C. G. Montgomery

Yale University, New Haven, Connecticut, United States

Are you C. G. Montgomery?

Claim your profile

Publications (28)46.03 Total impact

  • C. G. Montgomery · D. D. Montgomery
    Physical Review 11/1950; 80(4):757-757. DOI:10.1103/PhysRev.80.757
  • C. G. Montgomery · D. D. Montgomery · J. A. Northrop
    [Show abstract] [Hide abstract]
    ABSTRACT: A survey was made at Climax, Colorado (elevation 3510 meters) of the particles associated with nuclear explosions, of stars, which were capable of emerging from the thin-walled ionization chamber in which the stars were recorded, and of penetrating various thicknesses of lead absorber. The experiment was so designed as to distinguish between electrons and penetrating particles. It was found that in a small fraction of the nuclear events (1 to 2 percent) there were associated electrons. In some of these events there were pairs of associated rays capable of penetrating 8 inches of lead placed below the chamber. The absorption in lead was found to be exponential with a mean free path of 107±30 g/cm2.
    Physical Review 07/1950; 79(2). DOI:10.1103/PhysRev.79.293
  • C. G. Montgomery · D. D. Montgomery
  • C G MONTGOMERY · D D MONTGOMERY
    Review of Scientific Instruments 06/1947; 18(6):411-4. DOI:10.1103/physrev.59.1045 · 1.58 Impact Factor
  • C. G. Montgomery · D. D. Montgomery
    [Show abstract] [Hide abstract]
    ABSTRACT: Observations were made of the bursts of cosmic-ray ionization in a chamber covered by thin plates of lead, iron, and magnesium. From the observed multiplications of the numbers of rays in the shield, it is possible to separate the bursts of ionization caused by large atmospheric showers from bursts caused by heavily ionizing particles ejected from the chamber walls. Knowledge of the number of atmospheric showers allows the energy spectrum of the cosmic-ray electrons in the high atmosphere to be calculated. The integral spectrum is found to follow a power law with the exponent -3.1 in the region near 2×1015 electron volts.
  • C. G. Montgomery · D. D. Montgomery
  • C. G. Montgomery · D. D. Montgomery
    [Show abstract] [Hide abstract]
    ABSTRACT: Bursts of cosmic-ray ionization were observed in the open air and under heavy roofs, with and without a one-cm lead plate over the ionization chamber. The increase in the number of bursts in the presence of the lead under heavy roofs is interpreted as an increase in the number of rays in the showers from the roof, while in the open air the bursts from the lead probably originate to a large extent from the action of electrons of high energy which are not members of cascade showers starting at the top of the atmosphere. If the bursts from the atmosphere with no lead present are to be accounted for by the assumption that they are parts of extensive cascade showers, it is possible to derive the number and energy distribution of the primary cosmic-ray electrons of energies of the order of 2×1015 electron volts.
  • C. G. Montgomery · D. D. Montgomery
    [Show abstract] [Hide abstract]
    ABSTRACT: The number of alpha-particles released in the disintegration of boron by neutrons in the atmosphere was measured in an ionization chamber filled with boron trifluoride. Assuming a cross section for the n−α reaction of 3×10−21 cm2, the flux of neutrons of thermal energy was found to be 0.091±0.007 per square centimeter per minute, or one thermal neutron for every 16 ionizing cosmic rays. The consequences of the formation and absorption of this intensity of neutrons are discussed.
  • C. G. Montgomery · D. D. Montgomery
  • C. G. Montgomery · D. D. Montgomery
    [Show abstract] [Hide abstract]
    ABSTRACT: The measurements of W. E. Ramsey on the variation with time of the potential across a Geiger-Mueller counter (see preceding paper) are interpreted on the basis of the inductive action of the positive ion space charge moving across the counter. This inductive action, together with the hypothesis that the positive ions may eject electrons when they reach the cathode, furnishes a reasonable explanation of both the fast and slow types of breakdown of counters. This postulated mechanism leads to simple explanations of the quenching of a counter discharge and the necessary conditions for the maintenance of a steady discharge. In particular, it is predicted and verified experimentally that it is possible to operate a counter even when the potential is considerably in excess of that required for a continuous discharge, provided that the capacity of the counter wire is sufficiently reduced. A simple, although indirect, method is described for measuring the breakdown characteristic of a counter which gives results in good agreement with the direct determinations of W. E. Ramsey.
  • C. G. Montgomery · D. D. Montgomery
  • C. G. Montgomery · D. D. Montgomery
    [Show abstract] [Hide abstract]
    ABSTRACT: The behavior of electrons and photons of high energy is discussed in relation to the production of large bursts of cosmic-ray ionization, or Hoffmann Stösse, and the occurrence of nuclear "vaporizations." It is shown that the electrons from the disintegration of mesotrons have an importance equal to that of the cascade electrons. The number and size-frequency distribution of large showers (of a hundred or more rays) from thin and thick pieces of lead at sea level, and the variation with elevation of such showers are well accounted for by the action of electrons and photons from these two sources. It is unnecessary to invoke the direct production of bursts by penetrating rays by means of an explosion process. The behavior of showers of a few rays is likewise well accounted for. However, difficulties are encountered in explaining: (a) the relative numbers of bursts from large thicknesses of iron and lead, and (b) the occurrence of showers, from the air, which have a large number of rays per unit area. (See note added in proof page 261.) The hypothesis is advanced that the showers of heavily ionizing particles, or nuclear vaporizations, are produced by electrons and photons in the same range of energy as those which produce the large bursts. The identification of showers of heavily ionizing particles with Hoffmann Stösse is shown to be untenable. A determination of the absolute number of neutrons in the cosmic radiation at sea level is shown to be consistent with the supposition that these neutrons are produced in the nuclear vaporization process.
    Review of Modern Physics 01/1940; 229(5):666-667. DOI:10.1016/S0016-0032(40)90313-1 · 42.86 Impact Factor
  • C. G. Montgomery · D. D. Montgomery
    [Show abstract] [Hide abstract]
    ABSTRACT: First Page of the Article
    Review of Scientific Instruments 12/1939; DOI:10.1063/1.1751463 · 1.58 Impact Factor
  • C. G. Montgomery · D. D. Montgomery
    [Show abstract] [Hide abstract]
    ABSTRACT: An inquiry is made into the nature of the corpuscular entities which possess the properties necessary to explain the soft component of the cosmic radiation on the basis of the recent theory of W. F. G. Swann. The conclusion is reached that the most likely entities are protons which lose energy according to the relation −dEdx=λE+α, where α represents the energy lost per unit path by ionization, and λE the energy which goes into the production of secondaries in the amount that is actually observed in the form of showers.
  • C. G. Montgomery · D. D. Montgomery
  • C. G. Montgomery · W. E. Ramsey · D. B. Cowie · D. D. Montgomery
    [Show abstract] [Hide abstract]
    ABSTRACT: The following experiment was performed to measure the disintegration time of cosmic-ray mesons. Mesons falling on a lead plate were detected by a layer of counters above the plate. Some of these mesons presumably stopped within the plate and a short time later emitted a disintegration electron and a neutrino. The electron would, in a certain fraction of the cases, be detected by a second layer of counters placed below the plate. Those events were recorded in which a discharge of one of the upper counters was followed by a discharge in one of the lower counters after a time t1 and before a time t2. In the absence of the lead plate, no disintegration electrons were expected. However, a considerable number of counter discharges were recorded which must be interpreted as the result of an intrinsic time delay in the counter between the passage of the ionizing ray, and an appreciable change in potential of the counter wire. The number of disintegration electrons was measured by taking the difference in the counting rates with the lead plate present and absent. For t1 equal to 1.5 microseconds, and t2 equal to 20 microseconds, we expected 23 electrons per hour, assuming that the mean life of the mestron is 2.7 microseconds. A series of observations results in the measured number of 1.4+/-2.4 per hour, a value much smaller than expected. Possible explanations of this discrepancy are discussed, the most likely one perhaps being that most mesons are absorbed by some nuclear process before they come to rest.
  • C. G. Montgomery · D. D. Montgomery
  • C. G. Montgomery · D. D. Montgomery
  • C. G. Montgomery · D. D. Montgomery
    [Show abstract] [Hide abstract]
    ABSTRACT: In order to decide whether the multiplicative theory of showers offers an adequate explanation of the experimental data on large showers, or whether it is necessary to suppose that they are produced by some other process, such as has been outlined by Heisenberg, the following calculations are undertaken. The energy spectrum of the electrons and photons incident upon a small thickness of material is calculated from the observed frequency distribution in size of bursts of ionization produced by large showers, the effect of fluctuations being taken into account. The energy distribution obtained is of the form E-alpha, where alpha is 2.6 for energies of the order of 109 volts, and decreases slowly with increasing energy, in agreement with the energy distribution calculated by Heitler to explain the variation of cosmic-ray intensity with altitude. The maximum number of electrons necessary to give the observed frequency of bursts is less than 0.5 percent of the total number of particles observed in a cloud chamber at sea level in the energy range between 109 and 1010 volts, which is in good accord with the cloud chamber observations. This calculated incident energy spectrum is utilized to calculate the number and frequency distribution of large bursts for large thicknesses of material. These calculated values differ considerably from the experimental ones, but this difference is probably to be ascribed to the effect of the penetrating cosmic rays, and is not to be regarded as evidence of a breakdown of the cascade theory. The experiments on the absorption of a shower are also shown to be in harmony with the theoretical estimates. It is concluded that no mechanism involving the production of many shower particles in a single act need be invoked to explain the occurrence of large showers, but that the ordinary multiplicative processes are entirely adequate when proper account is taken of the fluctuations.
  • C. G. Montgomery · D. D. Montgomery
    [Show abstract] [Hide abstract]
    ABSTRACT: The absorption in lead of the shower rays which produce the bursts of cosmic-ray ionization is measured by two methods. The first method consists in observing the ionization produced above and below a lead absorber placed across the center of an ionization chamber; the second is to observe the probability that a burst of ionization in a chamber is accompanied by a simultaneous discharge of three Geiger-Müller counters over one of which has been placed an absorber. The results of the two methods are in good accord and may be stated in the form that the probability that a ray of a shower will penetrate a thickness of lead decreases linearly with the thickness, becoming zero at approximately 11 cm. The experiments serve to emphasize again the high energies that are involved in a large shower. The results are applied to observations on the effect of shielding on the ionization observed in the stratosphere.

Publication Stats

22 Citations
46.03 Total Impact Points

Institutions

  • 1947–1950
    • Yale University
      New Haven, Connecticut, United States
  • 1941
    • The Franklin Institute
      Swarthmore, Pennsylvania, United States