The Mechanism of Cosmic-Ray Counter Action

Abstract

A study of photographs taken in a very powerful magnetic field with the aid of a cloud chamber activated by counter responses shows (1) that such an arrangement has a strong selective action on showers; (2) that showers so selected have an exceptional multiplicity of tracks;(3) that the two counters show simultaneous responses when no single particle can pass through both of them; (4) that in general these showers consist of a mixture of positive and negative electrons rather than of electrons and protons, no effects certainly attributable to neutrons being observed; (5) that these electrons in getting out of the nucleus some times produce an intense photon spray of the nature of "brems st ranking"; (6) that these photon sprays are increasingly responsible for the simultaneous activation of the two counters the thicker the intervening lead; (7) that a light element like carbon has little effect in producing either showers or sprays; (8) that the total energy of a shower is not larger than that of single electrons (+ or -); (9) that the Dirac theory encounters certain difficulties in accounting for the observed effects.

International scientific cooperation during the 1930s. Bruno Rossi and the development of the status of cosmic rays into a branch of physics

“…151 . They actually specifically challenged Anderson, Millikan, Neddermeyer, and Pickering's paper criticizing Blackett and Occhialini and especially Rossi's results built on coincidences due to the passage of a single particles through counters ( [2]). From measurement of its ionization and momentum, Street and Stevenson deduced a value of about 130 electron masses, to be compared to the current accepted value of 105.65836715 ± 0.0000038) MeV/c 2 [18].…”

“…The League of Nations' International Commission on Intellectual Cooperation also excluded German and Austrian scientists when twenty-five chemists convened in Brussel for the first Solvay Chemistry Congress in 1922. 2 In the postwar Solvay Physics councils, Schrödinger was the only physicist from the former Central Powers who attended a meeting before 1927, and Einstein, who had been invited in 1921 and 1924, declared that in any case he would not participate as long as his German colleagues were excluded. The consequences of the war affected the traditional international conferences of mathematics, too.…”

“…3 In recognizing the necessity of a broad communication with the international community, IUPAP provided in these difficult years a more institutional base to a field that already 1 Orso Mario Corbino, who would soon support Enrico Fermi's career, convinced of the importance of relaunching Italian physics, was among the ten distinguished physicists forming the executive committee who prepared rules, regulations, and activities of the new organization. 2 The only German chemist invited to any Solvay council during the 1920s was Hermann Staudinger (in 1925), who was a pacifist and in different situations had taken position against chemical warfare.…”

A descoberta das correntes neutras das interações fracas

“…I have been pointed for two years in Pasadena seminars, in the Rome congress of nuclear physics in October, 1931, in New Orleans last Christmas at the A.A.A.S meeting, and in the report for the Paris Electrically Congress, that these counter experiments in my judgment actually measure the absorption coefficients of anything. [116] Essa posição seria enfatizada no ano seguinte quando segundo eles mostraram que [117]:…”

Theory Versus Experiment: The Case of the Positron

“…In 1934, Anderson was still moving within Millikan's theoretical framework when he wrote that "the simplest interpretation of the nature of the interaction of cosmic rays with the nuclei of atoms, lies in the assumption that when a cosmic-ray photon impinges upon a heavy nucleus, electrons of both sign are ejected from the nucleus […]. [The photographs] point strongly to the existence of nuclear reactions of a type in which the nucleus plays a more active role than merely that of the catalyst [emphasis added]" (Anderson et al 1934). …”