The leakage of electricity aoross a vacuum space in an electrostatic generator which employs a mixture of Sr/sup 90/ and Y/sup 90/ as the source of charging current was investigated. The vacuum is obtained by means of an oil pump. The leakage was shown to consist of a flow of positive and negative particles between the anode and the cathode. The positive particles were found to be primarily organic ions produced in a layer of oil on the surface of the anode. The negative particles were shown to be mostly electrons. Yields of secondary negative particles and secondary positive particles produced by average positive particles in the energy range from 50 to 200 kev were measured. Yields were found to be dependent on the nature of the target material as well as on the energy of the incident ion. A mass spectrometer was employed to study the nature of the positive ions. Most of these were charged fragments of organic molecules. Neutral particles were attributed to dissociation of a portion of positive ions during their flight from the anode to cathode. Electrons, most of which originate at the beta source, are presumed to be the agent for positive ion production. …

Thesis discussing the relative yield of neutral pions from elements in a reaction "as a function of the quantum-limit energy (the maximum energy of the quanta in the bremsstrahlung beam) of the Berkeley synchrotron." Interpretation of the results leads to values for the mean free path for absorption of the neutral pions in nuclear matter.