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Rossi's coincidence circuit, the first fast electronic coincidence circuit of the parallel type, became essential in cosmic-ray research. It allowed the simultaneous registration of electrical pulses from any number of Geiger-Mü ller counters and had a resolving time of 10 -3 second, an order of magnitude faster than Walther Bothe's coincidence circuit. The plates of the three triodes A, B, and C are connected together and to the positive terminal of a battery P whose negative terminal is grounded through the resistance R 7 . The grids of the three triodes are coupled electrostatically to the central wires of the three Geiger-Mü ller counters. The grids of the three triodes in a normal state are grounded, so a current then flows in them and in their common plate resistor R 7 , and the potential drop through it holds the grid of the triode D at a negative potential, thus inhibiting the plate current. If a charged particle enters one of the Geiger-Mü ller counters and causes it to discharge, then the corresponding grid will experience a negative potential and the plate current will stop. If this happens in one or two of the triodes, then the current in the third one will still experience a potential drop in the ground resistor R 7 , and the current in the triode D will still be inhibited. Only when all three Geiger-Mü ller counters discharge simultaneously will the current in the resistor R 7 stop, bringing the grid of the triode D to ground potential and starting a current flow in it. Source: Rossi, ''Method of Registering'' (ref. 10), p. 636.
Source publication
Bruno Rossi (1905–1993), one of the giants of 20th-century physics, was a pioneer in cosmic-ray physics and virtually every
other aspect of high-energy astrophysics. His scientific career began at the University of Florence in 1928 and continued
at the University of Padua until 1938, when the Fascist anti-Semitic racial laws were passed in Italy. H...
Citations
... Together they were able not only to optimize observation of cosmic rays but were the first to expound the pair formation mechanism, putting the positron -Dirac's hole-theory particle -into theoretical perspective. Since the early 1930s Blackett had very strong ties with the Italian physicists community and in 1938 he had offered Bruno Rossi a position in Manchester, when the latter was forced to leave his chair in Padua because of the 1938 antisemitic fascist laws (Bonolis 2011). In 1939 Rossi settled in the US helped by Arthur Compton and Hans Bethe. ...
In the history of the discovery tools of last century particle physics, central stage is taken by elementary particle accelerators and in particular by colliders. In their start and early development, a major role was played by the Austrian born Bruno Touschek, who proposed and built the first electron positron collider, AdA, in Italy, in 1960. In this note, we present a period of Touschek's life barely explored in the literature, namely the five years he spent at University of Glasgow, first to obtain his doctorate in 1949 and then as a lecturer. We shall highlight his formation as a theoretical physicist, his contacts and correspondence with Werner Heisenberg in G\"ottingen and Max Born in Edinburgh, as well as his close involvement with colleagues intent on building modern particle accelerators in Glasgow, Malvern, Manchester and Birmingham. We shall discuss how the Fuchs affair, which unraveled in early 1950, may have influenced his decision to leave the UK, and how contacts with the Italian physicist Bruno Ferretti led Touschek to join the Guglielmo Marconi Physics Institute of University of Rome in January 1953.
... This research developed along two main lines: one concerned with the cosmic rays themselves -what are they, where do they come from, how do they reach the space surrounding the Earth -and the other focussed on the interaction of this windfall of high-energy particles with matter. 31 [132]. 32 [112]. ...
... By that time there was a strong tradition of collaboration between Italian and British physicists, which became very important after World War II. 147 For a detailed reconstruction of Rossi's forced emigration from Italy see [31].). 148 [149] (note 9), 40-41. ...
... There were meetings in Switzerland very often, and I spent one summer in Germany. I felt a part of the European team, not of the italian team 156 These experiments are discussed in the article mentioned in note 21. 157 [31] (note 147). 158 Footnote 93,286 [. . . ...
During the 1920s and 1930s, Italian physicists established strong
relationships with scientists from other European countries and the United
States. The career of Bruno Rossi, a leading personality in the study of cosmic
rays and an Italian pioneer of this field of research, provides a prominent
example of this kind of international cooperation. Physics underwent major
changes during these turbulent years, and the traditional internationalism of
physics assumed a more institutionalised character. Against this backdrop,
Rossi's early work was crucial in transforming the study of cosmic rays into a
branch of modern physics. His friendly relationships with eminent scientists
-notably Enrico Fermi, Walther Bothe, Werner Heisenberg, Hans Bethe, and Homi
Bhabha- were instrumental both for the exchange of knowledge about experimental
practises and theoretical discussions, and for attracting the attention of
physicists such as Arthur Compton, Louis Leprince-Ringuet, Pierre Auger and
Patrick Blackett to the problem of cosmic rays. Relying on material from
different archives in Europe and United States, this case study aims to provide
a glimpse of the intersection between national and international dimensions
during the 1930s, at a time when the study of cosmic rays was still very much
in its infancy, strongly interlaced with nuclear physics, and full of
uncertain, contradictory, and puzzling results. Nevertheless, as a source of
high-energy particles it became a proving ground for testing the validity of
the laws of quantum electrodynamics, and made a fundamental contribution to the
origins of particle physics.
... http://dx.doi.org/10.1016/j.astropartphys.2013.05.008 autobiography [2] and George Clark's biographical notes [3,4]. Rossi's early work, up to the end of 1930s -beginning of 1940s, has already been discussed by the author in [5] and especially in [6]. For this reason, apart from some aspects which have not been particularly stressed in these articles, the present work will pay more attention to Rossi's involvement in the beginning of space science and in particular in the birth of X-ray astronomy, as such issues -strongly related to the main focus of this contribution-have never been discussed in more detail within the context of Rossi's whole scientific activity, except for descriptions contained in the above mentioned biographical sources. ...
... However, no known process at the time could explain the abundant production of secondary particles revealed by his experiments. 5 After the discovery of the production of secondary radiations in metal shields, Rossi had continued his investigations going much deeper into the origin of this unexpected phenomenon. Such unpredicted behavior of the radiation found its confirming synthesis in a curve which was to be universally known as the Rossi transition curve, representing the variation of the number of coincidences recorded by three counters in a triangular array as a function of the thickness (in mass per unit area) of layers of lead and iron placed above them and emitting the secondary particles [29]. ...
... 11 The result was quite surprising because the supporters of the corpuscular theory were convinced, more '' from prejudice than because of a logical argument,'' that the primary particles would turn out to be electrons [2, p. 36]. 5 Such was the novelty of the results, so contrary to the ''common sense'', that the editors of the scientific journal to which Rossi submitted his short note, most probably Die Naturwissenschaften, refused to publish it. It was accepted on February 10, 1932 by Physikalische Zeitschrift only after Heisenberg, with whom Rossi corresponded during the period 1930-1932, had vouched for its credibility. ...
... 3 Rossi's scientific life is extending across a period of about thirty years from the end of the 1920s to the early 1960s. The " Italian Years " include Bruno Rossi's scientific activity from the beginning of his academic and scientific life in Florence, in 1928, until 1938, when he was dismissed from his chair in Padova and was forced to emigrate by fascist racial laws [28]. At the beginning of 1930s he was a pioneer of cosmic ray research in Italy, while Enrico Fermi and Franco Rasetti were building up a research group in Rome, the group who would share with them the well known achievements in nuclear physics. ...
... By 1942 the evidence for the decay of the mesotron at the end of their range had changed from the first two cloud-chamber tracks photographed by Williams and Roberts in 1940 [169] to the curve presented by Rossi and Nereson, which contained thousands of decay events and showed an exponential decay with a lifetime of about 2 µs [99]. The style and elegance of these achievements have been unanimously recognized in the history of experimental physics [28]. These experiments, completed by Rossi during the war, symbolically closed an era that he himself called " the age of innocence of the experimental physics of elementary particles " [143, p. 204]. ...
Rossi's career paralleled the evolution of cosmic-ray physics. Starting from
the early 1930s his pioneering work on the nature and behavior of cosmic rays
led to fundamental contributions in the field of experimental cosmic-ray
physics and laid the foundation for high-energy particle physics. After the
war, under his leadership the Cosmic Ray group at MIT investigated the
properties of the primary cosmic rays elucidating the processes involved in
their propagation through the atmosphere, and measuring the unstable particles
generated in the interactions with matter. When accelerators came to dominate
particle physics, Rossi's attention focused on the new opportunities for
exploratory investigations made possible by the availability of space vehicles.
He initiated a research program which led to the first in situ measurements of
the density, speed and direction of the solar wind at the boundary of Earth's
magnetosphere and inspired the search for extra-solar X-ray sources resulting
in the detection of what revealed to be the most powerful X-ray source in
Earth's skies. The discovery of Scorpius X-1 marked the beginning of X-ray
astronomy, which soon became a principal tool of astrophysics research.
The contribution of Italian scientists and Italian institutions to the
study of cosmic rays will be covered from the precursor experiments in
1908-1910 up to the identification of the muon by Conversi, Pancini and
Piccioni in 1945-1946 experiments.
We trace the history of physics at New York University after its founding in 1831, focusing especially on its relatively recent
history, which can be divided into five periods: the Gregory Breit period from 1929 to 1934; the prewar period from 1935 to
1941; the wartime period from 1942 to 1945; the postwar period from around 1961 to 1973 when several semiautonomous physics
departments were united into a single all-university department under a single head; and after 1973 when the University Heights
campus was sold to New York City and its physics department joined the one at the Washington Square campus. For each of these
periods we comment on the careers and work of prominent members of the physics faculty and on some of the outstanding graduate
students who later went on to distinguished careers at NYU and elsewhere.
KeywordsAllen V. Astin–Jenny Rosenthal Bramley–Gregory Breit–David B. Douglass–Henry Draper–John C. Draper–John William Draper–Richard T. Cox–Eugene Feenberg–Gerald Goertzel–Louis P. Granath–Otto Halpern–Morton Hamermesh–Daniel Webster Hering–Norman Hilberry–Theodore Holstein–John C. Hubbard–Francis A. Jenkins–Hartmut Kallmann–Serge Korff–Alfred Lee Loomis–Elias Loomis–Francis Wheeler Loomis–James M. Mathews–Allan C.G. Mitchell–Samuel F.B. Morse–Robert S. Mulliken–Henry Primakoff–Frederick Reines–Arthur Roberts–Edward O. Salant–Clifford G. Shull–John A. Simpson–Henry Vethade–John H. Van Vleck–John A. Wheeler–Robert W. Wood–Bruno Zumino–New York University–University Heights campus–Washington Square campus–James Arthur Lectures–Stanley H. Klosk Lectures–history of physics
Theoretical and experimental developments in the 1920s that accompanied the
birth of coincidence methods, as well as later crucial applications during the
1930s and 1940s are presented. In 1924 Walther Bothe and Hans Geiger applied a
coincidence method to the study of Compton scattering with Geiger needle
counters. Their experiment confirmed the existence of radiation quanta and
established the validity of conservation principles in elementary processes. At
the end of the 1920s, Bothe and Werner Kolh\"orster coupled the coincidence
technique with the new Geiger-M\"uller counter to study cosmic rays, marking
the start of cosmic-ray research as a branch of physics. The coincidence method
was further refined by Bruno Rossi, who developed a vacuum-tube device capable
of registering the simultaneous occurrence of electrical pulses from any number
of counters with a tenfold improvement in time resolution. The electronic
coincidence circuit bearing Rossi's name was instrumental in his research on
the corpuscular nature and the properties of cosmic radiation during the early
1930s, a period characterized by a lively debate between Millikan and followers
of the corpuscular interpretation. The Rossi coincidence circuit was also at
the core of the counter-controlled cloud chamber developed by Patrick Blackett
and Giuseppe Occhialini, and became one of the important ingredients of
particle and nuclear physics. During the late 1930s and 1940s, coincidences,
anti-coincidences and delayed coincidences played a crucial role in a series of
experiments on the decay of the muon, which inaugurated the current era of
particle physics.
PACS numbers: 96.50.S-, 84.30.-r, 96.50.S-, 95.85.Ry, 29.40.-n, 13.35.Bv,
45.20.dh, 12.20.-m, 91.25.-r, 29.40.Cs, 13.20.-v, 14.60.Ef, 14.60.Cd, 78.70.Bj,
20.00.00, 95.00.00, 01.60.+q, 01.85.+f, 01.65.+g
