Abstract
In previous Papers the authors have shown that protons can be ejected from the nuclei of B, N, F, Na, Al and P by bombardment with α-particles, but no certain conclusions could be drawn in cases where the ejected particles had ranges less than 30 cm. in air. In the present experiments these particles were observed at right angles to the path of the incident α-particles, and the limit of the trustworthy range was thus reduced to 7 cm., or less in some cases. Disintegration was found in the case of the light elements Ne, Mg, Si, S, Cl, A and K, but not in the case of H, He, Li, C and O. The results with Be were doubtful. The following heavier elements failed to show the effect: Ni, Cu, Zn, Se, Kr, Mo, Pd, Ag, Sn, Xe, Au, U. Elements from Ca to Fe have not at present given conclusive results.
The comparative ranges of the ejected particles suggest that the nuclei of the even-numbered light elements are stable while those of the odd-numbered light elements are comparatively unstable. An estimate of the field of force within the atom is deduced from these ranges.