Harnessed by methods which are already well known, the wind could soon supply a substantial fraction of our energy needs at an economical cost; yet the government's pace is inexcusably slow. A prompt start might unshackle the United States from its nuclear ball and chain

In trying to avoid the extreme Malthusian catastrophe, expanded efforts should be made to develop safe and plentiful nuclear power while meeting the real needs of the near future by moderating unwarranted demands and improving conventional techniques. Instead, the present premature proliferation of commercial nuclear plants is prolonging extravagant consumption and accelerating the Malthusian threat. David Inglis is a member of the department of physics and astronomy at the University of Massachusetts.

In a 0-2-0 transition in a deformed nucleus excited by inelastic scattering of $\ensuremath{\alpha}$ particles, the pattern of $\ensuremath{\gamma}$ radiation sometimes rotates rapidly backward as the $\ensuremath{\alpha}$-particle scattering angle is increased. Previous papers employing a two-dimensional model have shown that this striking behavior may be attributed to the "beats" between incoming and outgoing waves at the edges of the nucleus. The most conspicuous effect there neglected was that of the "focus" of intensity of each of the distorted waves in the middle of its "shadow side" of the nucleus. Here it is shown that the influence of this effect modifies but need not destroy the reverse-rotation phenomenon, and that it provides an explanation for the failure of the reverse rotation to persist for small-angle scattering in most of the observations.

The validity of the concept of a localization elementary stripping event, as a source of waves to be superposed with appropriate phases, is investigated in simple models. The basic model is the one-dimensional deuteron encountering a simple potential step. The behaviour of its two-dimensional wave equation at appropriate boudaries and limits is discussed both without the use of perturbation theory and with a perturbation theory different from a Born approximation. This one-dimensional model is extended to the case of two or three dimensions with a potential step over an infinite face or a finite aperture. It is shown how the joining of the waves at the interface preserves the transverse momentum in such a way that the direction of emission of the proton is determined by the combined effects of the proton scattering and the internal deutron momentum as compatible with the final behaviour of the neutron.

The striking observation that the maxima of elastic scattering of such particles as alphas of fairly heavy nuclei coincide with the minima of inelastic scattering (with no parity change) is explained in as elementary a way as possible in terms of the simple superposition of waves, without dependence on special functions. Some qualitative features of the relation between this “Fraunhofer” treatment and a better approximation are discussed.

A qualitative explanation is found for the interesting contrast observed between the angular distributions of the groups going to the ground state and the second excited state in the reaction ${\mathrm{C}}^{12}({\mathrm{Li}}^{6}, \ensuremath{\alpha}){\mathrm{N}}^{14}$. The ground-state group of alphas has a peak only in the backward direction because only the mechanism of "heavy-particle stripping" can satisfy the requirements on the orbital angular momentum for the ground state of ${\mathrm{N}}^{14}$ (primarily a $^{3}D$). The "deuteron" of the incident ${\mathrm{Li}}^{6}$ initially has insufficient angular momentum about the final core but acquires more because the force attracting it toward the target nucleus is not directed toward the center of mass of the twelve nucleons (eight from the target ${\mathrm{C}}^{12}$ and four from ${\mathrm{Li}}^{6}$) which form the core of the final ${\mathrm{N}}^{14}$. The other four nucleons from the target form the product alpha. The second excited state of ${\mathrm{N}}^{14}$ is approximately a $^{3}S$ and there is no such angular momentum limitation so both light- and heavy-particle stripping occur and give rise to forward and backward peaks. The validity of the cluster model for ${\mathrm{Li}}^{6}$ is discussed.

When a parameter such as the nuclear radius is varied to raise the energy of a nuclear state towards the top of a potential barrier, the rate of rise is decelerated by the penetration of the barrier and the consequent spreading out of the wave function. This enhances the probability that states will be found in the energy intervals where this penetration becomes large. Empirically there seems to be a small enhancement of about the estimated magnitude, although there are too few cases to be sure.

In the usual shell-model procedure, the effective Hamiltonian contains only half the sum of the shell-model potentials of nucleons in order to avoid counting average pairwise interactions twice. Because of the factor one-half, the nondiagonal elements of this Hamiltonian in the harmonic oscillator representation do not vanish, but they have been neglected in previous calculations of nuclear deformations by Nilsson and others, in which one minimizes total shell-model energy at constant volume. It is here shown in typical cases (without taking spin-orbit coupling into account) that the equilibrium deformation is unaltered in second and third order and that the fourth-order modification arising from the nondiagonal elements is very small. The relation of these nondiagonal elements to those of the pairwise interactions is also discussed.

The nuclear moment of inertia may be calculated as the sum of individual contributions by treating the dynamics of one sample nucleon in the ellipsoidal harmony oscillator potential representing its interaction with the others, on the plauside assumption that the moment of inertia due to all the other nucleons is simply associated with the orientation of the axes of the distortion ellipsoid. The ellipsoid is allowed to move freely (in two dimensions) with conservation of angular momentum, but the is rather similar to that given earlier on the basis of a constant angular velocity of the ellipsoid (“cranked model”), and the result is the same. The moment of rigid value when the magnitude of the distortion of an open-shell nucleus is obtained in the most simple manner, by minimizing the sum of the oscillator energies with constant nuclear volume. The analogous problem of linear translation may be similarly

Part I is a simplified treatment of the droplet model. To bring the common fissionable nuclei to the region of the “saddle” in the energy surface, it is necessary to have deformations very far from the spherical shape. To study this region without expanding about a spherical shape, and to clarify some aspects of the process that might otherwise be hidden in large machine calculations, a simplified model of a nucleus near the saddle shape is introduced consisting of a cylinder with hemispherical ends. Relatively simple methods are used for estimating the change in electrostatic self-energy for small changes from this shape, and this is compared with the change of surface energy. A long charged cylinder of this sort does not expand indefinitely in length, and for the empirical values of the constants it always tends to contract. Above a certain minimum length, a neck may develop leading toward fission. The initial instability of the neck is considered under various conditions leading toward either symmetric or asymmetric fission. It is made clear that the neck has a strong tendency to start at the symmetric position, but if started asymmetrically it has a tendency to grow faster because of smaller reduced mass of the system. The droplet model alone does not provide an adequate explanation of the asymmetry of low-energy fission.

A careful search is made for evidence of possible excited states in ${\mathrm{Be}}^{8}$ in the reactions ${\mathrm{B}}^{11}(p, \ensuremath{\alpha}){\mathrm{Be}}^{8}$ and ${\mathrm{B}}^{10}(d, \ensuremath{\alpha}){\mathrm{Be}}^{8}$, by magnetic momentum analysis at a variety of angles and bombarding energies. In spite of observing the region corresponding to 3 to 8 Mev several times independently under different conditions, with several thousand counts per point on points spaced only about 100 kev apart, no indication was found of any of the states in this region reported by others on the basis of poorer statistics, mostly in other reactions. Each alpha-particle spectrum observed consists of a sharp ground-state peak and a broad peak of the alpha particles giving rise to the well-known 3-Mev excited state of ${\mathrm{Be}}^{8}$ superposed on a continuous background from the break-up of this state and from three-particle break-up. Peaks observed near the equivalent of 10 and 11 Mev in ${\mathrm{Be}}^{8}$ are identified as arising from a target impurity.