Marietta Blau (29 April 1894 â 27 January 1970) was an Austrian physicist of the 20th century who pioneered developments of photographic nuclear emulsions to image and accurately measure high-energy nuclear particles and events, significantly advancing the field of particle physics in her time. For this, she was awarded the Lieben Prize in 1937 by the ÃÂsterreichische Akademie der Wissenschaften (ÃÂAW). As a Jew, she became an émigré from Austria because of the 1938 Nazi Anschluss (annexe), her research continuing from Oslo, on to Mexico and the United States of America before eventually returning to Austria in 1960 where she was awarded the ÃÂAW Erwin Schrödinger Prize.
Blau discovered astronomically originating energy had a disintegrating effect on nuclei.
Blau was born on 29 April 1894 in Vienna to a Jewish family: Mayer (Markus) Blau (1854âÂÂ1919), a k.k. Gerichtsadvokaten and music publisher, and his wife Florentine Goldzweig. Markus' brother-in-law was the music publisher Josef Weinberger (died 1928).
Blau was schooled at , the Imperial and Royal Teacher Training Institute then from 1910 girls' grammar school. After having obtained the general certificate of education from the girls' high school run by the Association for the Extended Education of Women, Blau studied physics and mathematics at the University of Vienna from 1914 to 1918; her PhD, on the absorption of gamma radiation, was awarded in March 1919. Blau's thesis was approved by F.S. Exner and Stefan Meyer.
From 1919 to 1923, Blau held several positions in industrial and university research institutions in Austria and Germany; in 1921, she moved to Berlin to work at a manufacturer of x-ray tubes, a position she left to become an assistant at the Institute for Medical Physics at the University of Frankfurt am Main. From 1923 on, she worked as an unpaid scientist at the Institut für Radiumforschung of the ÃÂAW in Vienna. A stipend by the Austrian Association of University Women made it possible for her to do research also in Göttingen and Paris (1932/1933) at the Curie Institute.
From 1923 until 1938, Blau produced techniques using nuclear emulsion. The methodical goals which she pursued were the identification of particles, in particular alpha-particles and protons, and the determination of their energy based on the characteristics of the tracks they left in emulsions; there, she developed a photographic emulsion technique used in the study of cosmic rays, being the first scientist to use nuclear emulsions to detect neutrons. For this work, Blau and her former student Hertha Wambacher received the Lieben Prize of the Austrian Academy of Sciences in 1937. It was her greatest success when, also in 1937, she and Wambacher discovered "disintegration stars" in photographic plates that had been exposed to cosmic radiation at an altitude of 2,300 metres (âÂÂ7,500 feet) above sea level, a height they attained at a research station established by Victor Hess atop Hafelekar Mountain. These stars are the patterns of particle tracks from nuclear reactions (spallation events) of cosmic-ray particles with nuclei of the photographic emulsion.
As antisemitism grew in Austria during the late 1930s, Jewish researchers faced expulsion from their positions and Blau was no exception; in response to Georg Stettner (Nazi party member and director of the Institut für Radiumforschung) pressuring her to turn over her research and leave, she was invited to the University of Oslo.
Via Ellen Gleditsch, Blau left Austria for this research visit to Oslo on March 12, 1938, and because of the subsequent annexation she couldn't return; the following day, the Anschluss was completeâÂÂHitler had annexed Austria. Through the intercession of Albert Einstein, she eventually obtained a teaching position at the Instituto Politécnico Nacional in Mexico City and later at Universidad Michoacana de San Nicolás de Hidalgo. En route to Mexico City, Nazi officials seized her photographic plates at the airport in Hamburg. While in Mexico, Blau was personally acquainted with Guido Beck. Blau took the opportunity to move to the United States in 1944.
In the United States, Blau worked in industry until 1948, afterwards (until 1960) at Columbia University, Brookhaven National Laboratory and the University of Miami. At these institutions, she was responsible for the application of the photographic method of particle detection in high-energy experiments at particle accelerators.
She was nominated several times, during the period 1950 to 1957, for the Nobel Prize in Physics and once for the Nobel Prize in Chemistry by Erwin Schrödinger and Hans Thirring.
In 1960, Blau returned to Austria and conducted scientific work at the Institute for Radium Research until 1964 â again without pay. She headed a working group analyzing particle-track photographs from experiments at CERN and supervised a dissertation in this field. In 1962, she received the Erwin Schrödinger Prize of the Austrian Academy of Sciences, but an attempt to make her also a corresponding member of the academy was not successful.
In 1950, Cecil Powell received the Nobel Prize in Physics for work (partially) based on the work of Blau, specifically the development of the photographic film method for particle detection and the discovery of the meson.
The is a government scholarship (of the )
Marietta-Blau-Saal is a room in University Vienna sometimes used for coffee-breaks.
Marietta-Blau-Gasse in area 22 of Vienna is a street name.
Marietta Blau Institute for Particle Physics (merger of Stefan Meyer Institute for Subatomic Physics and the Institute of High Energy Physics (HEPHY)).
Marietta Blau died in Vienna from cancer on 27 January 1970. Her illness was related to her unprotected handling of radioactive substances as well as her cigarette smoking over many years. No obituary appeared in any scientific publication. Blau was interred in group 6 of the new section for Jewish burials of Wiener Zentralfriedhof at row 2, grave 16.
Report on the discovery of stars produced by cosmic rays:
On the absorption of divergent ó-radiation: