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Marietta Blau 1894-1970

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Pioneering work in the photographic method of studying particle tracks. She created emulsions with characteristics and development conditions that allowed for observation and measurement of proton tracks.

"Blau was indeed the first physicist to show that proton tracks could be separated from alpha-particle tracks in emulsion. Of course, lots of physicists had studied alpha tracks from the alpha-decay of very heavy nuclei in the emulsion, from very early times, in the 1890s, and even earlier. She went further, by identifying proton tracks resulting from a) the elastic scattering of alphas by protons in the hydrogen in the emulsion, and b) the reactions of alphas with the nuclei of the emulsion. She also exposed emulsion to neutron beams and measured the proton energies for protons resulting from elastic scattering of the neutrons by the hydrogen in the emulsion. In particular she used this method to detemine the spectrum of neutrons resulting from specific nuclear reaction processes." -- Professor R. H. Dalitz, Oxford University.

Worked with Ilford (UK) to obtain thick emulsions, and discovered development techniques to observe and measure tracks of higher energy protons and used these to study and detect protons and other heavy particles in cosmic rays.

Showed there were relatively large numbers of protons and neutrons in cosmic radiation.

Observed nuclear disintegrations caused by cosmic rays in nuclear emulsions, with H. Wambacher. These were known before WWII as Blau-Wambacher stars.

Early development of photomultiplier tubes.

"The photographic effect of natural H-rays," (in German), SBAWW (Sitzungsberichte Akademie der Wissenschaften in Wien) IIa 134: 427 (1925).

"The photographic action of H-rays," ibid., 136: 469 (1928).

"Photographic detection of protons liberated by neutrons. II," ibid., 141: 617 (1932), with Hertha Wambacher.

"Physical and chemical investigations on the method for the photgraphic detection of H-rays," ibid., 143: 285 (1934), with Hertha Wambacher.

Disintegration Processes by Cosmic Rays with the Simultaneous Emission of Several Heavy Particles," Nature 140: 585 (1937), with Hertha Wambacher.

"Photographic Tracks from Cosmic Rays," Nature 142: 613 (1938).

"The multiplier phototube in radioactive measurements," RSI 18: 715 (1947).

"Meson production by 500 Mev negative pions," Phys. Rev. 92: 516 (1953) with M. Coulton and J. E. Smith.

"Hyperfragments and slow K- mesons in stars produced by 3 Bev protons," Phys. Rev. 102: 495 (1956).

"Interaction of 750 Mev pi- mesons with emulsion nuclei," Phys. Rev. 102: 489 (1956) with A. R. Oliver.

Ignaz L. Lieben Prize of the Viennese Academy of Science, with H. Wambacher, 1937

E. Schrödinger Prize, with H. Wambacher(posthumous), 1962

Nominated several times for the Nobel Prize by E. Schrödinger. [LH]

Jobs/Positions

1920-21 a position in industry in Berlin [MBCV]

1921-23 Assistent, University-Institut, Frankfurt am Main

1923-1938 Unclassified (unpaid) position, Institut fur Radiumforschung and at Second Physical Institute, University of Vienna

1939-44 Professor, Technical University, Mexico City

1944-48 International Rare Metals Refinery, NY, the Gibbs Manufacturing and Research Corporation, and then the Canadian Radium and Uranium Corporation

1948-50 Research physicist (?), Columbia University

1950-55 Associate physicist(?), Brookhaven National Laboratory at the invitation of the Atomic Energy Commission

1955-60 Associate Professor, University of Miami

Education

Ph.D. University of Vienna 1919

Sources and References consulted

Leopold Halpern, [MBCV] (Marietta Blau's CV; English translation courtesy Ruth Lewin Sime)
and [33B LSG], [38 LH],

Additional Information/Comments

During this period she pioneered the photographic method of studying particle tracks. She was able to distinguish, for example, proton tracks from alpha particle tracks and measure them. One of the first papers to describe this was her 1925 paper, an English translation of which is hyperlinked here.

Though C. F. Powell received the Nobel Prize in Physics in 1950 "for his development of the photographic method of studying nuclear processes and his discoveries regarding mesons made with this method", it is known that the method was brought to his attention by Walter Heitler in 1938 who had learned it from Blau and Wambacher. (A. M. Tyndall)

After the discovery of Blau-Wambacher stars which were images of cosmic ray disintegrations of heavy nuclei in photographic emulsions, a very important discovery, her request for a better position at the Institute was rejected because she was a woman and a Jew.

From 1933 to 1934, Marietta Blau received a grant for Austrian women scientists from the Austrian Association of University Women and used it to work in Gottingen and then at the Curie Institute in Paris.

Marietta Blau left Austria just before the Anschluss and did not return until after WWII. At first she worked with Professor Ellen Gleditsch in Oslo for over a year. However she could not have permanent employment there. With recommendation from Albert Einstein, she was appointed professor at the Technical University in Mexico City. [LH]

She took a German ship to America; enroute German officials confiscated her scientific papers, including work on particle tracks in nuclear emulsions. [LH]

Erwin Schrodinger, himself a Nobel Laureate, nominated Blau for the Nobel Prize several times. [LH]

For additional references to her work, see:
Max Born, Atomic Physics, Hafner Publishing Co., 1935(first English edition); in seventh edition (1962), pp. 36-37.
Maurice M. Shapiro, "Tracks of Nuclear Particles in Photographic Emulsions," Rev. Mod. Phys. , 11: 58 (1941).

Recommended reading:

"Marietta Blau: Between Nazis and Nuclei" by Peter L. Galison, Physics Today, 50: 42 (1997).

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