A recent proposal to use ${}_{}{}^{37}{}_{}{}^{}\mathrm{Ar}$ electron capture decay as a neutrino calibration source for solar neutrino detectors neglected the internal bremsstrahlung radiation accompanying ${}_{}{}^{37}{}_{}{}^{}\mathrm{Ar}$ decay. Safety considerations require that MCi-type ${}_{}{}^{37}{}_{}{}^{}\mathrm{Ar}$ sources include sufficient shielding to reduce the flux of bremsstrahlung photons.

I reply to the preceding Comment.

The analysis of the structure seen in heavy-ion inelastic scattering by Pate et al. is discussed. It is shown that the differential cross sections close to 90° indicate the importance of including lower angular momentum values in a partial wave decomposition than those considered by Pate et al.

We point out some of the ambiguities inherent in the phase-shift analysis of our inelastic scattering data.

The purpose of the present Comment is twofold. First, we stress that the fusion cross section in region II of the critical distance model is not determined by the potential alone, but that dynamical effects (friction and deformation) play an essential role. Second, we point out that a proper single-folding potential accounts well for the fusion cross section in region I.

I reply to the preceding Comment.

The angular distributions of the inclusive (${\pi }^{+}$,pd) cross section were measured for ${}_{}{}^6{}_{}{}^{}\mathrm{Li}$, ${}_{}{}^7{}_{}{}^{}\mathrm{Li}$, and C at $T_{\pi }$=70, 130, and 165 MeV over a wide angular range. They were found very similar to that of the π${+}^3$H${(}^3$He)→N+d reaction at the low-momentum-transfer region, especially for Li isotopes. However, at the higher-momentum-transfer region, slight peaks which were not expected in the π${+}^3$H${(}^3$He)→N+d were observed.

Incomplete fusion reactions have been studied for the system ${}_{}{}^{20}{}_{}{}^{}\mathrm{Al}$ at 10.8, 14.7, and 19.2 MeV/nucleon by measuring correlations between evaporation residues and α-particles. The exclusive evaporation residue mass distribution can be explained in a breakup fusion model where preequilibrium emission of one α-particle occurs. Complete fusion and incomplete fusion compete over a wide range of impact parameters in the entrance channel.

A cluster model employing a local, effective cluster-core potential is used to investigate exotic decay from heavy nuclei as a quantum tunneling phenomenon within a semiclassical approximation. Excellent agreement with all reported experimental measurements of the decay widths for ${}_{}{}^{14}{}_{}{}^{}\mathrm{C}$ and ${}_{}{}^{24}{}_{}{}^{}\mathrm{Ne}$ emission is obtained. As an added bonus, the width for alpha particle emission from ${}_{}{}^{212}{}_{}{}^{}\mathrm{Po}$ is also calculated in good agreement with experiment.

The absolute lifetimes of the four decay modes of ${}_{}{}^{234}{}_{}{}^{}\mathrm{U}$, namely α, Ne, and Mg decay, and spontaneous fission, are calculated within the superfluid tunneling model. It is found that a number of particles, of the order of twice the reduced mass of the two residual nuclei are moved around in the different processes. These particles belong to the condensed phase of the system and display, in their coherent motion, an inertia that is controlled by the pairing gap of the system, as well as by the number of nucleons participating. The model gives an overall account of the data, reproducing the observed lifetimes within two to three orders of magnitude.

It is shown that the expected nonlocality in the imaginary optical potential implies a dependence on the projectile orbital angular momentum l. First, as a model of this effect, a potential with a Gaussian dependence on the nonlocal coordinate is expanded in multipoles, and the local equivalent potential is calculated using the Perey-Saxon method. It is shown that the local approximation tends to compensate for the falloff with l of the multipole expansion because of the smaller local radial wave number for higher l values. The l dependence of the resulting local equivalent potential depends fairly sensitively on whether or not the assumed Gaussian nonlocality is spherical. For a nonlocality that is greater in the angular direction than in the radial direction, there is a distinct residual falloff of the local-equivalent potential with l. Second, the local approximation has also been made to the l-dependent nonlocal potential resulting from the microscopic nuclear structure approach to the imaginary optical potential. It is found that although there is a considerable falloff of the imaginary optical potential with angular momentum as in the Gaussian model, the l dependence is somewhat erratic.

Differential cross sections and analyzing powers for scattering of 135-MeV protons by ${}_{}{}^{16}{}_{}{}^{}\mathrm{O}$ have been measured for all narrow states below 12.1 MeV of excitation up to a momentum transfer of 3.2 ${\mathrm{fm}}^{\mathrm{-}1}$. Calculations that employ accurate transition densities fitted to electroexcitation data are used to study medium modifications to the two-nucleon effective interaction with little residual uncertainty from nuclear structure. Definitive evidence for strong density dependence in the isoscalar spin-independent central component of the two-nucleon effective interaction has been found. The differential cross sections show that as the density increases, the strength of the central interaction is suppressed at low momentum transfer and enhanced at high momentum transfer. The analyzing powers exhibit strong negative excursions near 2.5 ${\mathrm{fm}}^{\mathrm{-}1}$, which support enhanced repulsion at high density. The data are well described by the local-density approximation, which employs the nuclear-matter effective interaction appropriate to the density in the vicinity of the interacting nucleons. We find that the qualitative results are insensitive to ambiguities in the local-density prescription, the local-exchange approximation, and the choice of distorted waves. However, effective interactions based upon the Paris, Bonn, and Hamada-Johnston potentials do give substantially different results. Of these, the Paris-Hamburg effective interaction provides the best description of normal-parity isoscalar transitions. The analysis also supports a rearrangement contribution to the effective interaction for inelastic scattering.

Longitudinal and transverse electron scattering form factors for the $2^{+}$ state at 1.37 MeV of the ${}_{}{}^{24}{}_{}{}^{}\mathrm{Mg}$ nucleus were evaluated with rotational model wave functions. Four different approaches were used for the transverse E2 form factor: projected Hartree Fock, cranking model, rigid rotor, and irrotational flow. For the nuclear intrinsic wave function, the Nilsson model was assumed in all approaches yielding the calculation of the form factor in the plane-wave and distorted-wave Born approximations. The results are discussed and compared with a recent measurement performed for 180° electrons scattered from this state. The distorted-wave Born approximation calculation, taking into account first-order corrections due to 〈$J_{\perp }^2$${〉}^{\mathrm{-}1}$, shows that projected Hartree Fock and irrotational flow models give the best agreement with the available data and compete in quality with more complex calculations performed in the ‘‘shell model’’ approach.

The absolute cross section of the photodisintegration of deuterium was measured at 2754 keV using an absorptive method by passing the photons through 2-m-long absorbers of ${\mathrm{H}}_2$O and ${\mathrm{D}}_2$O. The measured value is 1456±45 μb. The result is compared with calculations that include contributions from meson-exchange currents and isobar configurations.

We derive sets of equations which describe γ${+}^3$${\mathrm{H}}_{\mathrm{e}}$${\to }^3$${\mathrm{H}}_{\mathrm{e}}$, p+d, and 2p+n, where the photon is either real or virtual, by requiring four-body unitarity. The initial and final wave functions and the final-state interactions (in the case of p+d and 2p+n) are the solutions of the three-body (Faddeev) equation in the bound and continuum states, respectively. The driving terms in the sets of equations for the reactions consist of two parts: the impulse one-baryon current [the nucleon, Δ(1232), and $N^{\mathrm{*}}$(1440),. . . ] and an amplitude which satisfies a four-body equation and which includes the meson-exchange currents in lowest order.

The configuration-space Faddeev equations for the nucleon-deuteron scattering problem are solved for energies below the three-body breakup threshold. We extract the s-wave scattering lengths from fits to the calculated effective range functions, and the results are in good agreement with our previous zero-energy calculations. For the pd-doublet case we find a pole at negative energies which lies closer to the physical region than that for the nd-doublet case. Our calculated phase shifts fall within the existing experimental error bars, suggesting that accurate experiments for scattering energies below 0.3 MeV are necessary in order to obtain a reliable experimental estimate of the pd-doublet scattering length.

The two-component exciton model is reformulated to facilitate a solution of the master equation and to express transition rates via quasiparticle state densities calculated in the frame of the shell model. On this basis, flux flow between different substages of the composite nucleus is discussed. This analysis shows strong discrepancies in the strength of various transitions. In particular, particle-hole creation by a hole is found to be rather negligible. New closed form expressions for the transition rates, accounting for the shell gaps, are proposed. Their predictions are compared against microscopic results.

The neutron transition multipole moment, $M_n$, for ($0^{+}$→$2^{+}$, 1.84 MeV) transition is inferred by measuring the (α,α’) angular distribution at $E_{\alpha }$=50 MeV and comparing it with a microscopic distorted-wave Born approximation calculation. Proton transition densities are taken from electron scattering data. $M_n$/$M_p$ is found to be substantially less than N/Z in agreement with the (p,p’) result.