Nagy Ferenc: Ezerszáz év üzenete. A magyarok cselekedetei és nagyjai a tudomány és technika történetében (Budapest, 1996)

A magyarok cselekedetei és nagyjai a tudomány és technika történetében - Az atomkorszak, az űrkorszak és az információ korának úttörői

Albert Einstein, Szilárd Leó, és az amerikai elnöknek írt híres levél, amely az atomkorszak megnyitását eredményezte

United States Patent Office

2,708,656

Patentod May 17, 1958

1

2,798,454

NEUTRONIC REACTOB

Earico Feml, Seat* Ft, N. Mtx-, and Lao Sdlard, CM- 5 cago, HL, assignors to the Lotted State* o< Asnerica a* represented by the (Jattod State* A took Ebtrgj Cnmmlatina

Application December 19, 1944, Serial No. 548^04 10

8 data» (CL 204—193)

The present invention relates to the general subject of nuclear fission and particularly to the establishment of lj s«if-sustaining neutron chain fission reactions in systems embodying uranium having a natural isotopic content

Experiments by Hahn and Strassman, the results of which were published in January 1939. Naturwissen- -jo schäften, vol. 27, page 11, led to the conclusion that nuclear bombardment of natural uranium by slow neua

is converted by neutron capture to the isotope 92***. The latter is converted by beta decay to 93“ and this 93“ in turn is converted by beta decay to 94“. Other isotopes of 93 and 94 may be formed in small quantities. By slow or thermal neutron capture, 92“. on the other hand, can undergo nuclear fission to release energy appearing as heat and gamma and beta radiation, together with the formation of fission fragments appearing as radioactive isotopes of elements of lower mass numbers, and with the release of secondary neutrons.

The secondary neutrons thus produced by the fissioning of the 92“ nuclei have a high average energy, and must be slowed down to thermal energies in order to be in condition to cause slow neutron fission in other 92“ nuclei. This slowing down, or moderation of the neutron energy, is accomplished by passing the neutrons through a material where the neutrons are slowed by collision. Such a material is known as a moderator. While some of the secondary neutrons are absorbed by the uranium isotope 92“ leading to the production of element 94, and by other materials such as the moderator, enough neutrons can remain to sustain the chain reaction, when proper conditions are maintained.

Enrico Fenni és Szilárd Leó atomreaktor szabadalma

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