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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 thinwalled 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).

Physical Review  PHYS REV X. 01/1950; 80(4):757757.

Physical Review  PHYS REV X. 01/1949; 75(6):980980.

Review of Scientific Instruments 06/1947; 18(6):4114. · 1.60 Impact Factor

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ABSTRACT: Observations were made of the bursts of cosmicray 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 cosmicray 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. Physical Review  PHYS REV X. 01/1947; 72(2):131134.

Journal of The Franklin Instituteengineering and Applied Mathematics  J FRANKLIN INSTENG APPL MATH. 01/1941; 231(6):509545.

Journal of The Franklin Instituteengineering and Applied Mathematics  J FRANKLIN INSTENG APPL MATH. 01/1940; 229(5):664664.

Journal of The Franklin Instituteengineering and Applied Mathematics  J FRANKLIN INSTENG APPL MATH. 01/1940; 229(2):257259.

Journal of The Franklin Instituteengineering and Applied Mathematics  J FRANKLIN INSTENG APPL MATH. 01/1940; 229(5):666667.

Journal of The Franklin Instituteengineering and Applied Mathematics  J FRANKLIN INSTENG APPL MATH. 01/1940; 229(5):585611.

Review of Scientific Instruments  REV SCI INSTR. 01/1940; 11:237238.

Journal of The Franklin Instituteengineering and Applied Mathematics  J FRANKLIN INSTENG APPL MATH. 01/1940; 230(6):780780.

Review of Scientific Instruments 12/1939; · 1.60 Impact Factor

Journal of The Franklin Instituteengineering and Applied Mathematics  J FRANKLIN INSTENG APPL MATH. 01/1939; 227(3):419421.

Journal of The Franklin Instituteengineering and Applied Mathematics  J FRANKLIN INSTENG APPL MATH. 01/1939; 227(6):851853.

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ABSTRACT: The following experiment was performed to measure the disintegration time of cosmicray 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. Physical Review  PHYS REV X. 01/1939; 56:635639.

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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 Ealpha, 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 cosmicray 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. Physical Review  PHYS REV X. 01/1938; 53(12):955959.

Physical Review  PHYS REV X. 01/1938; 53(2):193195.

Journal of The Franklin Instituteengineering and Applied Mathematics  J FRANKLIN INSTENG APPL MATH. 01/1938; 225(5):585586.

Journal of The Franklin Instituteengineering and Applied Mathematics  J FRANKLIN INSTENG APPL MATH. 01/1937; 223(6):789792.