Knowledge Of Nuclei Research Articles

Performance of the OEDO beamline

The OEDO (Optimized Energy Degrading Optics for RI beam) beamline has been developed to obtain low-energy (10 – 50 MeV/u) RI beams by slowing down the secondary beams at RIBF, RIKEN. Such beams are useful probes to investigate nuclear structure by means of nucleon transfer and Coulomb excitation reactions. The beamline is designed to produce a well-focused beam of small energy spread with the help of the angle-tuneable wedge degrader and the radio-frequency deflector. The commissioning and first physics experiments using the OEDO beamline were carried out in 2017. OEDO successfully provided the energy-degraded beams of Se, Zr, and Pd. Its performance including the optics and transmission was evaluated using those experimental data and it functions properly as designed. We expect that our novel beamline shed a light on the experimental approaches involving nuclear reactions at several tens of MeV/u to expand our knowledge of nuclei far beyond the line of stability.

Nuclear data sheets for A = 171

The experimental data for nuclei in the mass chain A = 171 have been examined, and the results summarized. The compilers have deviated somewhat from standard Nuclear Data Sheet practices. They have done so 1) by excluding some symbols normally included in drawings (e.g., coincidence dots) 2) by minimizing the effort devoted to the data per se, and concentrating on only that data needed to summarize the present status of the physics involved. Of the ten nuclei identified thus far in this mass chain, the data yield considerable information pertaining to the low—lying structure of 171Yb and 171Lu. For these nuclei, many of the expected Nilsson states (and rotational bands) have been established. The probable decay of 171Ta (supposedly 7/2 +[404]) to members of the 1/2 −[521] band in 171Hf is somewhat puzzling. It is hoped that the present compilation might serve as a basis for choosing definitive experiments that would augment our knowledge of nuclei in this mass chain.

Nuclear data sheets for A = 129

The literature pertaining to nuclei in the A = 129 mass chain has been examined and the experimental data summarized in the present compilation. A minimum of numerical data is included. Few definitive spin and parity assignments could be made. Decay data for 129Ba indicate the existence of two isomers with nearly equal half-lives. Using unpublished results, the compilers propose these to consist of the g.s., J π = 1/2 +, and a level at 0.2771 MeV, J π = (11/2 −). Efforts have been made to indicte apparent discrepancies in the data. The present compilation might serve as a basis for choosing definitive experiments to augment our knowledge of nuclei in this mass chain.

Nuclear data sheets for A = 107

All literature containing nuclear structure data pertaining to the mass chain A = 107 has been reviewed and evaluated. The main data have been summarized and used to construct level and decay schemes. Overall, the data only allow few definitive spin and parity assignments to be made. Inconsistencies in the data are noted either by direct comparison or in footnotes. The present compilation might serve as a basis for choosing definitive experiments that would augment our knowledge of nuclei in this mass chain. Data received prior to November 1971 have been included.

Nuclear data sheets for A = 121

The literature has been surveyed for data pertaining to nuclei in the mass chain A = 121. Well over 200 papers and communications were considered, and information for approximately 100 has been included. The cutoff date was the end of February 1971. The data for this mass chain are rather fragmentary. Few spin assignments are firm. The half-life of the 8-keV isomer in 121Sn is still very much in doubt. The characteristics of the levels in 121Sb are not yet well defined, but the enhanced E2 component of the 66-keV transition between the 0.57308 (1/2 +) and 0.50754 (3/2 +) levels may imply a large deformation. There seems to be building a cumulation of evidence throughout the mass region A ≈ 100–140 indicating the presence of such a deformation at about 500–1000 keV of excitation. The present compilation might serve as a basis for choosing definitive experiments that would augment our knowledge of nuclei in this mass chain.

The gyromagnetic ratio of the proton

Abstract Certain nuclei can for many purposes be thought of as spinning round an axis like the Earth or like a top. In general the spin endows them with angular momentum and with a magnetic moment; the first because of their mass, the second because all or part of their electric charge may be rotating with the mass. Even the neutron, which does not have a net charge, has an electromagnetic moment. (The electro-magnetic moment is a vector quantity, the vector product of which with the magnetic flux density is equal to the torque). The quotient of the electro-magnetic moment to the angular momentum, called the gyromagnetic ratio, would be calculable if to each element of mass were associated a corresponding element of charge, but as the value thus obtained turns out to be very different from the measured value, roughly 5.6 times smaller in the case of the proton, we conclude that our knowledge of nuclei is not yet adequate for the calculation of the ratio. As however the nuclear gyromagnetic ratio γ, especi...