56]. RW is present and describes his ideas on storage rings in a discussion [Wi56]. RW meets O'Neill there.

1956... BBC (RW) starts constructing the Turin synchrotron for 105MeV electrons (with Gonella, Gleb Wataghin and others). It is a synchrotron with initial betatron regime.

1956-12-20 RW's German patent on the extraction of electrons from betatrons is accepted and published.

1957 Successful extraction of electrons from the betatron at the Inselspital in Berne.

1959-1963 RW is contracted as adviser to DESY (Synchrotron).

1959 The 32-MeV mobile betatron for the private clinic `Casa di Cura S. Ambrogio' (Prof. Dr. Cova) in Milan is installed (named `Asclepitron'). Still in operation in 1990.

1959-11-24 The CERN-Proton-Synchrotron (28 GeV) is commissioned and starts operation.

1959-12-18 The research centre DESY in Hamburg is founded. A synchrotron for 6,4-GeV-electrons is under construction.

1960 The Brookhaven 31-GeV-synchrotron starts operation.

1960-03-07 Bruno Touschek presents his proposal for the first electron-positron storage ring (AdA) at Frascati [To60].

1961-02-27 AdA starts operation in Frascati.

1962-07-10 RW receives a `Dr.h.c.' from the RWTH Aachen.

1962 RW becomes `Titular-Professor' at the ETH Zurich.

1962... RW's main interest: The effects of radiation on living cells. He develops a `Two-Components-Theory'.

1962 Kollath's book on accelerators: 2nd edition [Ko62].

1964-04 RW receives the `' from Zurich University.

1966 RW's thesis of 1928 appears in English (translated at DESY) in a book edited by Stan Livingston [Li66].

1969 RW retires from BBC - but continues working.

1969-05-03 RW receives the `Röntgenmedaille' of the City of Remscheid.

1970 BBC-betatrons for 45 MeV.

1971-01-24 RW receives the `Röntgenpreis' from the City of Würzburg and the Physical and Medical Society of Würzburg.

1972 RW's final lectures at the ETH Zurich.

1973 Gold Medal at the XIII JRC in Madrid.

1973 RW becomes a member of the Norwegian Academy of Sciences.

1981 Odd Dahl publishes `Trollmann og rundbrenner' (an autobiographic book) [Da81].

1982-01-10 RW's lecture at the University of Oslo about his life and scientific work. Until Jan. 17, Conference at Geilo.

1982-07-10 An article by Olav Aspelund on RW is published in `Morgenbladet' Oslo [As82].

1983 Finn Aaserud and Jan Vaagen publish a longer Article on RW in the Norwegian magazine »Naturen« [Aa83], after an interview in Oslo (see [Wi91]).

1984-02 RW's retrospective article in Europhys. News [Wi84].

1984 RW becomes honorary member of ESTRO.

1992-03 Per Dahl, son of Odd Dahl, reports on RW's life and work in an SSC-Report [Da92] (10 pages).

1992-04 RW is awarded the Robert-Wilson-Prize of the American Physical Society APS.

1992-07-11 RW celebrates his 90th birthday in Oslo.

1992-07 RW is honorary chairman in a session of the International Conference on High Energy Accelerators in Hamburg.

1992-12-02 A Symposium to celebrate RW's 90th anniversary takes place at the ETH in Zurich.