Table of contents

A considerable amount of theoretical data (assuming central nuclear forces) is now available concerning the elastic scattering of nucleons with energies up to 16 MeV by deuterons. Buckingham, Hubbard and Massey have taken the force to be of exponential shape with range consistent with the binding energy of the deuteron and triton while Christian and Gammel have used Yukawa and gaussian shape interactions with ranges consistent with all relevant two-body data but which are considerably too short to give the correct binding energy of the triton on the assumption of purely central forces. In the present paper the former calculations have been extended to allow fully for the contributions from high order phases.

The dependence of the theoretical predictions on the assumptions made about the range, shape and exchange character of the nuclear forces is discussed in detail. It is shown that the observed data are inconsistent with the assumption of mainly ordinary forces even for the least sensitive case of the short range gaussian interaction. Extension of the theory to include explicitly the tensor force is likely to be worth while as providing useful information about nuclear forces.

Using a scintillation counter for the measurement of the gamma radiation, the Q value of the reaction D(p,γ)³He was found to be 5.50±0.03 MeV. The Doppler shift has been measured. The angular distribution was found to be nearly a pure sin²Θ pattern at all proton bombarding energies from 0.5 to 2 MeV but evidence has been obtained for a small isotropic component. Neutrons were detected, arising, via the D(d, n)³He reaction, from the knock-on deuterons. The relative yield curve has been measured with a thin target and is in accord with the formula given by Fowler and his co-workers.

An approximate measurement of the absolute cross section at E_p = 1.0 MeV gave 4 × 10^-30 cm²±50%.

Proportional counters filled with neon have been used in conjunction with the Manchester magnetic spectrograph to investigate the relationship between the momentum and the most probable ionization loss for μ-mesons at momenta greater than about 10⁹ eV/c. The logarithmic increase of ionization loss with momentum is found to be in good agreement with that indicated by treatments which ignore interactions among the target molecules, and the onset of polarization effects is compared with that previously reported in oxygen.

The advantages of proportional counters over scintillation counters in the study of mesic x-rays from light elements are pointed out.

A preliminary investigation is described in which mesic x-rays from carbon are detected with proportional counters. Aluminium counters filled to a pressure of seven atmospheres of xenon were used.

The total electronic orbital angular momenta in the 1sσ_g, 2sσ_g and 3sσ_g states of H₂⁺ are calculated using the exact two-centre wave functions. For the lowest of these states, calculations are also carried out using apparently quite accurate approximate wave functions but the results obtained are seriously in error.

By applying the selection rules of auto-ionization to the (1s2s2p)⁴P state of the negative helium ion, it is shown that only the ⁴P_5/2 energy level is not liable to auto-ionization. Provided the lowest triplet state of the atom has positive electron affinity, this ionic state is metastable in the same sense as the triplet state.

A thorough energy calculation of the quartet state of the ion has been carried through, and a positive electron affinity of at least 0.075 eV is found, enough to explain the experimental observation of it in the mass spectrograph as reported by Hiby. The unexplained line 310 061 cm^-1 (322.5 Å) observed in the vacuum ultra-violet by Kruger may then probably correspond to the transition (2s2p²) ⁴P-(1s2s2p) ⁴P in He^-, yielding an error of only 0.083 eV in the energy calculations.

The vibrational analyses of three triplet band systems of aluminium monofluoride obtained in emission have been carried out. They arise from transitions from three ³Σ states to a common lower ³Π state. The order of the sub-levels of the ³Π state and of the corresponding state for BF is considered The relative position of the triplet and singlet levels for AlF is predicted.

Earlier work with underground emulsion has been extended by making observations at greater depths, and by obtaining more data at depths previously employed. The final result for the interaction cross section of fast μ-mesons with nucleons is (4.6±0.5) × 10^-30 cm². The flux of fast π-mesons is certainly less than 0.17% of the flux of fast μ-mesons, and a more probable figure for this ratio is 0.04%.