Electrostatic Analyzer for 1.5-Mev Protons

A system for analyzing the ion beam of an electrostatic generator is described. A weak magnetic field separates protons from heavier components and a 90° electrostatic deflection gives the required energy resolution. With the analyzer controlling the generator voltage, a proton beam of one microampere with an energy spread of the order of 300 volts in one million is obtained

A Short Ion Path High Voltage Tube

A vacuum tube for the acceleration of charged particles is described. The total acceleration of the ions takes place in a distance of 18 inches although the total height of the tube is about 14 feet. It has been used at one million volts peak a.c. with target currents of 5 ma of electrons and 0.2 ma of positive ions

A Simple Quartz Fiber Electrometer

The quartz fiber electrometer to be described in the following note has proved to be an extremely useful instrument in the study of weak radioactive sources. Because of its low capacity, simplicity of construction and general ruggedness, it has found many applications

Application of a Pressure Electrostatic Generator to the Transmutation of Light Elements by Protons

The design and performance of a pressure electrostatic generator capable of operating at 1.7 Mv in a cylindrical tank of over-all length 13′ 6″ and diameter 8′ at a pressure of 80 lb. per square inch is discussed. Studies of the gamma-radiation produced in the transmutation of F19, N15 and C13 by protons are also reported

Statistical Laws and Mechanics of Voronoi Random Lattices

We investigate random lattices where the connectivities are determined by the Voronoi construction, while the location of the points are the dynamic degrees of freedom. The Voronoi random lattices with an associated energy are immersed in a heat bath and investigated using a Monte Carlo simulation algorithm. In thermodynamic equilibrium we measure coordination number distributions and test the Aboav-Weaire and Lewis laws.Comment: 14 pages (figures not included), LaTeX, HLRZ-26/9

A New High Potential X-Ray Tube

An attempt has been made to develop apparatus and methods of operation for generating and investigating x-rays in the region beyond 300 kv. A tube is described which was designed to operate with 1000 kva, one million volt, transformers available at the California Institute of Technology. The tube is built up of glass cylinders internally shielded against electronic bombardment. The pheonomenon of "cold emission" is utilized for obtaining the electrons, the full potential being applied between electrodes of suitable curvature placed close together, (1 to 2 cm). A preliminary report of the results is given. This includes oscillograms showing the pecularities of the current due to "cold emission" as well as the actual potential across the tube. Absorption measurements of the x-rays have been made with lead up to 2 cm thick and it is shown that secondary emission plays an important part in the photo-chemical action of these rays. Satisfactory operation has been obtained up to 750 kv

Dependence of electron emission from metals upon field strengths and temperatures

This paper contains a full presentation of the reasons for believing, contrary to results recently obtained elsewhere, that field currents are only independent of temperature up to about 1100°K, and that at that temperature the energy of thermal agitation begins to assist the fields appreciably in causing the escape of electrons from metals. The precise form of function describing this dependence is not accurately determinable experimentally, but the form originally suggested by us fits the facts of observation thus far known satisfactorily, not better, however, than does the theoretical form suggested by Houston

Fluorine-plus-proton reactions

The properties of certain energy levels in O16, F19, and Ne20 have been studied by observations on the alpha particles and inelastic protons from the bombardment of fluorine by protons. A high-resolution magnetic analysis of the alpha-particle groups to the 2+ and 1- levels in O16 from the F19(p, α)O16* reaction failed to reveal any doublet structure in these known levels. The angular distributions of the alpha-particle groups to these levels did not indicate degeneracy with a 2- level, nor did a search for new excited levels in O16 up to 8.7-Mev excitation reveal a 2- level. These results are not in agreement with the alpha-particle model of the O16 nucleus which predicts a 2- state close in energy to the 2+ state. Angular distributions of the alpha particles were measured at proton bombarding energies of 873, 935, 1290, 1355, and 1381 kev. The distributions at 1355 kev indicated that the corresponding Ne20 resonance level at 14.16 Mev has spin 2 and odd parity. The spin and parity assignments previously found for the other levels were confirmed. A study of the inelastic proton groups from the F19(p, p′)F19* reaction gave 108.8±0.8 and 196.0±1.4 kev for the excitation energies of the two lowest excited levels of F19. The cross sections at the 1431-kev resonance for these groups in the center-of-mass system were 0.187±0.015 barn for the first group and 0.007 ±0.002 barn for the second group. At 1381 kev the cross section was 0.0427±0.0040 barn for protons to the second excited level. Angular distributions of the proton groups were measured and, in conjunction with other studies made in this laboratory, resulted in spin and parity assignments of ½- and 3/2+ for the first and second excited states of F19, respectively