Volume 14, Issue 9, September 1943
Index of content:
14(1943); http://dx.doi.org/10.1063/1.1770184View Description Hide Description
A medium‐sized cloud chamber for high pressures is described in which the pressure is sustained by the walls of an oil‐filled steel container rather than by the glass parts of the chamber itself. The chamber is 30 cm in diameter and 9 cm deep, and it was designed to operate at pressures up to 200 atmospheres. When filled at this pressure with argon the gas in the chamber has a stopping power for cosmic rays traversing the diameter equivalent to 80 meters of the atmosphere, 10 cm of water or nearly 1 cm of lead. Because of its high stopping power and a long period of sensitivity this chamber, at the maximum pressure, is approximately one thousand times more effective per expansion for studying rare cosmic‐ray phenomena than the largest chambers which have been operated at normal pressure. Details of the cloud chamber and its auxiliary devices are described.
14(1943); http://dx.doi.org/10.1063/1.1770185View Description Hide Description
Zinc oxide smoke and thinned gold foil were studied with x‐rays and electrons. Our x‐ray values for the lattice constants of zinc oxide and electron diffraction value for its axial ratio agree satisfactorily with Bunn's x‐ray values. Our investigation also reveals no variation in these lattice constants with the age of the sample. With regard to the relative values for the lattice constants of zinc oxide and gold, both methods give consistent results. Our work indicates that the wave‐length calibrations obtainable with zinc oxide smoke and with gold foil are in satisfactory agreement, contrary to the finding of Finch and Wilman.
14(1943); http://dx.doi.org/10.1063/1.1770186View Description Hide Description
A relatively inexpensive stroboscope of the Edgerton type for high speed photography has been built. A simple lamp of high light efficiency has been developed. Power requirements are of the order of 1 kva, and the parts are of the type found in most laboratories. Satisfactory photographs have been taken at rates up to 300 per second.