The rapid development of the field of atomic energy during the past few years now permits the exploration of applications to medicine involving new concepts in the treatment of cancer. One such has been the study of neutron capture therapy which is being developed at the Brookhaven National Laboratory.

The study of the interaction of the electromagnetic field with nuclei has proved very fruitful for the elucidation of many details of nuclear structure. The γ-ray transitions observed in either absorption or emission can be divided into three classes, depending on whether the matrix elements of the transition are (1) much larger, (2) approximately equal or (3) much smaller than those expected for single proton transitions which are usually taken as a norm. In class (1) we find (a) the broad transitions leading to the "giant resonances" in the nuclear photo-electric effect, and (b) the "fast" transitions between low lying states, especially for even-even nuclei far removed from magic numbers. The large matrix elements and the regular dependence of their magnitude on the atomic weight speak for cooperative phenomena in which many nucleons or the nuclei as a whole are involved. In class (2) we find the much studied M4 transitions which give strong support for the single particle model; they have rather uniform matrix elements. Some finer points remain to be understood, especially why some odd nuclei do not show the expected ratio for |M|^2 of ~ 2:1. The transitions belonging to class (3) require further selection rules and …

One might expect that the Cosmotron would offer certain advantages over cosmic rays for the study of heavy unstable particles; provided, of course, that it can produce them. In the first place, the conditions under which they are produced could be controlled to a considerably greater extent. In the second place, it might be possible to arrange conditions under which they would be observed more abundantly, an actual beam of heavy mesons being the ideal situation.