The Scattering Lengths of the Deuteron

Hurst, D. G.; Alcock, Norman

doi:10.1139/p51-005

Cited by 59 publications

(10 citation statements)

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“…7 shows, the present measurements are in very good agreement (except perhaps at the largest angle) with the calculated CG(obs) curves at all energies. The S-wave phases used in the calculation are consistent with one of two sets of experimental zeroenergy n-d scattering lengths, 43 namely, the quartet length 4 a= (6.4zb0.3)XlO~1 3 cm and the doublet length 2 #=(0.7±0.3)X10~1 3 cm. These experimental values (at least the value of 4 a) are in good agreement, furthermore, with n-d zero-energy scattering lengths derived from the p-d scattering lengths; and the latter in turn were consistent with the p-d phase-shift analysis described above.…”

Section: B Differential Cross Sectionsupporting

confidence: 65%

Polarization and Differential Cross Sections inn−dScattering

1962

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The polarization and differential cross section for neutrons scattered from deuterium are measured at five laboratory angles (22°, 48°, 80°, 100°, and 150°) for incident neutron energies of 0.5, 1.0, and 1.95 MeV. The neutrons were produced in the Li 7 (p,n)Be 7 reaction. The partially polarized beam emitted at 51° was used first directly and then with the spins precessed through 180° in the transverse field of an electromagnet in order to determine the asymmetry in the intensities after scattering from deuterium. The results at 0.5 and 1.0 MeV give zero polarization within 2-3%. At 1.95 MeV small positive polarizations up to 4% are observed. The differential cross sections measured are more peaked at large angles than in earlier work. These data are compared with earlier calculations and a new phase-shift analysis of these measurements is made.

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Section: B Differential Cross Sectionsupporting

confidence: 65%

Polarization and Differential Cross Sections inn−dScattering

1962

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“…With these overlapping datasets, the ν(q) dispersion relation was plotted for the [ζ00], [ζζ0], and [ζζζ] directions. The data showed that the phonon intensities were largest near the reciprocal lattice points varying such as kT/ν 2 at relatively high temperatures, as given by Equations (11) and (12).…”

Section: Figurementioning

confidence: 91%

“…Two accounts of measurements of the neutron scattering lengths of the two spin states of the deuteron were given [11,12] in 1950 and 1951, and in this case, the interest was on the impact on the theory of nuclear forces rather than the atomic physics of the molecule. First, 1.063 Å neutrons from the NRX reactor were selected by reflection from the (100) planes of NaCl and were scattered by D2 molecules at 30 atmospheres and 77.4 • K and counted in a BF3 counter.…”

Section: Nuclear Physics and The Consequences For Inelastic Scatteringmentioning

confidence: 99%

The First Two Decades of Neutron Scattering at the Chalk River Laboratories

Holden

2021

QuBS

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The early advances in neutron scattering at the Chalk River Laboratories of Atomic Energy of Canada are recorded. From initial nuclear physics measurements at the National Research Experimental (NRX) reactor came the realization that, with the flux available and improvements in monochromator technology, direct measurements of the normal modes of vibrations of solids and the structure and dynamics of liquids would be feasible. With further flux increases at the National Research Universal (NRU) reactor, the development of the triple-axis crystal spectrometer, and the invention of the constant-Q technique, the fields of lattice dynamics and magnetism and their interpretation in terms of the long-range forces between atoms and exchange interactions between spins took a major step forward. Experiments were performed over a seven-year period on simple metals such as potassium, complex metals such as lead, transition metals, semiconductors, and alkali halides. These were analyzed in terms of the atomic forces and demonstrated the long-range nature of the forces. The first measurements of spin wave excitations, in magnetite and in the 3D metal alloy CoFe, also came in this period. The first numerical estimates of the superfluid fraction of liquid helium II came from extensive measurements of the phonon–roton and multiphonon parts of the inelastic scattering. After the first two decades, neutron experiments continued at Chalk River until the shut-down of the NRU reactor in 2018 and the disbanding of the neutron effort in 2019, seventy years after the first experiments.

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“…Ifwe put on this plot the new (E T = --8.48 MeV, 2a = 0.15• fin [3]) and the old (E T = --8.48 MeV, 2a --~ 0.7• fm [4]) experimental points, it turns out that the PHILLIPS line goes through the old experimental point. If we accept the new experimental point, we are faced with the task of finding such features of the interaction between nucleons which, in a theoretical calculation, would lead us to the new experimental point, i.e.…”

mentioning

confidence: 98%

Binding energy of3H andn−d doublet scattering length with charge-dependent forces

Dąbrowski¹

1973

Acta Physica

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The relation between the triton binding energy (Ez) and the doublet n--d scattering length Za is discussed. It is shown that the interpretation of the experimental data is ah open question even if one assumes charge dependent forces. The existing calculations of the triton ground state energy ET, and of the neutron-deuteron doublet scattering length 2a, show a remarkable feature: The calculated values of E T and 2a stay close to a straight line (the PmLLIPS line [1]) on a E T --2a plot [2]. Ifwe put on this plot the new (E T = --8.48 MeV, 2a = 0.15• fin [3]) and the old (E T = --8.48 MeV, 2a --~ 0.7• fm [4]) experimental points, it turns out that the PHILLIPS line goes through the old experimental point. If we accept the new experimental point, we are faced with the task of finding such features of the interaction between nucleons which, in a theoretical calculation, would lead us to the new experimental point, i.e. which would enable us to get off the PnILLIPS line.The linear relation between E T and 2a is best established in calculations based on separable two-body forces in which some parameters (e.g. the singlet effective range, the strength of the tensor force, the hard shell radius) have been varied (see, e.g.[5], [6]). Most of the existing calculations with local twobody forces also stay close to the PHILLIPS line.* This suggests that by playing with locality versus nonlocality of the two-body forces we should not expect to get off the PHILLIrS line. Furthermore, this enables us to apply nonlocal separable interactions in investigating the cffect of some special features of nuclear forces on EŸ and 2a.In this talk we shall discuss whether the charge-dependence of nuclear forces may help us in reproducing the new experimental point. Best established is the charge-dependence in the 1S 0 state in which the n --p potential is about 2 ~ more attractive than the n-n potential (see, e.g., [10]). This conclusion is based on a comparison between the values of the n--p singlet scattering length and effective range [11], * An exception ate some of the results obtained in [7] and [8]. However, some of the two-body potentials applied in [8] have also been applied in [9] with the resuhing values for E T and 2a which differ from those of [8]. This shows that the accuracy of the numerical results of some of the local potential calculations is not satisfactory.

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The Scattering Lengths of the Deuteron

Cited by 59 publications

References 3 publications

Polarization and Differential Cross Sections inn−dScattering

Polarization and Differential Cross Sections inn−dScattering

The First Two Decades of Neutron Scattering at the Chalk River Laboratories

Binding energy of3H andn−d doublet scattering length with charge-dependent forces

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