Cyclotron investigation Heidelberg

CIOS File No. XXIX-47


Reported by:


On behalf of the

U.S. Technical Undustrial Intelligence Committee


CIOS Target Numbers 6. 21/65 & 24/17a

Metallurgy - Medical

June 1, 1945

This report is about some nuclear work done at Heidelberg University before the end of the war, based on Prof. Dr. W. Bothe information. This report is having some interesting aspects. I also regard the fact that Bothe discussed the U-Machine meant was what we know now as a 'nuclear reactor'. He also gives the differential equation of the minimum size of such a spherical machine. Please notice, that this report was released about the first official atomic bomb released over Japan, in August 1945! The interrogation took please in June thus before this event.


T Force Section Headquarters Sixth AG Group, 1 June 1945

The above investigators were accompanied by Dr. Max Knoll (a very famous person, who by the way belonged to the group who invented the magnetically deflected Electron Microscope, together with Ruska, who got for it a 'Nobel Prize', AOB) a German scientist of the Telefunken Co., who had been separated from the laboratories in and around Liebenstein and who had attached himself to the headquarters of the Ferdinand Braun Institute at Brannenburg. He was released by the local military government at Rosenheim for the trip to Bad Liebenstein and vicinity. It was he who supplied names of scientist and institutions in which the investigators had special interest.

It had been learned at Munich from Mr. Harry Marvin of the General Electric Co., another investigator, that the Bad Liebenstein area had been investigated by him but some of the targets had been overlooked. It was therefore agreed with Col. Jackson and Major Johnson-Ferguson at Munich that it would be proper to proceed to the Telefunken Laboratories in Bad Liebenstein area with Dr. Knoll as a guide and interpreter.

Interview with Prof. Walter Bothe, Kaiser Wilhelm Institute for Physics and Medicine, Heidelberg.

Since the route taken by the investigators passed through Heidelberg, advantage was taken of the opportunity to call on Dr. Walter Bothe, Im Backersfeld 6, Heidelberg, an internationally well-known nuclear physicist, who has been operating a cyclotron at Heidelberg. The cyclotron was shown to us by Dr. Bothe. He stated a Dr. Hoges of T Force (British?, AOB) had asked for his reports but none were available as they had been previously destroyed.

According Dr. Bothe, his activity with the cyclotron during the war had been confined mostly to the preparation of tracer materials for use in biological research directed by Dr. Richard Kuhn of Wilckenstrasse 23, Heidelberg. ...

Dr. Bothe said that, during the war, continuation of his work was permitted at first because the authorities had hope that the scientists might quickly learn to release and use atomic energy, even though the scientists secretly held no such hope. Later the authorities concluded that pure research was necessary and should be continued for its own sake.

His cyclotron installation came thru the combat period substantially intact and in working order. It is still apparently complete except for a 150,000 volt X-ray type rectifier which had been removed by a Major (Br) Signals. (Br may stand for British, what should a signal man do with a 150 kV rectifier? Was it taken as a souvenir?, AOB)


Keywords: Two Apiezon oil diffusion pumps ... ; The radio frequency drive equipment was designed for 70 kW output power in the range of 15 to 30 meters frequency adjustment. It had been built by Ader and Schwartz (Ader & Schwarz?), a small firm in Munich. The Heidelberg cyclotron; A full size cyclotron has been constructed since 1938, the donators were: Stiftverband der Deutschen Forschungsgemeinschaft, Helmholtz-Gesellschaft zur Förderung der physikalischen Forschung - Kaiser Wilhelm-Gesellschaft, zur Förderung der Wissenschaften, Max Planck-Stiftung, Geheimrat C.Bosch (I.G.Farbenindustrie, in fact BASF, AOB), Badisches Kulturministerium, Reichsforschungsrat; about 90% of the costs came from private sources. No prescriptions nor restrictions of any kind regarding the working program of the cyclotron were connected with these grants. The cyclotron has not been used for any work concerning war problems; The magnet has been constructed by Krupp and Siemens, the high frequency part by Rohde and Schwarz (R&S, AOB) .. ; Gentner - Prof. Joliot Paris ...and his staff and a small group of German physicists, for purely scientific research. It was settled that no war work should be done by neither side with the Paris cyclotron. The heidelberg cyclotron was in action from January to September 1944; deuteron beams of 9 MeV were produced. Afterwards some changes had to be made because the form of the magnetic field proved not quite satisfactory. Just before the occupation the cyclotron had begun to run again; Dr. Papkow; Dr. Schäfer of the I.G. Farbenindustrie; Dr. Stodtmeister (Medizinal Klinik der Universität Heidelberg; GM counters with sensitivity either independant of the hy or proportional to hy have been constructed. A cloud chamber with slow expansion was constructed .. ;p. Jensen, Passage of neutrons through matter, .. Bremslänge ... D20 .. ; Ball of U3O8   Flammersfeld Nuclear cross section of U .. ; Clusius-Dickel method .. UF6  Chain reaction in U. Hechingen-Haigerloch; In the last time experiments with a U-D2O arrangement of 1500 liters were made in KWI for physics at Berlin and were meant to be continued at Hechtingen-Haigerloch. The details of the last mentioned experiments were fixed between Prof. Heisenberg and Prof. Bothe, and a 1-3 members of the Institute were delegated to Prof. Heisenberg to participate in the experiments. The experimental method was for measuring neutron densities was one devised in our Institue; Mott formulla at low energies; A betatron for production of beta- and gamma-rays of about 10 MeV is nearly finished; Die Mindestgröße der U-Maschine (Auszug)



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