At first sight, nothing could be simpler than nuclear emulsions, those thin strips of film designed to trap the tracks of passing charged entities—nuclei, protons, electrons and the other objects that inaugurated the field of particle physics. But the method's seeming simplicity hides a complex history. Scientifically, emulsions posed myriad problems and required years of effort by a dedicated corps of emulsion physicists and chemists, who had to learn how to make the film sensitive to minimally ionizing particles, and how to store, process, dry and ultimately analyze the ramified skein of tracks. Developed in the 1930s by Marietta Blau, an Austrian physicist who fled her homeland following the Anschluss in March 1938, the nuclear emulsion method was taken over by Cecil Powell, who transformed it during the 1940s into a cottage industry, with female “scanners” and an international team of physicists and chemists. From Powell's laboratory in Bristol, England, the method migrated to the burgeoning, industrial‐scale accelerator centers at Berkeley and Brookhaven, until even there, emulsions were displaced by the mammoth bubble chambers of the 1950s and 1960s.

1.
M. Blau, “Uber Photographische Untersuchungen mit radioaktiven Strahlungen,” in F. Dessauer, ed., Zehn Jahre Forschung aufdem Physikalisch‐Medizinischen Grenzgebiet, George Thieme, Leipzig (1931), pp. 390–98.
2.
M.
Blau
,
Sitzungsberichte, Akad. Wiss. Wien, Math.‐naturwiss. Kl, Abt. IIa
134
,
427
(
1925
);
M.
Blau
,
Z. Phys.
34
,
285
(
1925
).
3.
M.
Blau
,
Sitzungsberichte, Akad. Wiss. Wien., Math.‐naturwiss. Kl, Abt. IIa
136
,
469
(
1927
).
M.
Blau
,
Z. Phys.
48
,
751
(
1928
).
4.
See
M.
Blau
,
H.
Wambacher
,
Sitzungsberichte, Akad. Wiss. Wien., Math.‐naturwiss. Kl, Abt. IIa
141
,
615
(
1932
).
5.
M.
Blau
,
J. Phys. Radium, 7th Ser.
5
,
61
(
1934
).
The invitation from Marie Curie appears on page 62.
6.
H. J.
Taylor
,
Proc. R. Soc. London, Ser. A
150
,
382
(
1935
).
In
H. J.
Taylor
,
V. D.
Dabholkar
,
Proc. R. Soc. London
48
,
285
(
1936
),
the authors qualified their objection somewhat.
7.
G. Kirsch, questionnaire, 20 May 1940, Personalakte Kirsch, Archiv der Republik, Vienna, Austria. With some pride, Kirsch testified that he had been a member of “the first NSDAP in Austria from 15 November 1923 until its demise, [and] since March 1934 [a member] of the V[aterlandischen] F[ront]”
8.
G. Stetter, questionnaire, 11 May 1938, folders 269, 272, on folder 269v, Personalakte Stetter, Archiv der Republik, Vienna, Austria.
9.
G.
Kirsch
,
H.
Wambacher
,
Sitzungsberichte, Akad. Wiss. Wien., Math.‐naturwiss. Kl, Abt. IIa
142
,
241
(
1933
).
10.
See, for example,
G.
Ortner
,
G.
Stetter
,
Z. Phys.
54
,
449
(
1929
).
11.
M.
Blau
,
H.
Wambacher
,
Nature
140
,
585
(
1937
).
12.
Letter from M. Blau to A. Einstein, 10 June 1938, Albert Einstein Papers, documents 52‐606‐1 and 2, Princeton U. Libraries, Princeton, N.J.
13.
Letter from A. Einstein to I. Batiz, n.d. (probably June 1938, although later dated in typed insertion as 1939).
14.
Letter from M. Blau to A. Einstein, Albert Einstein Papers, documents 54‐835‐1 and 2, Princeton U. Libraries, Princeton, N.J. Letter from A. Einstein to the Mexican ambassador to the US, Albert Einstein Papers, document 54‐837, Princeton U. Libraries, Princeton, N.J.
15.
M.
Blau
,
B.
Dreyfus
,
Rev. Sci. Instrum.
16
,
245
(
1945
).
M.
Blau
,
I.
Feuer
,
J. Opt. Soc. Am.
36
,
576
(
1946
).
16.
See, for example,
M.
Blau
,
M.
Caulton
,
J.
Smith
,
Phys. Rev.
92
,
516
(
1953
).
17.
M.
Blau
,
Phys. Rev.
75
,
279
(
1949
).
M.
Blau
,
M.
Caulton
,
Phys. Rev.
96
,
150
(
1954
).
18.
Letter from H. Wambacher to NSDAP, Reichsleitung München, Amt für Mitgliedschaftswesen, 24 January 1942, Archiv der Republik, Vienna, Austria.
19.
An excellent secondary source for information on the fate of academics dismissed from the Institut für Radiumforschung and other Austrian institutions of higher learning can be found in F. Stadler, Vertriebene Vernunft II: Emigration und Exil Österreichischer Wissenschaft, Jugend und Volk, Vienna, Austria (1988).
20.
W. J. Moore, Schrodinger, Life and Thought, Cambridge U.P., Cambridge, England (1988), pp. 479–80.
This content is only available via PDF.
You do not currently have access to this content.