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eactions, by Fritz G. Houtermans: A Communication from the
Laboratory of Manfred Von Ardenne, Berlin-Lichterfelde-Ost." 2
The paper is remarkable in several respects, not the least for its
revealing table of contents:
I. General Point of View
II. Competing Processes
III. Chain Reactions through Nuclear Fission with Fast Neutrons
I V. Nuclear Fission through Thermal Neutrons
1. Isotope Separation
2. Selection of a heavy Moderator Substance such as
Hydrogen, especially Heavy Water
3. Relative Advance of the Probability for 1/v Process through
Application of Low Temperatures
4. Self-Regulating reaction and the Significance of the
Doppler Effect at Low Temperatures
V. Chain Reactions at Final Trial Volumes
VI. The Importance of a Chain Reaction at Low Temperatures as
a Neutron Source as an Apparatus for Isotope
Transformation 3
The general outline suggests that Houtermans had already thought
his way through the process, not only of initiating nuclear
explosions via fast neutrons, but also of the transformation of U 235
into higher elements not chemical identifiable with it. This is the
first step toward plutonium, and to the use of plutonium rather than
U 235 as the explosive fuel for a bomb.
The contents of the paper confirms that this is what
Houtermans has figured out in no uncertain terms:
We are able to envision here an apparatus, that would allow...a certain
amount of U 235 to undergo nuclear reaction, simultaneously as an
isotope transforming apparatus. The advantage vis-a-vis an isotope
enrichment apparatus is therefore that the newly-created product,
which would have an atomic number of 93 or more, is not chemically
identical with uranium, and therefore is separable by chemical
methods. Now since much larger amounts, namely 139 times more, of
2 Thomas Powers, Heisenberg's War, p. 112. The table of contents page of
the original memorandum may be found in Mayer and Mehner, Das
Geheimnis, p. 33.
3 Ibid., p. 32.
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