Detonations on towers may be considered as low airbursts or ground bursts, depending upon the relative height of the detonation and its yield. A larger burst will create more fallout than a smaller burst on an equal height tower not only because of the additional fission products and weapon debris, but also because it will pull up more Earth materials, or even form a crater. In addition, the materials of the tower itself provide a source of easily activated materials. The particles of the tower material may also act as centers for the debris vapors to condense on to form the larger particles that lead to heavier early fallout. Devices that fission uranium or plutonium inefficiently will cause more of these radioactive components of the device residue to be dispersed. EXPERIMENTAL PROGRAM Central to the test series was the experimental program. This program and its requirements dictated the form of the test organization and the detail of personnel participation. Like most of the preceding nuclear test series, CASTLE's experimental program incorporated two aspects, the most important of which was the development of the weapons themselves; the secondary experiments involved the measurement of the explosive and radiation effects. These two aspects can serve as a rough measure of differentiation of interest between the major participants: the AEC interest in weapon de- velopment, and the DOD interest in the military application of the effects of the explosions. The several parts of the weapon development and the effects studies each had particular features that led to the possibility of radiation exposure. Weapon Development In testing devices, weapon designers are interested in two classes of measurements: the total energy release, or equivalent explosive yield, of the device, and the rate of release. The total energy release measure- ments are called yield measurements, and the rate of release measurements are called diagnostic measurements. 31