Absolute magnetic analysis of the alpha particles from polonium

Abstract

The present state of the theoretical treatment of the field of nuclear phenomena, and in particular the basic subject of nuclear forces, is rather unsatisfactory. It appears quite probable that this subject will undergo a development parallel to that of atomic structures a considerable amount of information must be gathered before the theories which arise from time to time may be properly evaluated. As in the atomic oases one of the phenomena which a satisfactory theory must quantitatively explain is the existence of excited energy states in the nucleus, the presence of which are deduced from observation of quanta and particles emitted from such nuclei. In addition a satisfactory theory must certainly take into account the binding energies and, nuclear masses inferred from the energy release an the disintegration of nuclei. Of the many techniques currently employed to obtain the basic data mentioned above, one which yields great precision is that of charged particle energy measurement by magnetic analysis. In the past few years this method has been used to determine the disintegration energies, or "Q-values", and the energy levels of the light nuclei. It was for this purpose that the Rice Institute annular magnet was constructed: in 1949. This magnet has the advantage of being capable of absolute measurement, whereas the magnets employed by the groups at the Massachusetts Institute of Technology and the California Institute of Technology are calibrated by means of the alpha particle group from the natural radioactive element P0210. The Rice Institute magnet has to date been used only to check some of the determinations made by these two laboratories, which have been responsible for most such determinations made in this country. The rice data have been in reasonable agreement with the results of these laboratories, and this fact indicates that the calibration standards are, at most, not very much in error. However, it was felt that it would be advantageous to use the facilities for absolute measurement available at Rice to check this standard. It is for that purpose that the experiments described in this thesis were conducted.