halban hans von (3 risultati)

Hardcover. Condizione: Good. ("The application of photoelectric cells to the measurement of light absorption in solutions.") Zeitschrift fur physikalishce Chemie, vol 96. pp 214-232 1920 ("An arrangement is described and illustrated diagrammatically by means of which light absorption in solution can be rapidly and accurately ascertained with the help of photoelectric alkali metal cells.") And: Hans van Halban and Heribrant Geigel, "Uber die Photochemie des Tetrbenzoylathylens 1", 233-250. Offered in the entire volume, including Hefts 1-6, 504pp. Bound volume with original wrappers bound in. Cloth, with leather spine labels. Xl Public Health Service. Good copy. $75.

The Discovery of Nuclear Fission and of the Chain Reaction. First edition, rare, journal issues in the original printed wrappers, of the complete sequence of papers in Nature by which nuclear fission was reported, theoretically interpreted, experimentally verified, and shown to liberate enough secondary neutrons to sustain a chain reaction-the sequence that, between 11 February and 3 June 1939, took physics from a chemical anomaly observed in Berlin to the certainty of a feasible nuclear bomb. Three of the eight issues offered here contain Printing and the Mind of Man entries (422b, the discovery and naming of fission; 422c, its experimental confirmation; 422d, the demonstration of neutron multiplication); the remaining five are the immediately surrounding papers without which the PMM trio cannot be properly read. Together they constitute the entire foundational literature of nuclear fission, in the form in which it first reached the working physicist on his subscriber's table, and in the four-month window between the Christmas-week calculation of Meitner and Frisch in a Swedish wood and the outbreak of the Second World War in Poland fewer than thirteen weeks after the appearance of the last paper here offered. The story begins in Berlin in December 1938. Otto Hahn and Fritz Strassmann had been bombarding uranium with neutrons since 1934, hoping to produce transuranic elements. Their chemical analyses kept yielding results that made no nuclear-physical sense: among the products, in repeated and unmistakable fashion, was an isotope of barium (Z = 56), an element less than two-thirds the atomic number of uranium (Z = 92). The reigning view of nuclear processes-that a slow neutron could only nudge a heavy nucleus by a unit or two of charge through the emission of ? or ? particles-made any such large change inconceivable. Hahn, an outstanding radiochemist with no theoretical training, wrote to his former collaborator of thirty years, the physicist Lise Meitner, who had fled Berlin five months earlier as the post-Anschluss racial laws closed in on Jewish scientists, and who was now working in straitened circumstances at Manne Siegbahn's institute in Stockholm. Meitner read Hahn's letter on 21 December 1938 and could not at first make sense of the chemistry either, except in the conviction-based on thirty years of joint work-that the chemistry was right. She read the letter again over the Christmas holiday at Kungälv on the west coast of Sweden, where she was the guest of her old friend Eva von Bahr-Bergius and where she was joined by her thirty-four-year-old nephew Otto Robert Frisch, then a junior researcher at Bohr's institute in Copenhagen. The two of them went out for a walk in the snow on the morning of Christmas Day-Frisch on skis, Meitner walking briskly alongside-to talk through what could possibly be wrong with Hahn's analysis, which they were certain was not. They sat down on a tree-trunk in the woods and did the calculation together. Treating the uranium nucleus as a deformable liquid drop, in the model that George Gamow had proposed in 1928 and that Niels Bohr and Carl Friedrich von Weizsäcker had developed through the middle 1930s, they reasoned that the surface tension that ordinarily held the drop spherical would be largely cancelled by the mutual electrostatic repulsion of the 92 protons in a nucleus as heavy as uranium. The drop should be on the verge of instability with respect to even small deformations. A captured neutron might set it oscillating; the oscillation could elongate it into a dumbbell; the electrostatic repulsion could then drive the two halves apart, with the release of about 200 MeV per nucleus. Where, Frisch asked, would the energy come from? Meitner, working from memory of the empirical mass formula, calculated that the daughter nuclei would together be about one-fifth of a proton-mass lighter than the parent, and that this mass deficit, multiplied by c , gave precisely 200 MeV. The mechanism, th. Signed.

1st Edition. FIRST EDITION IN ORIGINAL WRAPS of the first solid evidence that neutron multiplication is large enough (3.5) to creat a chain reaction, thus profiding "indirect proof of the neutron multiplication accompanying the fission of uranium nuclei after neutron capture" (Printing and the Mind of Man, 422). Halban, Joliot, and Kowarski reported that several free neutrons are released for each uranium that splits. Their experiments "recognized that under suitable conditions such secondary neutrons might in turn induce fission in other nuclei, setting in motion a chain reaction capable of sustaining itself until the uranium was entirely consumed" (Sikme, Lise Meitner: A Life in Physics, 261). The "experiments raised the prospect that fission might be used to generate immense quantities of energy" (ibid). CONDITION & DETAILS: London: Macmillan. 4to. (10.5 x 7.5 inches; 262 x 188mm). Original paper wraps with very slight remnants of creases within. Clean and bright inside and out.